Books by Prof. Dr. (Hoogleraar) R.P. Lamberts
"THE DEVELOPMENT OF AN EVIDENCED-BASED SUBMAXIMAL CYCLE TEST DESIGNED TO MONITOR AND PREDICT CYCL... more "THE DEVELOPMENT OF AN EVIDENCED-BASED SUBMAXIMAL CYCLE TEST DESIGNED TO MONITOR AND PREDICT CYCLING PERFROMANCE
The Lamberts and Lambert Submaximal Cycle Test
R.P. Lamberts, PhD
ISBN: 978-90-9024959-9
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Papers by Prof. Dr. (Hoogleraar) R.P. Lamberts
The reliability of the interval shuttle run test (ISRT) as a submaximal and maximal field test to... more The reliability of the interval shuttle run test (ISRT) as a submaximal and maximal field test to measure intermittent endurance capacity was examined. During the ISRT, participants alternately run for 30 seconds and walk for 15 seconds. The running speed is increased from 10 km.h(-1) every 90 seconds until exhaustion. Within a 2-week period, 17 intermittent sport players (i.e., 10 men and 7 women) performed the ISRT twice in a sports hall under well-standardized conditions. Heart rates per speed and total number of runs were assessed as submaximal and maximal performance measures. With the exception of the heart rates at 10.0 km.h(-1) for men and 10.0, 12.0, and 13.5 km.h(-1) for women, zero lay within the 95% confidence interval of the mean differences, indicating that no bias existed between the outcome measures at the 2 test sessions (absolute reliability). The results illustrate that it is important to control for heart rate before the start of the ISRT. Relative reliability was high (intraclass correlation coefficient > or = 0.86). We conclude that the reliability of the ISRT as a submaximal and maximal field test for intermittent sport players is supported by the results.
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The aim of this study was to determine the relationship between heart rate recovery (HRR) and an ... more The aim of this study was to determine the relationship between heart rate recovery (HRR) and an acute training "overload" by comparing HRR responses before and after an ultra-marathon road race. Ten runners completed a standardized laboratory protocol ∼7 days before and between 2 and 4 days after participating in the 87 km Comrades Marathon. The protocol included muscle pain ratings, a 5 bound test and 20 min of treadmill exercise at 70% of maximal oxygen uptake followed by 15 min of recovery. Respiratory gases and heart rate measurements were used to calculate steady state exercise responses, HRR and excess post-exercise oxygen consumption (EPOC) and participants also provided a rating of perceived exertion during exercise (RPE). RPE was significantly increased (13±2 vs. 11±1)(p < 0.01) and HRR was significantly faster (35±5 vs. 29±4 beats)(p < 0.01) following the post- vs. pre-race submaximal exercise bout with no significant changes in respiratory- or heart rate- parameters during exercise or in EPOC. Although previous studies have shown that faster HRR reflected an "adapted" state with enhanced training status, the current findings suggest that this may not always be the case. It follows that changes in HRR should be considered in the context of other factors such as recent training load and RPE during submaximal exercise.
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The aim of this study was to investigate if drinking ad-libitum can counteract potential negative... more The aim of this study was to investigate if drinking ad-libitum can counteract potential negative effects of a hypohydrated
start caused by fluid restriction during a 40-km time trial (TT) in the heat. Twelve trained males performed one 40-km
cycling TT euhydrated (EU: no water during the TT) and two 40-km cycling TTs hypohydrated. During one hypohydrated
trial no fluid was ingested (HYPO), during the other trial ad-libitum water ingestion was allowed (FLUID). Ambient
temperature was 35.2 ± 0.2°C, relative humidity 51 ± 3% and airflow 7 m·s−1. Body mass (BM) was determined at the start
of the test, and before and after the TT. During the TT, power output, heart rate (HR), gastrointestinal temperature, mean
skin temperature, rating of perceived exertion (RPE), thermal sensation, thermal comfort and thirst sensation were
measured. Prior to the start of the TT, BM was 1.2% lower in HYPO and FLUID compared to EU. During the TT, BM
loss in FLUID was lower compared to EU and HYPO (1.0 ± 0.8%, 2.7 ± 0.2% and 2.6 ± 0.3%, respectively). Hydration
status had no effect on power output (EU: 223 ± 32 W, HYPO: 217 ± 39 W, FLUID: 224 ± 35 W), HR, gastrointestinal
temperature, mean skin temperature, RPE, thermal sensation and thermal comfort. Thirst sensation was higher in HYPO than
in EU and FLUID. It was concluded that hypohydration did not adversely affect performance during a 40-km cycling TT in
the heat. Therefore, whether or not participants consumed fluid during exercise did not influence their TT performance.
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The purpose of this study was to assess predictive value of a new Submaximal Rowing Test (SmRT) o... more The purpose of this study was to assess predictive value of a new Submaximal Rowing Test (SmRT) on 2000 m ergometer rowing time-trial performance in competitive rowers. In addition, the reliability of the SmRT is investigated. Twenty-four competitive male rowers participated in this study. After determining individual HRmax, all rowers performed a SmRT followed by a 2000 m rowing ergometer time-trial. In addition, the SmRT was performed 4 times (2 days in between) in order to determine the reliability. The SmRT consists of two six-minute stages of rowing at 70 and 80% HRmax, followed by a three-minute stage at 90% HRmax. Power was captured during the three stages and 60 seconds of heart rate recovery (HRR60s) was measured directly after the third stage. Results show that predictive value of power during the SmRT on 2000 m rowing time also increases with stages. CVTEE% is 2.4%, 1.9% and 1.3%. Pearson correlations (CI) are -0.73 (-0.88 - -0.45), -0.80 (-0.94 - -0.67) and -0.93 (-0.97 - -0.84). 2000 m rowing time and HRR60s show no relationship. Reliability of power during the SmRT increases with stages. The Coefficient of Variation (CVTEM%) is 9.2%, 5.6% and 0.4%. Intra-class Correlation Coefficients (ICC) and Confidence Intervals (CI) are 0.91 (0.78 - 0.97), 0.92 (0.81 - 0.97) and 0.99 (0.97 - 1.00). The CVTEM% and ICC of HRR60s is 8.1% and 0.93 (0.82 - 0.98). In conclusion, the data of this study show that the SmRT is a reliable test that is able to accurately predict 2000 rowing time on a ergometer. The SmRT shows potential to be a practical and valuable monitoring tool for rowers and potentially can assist in fine-tuning and optimizing training prescription in rowers.
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Purpose T here is some evidence that measures of acute
post-exercise recovery are sensitive to t... more Purpose T here is some evidence that measures of acute
post-exercise recovery are sensitive to the homeostatic
stress of the preceding exercise and these measurements
warrant further investigation as possible markers of training
load. The current study investigated which of four different
measures of metabolic and autonomic recovery was most
sensitive to changes in exercise intensity.
Methods T hirty-eight moderately trained runners completed
20-min bouts of treadmill exercise at 60, 70 and
80 % of maximal oxygen uptake (VO2max) and four different
recovery measurements were determined: the
magnitude of excess post-exercise oxygen consumption
(EPOCMAG), the time constant of the oxygen consumption
recovery curve (EPOCτ), heart rate recovery within 1 min
(HRR60s) and the time constant of the heart rate recovery
curve (HRRτ) .
Results Despite significant differences in exercise parameters
at each exercise intensity, only EPOCMAG showed significantly
slower recovery with each increase in exercise intensity at the group level and in the majority of individuals.
EPOCτ was significantly slower at 70 and 80 % of
VO2max vs. 60 % VO2max and HRRτ was only significantly
slower when comparing the 80 vs. 60 % VO2max exercise
bouts. In contrast, HRR60s reflected faster recovery at 70
and 80 % of VO2max than at 60 % VO2max.
Conclusion Of the four recovery measurements investigated,
EPOCMAG was the most sensitive to changes in
exercise intensity and shows potential to reflect changes
in the homeostatic stress of exercise at the group and individual
level. Determining EPOCMAG may help to interpret
the homeostatic stress of laboratory-based research trials or
training sessions.
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Background:
Displaced and shortened clavicle shaft fractures can be treated by intramedullary f... more Background:
Displaced and shortened clavicle shaft fractures can be treated by intramedullary fixation; however, hardware migration and soft tissue irritation at the insertion site have complicated its use. The aim of this study was to determine whether this new intramedullary device (Sonoma CRx™) can be used successfully to treat displaced and shortened clavicle shaft fractures and restore the functional capacity of shoulder without the development of secondary complications.
Methods:
Forty-seven consecutive patients with displaced and shortened clavicle shaft fracture were treated with the CRx™ device. Incision size was captured during the surgical procedure while post-operatively union rate. Shoulder function was assessed by Disabilities of the Arm, Shoulder and Hand (DASH) score, the Constant Shoulder score and a Range of Movement score. Patients were assessed either after 3-6 months (Group I), 6-9 months (Group II) or 9-12 months (Group III) post-operatively.
Results:
All patients had achieved union at the time of review without any incidence of hardware migration. Three patients developed complications post-operatively (infection (1) and hardware failure (2)). No differences between the groups were found for DASH score (p=0.33), Constant Shoulder (p=0.38) and Range of Movement scores (p=0.96). DASH, Constant Shoulder and Range of Movement scores were similar to other successful treatment options, such as plating.
Conclusion:
The Sonoma CRx™ is a good alternative device to treat displaced and shortened clavicle shaft fractures and restore the functional capacity of the shoulder. Future research should focus on when nailing and plating should be used to treat clavicle shaft fractures most optimally.
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Background
A recent, novel approach to measuring training load has been to investigate measures ... more Background
A recent, novel approach to measuring training load has been to investigate measures of the post-exercise return towards resting homeostasis for potential in this role. For practical reasons, it is important to determine whether changes in training load produce changes in the recovery measurement that are in excess of the day-to-day variation or within-subject reliability of the measurement. However, the day-to-day variation in certain recovery measurements is not always known.
Research objective
To determine day-to-day variation in measures of heart rate recovery (HRR) and excess post-exercise oxygen consumption (EPOC) so as to determine the minimal detectable difference in these measurements for future research.
Type of study
Observational cohort study.
Methods
Twelve moderately trained runners completed 3 repetitions of a submaximal treadmill protocol on consecutive days. The protocol involved 20 min of running at 70% of maximal oxygen uptake and 15 min of controlled recovery. Day-to-day variation for exercise and recovery measurements was calculated as the typical error as a coefficient of variation (CVTEM).
Results
Recovery measurements showed CVTEM values of 8.0% (90% C.I. 6.7-10.3%) for the magnitude of EPOC, 12.9% (90% C.I. 10.6-16.4%) for the time constant of the oxygen consumption recovery curve, 8.7% (90% C.I. 7.2-11.2%) for 1 min HRR and 10.0% (90% C.I. 8.2-12.8%) for the time constant of the HRR curve. In contrast, most exercise parameters had CVTEM values of 2-4%.
Conclusions
For future studies in a similar setting, changes in training load that produce changes in HRR or EPOC greater than the CVTEM values of these recovery measurements might be interpreted as of likely practical significance.
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Iliac blood flow restrictions causing painful and “powerless” legs are often attributed to overtr... more Iliac blood flow restrictions causing painful and “powerless” legs are often attributed to overtraining and may develop for some time before being correctly diagnosed. In the current study, differences between actual performance parameters and performance parameters predicted from the Lamberts and Lamberts Submaximal Cycle test (LSCT-predicted) were studied in a world class cyclist with bilateral kinking of the external iliac artery before and after surgery. Two performance testing sessions, including a peak power output (PPO) and a 40km time trial (40km TT) tests were conducted before surgery, while one testing session was conducted after the surgery. Actual vs. LSCT-predicted performance parameters in the world class cyclists were compared to 82 symptom-free, trained-to-elite male cyclists. No differences were found between actual and LSCT-predicted PPO before and after surgical interventions. However, there were differences between actual and LSCT-predicted 40km TT time in the tests performed before the surgery (2:51(min:s) and 2:55(min:s), respectively). These differences were no longer apparent in the post-surgery 40km TT (2 s). This finding suggests that iliac blood flow restrictions seem to mainly impair endurance performance rather than peak cycling performance. A standard PPO test without brachial ankle blood pressure measurements might not be able to reflect iliac blood flow restrictions. Differences between actual and LSCT-predicted 40km TT time may assist in the earlier referral to a cardiovascular specialist and result the earlier detection of iliac blood flow restrictions.
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In high performance cycling, it is important to maintain a healthy balance between training load ... more In high performance cycling, it is important to maintain a healthy balance between training load and recovery. Recently a new submaximal cycle test, known as Lamberts and Lambert Submaximal Cycle Test (LSCT), has shown to be able to accurately predict cycling performance in 15 well-trained cyclists. The aim of this study was to determine the predictive value of the LSCT in 102 trained-to-elite cyclists (82 males and 20 females).
All cyclists performed on a LSCT test followed peak power output (PPO) test, which included respiratory gas analysis for the determination of maximal oxygen consumption (VO2max) and the LSCT test followed by a 40km time trial (40km TT) test, 72 hours later. Average power output during the three stages of the LSCT increased from 31, 60 and 79% of PPO, while the ratings of perceived exertion increased from 8 to 13 to 16.
Very good relationships were found between actual and LSCT-predicted PPO (r = 0.98 95%CI: 0.97-0.98, p<0.0001), VO2max (0.96 95%CI: 0.97-0.99, p<0.0001) and 40km TT time (r = 0.98 95%CI: 0.94-0.97, p<0.0001). No gender differences were found when predicting cycling performance from the LSCT (p=0.95).
The findings of this study show that the LSCT is able to accurately predict cycling performance in trained-to-elite male and female cyclists and potentially can be used to prescribe and fine tune training prescription in cycling.
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Exercise-induced-muscle-damage (EIMD) is a well-described phenomenon which leads to decreased for... more Exercise-induced-muscle-damage (EIMD) is a well-described phenomenon which leads to decreased force output and altered neuromuscular function. How these symptoms of EIMD affect brain function, in particular cortical activity has not been described. Therefore the aim of this study was to investigate the relationship between the symptoms of EIMD and cortical beta (β) activity during a submaximal biceps brachii movement. Half of the subjects participated in an EIMD protocol. Control and EIMD groups were monitored for 132 h thereafter. Muscle pain scores in the EIMD group peaked after 36 h with the lowest muscle torque reported at 12 h. Beta-1 and -2 activity was increased in the frontal and parietal area in the experimental group at 12 h. This suggests an impact of EIMD induced neuromuscular changes on the cortical proprioceptive and motor perceptive networks. Beta-2 activity decreased in the control group over time suggesting a loss in focused attention and greater familiarization with the protocol as the study progressed. These data suggest that a change in β-1 and -2 activity is associated with integrating movement perception and proprioception post-EIMD.
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"Purpose: The purpose of this study was to determine whether a sub-maximal cycling test could be ... more "Purpose: The purpose of this study was to determine whether a sub-maximal cycling test could be used to monitor and prescribe high-intensity interval training (HIT). Methods: Two groups of male cyclists completed four HIT sessions over a two week period. The Structured training Group (SG; n = 8, VO2max = 58.4 ± 4.2 ml.min-1.kg-1) followed a predetermined training programme while the Flexible training Group (FG; n = 7, VO2max = 53.9 ± 5.0 ml.min-1.kg-1) had the timing of their HIT sessions prescribed based on the data of the Lamberts and Lambert Sub-maximal Cycle Test (LSCT). Results: Effect size calculations showed 'large' differences in the improvements in 40kmTT performance following the HIT training between SG (8 ± 45 s) and FG (48 ± 42 s). Heart rate recovery, monitored during the study, tended to increase in FG and remain unchanged in SG. Conclusions: The results of the present study suggest that the LSCT may be a useful tool for coaches to monitor and prescribe high-intensity training.
"
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As female cycling attains greater professionalism, a larger emphasis is placed on the ability to ... more As female cycling attains greater professionalism, a larger emphasis is placed on the ability to predict and monitor changes in their cycling performance. The main aim of this study was to determine if peak power output (PPO) adjusted for body mass (W•kg-0.32) accurately predicts flat 40-km time trial performance (40km TT) in female cyclists as found in men. Twenty (well-) trained female cyclists completed a PPO test including maximal oxygen consumption (VO2max) and a flat 40km TT test. Relationships between cycling performance parameters were also compared to the cycling performance of 45 male cyclists. Allometrically scaled PPW (W•kg-0.32) most accurately predicted 40km TT performance in the female cyclists (r=-0.87, p<0.0001) compared to any other method, different slopes between the parameters were found in the female and male cyclists (p=0.000115). In addition gender differences were also found between the relationship between relative PPO (W•kg-1) and relative VO2max (ml•min-1•kg-1)(p<0.0001), while no gender differences were found between actual and predicted cycling performance based on the Lamberts and Lambert Submaximal Cycle Test (LSCT), which was used a standardized warm-up. In conclusion, relationships between relative cycling parameters seem to differ between genders, while relationships between absolute cycling parameters seem to be similar. Therefore gender specific regression equations should be used when predicting relative cycling performance parameters.
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""Exercise prescribed according to relative intensity is a routine feature in the exercise scienc... more ""Exercise prescribed according to relative intensity is a routine feature in the exercise science literature and is intended to produce an approximately equivalent exercise stress in individuals with different absolute exercise capacities. The traditional approach has been to prescribe exercise at a percentage of maximal oxygen uptake (VO2max) or maximum heart rate (HRmax). However, exercise fixed by %VO2max or %HRmax may produce large inter-individual differences in blood lactate response and it has been argued that prescribing exercise relative to metabolic thresholds such as the aerobic threshold and the anaerobic threshold is a more effective means of standardizing exercise stress. The aim of the current review was to provide a balanced assessment of these 4 methods of relative exercise intensity prescription, including both the physiological basis of each measurement and the practical implications of using the measurement for laboratory testing.
It is well-established that training standardized by %VO2max is associated with large inter-individual variation in training response. However, the relative contribution of an inadequately standardized exercise stimulus vs. hereditary factors is unclear. Conversely, a more homogenous training response following training prescribed relative to threshold measurements has yet to be demonstrated. Despite these considerations, the contention that threshold measurements are a more effective means of standardizing exercise stress at the level of the active muscle than %VO2max or %HRmax has a sound physiological basis.
On a practical level, however, threshold measurements have distinct disadvantages compared to VO2max and HRmax. Thresholds determined by graphical analysis cannot be assumed to be accurate in all individuals without verification trials. Verification trials would involve 2-3 additional laboratory visits and would add considerably to the testing burden on both the participant and researcher. Threshold determination and verification would also often involve blood lactate sampling which is aversive to some participants and has a number of intrinsic and extrinsic sources of variation. Threshold measurements also tend to show higher day-to-day variation than VO2max and HRmax.
In summary, each method of prescribing relative exercise intensity has both advantages and disadvantages when both theoretical and practical considerations are taken into account. It follows that the most appropriate method of relative exercise intensity prescription may vary depending on the design, outcome measures, participant numbers and resources available for conducting a particular study. Considering a method’s limitations as well as advantages and increased reporting of inter-individual variation in exercise response will facilitate accurate interpretation of findings and help to identify important areas for further study.
""
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Objective: The purpose of this study was to determine if peak power output adjusted for body mass... more Objective: The purpose of this study was to determine if peak power output adjusted for body mass0.32 is able to accurately predict 40km time trial performance. Methods: Forty-five trained male cyclists completed after familiarization, a peak power output test including respiratory gas analysis, and a 40km time trial. Peak power output (PPO), maximal oxygen consumption (VO2max) and 40km time trial time were captured. Relationships between 40km TT performance and (I) absolute PPO (W) and VO2max (l/min), (II) relative PPO (W/kg) and VO2max (ml/min/kg) and (III) PPO and VO2max adjusted for body mass (W/kg-0.32 and ml/min/kg-0.32, respectively) were studied. Results: The continuous ramp protocol resulted in a similar relationship between PPO and VO2max (r = 0.96; P < 0.0001) compared to a step-wise testing protocol, but was associated with a lower standard error of the estimated when predicting VO2max. PPO adjusted for body mass (W/kg-0.32) had the strongest relationship with 40km TT performance (s) (r = -0.96; P < 0.0001). Although, significant relationships were also found between absolute (W) and/or relative PPO (W/kg-1) and 40km TT performance (s), these relationships were significantly weaker than the relationship between 40km TT performance and PPO adjusted for body mass (W/kg-0.32) (P < 0.0001). Conclusions: VO2max can be accurately predicted from PPO when using a continuous ramp protocol, possibly even more accurately than when using a step-wise testing protocol. 40km TT performance (s) in trained cyclists can be predicted most accurately by PPO adjusted for body mass (W/kg-0.32). As both VO2max and 40km TT performance can be accurately predicted from a PPO test, this suggests that (well)-trained cyclists can possibly be monitored more frequently and with fewer tests.
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Heart rate recovery (HRR) has been proposed as a marker of autonomic function and training status... more Heart rate recovery (HRR) has been proposed as a marker of autonomic function and training status in athletes. We performed a systematic review of studies that examined HRR after training. Five cross sectional studies and eight studies investigating changes over time (longitudinal) met our criteria. Three out of five cross sectional studies observed a faster HRR in trained compared to untrained subjects, while two papers showed no change as a result of training. Most longitudinal studies observed a corresponding increase in HRR and power output (training status). Although confounding factors such as age, ambient temperature and the intensity and duration of the exercise period preceding HRR make it difficult to compare these studies, the available studies indicated that HRR was related to training status. Therefore, we conclude that HRR has the potential to become a valuable tool to monitor changes in training status in athletes and less well-trained subjects, but more studies and better standardization are required to match this potential.
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Objective: The purpose of this study was to determine the reliability and predictive value of per... more Objective: The purpose of this study was to determine the reliability and predictive value of performance parameters measured by a new novel submaximal cycle protocol, on peak power and endurance cycling performance in well-trained cyclists. Methods: Seventeen well-trained competitive male road racing cyclists completed four peak power output tests (PPO) and four 40-km time trials (40-km TT). Before each test all cyclists performed a novel submaximal cycle test (LSCT). Parameters associated with performance such as power, speed, cadence and rate of perceived exertion (RPE) were measured during the 3 stages of the test when cyclists rode at workloads coinciding with fixed predetermined heart rates. Heart rate recovery (HRR) was measured after the last stage of the test. Results: Parameters measured during the second and third stage of the LSCT were highly reliable (Intraclass correlation range: R=0.85–1.00) with low typical error of measurements (TEM-range: 1.3–4.4%). Good relationships were found between the LSCT and cycling performance measured by the PPO and 40-km TT tests. Mean power had stronger relationships with measures of cycling performance during the second (r = 0.80-0.89) and third stage (r = 0.91-0.94) of the LSCT than HRR (r = 0.55-0.68) Conclusions: The LSCT is a reliable novel test which is able to predict peak and endurance cycling performance from submaximal power, RPE and HRR in well-trained cyclists. As these parameters are able to detect meaningful changes more accurately than VO2max, the LSCT has the potential to monitor cycling performance with more precision than other current existing submaximal cycle protocols.
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We evaluated possible methods of normalising EMG measured during running. MVC, Sprint and 70% Pea... more We evaluated possible methods of normalising EMG measured during running. MVC, Sprint and 70% Peak Running Speed methods were evaluated and their repeatability, reliability and sensitivity to incremental running speed were compared. Twelve runners performed the same experimental protocol on three separate occasions. Each day, subjects firstly performed MVCs, followed by a 20 mmaximal sprint (with a 20–30 m run-up). Following this, they performed the peak running speed (PRS) test until exhaustion. After which they ran at 70% of PRS for 5 laps. Results indicated that normalising EMG data to MVC and Sprint methods are more repeatable for VM, BF, MG and RF, VL, LG, respectively, with the average ICC > 0.80. The 70% PRS demonstrated poor to fair levels of repeatability ranging between ICC 0.27 and 0.70. Whereas the 70% PRS method had the least intra-subject variability and the greatest sensitivity to increasing running speeds. More specifically, demonstrating significant changes in muscle activity in VM with increasing running speed while MVC and Sprint methods were unable to detect these changes. The dynamic methods were the most appropriate for EMG normalisation showing repeatability, better intra-subject reliability and better sensitivity during running over different days and for once-off measurements.
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Heart rate after a standardized test varies with a change in training status, possibly compromisi... more Heart rate after a standardized test varies with a change in training status, possibly compromising the accuracy of measuring changes in heart rate recovery (HRR). The aim of this study was to determine if a change in the exercise intensity would result in a change in heart rate recovery and/or the accuracy of the heart rate recovery measurement. Thirty-one subjects performed four submaximal running tests (HIMS). Based on the heart rate after the first HIMS, subjects either completed four identical HIMS (SAME (n=9)), two standard and two faster HIMS (FASTER (n=10)) or two standard and two slower HIMS (SLOWER (n=12)). Although no changes in heart rate recovery were found when the HIMS protocol was adapted, lower coefficients of variation (CV) and typical errors of measurement (TEM) were found in the SLOWER (CV: 11 ± 7 to 5 ± 3% (p = 0.025)), TEM: 6 to 3 beats and FASTER group (CV: 11 ± 7 to 4 ± 3% (p = 0.048), TEM: 7 to 3 beats)). To ensure the highest level of sensitivity in detecting meaningful changes in HRR over time, submaximal testing protocols should target exercise intensities ranging in-between 86 to 93% of heart rate maximum.
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Peripheral vascular disease limits exercise performance due to claudication pain, which is believ... more Peripheral vascular disease limits exercise performance due to claudication pain, which is believed to originate from ischemia and increased blood lactate concentrations. However, no research has investigated the relationship between muscle activity, claudication pain and functional capacity. We report on a patient with a single tight stenosis of the femoral artery treated by performing percutaneous transluminal angioplasty. We measured muscle activity, exercise performance and other physiological variables before and 3 days after angioplasty. The patient performed maximal voluntary contractions prior to walking on the treadmill until exhaustion using the Graded Treadmill exercise test (GTET) protocol. Electromyography, heart rate, brachial blood pressure, rating of perceived exertion, pain score, oxygen consumption and blood lactate concentrations were measured during both trials. Muscle activity in the diseased leg was found to increase after angioplasty, with an increase in functional capacity and decrease in claudication pain. His physiological variables and force outputs improved after angioplasty, however the blood lactate concentrations were low ranging between 2.00 – 1.75 mmol.l-1 before angioplasty and 1.75 – 1.50 mmol.l-1 after angioplasty. This case report demonstrates the change in muscle activity once blood flow is restored to the affected limb. We encourage clinicians and researchers to be attentive to the probable alteration in muscle activity and the role it plays in these patients’ functional capacity and claudication pain. The findings of this study presents possible usage for EMG in this patient population, 1) used as a additional screenings tool to objectively measure when the occlusion affects neuromuscular function and if so then angioplasty intervention could be justified; 2) as a monitoring tool of neuromuscular function during and after rehabilitation 3) possibly be used as a screening tool for re-occlusions.
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Books by Prof. Dr. (Hoogleraar) R.P. Lamberts
The Lamberts and Lambert Submaximal Cycle Test
R.P. Lamberts, PhD
ISBN: 978-90-9024959-9
Papers by Prof. Dr. (Hoogleraar) R.P. Lamberts
start caused by fluid restriction during a 40-km time trial (TT) in the heat. Twelve trained males performed one 40-km
cycling TT euhydrated (EU: no water during the TT) and two 40-km cycling TTs hypohydrated. During one hypohydrated
trial no fluid was ingested (HYPO), during the other trial ad-libitum water ingestion was allowed (FLUID). Ambient
temperature was 35.2 ± 0.2°C, relative humidity 51 ± 3% and airflow 7 m·s−1. Body mass (BM) was determined at the start
of the test, and before and after the TT. During the TT, power output, heart rate (HR), gastrointestinal temperature, mean
skin temperature, rating of perceived exertion (RPE), thermal sensation, thermal comfort and thirst sensation were
measured. Prior to the start of the TT, BM was 1.2% lower in HYPO and FLUID compared to EU. During the TT, BM
loss in FLUID was lower compared to EU and HYPO (1.0 ± 0.8%, 2.7 ± 0.2% and 2.6 ± 0.3%, respectively). Hydration
status had no effect on power output (EU: 223 ± 32 W, HYPO: 217 ± 39 W, FLUID: 224 ± 35 W), HR, gastrointestinal
temperature, mean skin temperature, RPE, thermal sensation and thermal comfort. Thirst sensation was higher in HYPO than
in EU and FLUID. It was concluded that hypohydration did not adversely affect performance during a 40-km cycling TT in
the heat. Therefore, whether or not participants consumed fluid during exercise did not influence their TT performance.
post-exercise recovery are sensitive to the homeostatic
stress of the preceding exercise and these measurements
warrant further investigation as possible markers of training
load. The current study investigated which of four different
measures of metabolic and autonomic recovery was most
sensitive to changes in exercise intensity.
Methods T hirty-eight moderately trained runners completed
20-min bouts of treadmill exercise at 60, 70 and
80 % of maximal oxygen uptake (VO2max) and four different
recovery measurements were determined: the
magnitude of excess post-exercise oxygen consumption
(EPOCMAG), the time constant of the oxygen consumption
recovery curve (EPOCτ), heart rate recovery within 1 min
(HRR60s) and the time constant of the heart rate recovery
curve (HRRτ) .
Results Despite significant differences in exercise parameters
at each exercise intensity, only EPOCMAG showed significantly
slower recovery with each increase in exercise intensity at the group level and in the majority of individuals.
EPOCτ was significantly slower at 70 and 80 % of
VO2max vs. 60 % VO2max and HRRτ was only significantly
slower when comparing the 80 vs. 60 % VO2max exercise
bouts. In contrast, HRR60s reflected faster recovery at 70
and 80 % of VO2max than at 60 % VO2max.
Conclusion Of the four recovery measurements investigated,
EPOCMAG was the most sensitive to changes in
exercise intensity and shows potential to reflect changes
in the homeostatic stress of exercise at the group and individual
level. Determining EPOCMAG may help to interpret
the homeostatic stress of laboratory-based research trials or
training sessions.
Displaced and shortened clavicle shaft fractures can be treated by intramedullary fixation; however, hardware migration and soft tissue irritation at the insertion site have complicated its use. The aim of this study was to determine whether this new intramedullary device (Sonoma CRx™) can be used successfully to treat displaced and shortened clavicle shaft fractures and restore the functional capacity of shoulder without the development of secondary complications.
Methods:
Forty-seven consecutive patients with displaced and shortened clavicle shaft fracture were treated with the CRx™ device. Incision size was captured during the surgical procedure while post-operatively union rate. Shoulder function was assessed by Disabilities of the Arm, Shoulder and Hand (DASH) score, the Constant Shoulder score and a Range of Movement score. Patients were assessed either after 3-6 months (Group I), 6-9 months (Group II) or 9-12 months (Group III) post-operatively.
Results:
All patients had achieved union at the time of review without any incidence of hardware migration. Three patients developed complications post-operatively (infection (1) and hardware failure (2)). No differences between the groups were found for DASH score (p=0.33), Constant Shoulder (p=0.38) and Range of Movement scores (p=0.96). DASH, Constant Shoulder and Range of Movement scores were similar to other successful treatment options, such as plating.
Conclusion:
The Sonoma CRx™ is a good alternative device to treat displaced and shortened clavicle shaft fractures and restore the functional capacity of the shoulder. Future research should focus on when nailing and plating should be used to treat clavicle shaft fractures most optimally.
A recent, novel approach to measuring training load has been to investigate measures of the post-exercise return towards resting homeostasis for potential in this role. For practical reasons, it is important to determine whether changes in training load produce changes in the recovery measurement that are in excess of the day-to-day variation or within-subject reliability of the measurement. However, the day-to-day variation in certain recovery measurements is not always known.
Research objective
To determine day-to-day variation in measures of heart rate recovery (HRR) and excess post-exercise oxygen consumption (EPOC) so as to determine the minimal detectable difference in these measurements for future research.
Type of study
Observational cohort study.
Methods
Twelve moderately trained runners completed 3 repetitions of a submaximal treadmill protocol on consecutive days. The protocol involved 20 min of running at 70% of maximal oxygen uptake and 15 min of controlled recovery. Day-to-day variation for exercise and recovery measurements was calculated as the typical error as a coefficient of variation (CVTEM).
Results
Recovery measurements showed CVTEM values of 8.0% (90% C.I. 6.7-10.3%) for the magnitude of EPOC, 12.9% (90% C.I. 10.6-16.4%) for the time constant of the oxygen consumption recovery curve, 8.7% (90% C.I. 7.2-11.2%) for 1 min HRR and 10.0% (90% C.I. 8.2-12.8%) for the time constant of the HRR curve. In contrast, most exercise parameters had CVTEM values of 2-4%.
Conclusions
For future studies in a similar setting, changes in training load that produce changes in HRR or EPOC greater than the CVTEM values of these recovery measurements might be interpreted as of likely practical significance.
All cyclists performed on a LSCT test followed peak power output (PPO) test, which included respiratory gas analysis for the determination of maximal oxygen consumption (VO2max) and the LSCT test followed by a 40km time trial (40km TT) test, 72 hours later. Average power output during the three stages of the LSCT increased from 31, 60 and 79% of PPO, while the ratings of perceived exertion increased from 8 to 13 to 16.
Very good relationships were found between actual and LSCT-predicted PPO (r = 0.98 95%CI: 0.97-0.98, p<0.0001), VO2max (0.96 95%CI: 0.97-0.99, p<0.0001) and 40km TT time (r = 0.98 95%CI: 0.94-0.97, p<0.0001). No gender differences were found when predicting cycling performance from the LSCT (p=0.95).
The findings of this study show that the LSCT is able to accurately predict cycling performance in trained-to-elite male and female cyclists and potentially can be used to prescribe and fine tune training prescription in cycling.
"
It is well-established that training standardized by %VO2max is associated with large inter-individual variation in training response. However, the relative contribution of an inadequately standardized exercise stimulus vs. hereditary factors is unclear. Conversely, a more homogenous training response following training prescribed relative to threshold measurements has yet to be demonstrated. Despite these considerations, the contention that threshold measurements are a more effective means of standardizing exercise stress at the level of the active muscle than %VO2max or %HRmax has a sound physiological basis.
On a practical level, however, threshold measurements have distinct disadvantages compared to VO2max and HRmax. Thresholds determined by graphical analysis cannot be assumed to be accurate in all individuals without verification trials. Verification trials would involve 2-3 additional laboratory visits and would add considerably to the testing burden on both the participant and researcher. Threshold determination and verification would also often involve blood lactate sampling which is aversive to some participants and has a number of intrinsic and extrinsic sources of variation. Threshold measurements also tend to show higher day-to-day variation than VO2max and HRmax.
In summary, each method of prescribing relative exercise intensity has both advantages and disadvantages when both theoretical and practical considerations are taken into account. It follows that the most appropriate method of relative exercise intensity prescription may vary depending on the design, outcome measures, participant numbers and resources available for conducting a particular study. Considering a method’s limitations as well as advantages and increased reporting of inter-individual variation in exercise response will facilitate accurate interpretation of findings and help to identify important areas for further study.
""
The Lamberts and Lambert Submaximal Cycle Test
R.P. Lamberts, PhD
ISBN: 978-90-9024959-9
start caused by fluid restriction during a 40-km time trial (TT) in the heat. Twelve trained males performed one 40-km
cycling TT euhydrated (EU: no water during the TT) and two 40-km cycling TTs hypohydrated. During one hypohydrated
trial no fluid was ingested (HYPO), during the other trial ad-libitum water ingestion was allowed (FLUID). Ambient
temperature was 35.2 ± 0.2°C, relative humidity 51 ± 3% and airflow 7 m·s−1. Body mass (BM) was determined at the start
of the test, and before and after the TT. During the TT, power output, heart rate (HR), gastrointestinal temperature, mean
skin temperature, rating of perceived exertion (RPE), thermal sensation, thermal comfort and thirst sensation were
measured. Prior to the start of the TT, BM was 1.2% lower in HYPO and FLUID compared to EU. During the TT, BM
loss in FLUID was lower compared to EU and HYPO (1.0 ± 0.8%, 2.7 ± 0.2% and 2.6 ± 0.3%, respectively). Hydration
status had no effect on power output (EU: 223 ± 32 W, HYPO: 217 ± 39 W, FLUID: 224 ± 35 W), HR, gastrointestinal
temperature, mean skin temperature, RPE, thermal sensation and thermal comfort. Thirst sensation was higher in HYPO than
in EU and FLUID. It was concluded that hypohydration did not adversely affect performance during a 40-km cycling TT in
the heat. Therefore, whether or not participants consumed fluid during exercise did not influence their TT performance.
post-exercise recovery are sensitive to the homeostatic
stress of the preceding exercise and these measurements
warrant further investigation as possible markers of training
load. The current study investigated which of four different
measures of metabolic and autonomic recovery was most
sensitive to changes in exercise intensity.
Methods T hirty-eight moderately trained runners completed
20-min bouts of treadmill exercise at 60, 70 and
80 % of maximal oxygen uptake (VO2max) and four different
recovery measurements were determined: the
magnitude of excess post-exercise oxygen consumption
(EPOCMAG), the time constant of the oxygen consumption
recovery curve (EPOCτ), heart rate recovery within 1 min
(HRR60s) and the time constant of the heart rate recovery
curve (HRRτ) .
Results Despite significant differences in exercise parameters
at each exercise intensity, only EPOCMAG showed significantly
slower recovery with each increase in exercise intensity at the group level and in the majority of individuals.
EPOCτ was significantly slower at 70 and 80 % of
VO2max vs. 60 % VO2max and HRRτ was only significantly
slower when comparing the 80 vs. 60 % VO2max exercise
bouts. In contrast, HRR60s reflected faster recovery at 70
and 80 % of VO2max than at 60 % VO2max.
Conclusion Of the four recovery measurements investigated,
EPOCMAG was the most sensitive to changes in
exercise intensity and shows potential to reflect changes
in the homeostatic stress of exercise at the group and individual
level. Determining EPOCMAG may help to interpret
the homeostatic stress of laboratory-based research trials or
training sessions.
Displaced and shortened clavicle shaft fractures can be treated by intramedullary fixation; however, hardware migration and soft tissue irritation at the insertion site have complicated its use. The aim of this study was to determine whether this new intramedullary device (Sonoma CRx™) can be used successfully to treat displaced and shortened clavicle shaft fractures and restore the functional capacity of shoulder without the development of secondary complications.
Methods:
Forty-seven consecutive patients with displaced and shortened clavicle shaft fracture were treated with the CRx™ device. Incision size was captured during the surgical procedure while post-operatively union rate. Shoulder function was assessed by Disabilities of the Arm, Shoulder and Hand (DASH) score, the Constant Shoulder score and a Range of Movement score. Patients were assessed either after 3-6 months (Group I), 6-9 months (Group II) or 9-12 months (Group III) post-operatively.
Results:
All patients had achieved union at the time of review without any incidence of hardware migration. Three patients developed complications post-operatively (infection (1) and hardware failure (2)). No differences between the groups were found for DASH score (p=0.33), Constant Shoulder (p=0.38) and Range of Movement scores (p=0.96). DASH, Constant Shoulder and Range of Movement scores were similar to other successful treatment options, such as plating.
Conclusion:
The Sonoma CRx™ is a good alternative device to treat displaced and shortened clavicle shaft fractures and restore the functional capacity of the shoulder. Future research should focus on when nailing and plating should be used to treat clavicle shaft fractures most optimally.
A recent, novel approach to measuring training load has been to investigate measures of the post-exercise return towards resting homeostasis for potential in this role. For practical reasons, it is important to determine whether changes in training load produce changes in the recovery measurement that are in excess of the day-to-day variation or within-subject reliability of the measurement. However, the day-to-day variation in certain recovery measurements is not always known.
Research objective
To determine day-to-day variation in measures of heart rate recovery (HRR) and excess post-exercise oxygen consumption (EPOC) so as to determine the minimal detectable difference in these measurements for future research.
Type of study
Observational cohort study.
Methods
Twelve moderately trained runners completed 3 repetitions of a submaximal treadmill protocol on consecutive days. The protocol involved 20 min of running at 70% of maximal oxygen uptake and 15 min of controlled recovery. Day-to-day variation for exercise and recovery measurements was calculated as the typical error as a coefficient of variation (CVTEM).
Results
Recovery measurements showed CVTEM values of 8.0% (90% C.I. 6.7-10.3%) for the magnitude of EPOC, 12.9% (90% C.I. 10.6-16.4%) for the time constant of the oxygen consumption recovery curve, 8.7% (90% C.I. 7.2-11.2%) for 1 min HRR and 10.0% (90% C.I. 8.2-12.8%) for the time constant of the HRR curve. In contrast, most exercise parameters had CVTEM values of 2-4%.
Conclusions
For future studies in a similar setting, changes in training load that produce changes in HRR or EPOC greater than the CVTEM values of these recovery measurements might be interpreted as of likely practical significance.
All cyclists performed on a LSCT test followed peak power output (PPO) test, which included respiratory gas analysis for the determination of maximal oxygen consumption (VO2max) and the LSCT test followed by a 40km time trial (40km TT) test, 72 hours later. Average power output during the three stages of the LSCT increased from 31, 60 and 79% of PPO, while the ratings of perceived exertion increased from 8 to 13 to 16.
Very good relationships were found between actual and LSCT-predicted PPO (r = 0.98 95%CI: 0.97-0.98, p<0.0001), VO2max (0.96 95%CI: 0.97-0.99, p<0.0001) and 40km TT time (r = 0.98 95%CI: 0.94-0.97, p<0.0001). No gender differences were found when predicting cycling performance from the LSCT (p=0.95).
The findings of this study show that the LSCT is able to accurately predict cycling performance in trained-to-elite male and female cyclists and potentially can be used to prescribe and fine tune training prescription in cycling.
"
It is well-established that training standardized by %VO2max is associated with large inter-individual variation in training response. However, the relative contribution of an inadequately standardized exercise stimulus vs. hereditary factors is unclear. Conversely, a more homogenous training response following training prescribed relative to threshold measurements has yet to be demonstrated. Despite these considerations, the contention that threshold measurements are a more effective means of standardizing exercise stress at the level of the active muscle than %VO2max or %HRmax has a sound physiological basis.
On a practical level, however, threshold measurements have distinct disadvantages compared to VO2max and HRmax. Thresholds determined by graphical analysis cannot be assumed to be accurate in all individuals without verification trials. Verification trials would involve 2-3 additional laboratory visits and would add considerably to the testing burden on both the participant and researcher. Threshold determination and verification would also often involve blood lactate sampling which is aversive to some participants and has a number of intrinsic and extrinsic sources of variation. Threshold measurements also tend to show higher day-to-day variation than VO2max and HRmax.
In summary, each method of prescribing relative exercise intensity has both advantages and disadvantages when both theoretical and practical considerations are taken into account. It follows that the most appropriate method of relative exercise intensity prescription may vary depending on the design, outcome measures, participant numbers and resources available for conducting a particular study. Considering a method’s limitations as well as advantages and increased reporting of inter-individual variation in exercise response will facilitate accurate interpretation of findings and help to identify important areas for further study.
""
Changes in heart rate recovery (HRR) are generally associated with a change in training status. A faster HRR is generally being associated with an improvement in training status, while a slower HRR is generally associated with a decrease in training status. However a few recent studies (Dupey et al. & Lamberts et al.) have reported a faster HRR after a strong increase in training load, while Capostagno et al. has suggested that HRR can be used to monitor and fine tune training. The aim of this study was to determine the relationship between HRR and an acute training “overload” by comparing HRR responses before and after an ultra-marathon road race.
Methods
Ten runners completed a standardized laboratory protocol ~7 days before and between 2 and 4 days after participating in the 87 km Comrades Marathon. The protocol included muscle pain ratings, a 5 bound test and 20 min of treadmill exercise at 70% of maximal oxygen uptake followed by 15 min of recovery. Respiratory gases and heart rate measurements were used to calculate steady state exercise responses, HRR and excess post-exercise oxygen consumption and participants also provided a rating of perceived exertion during exercise (RPE).
Results
All participants completed the 87 km race with finishing times of between 8 h 11 min and 11 h 39 min. A strong correlation was found between PTRS and race finishing time (r = -0.89, p = 0.0005), suggesting that all runners ran at their own ‘maximal’ capacity. After the race, perceived pain in the quadriceps muscles (p < 0.01) and hamstring muscles (p < 0.05) was significantly higher. During the post-submaximal exercise test, RPE was significantly higher (13±2 vs. 11±1; p < 0.01) while HRR was significantly faster (35±5 vs. 29±4 beats; p < 0.01). No changes in respiratory and/or heart rate parameters were found during the test.
Discussion
This study shows increased RPE levels and a faster HRR in subjects who finished an 87km ultra-marathon. These findings are paradoxical, as fatigue is generally associated with a slower HRR. However our finding are in line with studies of Dupey et al. and Lamberts et al, who also reported a faster HRR in functionally overreached participants. The current study emphasises that changes in HRR should always be interpreted in the light of changes other parameters and that these interpretations can potentially be used as highly valuable and practical tools to monitor and fine-tune training prescription.
References
Dupuy O et al. (2013). Appl Physiol Nutr Metab 38: 200-208
Lamberts RP et al. (2010) Eur J Appl Physiol 108: 183–90, 2010.
Capostagno B. et al (2013) Int. J. Sports. Physiol and Perform. 9:292-301
It is well established heart rate recovery (HRR) is able to reflect training status in a heterogeneous population and reflect changes in training status both in untrained as in high performance athletes (Daanen et al., 2013). However in a homogeneous group of similarly trained subjects, HRR loses its power to accurately predict training status due to genetic polymorphisms (Hautula et al., 2006). More recently parasympathetic reactivation has shown to be an alternative method to predict and monitor training status (Bucheit et al., 2007). Therefore the aim of this study was to determine the reliability and predictive value of parasympathetic reactivation after a submaximal cycle test.
Methods
Both HRR and parasympathetic reactivation were captured as part of the part of the LSCT (Lamberts et al., 2014). The study consists of two parts. In part I, 15 trained cyclists (4.9 ± 0.4 W/kg; 57.5 ± 6.0 ml/min/kg), were asked to perform the LSCT over 6 consecutive days to establish the reliability and associated typical error of measurement TEM) of the parasympathetic reactivation measured over time frames of 30, 60 and 90 seconds. In part II, 50 trained to elite cyclists (3.8–7.1 W/kg; 47.8–76.8 ml/min/kg) performed the LSCT followed by a Peak Power output (PPO) test and 2 days later a LSCT followed by a 40km time trial (40km TT).
Results
The reliability and associated TEM of the parasympathetic measurements were the lowest over the 60 second period (RMSSD60s) (ICC: 0.99; TEM: 7.7%) in comparison to 30 and 90 second periods (RMSDD30S: ICC: 0.98, TEM: 11.1% and RMSSD90S: ICC: 0.99, TEM 14.0%). Very good relationships were found between RMSSD60s and PPO (r = 0.94, SEE: 11W), VO2max (r = 0.71, SEE: 4.5 ml/min/kg) and, 40km TT time (r = 0.88, SEE: 81 seconds). Substantially weaker relationships were found between HRR and PPO (r = 0.69, SEE: 24W), VO2max (r = 0.67, SEE: 4.7 ml/min/kg) and, 40km TT time (r = 0.76, SEE: 109 seconds).
Discussion
The measurement of parasympathetic reactivation measurement (TEM: 7.7%) was reliable, but slightly lower than the reliability of HRR (TEM: 4.1%). In contrast, parasympathetic reactivation was able to predict PPO, VO2max and 40km TT time more accurately than HRR. Parasympathetic reactivation shows great potential to further improve the capacity to accurately predict, monitor and prescribe training to cyclists. Future research should aim to determine if parasympathetic reactivation can also reflect a change in training status or not.
References
Daanen HAM et al. (2012). Int J of Sports Physiol and Performance. 7,251-260
Hautula AJ et al. (2006). Am.J. Physiol Heart Circ Physiol 291,H459-H466
Buccheit M et al (2007) Am.J. Physiol Heart Circ Physiol 293,H133-H141
Lamberts RP (2014). Int J of Sports Physiol and Performance, EPub; Ahead of print. Exp. publ. date: 9(4) July "
"
In a recent publication Swart et al. differentiated between physical sensations and the psychic sensations generated during exercise, measured by an adapted RPE scale (P-RPE) and a Task Effort Awareness scale (TEA), respectively. During a self paced 100km time trial (100km TT) and a 100km TT test performed at 70% of this intensity, they found that TEA scores were attenuated in relation to P-RPE scores, indicating a lower awareness of task effort when exercising at a lower intensity. It is unknown however whether factors other than intensity can also influence this task effort sensation. Therefore, the aim of this study was to determine whether task effort awareness would change when performing a time trial in differing environmental conditions.
Methods
Ten experienced well-trained male cyclists between 18 and 45 years (393 ± 23 W) completed four 40km TT in 20, 25, 30 and 35 °C in a randomized order. Rating of physical exertion (P-RPE) and task effort awareness were recorded every 5 km. Subjects randomly assigned to different environmental conditions, while data was collected over a 2 week period. To minimize the effect of the season of the year, all data was collected within a 6 week testing period.
Results
Time to complete the 40km TT increased significantly with temperature (p < 0.001) from 3874 ± 92 s in 20 degrees Celsius to 4199 ± 99 s in 35 degrees Celsius. Physical rating of perceived exertion (P-RPE) were similar during all 4 time trials in 20, 25, 30 and 35 °C, starting at approximately 16 and finishing at approximately 19 or 20. Task effort awareness levels (TEA) differed significantly between the four different temperatures, being higher in warmer environmental conditions. Differences in task effort awareness were seen from 5 km (ranging from 7.5 ± 0.4 in 20 degrees Celsius to 8.6 ± 0.2 in 35 degrees Celsius) and finished at a similar task effort awareness level of 9 to 9.5 in all the trials.
Discussion
Although that self paced time trial performance decreases with a rise in environmental temperature, physical ratings of perceived exertion (P-RPE) were similar during the all 4 trials, as reported before (Swart et al., 2009; Crewe et al., 2008). In contrast, levels of task effort awareness were higher when performing the time trials in warmer environmental conditions. This finding supports the capacity of the TEA scale to differentiate between physical and psychic sensation during exercise. We hypothesize that increased afferent feed-back when cycling in warmer conditions results in higher task effort awareness levels, as seen in this study and that rising task effort is responsible for the reduction in exercise intensity in an attempt to maintain the P-RPE within the constraints of the pre-determined P-RPE template.
References
Swart J, Lindsay TR, Lambert MI, Brown JC, Noakes TD. (2012). Br. J. Sports Med. 46,42-48
Swart J, Lamberts RP, Lambert MI, Lambert EV, Woolrich RW, Johnston S Noakes TD. (2009) Br. J. Sports Med. 43,775-781
Crew H, Tucker R, Noakes, TD. (2008) Eur J Appl Physiol 103, 569-577
Kinking of the common or external iliac artery is most commonly seen in professional cyclists, who spend a substantial amount of their training time in an aerodynamic position and flexing their hips as much as 8 million times per year (Schep et al., 2002), which causes limited blood flow to the lower extremity resulting in underperformance and complains about pain and powerlessness. It is unknown however if this pathology mainly restrict endurance cycling capacity or also peak power output (PPO).
Methods
A 32 year old professional cyclist (460 W; 6.1 W•kg-1) and participated in a monitoring/observation study, was diagnosed with kinking of both the left and right external iliac artery, after underperforming and complaining about
painful/powerless legs. During the monitoring period the cyclists performed two PPO tests, including respiratory gas analysis (VO2max), and two 40km time trials (40km TT). Before all performance tests, the cyclists performed the LSCT, a submaximal cycle test which is able to predict cycling performance (Lamberts et al., 2009). After surgery of both left and right external iliac artery and a rehabilitation period, a third PPO and 40km TT test, including the LSCT, was performed. Actual performance and predicted performance of the cyclist was compared to normative data of 74 healthy cyclists (Lamberts et al., 2009)
Results
No meaningful differences were found between actual PPO (460W, 484W and 410W, respectively) and predicted PPO based on the LSCT (456W, 486W and 410W, respectively). No differences were also found between actual VO2max (5.4 , 5.5, 4.7 l•min-1, respectively) and predicted VO2max (5.4, 5.7, 4.7 l•min-1, respectively). Meaningful differences (Lamberts et al., 2009) were found between actual and predicted 40km TT performance before surgery during which the cyclist under-performed by 3 minutes and 32 seconds and 4 minutes and 15 seconds, while after surgery no meaningful differences were found (9 seconds)
Discussion
The main finding of this case study is that meaningful discrepancies were found between actual and predicted 40km TT performance with kinking of the external iliac arteries in a professional cyclists. These finding suggest that kinking of the iliac artery mainly impairs endurance performance and not or less PPO and VO2max. Therefore additional measurements such as ankle systolic blood pressure measurements, echo doppler and magnetic-resonance imaging either with or without angiography (Schep et al., 2001, 2002), seem to be crucial for diagnosing kinking of the iliac artery within a PPO test. In addition this study shows that a discrepancy between predicted 40km TT performance, from the LSCT, and actual 40km TT performance can possibly be used as an early screenings tool.
References
Schep G, Bender MG, van de Tempel G, Wijn PF, de Vries WR, Eikelboom BC (2002). Lancet. 359, 466-473
Lamberts RP (2009). Book (ISBN: 978-90-9024959-9), Enschede, The Netherlands, Ipskamp Drukkers
Schep G, Kaandorp DW, Bender MH, Weerdenburg H, van Engeland S, Wijn PF (2001). Physiol Meas. 22, 475-487
Aim To describe accomplishment and satisfaction levels in life habits in adults with bilateral spasticity, living in a developing country (South Africa), more than 15 years after Selective Dorsal Rhizotomy and Orthopaedic (‘SDR+Orth’) or only Orthopaedic (‘Orth’) interventions. A secondary aim was to determine if relationships existed between these accomplishment and satisfaction levels and personal characteristics.
Methods and subjects Levels of accomplishment and satisfaction were determined based on the Life-Habit questionnaire. In addition, personal characteristics such as age, education, employment, marital and socio-economic status were captured. The study cohort consisted of 61 subjects of which 31 received ‘SDR+Orth’ (mean age: 28.7 ± 5.5 years, range: 21-44 years) and 30 ‘Orth’- (mean age: 33.1 ± 7.7 years, range: 19-47 years) during their childhood in hospitals of Cape Town, South Africa.
Results and Discussion On average over all domains 73% of the study cohort experienced no difficulties and were fully independent in accomplishing all life habits. This level of performance was substantially higher in the ‘SDR+Orth’ than in the ‘Orth’ group, with 80% and 66% respectively. Most limitations were reported in the domains Mobility and Recreation, also resulting in lower satisfaction scores. Over all domains, accomplishment levels were significant correlated with satisfaction levels (r=0.67, p<0.001). However, no relationships were found between Life-Habit outcomes and personal characteristics. In conclusion, the majority of adults with bilateral spasticity who received SDR and/or Orthopaedic interventions in South Africa are able to accomplish all life habits independently and reported high levels of satisfaction, which is not dependent on their socio-economic status or other personal characteristics.
There is a debate if the Gross Motor Function Classification System (GMFCS) is stable or GMFCS levels can change over time with interventions, such as Selective Dorsal Rhizotomy (SDR) and/or Orthopaedic (Orth) interventions.
Aim
To compare the GMFCS levels of patients with bilateral spasticity before and more than 15 years after ‘SDR+Orth’ or only ‘Orth’ interventions. A secondary aim was to determine if relationships existed between the change in GMFCS levels and personal characteristics.
Methods and subjects
Based on detailed clinical reports, pre-operative GMFCS levels were retrospectively determined (blinded), compared, and discussed. Current GMFCS levels and personal characteristics, such as age, education, employment, marital and socio-economic status, were captured during a visit to the research unit. The study cohort consisted of 61 subjects of which 31 received ‘SDR+Orth’ (mean age: 28.7±5.5 years, range: 21-44 years) and 30 ‘Orth’ (mean age: 33.1±7.7 years, range: 19-47 years) during childhood in hospitals of Cape Town, South Africa. The mean follow-up time was 24.3±6.2 years.
Results and Discussion
There was a significant difference between subjects’ GMFCS levels indicated before and more than 15 years after surgery (p< 0.001). Forty-six percent of the total study cohort improved at least one GMFCS level, while 5% deteriorated in function. The positive change was higher in the ‘SDR+Orth’ group compared to the ‘Orth’ group, with improvement seen in 58% and 33%, no change in 42% and 57%, and deterioration in 0 and 10%, respectively. The change in GMFCS levels was associated with current age, however this correlation was not very strong (r = 0.27, p=0.03). No other associations were found. In conclusion, GMFCS can change with surgical interventions such as SDR and/or orthopedic interventions over time.
Heart rate after a standardized exercise test varies with a change in training status (Borresen and Lambert, 2007; Buchheit et al., 2008; Lamberts et al., 2009) possibly compromising the accuracy of measuring changes in heart rate recovery (HRR). Therefore the aim of this study was to determine if a change in exercise intensity would result in a change in HRR and its associated typical error of measurement. The practical aim of this study was to determine the range of exercise intensity following which HRR is relatively stable and can therefore be used as an accurate monitoring tool.
Methods
Thirty-one subjects were recruited for this study and asked to perform four submaximal running tests (HIMS). Based on the heart rate after the first HIMS, and with the aim to achieve heart rates in between 85-90% of heart rate maximum (HRmax),subjects were allocated to either group SAME (85-90% of HRmax (n=9)) - completing four identical HIMS (starting speed 7.2 km•h-1), group FASTER (< 85% HRmax (n=10)) completing two standard and two faster HIMS (starting speed 8.6 km•h-1) or to group SLOWER (> 90% HRmax (n=12)) completing two standard and two slower HIMS (starting speed 6.0 km•h-1) on alternating days.
Results
Adapting the HIMS resulted in the HRmax of SLOWER at the end of the HIMS decreasing from 94% HRmax to 89% HRmax (p = 0.000136), while HRmax increased from 82% HRmax to 88% HRmax in the FASTER group (p = 0.000136). There were no changes in absolute HRR at the end of the HIMS in either of these groups. However, improved coefficient of variation (CV) and lower typical errors of measurement (TEM) were found in both the SLOWER and FASTER group (SLOWER: CV 11 ± 7 to 5 ± 3% (p = 0.025), TEM 6 to 3 beats; FASTER: CV 11 ± 7 to 4 ± 3% (p = 0.048), TEM 7 to 3 beats) when the HIMS protocol was adapted.
Discussion
This study shows that although no changes in absolute HRR occurred with a change in exercise intensity, the capacity to detect meaningful changes improved significantly when the exercise intensity of the HIMS protocol was adapted. The highest sensitivity to detect meaningful changes on a day-to-day basis occurred at exercise intensities ranging from 86 to 93% of HRmax. To ensure the highest level of sensitivity in detecting meaningful changes in HRR, submaximal testing protocol should be adapted when ≤ 85% or ≥ 94% of HRmax is reached.
References
Borresen J, Lambert MI. (2007). Sports Med. 28, 633-646.
Buchheit M, Millet GP, Parisy A, Pourchez S, Laursen PB, Ahmaidi S. (2008). Med. Sci Sports Exerc. 40, 362-371.
Lamberts RP, Lambert MI. (2009). J. Strength. Cond. Res. 23, 1005-1010.
Lamberts RP, Swart J, Noakes TD, Lambert MI. (2009). Eur. J Appl. Physiol 105, 705-713.
Being able to predict several performances parameters from a single test is important for monitoring purposes in well trained and elite athletes. As performance tests, such as a peak power output test (PPO) and a 40km time trial test (40km TT), generally interfere with the normal training habits of athletes monitoring of a regular basis is difficult. As maximal oxygen consumption (VO2max) is related to exercise capacity (Arts and Kuipers, 1994), VO2max has become a popular measurement to determine training status in athletes. However, this parameter loses its predictive accuracy in well-trained cyclists (Lamberts et al., 2009). In an attempt to overcome this limitation, Swain (1994) has suggested that body mass should be corrected to the power of 0.32 (kg0.32) when predicting flat time trail performance. Therefore the purpose of this study was to determine if peak power output adjusted for body mass0.32 is able to accurately predict 40km TT performance and possibly maximal oxygen consumption.
Methods
Forty-five trained male cyclists completed a peak power output test, including respiratory gas analysis, and a 40km TT after being familiarized. Performance parameters such as peak power output (PPO), maximal oxygen consumption (VO2max) and 40km time trial time were measured. Peak power output was normalized for body mass to the exponent of 0.32 (W•kg-0.32) after which the relationship with 40km TT performance and maximal oxygen consumption was determined.
Results
As expected, a strong relationship occurred between peak power output and VO2max before adjustment for body mass (r = 0.96 (95%CI: 0.93 – 0.98); P < 0.0001). After adjusting PPO for body mass0.32 (W•kg-0.32), there was a strong relationship with 40km TT time (r = -0.96: 95%CI: -0.93 – -0.98; P < 0.0001), with a standard error of estimate of 52 s. Although significant relationships were also found between absolute (W) and relative PPO (W•kg-1) and 40km TT performance, slope analyses showed that the relationships with 40km TT performance were significantly weaker than adjusted PPO (W•kg-0.32) (both p < 0.0001).
Discussion
This study to shows PPO adjusted for body mass0.32 (W•kg-0.32) is able to accurately 40km TT performance in trained cyclists. In addition, VO2max could also be accurately predicted from PPO measured within the same test. The practical relevance of this study is that VO2max and 40km TT performance can be predicted with a reasonable amount of accuracy from just one PPO test. As this possibly can reduce the amount of performance tests throughout the year in well-trained and elite cyclists, this method might possibly allow more regular testing for monitoring purposes.
References
Arts FJ, Kuipers H. (1994). Int J Sports Med 15, 228-231.
Lamberts RP, Swart J, Woolrich RW, Noakes TD, Lambert MI. (2009). Int SportMed J 10, 33-44
Mujika I, Padilla S. (2001) Sports Med 31, 479-87.
Exercise induced muscle damage (EIMD) is characterized by muscle pain, symptoms of swelling, muscle shortening, increased serum creatine kinase activity, decreased force output and altered neuromuscular function (Armstrong et al 1991). The aim of this study was to determine how the symptoms of EIMD influence the neuromuscular recruitment patterns during maximal and submaximal isometric and submaximal flexion–extension movements.
Methods
Twenty-five right-handed males were recruited for this study, and were allocated to either a control (n = 13) or experimental group (n = 12). In contrast to the control group, the experimental group participated in an EIMD protocol of the elbow flexor muscles. Subsequently, muscle soreness, arm circumference, resting elbow angle, serum creatine kinase activity, muscle function and EMG activity during maximal voluntary contraction, isometric low force contraction and a submaximal flexion-extension protocol were monitored in both groups for up to 132 hours after the EIMD protocol.
Results
After the EIMD protocol, muscle pain scores in the experimental group peaked after 36 hours with serum creatine kinase activity peaking after 108 hours. Twelve hours after the EIMD protocol, EMG activity had decreased by 20% during a maximal voluntary contraction in the experimental group (X2 = 21.70, p = 0.001) and decreased by a further 10% until the end of the study (132 hours after the EIMD protocol) (X2 = 21.70, p = 0.01). In contrast, EMG activity during submaximal movement increased significantly during the last two seconds (s2, s3) of the flexion (s2: H = 9.61, p = 0.0019; s3: H = 11.01, p = 0.0009) as well as the first two seconds (s4, s5) of the extension movement (s4: H = 8.00, p = 0.0047; s5: H = 4.05, p = 0.0442) from 12 hours after the EIMD protocol.
Discussion
Classical symptoms of EIMD (increased muscle soreness, swelling, muscle shortening and increased creatine kinase activity, decreased muscle function and force output) (Lambert et al., 2002; Prasartwuth et al., 2005) were observed in the experimental group. A dissociation in EMG response was found in the experimental group between the EMG response during maximal voluntary contraction (decrease) and during submaximal movements (increase). This dissociated EMG response suggests that central regulation influences the neural firing patterns and motor unit activity.
References
Armstrong RB, Warren GL, Warren JA. (1991) Sport Med 12, 184-207
Lambert MI, Marcus P, Burgess T, Noakes TD. (2002) Med Sci Sport Exerc 34, 602-607
Prasartwuth O, Taylor JL, Gandevia SC. (2005) J Physiol 567, 337-348
Partt 2 (#2) Background: Fitting an elite cyclist properly on his bicycle is important to produce maximal sustainable power, guarantee optimal cycling efficiency and reduce risk on overuse injuries [2]. Purpose: The purpose of the workshop is to explain how biomechanical cycling analysis can be used to identify overuse injuries. In addition, the participants will be shown how to analyse, change and determine a correct bicycle fit for different level cyclists. Intended learning objectives: The intended learning objectives of the workshop are to be able to use biomechanical analyses to identify overuse injuries and to analyse a correct bicycle fitting of cyclists. Background presenting researcher: Dr. Jeroen Swart is a sports physician with a professional mountain bike background and a specific research interest in cycling biomechanics. Dr Swart has also working with international professional road, mountain bike and cyclo-cross cyclists.
References
1 Lamberts RP, Swart J, Noakes TD, Lambert MI. A novel submaximal cycle test to monitor fatigue and predict cycling performance. Br J Sports Med 2009;Epub; ahead of publication.
2 Swart J, Tucker R, Lamberts RP, Albertus Y, Lambert MI. Case Report: Chronic anterior knee pain related to low cadence in a Tour De France winning cyclist. Int SportMed J 2008;9:162-72.
References
1.Paton CD, Hopkins WG. Ergometer error and biological variation in power output in a performance test with three cycle ergometers. Int.J Sports Med. 2006;27, 444-447.
2.Currell K, Jeukendrup AE. Validity, reliability and sensitivity of measures of sporting performance. Sports Med. 2008;38, 297-316.
3.Paton CD, Hopkins WG. Tests of cycling performance. Sports Med. 2001;31, 489-496.
4.Swart J, Lamberts RP, Lambert MI, et al. Exercising with reserve: Evidence that the CNS regulates prolonged exercise performance. Br.J Sports Med 2009;43, 782-788