We studied the relationship between the speed at the gas exchange thresholds for walking and runn... more We studied the relationship between the speed at the gas exchange thresholds for walking and running and the preferred gait transition speed (PTS), and the correspondence of PTS and energetically optimal transition speed (EOTS). Twenty-two men (age: 21.4 ± 2.4 years, mass: 78.1 ± 8.2 kg) performed four tests during which we determined VO2max, walking/running gas exchange thresholds, walk-to-run/run-to-walk PTS, and EOTS. There were no significant differences (P > 0.05) between PTS, and the speed at the aerobic threshold for walking (AeTw) and running (AeTr). Both walk-to-run and run-to-walk PTS significantly correlated to AeTr (r = 0.82 and 0.79; P < 0.01) but not to AeTw (r = -0.03 and 0.06; P > 0.05). Finally, EOTS and the corresponding VO2 were significantly higher (P < 0.05) than the speed and VO2 at PTS. Our results indicate that running rather than walking dynamics determines gait transitions in men.
We studied the relationship between the speed at the gas exchange thresholds for walking and runn... more We studied the relationship between the speed at the gas exchange thresholds for walking and running and the preferred gait transition speed (PTS), and the correspondence of PTS and energetically optimal transition speed (EOTS). Twenty-two men (age: 21.4 ± 2.4 years, mass: 78.1 ± 8.2 kg) performed four tests during which we determined VO2max, walking/running gas exchange thresholds, walk-to-run/run-to-walk PTS, and EOTS. There were no significant differences (P > 0.05) between PTS, and the speed at the aerobic threshold for walking (AeTw) and running (AeTr). Both walk-to-run and run-to-walk PTS significantly correlated to AeTr (r = 0.82 and 0.79; P < 0.01) but not to AeTw (r = -0.03 and 0.06; P > 0.05). Finally, EOTS and the corresponding VO2 were significantly higher (P < 0.05) than the speed and VO2 at PTS. Our results indicate that running rather than walking dynamics determines gait transitions in men.
The studies exploring the influence of resistance training on endurance in men have produced inco... more The studies exploring the influence of resistance training on endurance in men have produced inconsistent results. The aim of this study was to examine the influence of an Olympic weight lifting training programme on parameters of aerobic and anaerobic endurance in moderately physically active men. Eleven physical education students (age: 24.1 +/- 1.8 yr, height: 1.77 +/- 0.04 m, body mass: 76.1 +/- 6.4 kg; X +/- SD) underwent a 12-week, 3 times/wk training programme of Olympic weight lifting. Specific exercises to master the lifting technique, and basic exercises for maximal strength and power development were applied, with load intensity and volume defined in relation to individual maximal load (repetitio maximalis, RM). Parameters of both, aerobic and anaerobic endurance were estimated from gas exchange data measured during a single incremental treadmill test to exhaustion, which was performed before, and after completion of the 12-wk programme. After training, there was a small, but significant increase in body mass (75.8 +/- 6.4 vs. 76.6 +/- 6.4, p &amp;amp;lt; 0.05) and peak VO2 (54.9 +/- 5.4 vs. 56.4 +/- 5.3 mL O2/min/kg, p &amp;amp;lt; 0.05), with no significant change of the running speed at the anaerobic threshold (V(AT)) and at exhaustion (V(max)) (both p &amp;amp;gt; 0.05). However, there was a significant increase of anaerobic endurance, estimated from the distance run above V(AT), from V(AT) to V(max), (285 +/- 98 m vs 212 +/- 104 m, p &amp;amp;lt; 0.01). The results of this study indicate that changes in both, anaerobic and aerobic endurance due to a 12-wk period of strength training in untrained persons can be determined from a single incremental treadmill test to exhaustion. The possible causes of those training effects include several possible mechanisms, linked primarily to peripheral adaptation.
Oxidative stress is an important pathogenic factor of cancer and cardiovascular, metabolic and de... more Oxidative stress is an important pathogenic factor of cancer and cardiovascular, metabolic and degenerative diseases. On the other hand, mild oxidative stress, as in case of physical exercise, can increase the antioxidant defense system. However, the mechanisms underlying such desirable effects of mild oxidative stress are not well understood, because the production of hydroxyl radical, the most aggressive oxygen free radical, was not yet evaluated under physiological circumstances. Therefore, in this study, we evaluated the overall production of hydroxyl radical using blood samples of ten healthy male students before and 1 h after ergometry. One h before exercise, they took salicylic acid (1g) orally so that hydroxyl radical was trapped with salicylic acid, yielding a measurable reaction product, 2,3-dihydroxybenzoic acid. Oxidative stress response to exercise was also evaluated in the volunteers without premedication by measuring serum peroxides and total antioxidant capacity of serum. These parameters of oxidative stress were then correlated with physical performance of the subjects. Ergometry caused an increase of the plasma hydroxyl radical level by 37.5% (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), whereas the levels of total serum peroxides did not change significantly. Total serum antioxidant capacity, measured as uric acid equivalents, was higher after ergometry by 39.7% (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), and was in positive correlation (r = 0.81) with anaerobic threshold, an indicator of physical condition. Hence, ergometry induces hydroxyl radical production and systemic oxidative stress response in the healthy subjects. Egometry could be used to study physiological oxidative stress response and to improve antioxidant defense capacities in humans.
We studied the relationship between the speed at the gas exchange thresholds for walking and runn... more We studied the relationship between the speed at the gas exchange thresholds for walking and running and the preferred gait transition speed (PTS), and the correspondence of PTS and energetically optimal transition speed (EOTS). Twenty-two men (age: 21.4 ± 2.4 years, mass: 78.1 ± 8.2 kg) performed four tests during which we determined VO2max, walking/running gas exchange thresholds, walk-to-run/run-to-walk PTS, and EOTS. There were no significant differences (P > 0.05) between PTS, and the speed at the aerobic threshold for walking (AeTw) and running (AeTr). Both walk-to-run and run-to-walk PTS significantly correlated to AeTr (r = 0.82 and 0.79; P < 0.01) but not to AeTw (r = -0.03 and 0.06; P > 0.05). Finally, EOTS and the corresponding VO2 were significantly higher (P < 0.05) than the speed and VO2 at PTS. Our results indicate that running rather than walking dynamics determines gait transitions in men.
We studied the relationship between the speed at the gas exchange thresholds for walking and runn... more We studied the relationship between the speed at the gas exchange thresholds for walking and running and the preferred gait transition speed (PTS), and the correspondence of PTS and energetically optimal transition speed (EOTS). Twenty-two men (age: 21.4 ± 2.4 years, mass: 78.1 ± 8.2 kg) performed four tests during which we determined VO2max, walking/running gas exchange thresholds, walk-to-run/run-to-walk PTS, and EOTS. There were no significant differences (P > 0.05) between PTS, and the speed at the aerobic threshold for walking (AeTw) and running (AeTr). Both walk-to-run and run-to-walk PTS significantly correlated to AeTr (r = 0.82 and 0.79; P < 0.01) but not to AeTw (r = -0.03 and 0.06; P > 0.05). Finally, EOTS and the corresponding VO2 were significantly higher (P < 0.05) than the speed and VO2 at PTS. Our results indicate that running rather than walking dynamics determines gait transitions in men.
The studies exploring the influence of resistance training on endurance in men have produced inco... more The studies exploring the influence of resistance training on endurance in men have produced inconsistent results. The aim of this study was to examine the influence of an Olympic weight lifting training programme on parameters of aerobic and anaerobic endurance in moderately physically active men. Eleven physical education students (age: 24.1 +/- 1.8 yr, height: 1.77 +/- 0.04 m, body mass: 76.1 +/- 6.4 kg; X +/- SD) underwent a 12-week, 3 times/wk training programme of Olympic weight lifting. Specific exercises to master the lifting technique, and basic exercises for maximal strength and power development were applied, with load intensity and volume defined in relation to individual maximal load (repetitio maximalis, RM). Parameters of both, aerobic and anaerobic endurance were estimated from gas exchange data measured during a single incremental treadmill test to exhaustion, which was performed before, and after completion of the 12-wk programme. After training, there was a small, but significant increase in body mass (75.8 +/- 6.4 vs. 76.6 +/- 6.4, p &amp;amp;lt; 0.05) and peak VO2 (54.9 +/- 5.4 vs. 56.4 +/- 5.3 mL O2/min/kg, p &amp;amp;lt; 0.05), with no significant change of the running speed at the anaerobic threshold (V(AT)) and at exhaustion (V(max)) (both p &amp;amp;gt; 0.05). However, there was a significant increase of anaerobic endurance, estimated from the distance run above V(AT), from V(AT) to V(max), (285 +/- 98 m vs 212 +/- 104 m, p &amp;amp;lt; 0.01). The results of this study indicate that changes in both, anaerobic and aerobic endurance due to a 12-wk period of strength training in untrained persons can be determined from a single incremental treadmill test to exhaustion. The possible causes of those training effects include several possible mechanisms, linked primarily to peripheral adaptation.
Oxidative stress is an important pathogenic factor of cancer and cardiovascular, metabolic and de... more Oxidative stress is an important pathogenic factor of cancer and cardiovascular, metabolic and degenerative diseases. On the other hand, mild oxidative stress, as in case of physical exercise, can increase the antioxidant defense system. However, the mechanisms underlying such desirable effects of mild oxidative stress are not well understood, because the production of hydroxyl radical, the most aggressive oxygen free radical, was not yet evaluated under physiological circumstances. Therefore, in this study, we evaluated the overall production of hydroxyl radical using blood samples of ten healthy male students before and 1 h after ergometry. One h before exercise, they took salicylic acid (1g) orally so that hydroxyl radical was trapped with salicylic acid, yielding a measurable reaction product, 2,3-dihydroxybenzoic acid. Oxidative stress response to exercise was also evaluated in the volunteers without premedication by measuring serum peroxides and total antioxidant capacity of serum. These parameters of oxidative stress were then correlated with physical performance of the subjects. Ergometry caused an increase of the plasma hydroxyl radical level by 37.5% (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), whereas the levels of total serum peroxides did not change significantly. Total serum antioxidant capacity, measured as uric acid equivalents, was higher after ergometry by 39.7% (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), and was in positive correlation (r = 0.81) with anaerobic threshold, an indicator of physical condition. Hence, ergometry induces hydroxyl radical production and systemic oxidative stress response in the healthy subjects. Egometry could be used to study physiological oxidative stress response and to improve antioxidant defense capacities in humans.
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