Sandra Shultz
University of North Carolina at Greensboro, Kinesiology, Faculty Member
Clinical femoral anteversion (Craig test) and hip range of motion (ROM) have been associated with valgus collapse, but their clinical usefulness in predicting biomechanics is unknown. Our purpose was to determine the individual and... more
Clinical femoral anteversion (Craig test) and hip range of motion (ROM) have been associated with valgus collapse, but their clinical usefulness in predicting biomechanics is unknown. Our purpose was to determine the individual and combined predictive power of femoral anteversion and passive hip ROM on 3-dimensional valgus collapse (hip internal rotation and adduction, knee rotation, and abduction) during a single-leg forward landing in females. Femoral anteversion and passive hip ROM were measured on 20 females (24.9 [4.1] y, 168.7 [8.0] cm, 63.8 [11.6] kg). Three-dimensional kinematics and kinetics were collected over 5 trials of the task. Each variable was averaged across trials. Backward, stepwise regressions determined the extent to which our independent variables were associated with valgus collapse. The combination of greater hip internal and external rotation ROM (partial r = .52 and .56) predicted greater peak knee internal rotation moment (R2 = .38, P = .02). Less hip internal rotation ROM (partial r = −.44) predicted greater peak knee abduction moments (R2 = .20, P = .05). Greater total hip ROM (internal and external rotation ROM) was not consistently associated with combined motions of valgus collapse but was indicative of isolated knee moments. Passive hip ROM is more associated with knee moments than is femoral anteversion as measured with Craig test.
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This chapter summarizes the findings and discussion focused on ACL risk factors, screening, and injury prevention from the 2015 ACL Research Retreat. Risk factors include neuromuscular, anatomical, structural, genetic, and hormonal. For... more
This chapter summarizes the findings and discussion focused on ACL risk factors, screening, and injury prevention from the 2015 ACL Research Retreat. Risk factors include neuromuscular, anatomical, structural, genetic, and hormonal. For each risk factor, the current understandings, key unknowns, and directions for future research are described. In addition, risk factor screening and injury prevention are discussed in a similar manner. A consensus statement was devised that reflects the most recent advances in this field.
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Research Interests: Sports Medicine, Plyometrics, Medicine, Physical Medicine and Rehabilitation, Physical Therapy, and 14 moreAnterior Cruciate Ligament, Sports, Emergency Medical Services, Sudden Death, Humans, Diabetes mellitus, ACL injury, Flexibility in engineering design, Athletic Training, Athletes, Spinal Cord Injuries, Hyponatremia, Athletic injuries, and Heart arrest
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Purpose Greater femoral internal rotation (via anteversion or passive hip ROM) is associated with knee biomechanics thought to contribute to anterior cruciate ligament (ACL) injury, but it is unknown if femoral internal rotation... more
Purpose Greater femoral internal rotation (via anteversion or passive hip ROM) is associated with knee biomechanics thought to contribute to anterior cruciate ligament (ACL) injury, but it is unknown if femoral internal rotation contributes to actual ACL injury occurrence. The objective of this systematic review and meta-analysis was to quantify the extent to which femoral anteversion and hip range of motion (ROM) influence knee biomechanics consistent with ACL injury and actual ACL injury occurrence. Methods Using PRISMA guidelines, PubMed, CINAHL, SportDiscus, and Scopus databases were searched. Inclusion criteria were available passive hip ROM or femoral anteversion measure, ACL injury OR biomechanical analysis of functional task. Two reviewers independently reviewed titles, abstracts, and full texts when warranted. Included studies were submitted to Downs & Black Quality Assessment Tool. Meta-analyses were conducted for comparisons including at least two studies. Results Twenty-...
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ContextTemporal prediction of the lower extremity (LE) injury risk will benefit clinicians by allowing them to better leverage limited resources and target those athletes most at risk.ObjectiveTo characterize the instantaneous risk of LE... more
ContextTemporal prediction of the lower extremity (LE) injury risk will benefit clinicians by allowing them to better leverage limited resources and target those athletes most at risk.ObjectiveTo characterize the instantaneous risk of LE injury by demographic factors of sex, sport, body mass index (BMI), and injury history.DesignDescriptive epidemiologic study.SettingNational Collegiate Athletic Association Division I athletic program.Patients or Other ParticipantsA total of 278 National Collegiate Athletic Association Division I varsity student-athletes (119 males, 159 females; age = 19.07 ± 1.21 years, height = 175.48 ± 11.06 cm, mass = 72.24 ± 12.87 kg).Main Outcome Measure(s)Injuries to the LE were tracked for 237 ± 235 consecutive days. Sex-stratified univariate Cox regression models were used to investigate the association between time to first LE injury and sport, BMI, and LE injury history. The instantaneous LE injury risk was defined as the injury risk at any given point in...
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Research Interests: Medicine and Muscle mass
Anterior tibial translation (ATT) loads the anterior cruciate ligament (ACL) as the knee transitions from non-weight bearing (NWB) to weight bearing (WB). Therefore, any factors able to effectively reduce ATT during initial WB would... more
Anterior tibial translation (ATT) loads the anterior cruciate ligament (ACL) as the knee transitions from non-weight bearing (NWB) to weight bearing (WB). Therefore, any factors able to effectively reduce ATT during initial WB would theoretically reduce ACL loading. This study evaluated the extent to which hamstring musculo-articular stiffness (KHAM) is associated with ATT as the knee transitions from NWB to WB in 10 healthy females (19.9 ± 1.5 yrs, 1.65 ± 0.06 m, 62.3 ± 6.3 kg). Linear regression revealed that KHAM predicted 48.6% of the variance in ATT (R2 = .486, p = .025), with higher KHAM being associated with less ATT. KHAM is modifiable through training, and thus may be an important factor to consider from ACL injury prevention and rehabilitation perspectives.
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The third edition of Examination of Musculoskeletal Injuries assists both current and future rehabilitation professionals in recognizing musculoskeletal injuries, performing musculoskeletal examinations of athletic injuries, and... more
The third edition of Examination of Musculoskeletal Injuries assists both current and future rehabilitation professionals in recognizing musculoskeletal injuries, performing musculoskeletal examinations of athletic injuries, and evaluating if and when to refer clients to a physician's care. The text will help students master the skills required for completing the Board of Certification examination for athletic trainers by thoroughly covering all the content in this area of specialization set forth in the National Athletic Trainers' Association (NATA) Athletic Training Educational Competencies. Completely updated and expanded, the third edition of Examination of Musculoskeletal Injuries incorporates an increased emphasis on clinical decision making, problem solving, and integration of skill application. Revised chapter-opening scenarios present open-ended real-life situations that initiate discussion of the complexity of athletic injury examination. Review and critical thinki...
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The purpose of this study was to compare hamstring musculo-articular stiffness (MAS) and lower extremity (LE) body composition in the dominant (D) and non-dominant (ND) legs of men and women, and then to examine relationships between MAS... more
The purpose of this study was to compare hamstring musculo-articular stiffness (MAS) and lower extremity (LE) body composition in the dominant (D) and non-dominant (ND) legs of men and women, and then to examine relationships between MAS and LE body composition while controlling for sex. No differences in MAS or LE body composition were found between D and ND legs in either sex. Males demonstrated greater MAS and LE % lean mass (%LM) than females, while females had greater LE % fat mass (%FM) than males. The combination of sex and %FM explained ~60% of the variance in MAS, while ~31% of the variance could be attributed to sex alone. Findings suggest that between-sex differences may potentially mask relationships between MAS and the factors influencing this measure, highlighting the need for future sex-stratified designs.
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Context: A bias toward femoral internal rotation is a potential precursor to functional valgus collapse. The gluteal muscles may play a critical role in mitigating these effects. Objective: Determine the extent to which gluteal strength... more
Context: A bias toward femoral internal rotation is a potential precursor to functional valgus collapse. The gluteal muscles may play a critical role in mitigating these effects. Objective: Determine the extent to which gluteal strength and activation mediate associations between femoral alignment measures and functional valgus collapse. Design: Cross-sectional. Setting: Research laboratory. Patients or Other Participants: Forty-five females (age = 20.1 [1.7] y; height = 165.2 [7.6] cm; weight = 68.6 [13.1] kg) and 45 males (age = 20.8 [2.0] y; height = 177.5 [8.7] cm; weight = 82.7 [16.5] kg), healthy for 6 months prior. Intervention(s): Femoral alignment was measured prone. Hip-extension and abduction strength were obtained using a handheld dynamometer. Three-dimensional biomechanics and surface electromyography were obtained during single-leg forward landings. Main Outcome Measures: Forward stepwise multiple linear regressions determined the influence of femoral alignment on func...
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Exercising women report three to six times more ACL tears than men, which happen, in the majority of cases, with a non-contact mechanism. This sex disparity has, in part, been attributed to the differences in reproductive hormone profiles... more
Exercising women report three to six times more ACL tears than men, which happen, in the majority of cases, with a non-contact mechanism. This sex disparity has, in part, been attributed to the differences in reproductive hormone profiles between men and women. Many studies have shown that anterior knee (AK) laxity and the rate of non-contact ACL injuries vary across the menstrual cycle, but these data are inconsistent. Similarly, several studies have investigated the potential protective effect of hormonal contraceptives on non-contact ACL injuries, but their conclusions are also variable. The purpose of this systematic review and meta-analysis is to, identify, evaluate and summarise the effects of endogenous and exogenous ovarian hormones on AK laxity (primary outcome) and the occurrence of non-contact ACL injuries (secondary outcome) in women. We will perform a systematic search for all observational studies conducted on this topic. Studies will be retrieved by searching electron...
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Taylor, JB, Ford, KR, Schmitz, RJ, Ross, SE, Ackerman, TA, and Shultz, SJ. Biomechanical differences of multidirectional jump landings among female basketball and soccer players. J Strength Cond Res 31(11): 3034-3045, 2017-Anterior... more
Taylor, JB, Ford, KR, Schmitz, RJ, Ross, SE, Ackerman, TA, and Shultz, SJ. Biomechanical differences of multidirectional jump landings among female basketball and soccer players. J Strength Cond Res 31(11): 3034-3045, 2017-Anterior cruciate ligament (ACL) injury prevention programs are less successful in basketball than soccer and may be due to distinct movement strategies that these athletes develop from sport-specific training. The purpose of this study was to identify biomechanical differences between female basketball and soccer players during multidirectional jump landings. Lower extremity biomechanics of 89 female athletes who played competitive basketball (n = 40) or soccer (n = 49) at the middle- or high-school level were analyzed with 3-dimensional motion analysis during a drop vertical jump, double- (SAG-DL) and single-leg forward jump (SAG-SL), and double- (FRONT-DL) and single-leg (FRONT-SL) lateral jump. Basketball players landed with either less hip or knee, or both hip and knee excursion during all tasks (p ≤ 0.05) except for the SAGSL task, basketball players landed with greater peak hip flexion angles (p = 0.04). The FRONT-SL task elicited the most distinct sport-specific differences, including decreased hip adduction (p < 0.001) angles, increased hip internal rotation (p = 0.003), and increased relative knee external rotation (p = 0.001) excursions in basketball players. In addition, the FRONT-SL task elicited greater forces in knee abduction (p = 0.003) and lesser forces in hip adduction (p = 0.001) and knee external rotation (p < 0.001) in basketball players. Joint energetics were different during the FRONT-DL task, as basketball players exhibited less sagittal plane energy absorption at the hip (p < 0.001) and greater hip (p < 0.001) and knee (p = 0.001) joint stiffness. Sport-specific movement strategies were identified during all jump landing tasks, such that soccer players exhibited a more protective landing strategy than basketball players, justifying future efforts toward sport-specific ACL injury prevention programs.