Gender Differences During an Overhead Squat Assessment

Research Review: Sex Differences During an Overhead Squat Assessment

By Joshua Saxton BESSEP, ESSAM, AEP, AES

Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Mauntel, T. C., Post, E. G., Padua, D. A. and Bell, D. R. (2015). Sex differences during an overhead squat assessment. Journal of Applied Biomechanics, 31(4), 244-249.

Why the Study is Relevant: The overhead squat assessment (OHSA) is used to identify common deviations from optimal motion. Some research suggests that deviations from optimal motion may increase the risk of injury (1-3); however, research has also demonstrated that injury rates between men and women may differ (4-7). In this 2015 study, researchers investigated whether gender differences were observed during the OHSA ; results demonstrated significant differences in hip and ankle range of motion. Human movement professionals should carefully assess men and women, and expect that interventions will differ for each group, even in team and class settings.

Caption: Dr. Brent Brookbush teaches the sign "Posterior Pelvic Tilt" during a lecture on the Overhead Squat Assessment

OHSA with Modification (Heel Rise)

Study Summary

Study Design	Comparative study
Level of Evidence	III - Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies and case-control studies
Subject Characteristics	The participants were selected from a cohort gathered by Stiffler et al. (9). Gender: 70 female, 30 male were initially chosen this was refined to 21 matched pairs (matched by BMI (24.16±1.98) and Tegner Activity Level Scale (6.05±1.20)) Scored ≥4 on the Tegner Activity Level Scale(0 = sedentary, 10 competes in elite sport) (4) Self-reported to be in good health Exclusion Criteria: Current lower limb/lower back pain Pain within the last 6 months that led to 3 or more consecutive days of missed activity Lower limb/lower back surgery
Methodology	Participants performed 5 overhead squats in succession (feet shoulder width, toes forward, heels on floor, arms extended overhead). Participants were instructed to squat in a deep, slow and controlled manner. An overhead squat was considered a successful test when the participant performed the squat while maintaining: head facing forward arms extended overhead heels on the floor appropriate speed fluid movement
Data Collection and Analysis	An electromagnetic tracking system controlled by MotionMonitor software was used with a nonconductive platform to quantify lower limb kinematics. Electromagnetic sensors were placed on the C7 spinous process, sacrum, lateral aspect of the thigh and the anteromedial aspect of the proximal tibia. The passive and active range of motion was assessed using standard goniometer protocols for dorsiflexion, hip internal and external rotation, and hip abduction. This was performed in addition to the OHS assessment and was conducted on the dominant leg.
Outcome Measures	The following were assessed and compared: Peak joint angles Peak normalized ground reaction forces and internal joint moments Range of motion (single joint goniometry) In relation to: Knee flexion Knee valgus moment Knee internal rotation Hip flexion Hip adduction Hip internal rotation Trunk flexion Trunk lateral flexion
Results	Significant differences between matched pairs of participants were noted in Peak knee valgus (Males -12.62 ± 11.00, Females -4.86 ± 4.12), Peak hip flexion angle (Males -117.02 ± 9.88, Females -105.19 ± 13.69) Normalized peak vertical ground reaction forces (males 0.67 ± 0.07, females 0.62 ± 0.06) N 0.09 ± 0.02), No significant difference in peak knee flexion or internal rotation angles, peak trunk flexion or lateral flexion Significant gender difference in ankle dorsiflexion with the knee at full extension (males -0.24 ± 5.96, females 3.79 ± 5.27), and hip in both internal (males 28.78 ± 11.45, females 37.51 ± 10.76) or external rotation (males 36.92 ± 11.61, females 46.19 ± 14.70) No significant difference in peak knee flexion or internal rotation angles, peak trunk flexion or lateral flexion Significant gender difference in ankle dorsiflexion with the knee at full extension (males -0.24 ± 5.96, females 3.79 ± 5.27), and hip in both internal (males 28.78 ± 11.45, females 37.51 ± 10.76) or external rotation (males 36.92 ± 11.61, females 46.19 ± 14.70)
Our Conclusions	Significant gender specific differences in the OHSA, including differences in lower limb mechanics. Males demonstrated greater peak knee valgus angle, hip flexion angle, minimum hip flexion angles and normalized ground reaction forces; reduced active dorsiflexion angle; and normalized peak hip extension moments. Females demonstrated greater active dorsiflexion and hip internal and external rotation. A direct link between findings from the OHS assessment and vulnerability to injuries cannot be made, however further study may provide better clinical evidence.
Researchers' Conclusions	The mechanical differences noted during the OHSA are likely influenced in part by the differences observed in lower extremity ranges of motion (females exhibiting greater range of motion). Biomechanical and range of motion differences between males and females may also help to explain the discrepancies observed between male and female non-contact lower extremity injury rates.

Caption: Pictures of workshop participants practicing the Overhead Squat Assessment during Advancement in Exercise Selection

Overhead Squat Assessment during BI Live Event - Advancements in Exercise Selection

Review & Commentary:

This study adds to a body of research on the reliability, validity and utility of the overhead squat assessment (OHSA) , demonstrating that significant kinematic differences may be noted between sexes. Women generally demonstrated greater hip and ankle range of motion during the OHSA and standard goniometry . The differences in motion may contribute to our understanding of the varied rates of injury between men and women.

Strengths

Carefully matching pairs of male and female participants decreased the risk of bias from other factors including height, weight, BMI and activity level.
The exclusion criteria reduced the chance that pre-existing injuries and previous treatment would add confounding variables to the study.
The use of a large data set from the Stiffler et al. (9) study provided a large number of matched pairs, increasing the strength of the study and confidence in findings.

Weaknesses and limitations

The study did not limit findings on the OHSA to the 8 - 10 reliably observable signs used in practice. Although kinematic data using video capture software is objective and reliable, it is not necessarily reliable when determined visually by a practitioner.
The homogeneous sample (21 matched pairs) of young, healthy individuals may limit transferability of findings to other populations.
Only the dominant leg was observed. This may have resulted in the omission of asymmetries that differ between sexes.

How This Study is Important:

This study demonstrated the ability of the OHSA to identify differences in movement between men and women, and potentially relate those differences to range of motion observed using standard goniometry . Differences in peak knee valgus, peak hip flexion and ankle dorsiflexion were reliably measured, and significant differences were noted between genders.

How the Findings Apply to Practice:

Human movement professionals should consider adding the OHSA to their repertoire of assessments. This study demonstrates both reliability, and the ability of the test to identify differences between groups. As noted previously, some research suggests that deviations from optimal motion may increase the risk of injury (1-3). Further research is needed to determine reliability of the OHSA to identify impairments that may increase the risk of injury. Further, although similar corrective and rehabilitation interventions are often recommended to both genders, this study suggests that it may be necessary to adopt a gender-specific programming.

How does it relate to Brookbush Institute Content?

The findings support the Brookbush Institute’s (BI) use of the overhead squat assessment (OHSA) as an integral piece of client/patient evaluation. Further, this study demonstrates that signs on the OHSA likely relate to specific range of motion deficits and may be correlated with goniometry . The idea that specific deficits may be correlated with each sign is a cornerstone assumption of the analyses in the articles Overhead Squat Assessment: Sign of Dysfunction and Overhead Squat Assessment: Sign Clusters and Compensation Patterns ; research studies like these were considered in the development of those analyses. The BI may have to consider how gender should influence assessment and intervention development, at least resulting in sample protocols that take the differences identified in this study into consideration.

The following are sample videos from our collection of education materials on the overhead squat assessment (OHSA) :

Overhead Squat Assessment Video 1: Introduction

Overhead Squat Assessment Video 6: Knees Bow In

Overhead Squat Assessment Video 12: Lower Extremity Dysfunction

Overhead Squat Assessment Video 17: Posterior Pelvic Tilt and Inadequate Forward Lean

Bibliography:

Hewett, T. E., Myer, G. D., Ford, K. R., Heidt, R. S., Colosimo, A. J., McLean, S. G., & Succop, P. (2005). Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes A prospective study. The American journal of sports medicine, 33(4), 492-501.
Ramskov, D., Barton, C., Nielsen, R. O., and Rasmussen, S. (2015). High Eccentric Hip Abduction Strength Reduces the Risk of Developing Patellofemoral Pain Among Novice Runners Initiating a Self-Structured Running Program: A 1-Year Observational Study. Journal of orthopaedic and sports physical therapy, 45(3), 153-161
Zazulak, B. T., Hewett, T. E., Reeves, N. P., Goldberg, B., and Cholewicki, J. (2007). Deficits in neuromuscular control of the trunk predict knee injury risk. The American journal of sports medicine, 35(7), 1123-1130
Hootman, J. M., Dick, R., & Agel, J. (2007). Epidemiology of collegiate injuries for 15 sports: summary and recommendations for injury prevention initiatives. Journal of athletic training, 42(2), 311.
Cameron, K. L., Peck, K. Y., Owens, B. D., Svoboda, S. J., Padua, D. A., DiStefano, L. J., … & Marshall, S. W. (2013). Biomechanical risk factors for lower extremity stress fracture. Orthopaedic Journal of Sports Medicine, 1(4 suppl), 2325967113S00019.
Knapik, J. J., Sharp, M. A., Canham-Chervak, M., Hauret, K., Patton, J. F., & Jones, B. H. (2001). Risk factors for training-related injuries among men and women in basic combat training. Medicine and science in sports and exercise, 33(6), 946-954.
Boling, M., Padua, D., Marshall, S., Guskiewicz, K., Pyne, S., & Beutler, A. (2010). Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scandinavian journal of medicine & science in sports, 20(5), 725-730.
Leardini, A., Cappozzo, A., Catani, F., Toksvig-Larsen, S., Petitto, A., Sforza, V., Cassanelli, G. and Giannini, S., 1999. Validation of a functional method for the estimation of hip joint centre location. Journal of biomechanics, 32(1), pp.99-103.
Stiffler MR, Pennuto AP, Smith MD, Olson ME, Bell DR. Range of motion, postural alignment, and LESS score differences of those with and without excessive medial knee displacement. Clin J Sport 2015;25(1):61–66

Questions, comments, and criticisms are welcomed and encouraged -

Gender Differences During an Overhead Squat Assessment

Research Review: Sex Differences During an Overhead Squat Assessment

Bibliography:

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