U.S. Sports Academy
Authors: Ashley Calvillo1, Guillermo Escalante2, and Morey J. Kolber3
1Los Angeles Sunset Department of Physical Therapy, Kaiser Permanente, Los Angeles, CA, USA
2Department of Kinesiology, California State University- San Bernardino, San Bernardino, CA, USA
3Department of Physical Therapy, Nova Southeastern University, Fort Lauderdale, FL, USA
Guillermo Escalante, DSc, MBA, ATC, CSCS*D, CISSN
California State University- San Bernardino
Department of Kinesiology
5500 University Parkway
San Bernardino, CA 92407
(909) 537-7085 fax
Ashley Calvillo, PT, DPT, OCS is a physical therapist at Kaiser Permanente- Sunset in Los Angeles where she focuses on treatment of orthopedic injuries. Her research interests are in the areas of orthopedic physical therapy.
Guillermo Escalante, DSc, MBA, ATC, CSCS*D, CISSN is a Dean Fellow for the College of Natural Sciences and an Associate Professor of Kinesiology at California State University- San Bernardino in San Bernardino, CA. His research interests focus on body composition, improving muscle strength/hypertrophy/sports performance, sports injury prevention/rehabilitation, and sports nutrition.
Morey J. Kolber, PT, PhD, OCS, CSCS*D is a professor of physical therapy at Nova Southeastern University in Fort Lauderdale, FL. His research interests are in orthopedics, diagnostic imaging, and regenerative medicine.
The relationship between hip extensor strength and contralateral and ipsilateral hip flexor muscle length in healthy men and women
This study investigated the relationship between hip extensor (HE) strength to contralateral and ipsilateral hip flexor muscle length. Bilateral hip extension range of motion (ROM) was evaluated using the modified Thomas test using a hand-held goniometer in seventeen males (26 ± 7 yrs, 174.9 ± 6.72 cm, 79.4 ± 7.9 kg) and twenty-seven females (24 ± 2 yrs, 162.7 ± 6.40 cm, 67.2 ± 13.1 kg). Participants were classified as: a) restricted hip flexors (hip extension ROM > 6° from horizontal), b) neither restricted nor normal hip flexors (hip extension ROM between 0° to 6° from horizontal), and c) normal hip flexors (hip extension ROM < 0° from horizontal). Peak isometric HE force was obtained via a Biodex dynamometer where maximum voluntary contraction (MVC) was determined. Correlations were used to determine the relationship between flexor length to contralateral and ipsilateral HE relative strength. A One-way ANOVA was used to examine HE relative strength in relation to hip flexor length classified as restricted vs neither vs normal. There were no correlations between right hip flexor length and contralateral HE strength (r = -0.228, p = 0.137), right hip flexor length and ipsilateral HE strength (r = -0.241, p = 0.115), left hip flexor length and contralateral HE strength (r = -0.193, p = 0.210), and left hip flexor length and ipsilateral HE strength (r = -0.111, p = 0.472). The One-way ANOVA revealed no significant differences between the groups for the most restricted hip flexor and contralateral HE relative strength (p = 0.179) nor for the most restricted hip flexor and ipsilateral HE relative strength (p = 0.670). No significant relationships were found between HE strength and contralateral or ipsilateral hip flexor length. Although it is commonly suggested that practitioners address hip flexor length to assist with improving gluteal muscle strength, the results of this study do not validate this clinical practice. Despite the results indicating no correlations, practitioners are encouraged to address these impairments from both a functional and performance based perspective.