The relationship between hip extensor strength and contralateral and ipsilateral hip flexor muscle length in healthy men and women

• Published in: The sport journal p. 1
• Main Authors: Calvillo, Ashley, Escalante, Guillermo, Kolber, Morey J
• Format: Journal Article
• Language: English
• Published: Daphne United States Sports Academy 09.04.2021
• ISSN: 1543-9518

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.