title: Lower extremity strength and the range of motion in relation to squat depth.
abstract: The purpose of this study was to determine which variables of the range of motion (ROM) and strength of the hip, and ankle are associated with squat depth. In total, 101 healthy subjects (64 males, 37 females) participated in the study. Outcome measures consisted of the ROM of hip flexion, hip internal rotation, external rotation, ankle dorsiflexion with an extended and flexed knee joint, and strength of the hip flexor and ankle dorsiflexor. Squat depth was measured using SIMI motion analysis software. Pearson correlation was used to determine the relationship between variables and squat depth. Multiple stepwise regression analysis was performed to determine variables associated with squat depth. The multiple regression model indicated that ankle dorsiflexion with a flexed knee and the hip flexion ROM were significantly associated with squat depth in male subjects (R(2) = 0.435) and ankle dorsiflexion with an extended knee and dorsiflexor strength were significantly associated with squat depth in female subjects (R(2) = 0.324). Thus, exercises to increase the ROM of the ankle dorsiflexion, hip flexion, and dorsiflexor strength can be recommended to improve squat performance. Future studies should assess an increased ROM of the ankle dorsiflexion, hip flexion, or dorsiflexor strength effect on deep squat performance.
authors.affiliation: Kinetic Ergocise Based on Movement Analysis Laboratory, Yonsei University, Wonju, South Korea.
authors.forename: Si-Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Physical Therapy, Kinetic Ergocise Based on Movement Analysis Laboratory, College of Health Science, Yonsei University, Wonju, South Korea.
authors.forename: Oh-Yun
authors.initials: OY
authors.lastname: Kwon
authors.affiliation: Department of Physical Therapy, College of Medical Science, Jeonju University.
authors.forename: Kyue-Nam
authors.initials: KN
authors.lastname: Park
authors.affiliation: Department of Physical Therapy, Graduate School, Yonsei University, Wonju, South Korea.
authors.forename: In-Cheol
authors.initials: IC
authors.lastname: Jeon
authors.affiliation: Department of Physical Therapy, College of Tourism & Health, Joongbu University, Chungnam, South Korea.
authors.forename: Jong-Hyuck
authors.initials: JH
authors.lastname: Weon
keywords: dorsiflexion; hip flexion; range of motion; squat