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Updated: Aug 9, 2026

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
The effects of active release technique on hamstring flexibility: a pilot study
James W George1, Andrew C Tunstall, Rodger E Tepe
1Department of Research, Logan College of Chiropractic, St. Louis, MO, USA.
Objective:
The aim of this study is to determine if active release technique (ART) significantly increases hamstring flexibility in healthy male participants.
Methods:
Twenty physically active male participants with no current or previous history of lower extremity injury received ART on the origins and insertions of the hamstrings and dorsal sacral ligament. The sit-and-reach test was used before and after treatment to determine hamstring flexibility. Summary statistics were calculated, and pre and post hamstring flexibility scores were compared using a related samples t test.
Results:
There was a significant difference between the pre- and posttest groups (mean pre = 35.5 cm, df = 19, SD = 7.56; mean post = 48.3 cm, df = 19, SD = 7.07; P = .0015). All 20 participants increased their sit-and-reach scores following the application of ART.
Conclusions:
This study demonstrated that a single ART treatment increased hamstring flexibility in a group of healthy, active male participants.
