Related Experiment Video
Updated: May 18, 2026

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Comparison of active stretching technique in males with normal and limited hamstring flexibility
F Ayala1, P Sainz de Baranda, M De Ste Croix
1Research Group: Musculoskeletal System, Physiotherapy and Sports. University of Murcia, Murcia, Spain. Franciscoayalarodriguez@gmail.com
Objective:
(1) to analyse the accumulative effects of a 12-week active stretching program on hip flexion passive range of motion (HF-PROM), and (2) to compare whether participants with different PROM baseline scores (normal and limited hamstring flexibility) respond in the same way to stretching.
Design:
Repeated measures design.
Setting:
Controlled laboratory environment.
Participants:
138 males were categorized according to hamstring flexibility in the unilateral passive straight-leg raise test (PSLR) and assigned to one of two groups: normal hamstring flexibility (≥80°) or limited hamstring flexibility (<80°). In each group, participants were randomly distributed into one of two treatment subgroups: (a) control or (b) active stretching. The active stretching subgroups performed 12 weeks of flexibility training, the control subgroups did not stretch.
Main Outcome Measures:
HF-PROM was determined through the PSLR test.
Results:
Both stretching subgroups significantly improved (p < 0.01) their HF-PROM from baseline. The control subgroups did not.
Conclusions:
12 weeks of an active stretching program performed 3 days per week with a daily stretch dose of 180 s improved HF-PROM in both populations (normal and limited hamstring flexibility). The stretching program was equally effective in terms of absolute improvement values for males with normal and limited hamstring flexibility.

