Effects of Stretching on Strength of Proximal and Distal Group of Muscles - A Comparative Study

OBJECTIVE: To compare the effects of 2, 4, and 8 min of static stretching (SS) on isometric maximum voluntary contraction (MVCF) force between proximal (Hamstrings) and distal group (Calf) of muscles.

DESIGN: Two-group pretest-posttest experimental design. METHODS: Each subject visited the Rehabilitation center on three days: On day-I for static stretching for 2 minutes (SS2), day-II for 4 minutes (SS4), and day-III for 8 minutes (SS8). Isometric Maximum Voluntary Contraction Force (MVCF) measurement was done prior (Pre), 0-min, 10-min, and 20-min post-intervention (i.e. stretching). Each visit was separated by a gap of at least 3-4 days. On each visit, each subject underwent (a). Pre-intervention evaluation, (b). Intervention, (c). Post-intervention evaluation. Subjects performed stretching exercises under the supervision of expert Physical Therapist. The outcome assessor who was kept blind to study protocol did all measurements.

Inclusion criteria

For group A: subjects performed active knee extension test and those lacking at least 20 degrees of active knee extension range, with hip in 90 degree of flexion were selected. For group B (Calf): Subjects performed active foot dorsiflexion in long sitting position with back supported against the wall and those having not more than 20-degree range of motion were selected.

Selected subjects used to engage in 1-5 hours of regular physical activity per week (recreationally active) that does not involve stretching exercise

Exclusion criteria

Subjects reporting any current or ongoing neuromuscular disease, injury specific to lower limb joints, any apparent limit in knee or ankle ROM and competitive/professional athletes were excluded from study.