A comparison of strength and stretch interventions on active and passive ranges of movement in dancers: a randomized controlled trial.

Abstract

The majority of stretching interventional research has focused on the development of a muscle's passive range of movement (PROM). Active range of movement (AROM) refers to the functional range of movement (ROM) available to the participant and provides a better insight into the relationship between muscular antagonistic pairings. The purpose of this study was to assess the effect of 3 strengthening or stretching interventions on hip and lower limb active (AROM) and passive (PROM) ranges of movement. Thirty-nine female dance students (17 ± 0.52 years; 61.7 ± 8.48 kg; 164.4 ± 5.49 cm) volunteered. They were randomly divided into 3 groups, strength training (n = 11); low-intensity stretching (n = 13); moderate-intensity or high-intensity stretching (n = 11). Four dancers withdrew during the study. All groups carried out a 6-week intervention. The strength training group focused on end of range hip flexor strength; the low-intensity and moderate-intensity stretch group carried out a series of stretches at 3/10 and 8/10 perceived exertion, respectively. Active range of movement and PROM were measured preintervention and postintervention using 2-d video analysis. Repeated measures analysis indicated that although all 3 groups improved their PROM during the experimental period (range increase: 9-200 p < 0.01), no significant differences were found between the groups. For AROM, both the strength training and the low-intensity stretch groups revealed significant improvements in ROM (range increase: 20-300) compared with the moderate-intensity or high-intensity stretch group (p < 0.01). The present data show that interventions based on strengthening agonist muscles or decreasing the resistance of antagonist muscles through low-intensity stretching are beneficial in the development of both active and passive ranges of movement and provide functional training techniques that are often over looked in favor of the more conservative moderate-intensity stretching programs.