Seven weeks of pectoralis muscle stretching does not induce non-local effects in dorsiflexion ankle range of motion

Abstract

Both an acute bout, as well as chronic static stretching (SS), can increase the joint range of motion (ROM). However, ROM increases of a non-stretched muscle (non-local) are reported following an acute SS session, and these effects have not been studied for long-term SS training. Therefore, this study aimed to investigate the effects of a comprehensive 7-week SS training program of the pectoralis muscles on ankle dorsiflexion ROM. Thirty-three healthy, physically active participants (20 male and 13 female) were assigned to either the SS (n = 18) or the control (n = 15) group. The SS group performed a 7-week SS intervention that comprised three sessions a week, including three exercises of the pectoralis muscles for 5-min each. Before and after the intervention period, the ankle dorsiflexion ROM was tested with a dynamometer. There was no significant time (p = 0.93, F1,31 = 0.008; η2 = 0.000) or time x group effect (p = 0. 56, F1,31 = 0.342; η2 = 0.011) in ankle dorsiflexion ROM, indicating no changes in ROM in the intervention as well as the control group. Although previous studies on the acute effects of stretching reported non-local increases in ROM, our study showed no such changes after 7 weeks of SS training. Consequently, if the goal is to chronically increase the ROM of a specific joint, it is recommended to directly stretch the muscles of interest.