EMG Onset after a 10-Week Stretching Intervention: A Comparison between Older and Younger Adults

Abstract

The purpose of this study was to investigate the effect of a standardized 10-wk stretch training program on flexibility and EMG onset in older and younger adults. Subjects undertook static stretch training of the ischiocrural muscles. Data were collected using a straight leg raise test. Maximum range of motion (RoM max.) and both absolute EMG onset (EMG onset) and relative EMG onset (EMG onset-%) were recorded. Followin training, both age groups showed an increased RoM max. (°) (RoM max.-old : 86.70 ± 14.90 vs. 94.72 ± 15.65, RoM max.-young : 93.00 ± 15.44 vs. 101.40 ± 13.01). The absolute EMG onset (°) remained virtuall unchanged over the period of time (EMG onset-old : 69.19 ± 5.21 vs. 70.67 ± 4.83, EMG onset-young : 68.66 ± 17.86 vs. 68.84 ± 18.13). The relative EMG onset-% (%) decreased in both age groups (EMG onset-%-old : 77.30 ± 11.64 vs. 71.79 ± 6.07, EMG onset-%-young : 74.33 ± 16.57 vs. 68.24 ± 17.03). Overall, the results showed no difference based on age in the change in flexibility or EMG onset after a long-term stretch training. Both the younger and older age groups benefited to the same extent from the 10-wk stretching intervention. Although flexibility did increase, the absolute EMG onset remained relatively similar over the intervention period. Therefore, it can be assume that EMG onset has no effect on flexibility.