The acute effect of local vibration as a recovery modality from exercise-induced increased muscle stiffness

Exercise involving eccentric muscle contractions is known to decrease range of motion and increase passive muscle stiffness. this study aimed at using ultrasound shear wave elastography to investigate acute changes in biceps brachii passive stiffness following intense barbell curl exercise involving both concentric and eccentric contractions. the effect of local vibration (lv) as a recovery modality from exercise-induced increased stiffness was further investigated. eleven subjects performed 4 bouts of 10 bilateral barbell curl movements at 70% of the one-rep max-imal flexion force. an arm-to-arm comparison model was then used with one arm randomly assigned to the passive recovery condition and the other arm assigned to the lv recovery condition (10 min of 55-hz vibration frequency and 0.9-mm amplitude). biceps brachii shear elastic modulus measurements were performed prior to exercise (pre),immediately after exercise (post-ex) and 5 min after the recovery period (post-rec). biceps brachii shear elastic modulus was significantly increased at post-ex (+53 ± 48%; p < 0.001) and post-rec (+31 ± 46%; p = 0.025) when compared to pre. no differences were found between passive and lv recovery (p = 0.210). lv as a recovery strategy from exercise-induced increased muscle stiffness was not beneficial,probably due to an insufficient mechan-ical action of vibrations. © journal of sports science and medicine