Whole body vibration applied on upper extremities: the EMG activity to determine the optimal acceleration load

AIM: The purpose of the present study was to assess the optimal acceleration load by monitoring the EMG muscle activities of the subjects (including the pectoralis major [PM], triceps brachii [TB], anterior deltoid [DE] and flexor carpi radialis [FCR] muscle activities) that were mostly involved in maintaining the posture assumed on the plate during whole-body vibration superimposed to an isometric push-up. METHODS: During the test protocol all subjects (thirty male sport sciences students [n = 30; age, 24.4.0 ± 1.16 yr; height, 178.2 ± 2.1 cm; body mass, 74.9 ± 2.8 kg; body mass index, 21.8 ± 1.3 kg/m2])assumed an isometric push-up position and performed several trials with different acceleration loads (from 0.12 to 5.72 g). There was a 1-min pause between trials, and each trial lasted 10 s. The trial order for each subject was randomized across the accelerations. The surface EMG root mean square (EMGrms) was normalized to Maximal Isometric Voluntary Contractions (bench press and grip strength tests). RESULTS: The PM, TB, and FCR muscle activation degrees were dependent upon the acceleration load (P = 0.0001), whereas the DE muscle was not conditioned (P = 0.063) (Figure 1). The intra-day procedure reliabilities were 0.97, 0.96, 0.95, and 0.94 for the PM, DE, TB, and FCR muscles, respectively. The inter-day reliabilities were 0.97, 0.85, 0.85, and 0.78 for the PM, DE, TB, and FCR muscles, respectively. CONCLUSION: This study indicate that EMG monitoring during different acceleration loads can represent an appropriate method for identifying an individual’s vibration of stimulation when applying whole body vibration on upper extremities. Therefore, an individualized acceleration load can be prescribed similarly to exercise prescription for progressive resistance exercise in terms of load, number of repetitions, and series.