The Effects Of Whole-body Vibration And Fatigue On Isometric Mid-thigh Pull

Abstract

Musculature exposed to continuous stress overtime will begin to decrease performance as a result of fatigue. However, past research has shown that Whole Body Vibration (WBV) can have a positive effect on performance by increasing motor unit recruitment. PURPOSE: The purpose of this study is to analyze the effects of WBV and Fatigue on Isometric Mid-Thigh Pull (IMTP). METHODS: Sixteen active males and females (age: 23.19 ± 2.56yr, weight: 79.05 ± 16.97kg, height: 174.36 ± 12.11cm) volunteered to participate in a 5-day study. Day 1 consisted of familiarization where participants completed an IRB approved informed consent, Health History Questionnaire, and a PARQ. Following anthropometrics measurements, participants were familiarized with all the testing protocols and interventions. Day 2-5 testing sessions consisted of a dynamic warm-up followed by pre-testing of IMTP’s. Post-tests for IMTP were taken following the completion of one of 4 conditions, each performed on separate days. Conditions consisted of C1 (No WBV-No Fatigue), C2 (WBV-Fatigue), C3 (WBV-No Fatigue), and C4 (No WBV-Fatigue) in a randomized order. Peak Force for the IMTP was measured using an AMTI Portable Force Plate. WBV was administered while performing quarter squats at a frequency of 50Hz and low amplitude on for a total of 4min with a work to rest ratio of 30s/30s. The Bosco fatigue protocol was administered to induced lower-body fatigue by having participants perform 60s of jump squats. Percent change scores were calculated between pre- and post-tests for each condition and analyzed for statistical differences between conditions. SPSS was used to run a Repeated Measures ANOVA to compare condition differences of percent change scores (%Δ). An alpha level was set at p <0.05 to determine significance. RESULTS: There were no significant (p=0.84) differences found between conditions (C1 1.25 ± 9.98 %Δ; C2= -0.79 ± 7.77 %Δ; C3= 1.53 ± 5.95 %Δ; C4= 1.32 ± 10.69 %Δ) for peak force. CONCLUSIONS: Although no significant differences were found for peak force between pre- and post-tests for IMTP, further studies need to investigate alternative ways to evaluate the effects WBV on lower-body muscular performance.