Effectiveness of TENS Unit on Quadriceps Muscular Endurance During Weight Bearing Exercise

Abstract

PURPOSE: To examine the effectiveness of TENS use on quadriceps muscular endurance during weight bearing exercise for healthy populations. METHODS: Fifteen male and fifteen female volunteers (Fifteen male and fifteen female volunteers (N = 30; AGE = 21.6 ± 3.0 yrs; HT = 172.1 ± 9.0 cm; BM = 72.8 ± 12.6 kg) provided informed consent prior to participation. In Session 1, participants height, body mass, and one repetition maximum (1-RM) for non-dominant quadriceps was assessed using a knee extension machine. In Session 2, participant’s baseline maximum repetitions of non-dominant knee extensions at 40% of 1-RM was attained. Participants were then randomly selected into three groups: EXP: TENS unit with TENS activation; CON: no TENS unit with no TENS activation; PLA: TENS unit with no TENS activation. In Session 3, EXP, CON, and PLA participants performed maximum repetitions of non-dominant leg at 40% of 1-RM on the knee extension machine. Participant characteristics were examined using ANOVA for continuous and chi-squared for categorical variables. Analysis of covariance (ANCOVA) was used to compare the change in repetitions from session 2 and session 3 between each treatment group, while controlling for baseline repetitions. Tukey Post-Hoc test was used to determine the location of significance between treatment groups. RESULTS: No significant differences were found between groups in number of repetitions achieved at baseline (p=0.703). The EXP group were able to perform significantly more repetitions (change=2.40 ± 3.27) than participants in either the CON group (change=-1.30 ± 2.31) (p=0.001) or PLA group (change=-0.20 ± 1.14) (p=0.011) when controlling for baseline repetitions. CONCLUSION: The use of TENS during weight-bearing quadriceps muscular endurance activity significantly improves the number of repetitions performed by healthy populations.