Evaluation of signal-to-noise ratios of practical neuromuscular tests

Abstract

Aim: Although several tests have been used for monitoring neuromuscular function, their sensitivity to fatigue in athletes of team-based sports remains inconclusive. This study investigated the signal-to-noise ratio (SNR) of countermovement jump (CMJ), squat jump (SJ), sprint performance of 10 and 30 m (Sp-10 m; and Sp-30 m, respectively), and mechanical properties of sprints obtained through the MySprint app. Methods: Thirteen national rugby sevens players performed eight CMJ and SJ, and four sprint trials for baseline assessment, repeating all tests at 24-, 48-, and 72-h after a sport-specific fatigue protocol. Data analysis was performed using a linear multilevel modelling procedure through established Bayesian methods. Acceptable sensitivity was assumed for measures with SNR equal to or below -1. Results: The highest mean estimates of SNR at all moments were found in rate of force in 10 m (RF-10 m) (posterior mode: -2.15 to -2.33), followed by CMJ, SJ, Sp-30 m, maximal power output (Pmax), peak of rate of force (RFpeak), and theoretical and measured maximal horizontal velocity (V0, and Vmax), which showed similar mean values of SNR at 24-, 48-, and 72-h after exercise (posterior mode: -1.29 to -1.80). Conclusions: These results suggest that measures more specific to the task performed during the fatigue protocol showed higher sensitivity. Therefore, tests considering physiological and biomechanical determinants of rugby gestures should be used for fatigue monitoring.