Spectral parameters of surface electromyography and performance in swim bench exercises during the training of elite and junior swimmers

Abstract

Spectral parameters of surface electromyography (EMG) are used to assess intramuscular coordination in terms of fatigue and motor unit recruitment. The aim of the present study was to examine changes in performance and EMG spectral parameters of the propulsive muscles during a swim bench exercise in swimmers to determine the intra-individual effects of different training periods in the normal training process. Ten swimmers of different ages and standards were investigated in a longitudinal study. Electromyograms of the relevant muscles (triceps longum, triceps lateralis, and latissimus dorsi) were recorded during the tests, and spectral parameters calculated using time-variant spectral analysis. In the elite swimmers, we observed variation in performance throughout the training season with respect to training load, whereas for the junior swimmers there was a trend to improve performances irrespective of training load. Correlations with performance were observed for the median frequencies of the triceps longus for the elite athletes. Performances and frequencies were increased in the taper period, whereas they were reduced after periods of high training loads. For the junior swimmers, no such correlations were observed. Based on our results, spectral parameters could provide information about the fatigue of the neuromuscular system of elite swimmers during periods of high training loads and enhanced intramuscular coordination in the taper period before competition.