Monitoring Perceived Respiratory and Muscular Exertions and Physical Fitness in Young Professional Soccer Players during a 32-week Period

The aim of this study was to examine the association of perceived respiratory and muscular exertions and associated training load (TL) for monitoring changes in several aerobic fitness and neuromuscular performance parameters during 32 weeks of soccer training in young professional players. Twenty male soccer players (age=20.6±1.8 years, body height=1.80±.06 m, body mass=73.6±6.7 kg) belonging to the same reserve team of a Spanish La Liga Club participated in this study. Countermovement jump (CMJ), CMJ with arm swing, linear sprint running (over 5 m and 15 m) and an aerobic fitness running test were performed at the start of the pre-season (Test 1) and 32 weeks later (Test 2). During these eight months, after each training session and match, players rated their perceived exertion (sRPE) separately for respiratory (sRPEres) and leg musculature (sRPEmus) effort. Training load was calculated by multiplying the sRPE value by the duration of each training session or match. Accumulated training and match volume (i.e., time) and associated respiratory and muscular training loads were negatively correlated with the changes in aerobic fitness performance after 32 weeks of training (r=-.53/-.62). In addition, accumulated perceived respiratory load was negatively correlated with the changes in 15 m sprint performance (r=-.51/-.53). A high practice volume (time) and associated respiratory and leg muscular TL can impair the long-term improvement of aerobic fitness and sprint performance in professional soccer players.