Abstract

Intermittent exercise with short bouts (30–500 m) of high intensity exercise (90–100% of running intensity) separated by different recovery periods (3–15 minutes) are habitually used by sprinters during training sessions (Gorostiaga et al. JSCR 2010;24:1138–1149). Repetition of sprints may induce neuromuscular fatigue (NMF). The aim of the present study was to quantify the extent of NMF while performing sprint workouts (SW) by analysing the acute metabolic and mechanical response to different SW. Nine high level sprinters (age 23±4 y, body mass 73.7±4.6 kg, height 177.6±5.9 cm; body fat 9.6±2.9%) performed eight SW separated by a week. SW with different number of repetitions (R) for each subject in short distance travelled (DT) [(x)RxDT] and SW with same number of R in long DT [3xDT]. Mechanical responses (i.e. height performance in CMJ and speed loss) and metabolic responses (i.e. blood lactate and ammonia concentrations) were measured pre-exercise, during exercise each repetition performed and post-exercise. CMJ height loss pre-post session were significant for all sprint workouts and competitions analysed and highly correlated to metabolic responses (r=0.86–0.98). These losses were between 9% for 40 m and 26% for 500 m. The fatigue, measured as CMJ height loss, increases with DT, and is strongly correlated to lactate (r=0.93) and ammonia (r=0.98). The metabolic stress developed during the effort can be estimated by controlling CMJ because of the high correlation between CMJ and blood lactate and ammonia concentrations (Jiménez-Reyes et al. MSSE 2012;44(5):582). The high correlations found between mechanical (speed and CMJ height losses) and metabolic (lactate and ammonia) measures of fatigue highlight the utility and validity of using CMJ to monitor training load in different sprint workouts and quantify objectively NMF during SW and competitions.