Physiological and mechanical assessment of an intermittent sub-maximal field-based test in young soccer players

Aim: Monitoring the performance is important to evaluate training programmes effectiveness and to optimizing physical development. Traditionally, specific tests performed with increase velocity such as yo-yo intermittent recovery tests (Krustrup P et al. 2003) are characterized by increasing the running intensity at each stage with a decrease in the time interval between audio cues (beep) until the subject is exhausted. The aim of this study was to investigate the physiological assessment of an intermittent sub-maximal test. Methods: twenty-four male sub-elite players (age 17,5±0.6 yr, height 176.5±3.5 cm, body mass 70.5±6,9 kg), were involved in the study. The test consists of 2x25m runs at constant speed of 15 km/h, interspersed by 8 s (5+5m) of active recovery, controlled by audio signals. The total time of the test was 5 min. Performance was monitored using HR device (Polar), GPS (K-Sport) and portable lactate analyser (Nova Biomedical). Results: Heart rate was reported in absolute and relative percentage of the maximal heart rate (HRmax); HR mean 163±8 bpm, 83.0%±3.8 HRmax; HR peak 177±8 bpm, 89.9±4.2% HRmax; HR last min 174±9 bpm, 88.7±4.2% HRmax. Blood lactate concentration was 3.35±2.13 mmol/l one minute after the end of the test. Distance at SHI (speed high intensity >4.44 m/s) was 175.3±88 m and distance at MPHI (metabolic power high intensity >20 W/kg) was 329±70 m. Conclusions: This study showed that such field-based test was appropriate to investigate aerobic level of players due to the low lactate concentration occurred at the end. Additionally, HR mean obtained during the test was 83% HRmax, which is similar to the average value registered during a match (Bangsbo 1994). The practical use if this test, based on its sub-maximal nature, play a role in physiological and mechanical assessments of soccer players. Further studies are needed to investigate the test-retest reliability.