Monitoring the jump height as human motor system fatigue marker and in competitive cycle of basketball players

Competition and training induced physical fatigue, as an outcome of involvement in sport, has been shown to affect the motor skill execution of athletes (Aune et al., 2008). There are number of studies showing that fatigue from the frequent training sessions overload and insufficient recovery leads to overreaching and overtraining (Urhausen et al., 1995; Demorest, Landry, 2004; Main et al., 2010; Matos et al, 2010; Winsley, Matos, 2011). There are no studies to investigate jump height changes as a marker of overreaching state despite that vertical jump test is highly reliable and it is practical for use. Hypothesis: jump height changes will show general physical and mental fatigue while performing in different conditions. Aim: to determine jump changes influenced by peripheral and central nervous system fatigue and in competitive cycle of basketball players. Objectives: 1. To determine jump height changes influenced by metabolic, CNS fatigue and muscle damage; 2. To determine jump height changes in competitive cycle of basketball players. Methods: Four investigations have been made, where healthy and physically active men (n=43) have taken the part. Metabolic fatigue was caused by intermittent increasing cycling exercise untill exhaustion, followed by the measuring of jump height (immediately after the exercise, after 3 and 30 min) and blood lactate concentration (after 5 and 30 min). Muscle damage was caused by 70 drop jumps from 50 cm height platform every 20 seconds, after which the jump height, electrostimulation-induced and maximal voluntary contraction force (MVC), blood CK level and muscle soreness were measured. CNS fatigue was caused by preventing subjects from sleeping for 24 hours. The jump height, electrostimulation-induced and maximal voluntary contraction force (MVC), information processing speed and emotional state were measured in this stage. The jump height of basketball players of LKKA “Atletas” team was measured for 9 weeks at the beginning of each practice. Concentrations of blood urea and magnesium were estimated as well. Results: blood lactate level increased and jump height decreased significantly after intermittent increasing cycling exercise. There was identified significant strong correlation between relative decrease of jump height and lactate level. Jump height also decreased significantly and remained significantly decreased after 48 hours. CK level in blood increased significantly and muscle soreness appeared. Furthermore, there was a significant decrease of MVC and electrostimulation-induced force. When CNS fatigue occurred jump height didn’t change as there was a significant decrease of information processing speed and an increase of subjectively assessed fatigue by the subjects. The jump height results of basketball players changed significantly in studied period. Weak and very weak negative correlation was established between time played in competitions and change of the jump height. Conclusions: 1. A change in jump height isn‘t universal fatigue index of the human motor system, whereas it depends on the kind of physical load. The jump height can remain stable in the case of central fatigue as the jump height is greatly reduced by the metabolic fatigue, but recovers quickly (≈30–60 min). After the load that causes muscle damage jump height recovery lasts 48 hours, although a change is significantly smaller than control value than after metabolic load. 2. The avarage jump height changed significantly in 9 weeks competitive cycle of basketball players, however, individual analysis showed that there is no obvious tendency of change of the jump height. Weak correlation was established between time played in competitions and change of the jump height