Reaction time as a possible marker for overtraining syndrome

The consequences of high training loads in combination with poor regeneration are characterised by performance decrements and fatigue in combination with other complaints as concentration problems, altered sleeping and eating patterns and negative moods. The consequences are divided into three categories: Functional overreaching (FO), non-functional overreaching (NFO) and overtraining syndrome (OTS). FO has no negative consequences for the athlete on the long term, supercompensation might even occur in some cases after a period of relative rest. The athlete suffers from NFO if recovery does not occur within some weeks. The term-OTS is used only in the most severe cases, cases in which recovery takes months up to years. Athletes can be prevented from NFO and OTS by using an objective, not manipulable, not too demanding and inexpensive marker which is practical for use in training practice. Reaction time might be such a marker. Some support for the use of reaction time as an early marker for NFO and OTS has already been found, in the sports practice as well as in sport science. More research is necessary before it can be used in practice. Until then, keeping training load and perceptions of that load in a training diary will remain the method of choice for prevention of NPO and OTS