Effect of blood lactate concentration and the level of oxygen uptake immediately before a cycling sprint on neuromuscular activation during repeated cycling sprints.

The purpose of this study was to determine whether neuromuscular activation is affected by blood lactate concentration (La) and the level of oxygen uptake immediately before a cycling sprint (preVO(2)). The tests consisted of ten repeated cycling sprints for 10 sec with 35-sec (RCS(35)) and 350-sec recovery periods (RCS(350)). Peak power output (PPO) was not significantly changed despite an increase in La concentration up to 12 mmol/L in RCS(350). Mean power frequency (MPF) of the power spectrum calculated from a surface electromyogram on the vastus lateralis showed a significantly higher level in RCS(350). In RCS(35), preVO(2) level and La were higher than those in RCS(350) in the initial stage of the RCS and in the last half of the RCS, respectively. Thus, neuromuscular activation during exercise with maximal effort is affected by blood lactate concentration and the level of oxygen uptake immediately before exercise, suggesting a cyclic system between muscle recruitment pattern and muscle metabolites.