Maximal lactate steady state concentration (MLSS): experimental and modelling approaches

Abstract.

It is assumed that the maximal lactate steady state (MLSS) can be used to establish the highest workload that can be maintained over time without continual blood lactate accumulation. In untrained subjects, and in both elite and junior athletes, MLSS occurs at different blood lactate concentrations (BLC) for different exercise modes. This suggests that MLSS depends on the motor pattern of exercise and may be a function of the relationship between power output per unit muscle mass and the mass of the muscle primarily engaged in the activity. A computer model has been developed that takes account of current theories relating to the effect of exercise on BLC and to the factors that limit oxygen transport to the muscle cell. Simulations using this model support the suggestion that load per unit of engaged muscle mass accounts for task-specific levels of MLSS. Simulated differences in MLSS appear because the MLSS does not necessarily reflect the real maximal equilibrium between lactate formation and utilization, the LLSS. The higher difference between MLSS and LLSS measured in rowing ergometry compared to cycle ergometry seems to indicate a greater task sensitivity of the BLC response to given changes of exercise intensity during rowing. Whether such a difference may be relevant for a deeper understanding of task-specific training strategies remains a matter for further investigation.