Maximal lactate steady state in T53/54 wheelchair racing

The maximal lactate steady state (MLSS), a physiological state corresponding to the highest workload maintainable over time without continual blood lactate accumulation, is widely used to assess endurance performance and formulate training programs. However, currently accepted values for MLSS are based on non-disabled individuals and may be unsuitable for wheelchair racers. This study measured the blood lactate concentration (BLC) at MLSS and the corresponding load for class T53/54 wheelchair racers. Additionally, the validity of using a fixed BLC for calculating the workload at MLSS was assessed.

Nine elite T53/54 wheelchair racers (23.7 ± 4.8 years, 59.4 ± 8.6 kg, training time 4.4 ± 2.7 years) were included in a 1,500-m simulation test, a six-level incremental test, and two to five 30-min submaximal constant load tests on an out door standard 400-m track. Earlobe BLC, heart rate, and velocity were measured. MLSS represented the highest BLC with an increase of ≤ 1.0 mM during the final 20 min of the constant load tests.

The BLC at MLSS was 5.3 ± 1.1 mM. The speed measured at MLSS was significantly higher than that measured during the incremental test at BLC = 4 mM (P < 0.05), but similar to that at 5.3 mM. The rating of perceived exertion at MLSS was 12.9 ± 1.1, and the velocity at MLSS was 80.6 ± 2.5% of the maximum workload corresponding to the incremental test.

A BLC of 5.3 mM is a more accurate 'group' estimate for wheelchair racers than the four mM threshold identified in non-disabled individuals. Furthermore, this intensity corresponds to approximately 80.6% of maximal workload and a rating of perceived exertion (RPE) of 13, providing a multi-faceted, sport-specific method for prescribing training.