CONTEXT: Postexercise urine lactate may be a novel biomarker of lactate production capacity during exercise. OBJECTIVE: To evaluate the reliability and utility of the urine lactate concentration after maximal swimming trials between different training protocols (6 × 50 m and 3 × 100 m) and training states (active and nonactive swimmers). MATERIALS AND METHODS: Lactate and creatinine were determined by spectrophotometry in blood and urine. RESULTS: Blood and urine lactate concentrations were correlated in-between training protocols and in participants of different training states. The reliability of the urine lactate concentration was moderate for one of the training protocols and good or moderate for the two training states. Additionally, it was lower than that of the blood lactate concentration, and did not improve after normalizing to the urine creatinine concentration. DISCUSSION AND CONCLUSION: Although promising as a biomarker of lactate production capacity, urine lactate requires further research to improve its reliability.
CONTEXT: Postexercise urine lactate may be a novel biomarker of lactate production capacity during exercise. OBJECTIVE: To evaluate the reliability and utility of the urine lactate concentration after maximal swimming trials between different training protocols (6 × 50 m and 3 × 100 m) and training states (active and nonactive swimmers). MATERIALS AND METHODS:Lactate and creatinine were determined by spectrophotometry in blood and urine. RESULTS: Blood and urine lactate concentrations were correlated in-between training protocols and in participants of different training states. The reliability of the urine lactate concentration was moderate for one of the training protocols and good or moderate for the two training states. Additionally, it was lower than that of the blood lactate concentration, and did not improve after normalizing to the urine creatinine concentration. DISCUSSION AND CONCLUSION: Although promising as a biomarker of lactate production capacity, urine lactate requires further research to improve its reliability.