Metabolic and respiratory adaptations during intense exercise following long-sprint training of short duration

This study aimed to determine metabolic and respiratory adaptations during intense exercise and improvement of long-sprint performance following six sessions of long-sprint training. Nine subjects performed before and after training (1) a 300-m test, (2) an incremental exercise up to exhaustion to determine the velocity associated with maximal oxygen uptake (v-VO2max), (3) a 70-s constant exercise at intensity halfway between the v-VO2max and the velocity performed during the 300-m test, followed by a 60-min passive recovery to determine an individual blood lactate recovery curve fitted to the bi-exponential time function: La(t) = La(0) + A(1)(1 - e(-gamma 1t)) + A(2)(1 - e(-gamma 2t)), and blood metabolic and gas exchange responses. The training program consisted of 3-6 repetitions of 150-250 m interspersed with rest periods with a duration ratio superior or equal to 1: 10, 3 days a week, for 2 weeks. After sprint training, reduced metabolic disturbances, characterized by a lower peak expired ventilation and carbon dioxide output, in addition to a reduced peak lactate (P < 0.05), was observed. Training also induced significant decrease in the net amount of lactate released at the beginning of recovery (P < 0.05), and significant decrease in the net lactate release rate (NLRR) (P < 0.05). Lastly, a significant improvement of the 300-m performance was observed after training. These results suggest that long-sprint training of short durations was effective to rapidly prevent metabolic disturbances, with alterations in lactate accumulation and gas exchange, and improvement of the NLRR. Furthermore, only six long-sprint training sessions allow long-sprint performance improvement in active subjects.