Dry-land strength training vs. electrical stimulation in sprint swimming performance.

This study was undertaken to compare the effects of dry-land strength training vs. an electrical stimulation program on swimmers. Twenty-four national-level swimmers were randomly assigned to 3 groups: the dry-land strength training program (S), the electrical stimulation training program (ES), and the control (C) group. The training program lasted 4 weeks. The subjects were evaluated before the training, at the end of the training program, and 4 weeks later. The outcome values ascertained were peak torque during arm extension at different velocities (from -60 to 180°·s(-1)) using an isokinetic dynamometer and performance, stroke rate, and stroke length during a 50-m front crawl. A significant increase in swimming velocity and peak torque was observed for both S and ES at the end of the training and 4 weeks later. Stroke length increased in the S group but not in the ES group. However, no significant differences in swimming velocity between S and ES groups were observed. No significant changes occurred in the C group. Programs combining swimming training with dry-land strength or electrical stimulation programs led to a similar gain in sprint performance and were more efficient than swimming alone.

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-VO(2max)), (3) a 70-s constant exercise at intensity halfway between the v-VO(2max) 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: [Formula: see text], 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.

[Dynamics of oxygen uptake during a 100 m front crawl event, performed during competition ]. / Dynamique des réponses aérobies lors d'un 100 m nage libre, réalisé dans des conditions de compétition.

The main purpose of this study is to estimate the dynamics of oxygen uptake (VO2) during a 100 m front crawl event, performed in competition conditions. Eleven trained swimmers participated in 2 separate sessions, in a 25 m swimming pool. Maximal oxygen uptake (VO2max) was determined during a 400 m maximal event. Swimmers also performed a 100 m front crawl in competition conditions, and then, 3 tests (25, 50, and 75 m) following the pacing strategy of the 100 m event. To be free of technical constraints, VO2 was not measured during the tests, but before and just at the end of each test with a 1 min breath-by-breath method. Each post-test VO2 measurement (after 25, 50, 75, and 100 m) allows us to reconstruct the VO2 kinetics of the 100 m performance. Our results differ from previous studies in that VO2 increases faster in the first half of the race (at 50 m, VO2 ≈ 94% VO2max), reaches VO2max at the 75 m mark; then a decrease in VO2 corresponding to 7% of VO2max appears during the last 25 m. These differences are supposed to be mainly the consequences of the adoption of technical elements and a pacing strategy similar to competition conditions. In the future, these observations may lead to different considerations of the bioenergetic contributions.