The transfer of dry-land strength & power into thrust in competitive swimming

The aim was to compare the transfer of dry-land strength and power (S&P) of the shoulder into thrust in front-crawl between swimmers of different competitive levels. Four elite and six sub-elite swimmers were selected to perform a dry-land or an in-water test in random order. The dry-land S&P measurements comprised mean torque, peak torque and mean power of the shoulder rotators of the dominant and non-dominant upper-limbs that were assessed on an isokinetic dynamometer at 90°/s and 180°/s. In-water mean thrust, peak thrust and peak power were collected using an in-house customised system composed of differential pressure sensors and an underwater camera during a 25 m freestyle swim at three different paces (400 m pace, 200 m pace, all-out). There were non-significant and trivial variations in dry-land S&P between elite and sub-elite swimmers. The variations were non-significant but mostly large in the case of thrust. Correlation coefficients of elite swimmers were significantly larger than sub-elite counterparts. In conclusion, elite swimmers seem to be more efficient than sub-elite swimmers at transferring dry-land S&P into thrust.

The effects of intensity on V̇O2 kinetics during incremental free swimming

Swimming and training are carried out with wide variability in distances and intensities. However, oxygen uptake kinetics for the intensities seen in swimming has not been reported. The purpose of this study was to assess and compare the oxygen uptake kinetics throughout low-moderate to severe intensities during incremental swimming exercise. We hypothesized that the oxygen uptake kinetic parameters would be affected by swimming intensity. Twenty male trained swimmers completed an incremental protocol of seven 200-m crawl swims to exhaustion (0.05 m·s(-1) increments and 30-s intervals). Oxygen uptake was continuously measured by a portable gas analyzer connected to a respiratory snorkel and valve system. Oxygen uptake kinetics was assessed using a double exponential regression model that yielded both fast and slow components of the response of oxygen uptake to exercise. From low-moderate to severe swimming intensities changes occurred for the first and second oxygen uptake amplitudes (P ≤ 0.04), time constants (P = 0.01), and time delays (P ≤ 0.02). At the heavy and severe intensities, a notable oxygen uptake slow component (>255 mL·min(-1)) occurred in all swimmers. Oxygen uptake kinetics whilst swimming at different intensities offers relevant information regarding cardiorespiratory and metabolic stress that might be useful for appropriate performance diagnosis and training prescription.