Hydrodynamic skills in young swimmers : repeatability of some gliding tests

INTRODUCTION. Analysis conducted in swimming competitions of distances up to 400m pointed out that the first 15m play an important role for the result of the entire performance. Hence the hydrodynamic ability to glide underwater in a streamline position should not be neglected during training, especially in young competitors. AIM The purpose of this study was to identify some tests to evaluate gliding skills in young swimmers, which might be repeatable and correlated to their performances in 15m crawl and breaststroke. MATERIAL AND METHODS Fifteen males (M, mean±SD, age 16.5±1.9 years, height 180±8 cm, body mass 69.3±11.3 kg) and sixteen females (F, mean±SD, age 15.6±1.5 years, height 170±6 cm, body mass 57.4±6.3 kg) at national level were tested. After familiarisation, participants were positioned on a starting block and asked to dive and swim for 15m crawl (CR) and 15m breaststroke (BR) in two different trials. Later subjects underwent a series of hydrodynamic tests such as: diving and gliding underwater in a streamline position for 8m (DG), pushing off from the wall and gliding underwater in a streamline position for 8m (PG), pushing off from the wall, gliding and swimming crawl for 12.5m (PGC), pushing from the wall, gliding and swimming breaststroke for 12.5m (PGB), sculling while floating on the back for 10m (SC). Time was recorded and all tests were repeated five times on the same day and again on a different day to assess their repeatability. RESULTS Repeatability was assessed through intraclass correlation coefficient (ICC: DG=0.90 vs 0.84, PG=0.89 vs 0.88, PGC=0.85 vs 0.81, PGB=0.88 vs 0.76, SC=0.84 vs 0.63, M and F respectively). M performed significantly better than F in all trials (mean±SD, CR=6.16±0.4 vs 6.88±0.2 s, BR=7.74±0.4 vs 8.58±0.5 s, DG=2.16±0.3 vs 2.61±0.2 s, PG=4.10±0.6 vs 4.62±0.6 s, PGC=5.27±0.2 vs 6.06±0.2 s, PGB=7.07±0.4 vs 8.08±0.5 s, SC=9.52.±0.7 vs 10.60±0.6 s , p<0.02, M and F respectively). Tests significantly correlated with both CR (CR vs DG r=0.83, CR vs PG r=0.68, CR vs PGC r=0.93, CR vs PGB r=0.76, p<0.01) and BR (BR vs DG r=0.77, BR vs PG r=0.67, BR vs PGC r=0.84, BR vs PGB r=0.83, p<0.01) performances. CONCLUSIONS The tests carried out on the groups were repeatable and the male group performed better than the female group. According to the literature, these gliding tests correlated well with the performance in 15m crawl and breaststroke, factors which highly influence the results in sprint competitions.