Comparison between swimming in clothes and swimming in swimming wear in view of physical and physiological exercise intensity in a group of children. <Articles>

軽装時の児童の水辺事故防止の観点から, Tシャツだけ及びTシャツ+長ズボンを着用した着衣泳と水着泳の間で, 泳速, ストローク頻度とストローク長, 及び心拍数を比較検討した。10名の児童を対象に, クロール, 平泳及び背泳の3泳法で25mを全力で泳がせた。その結果, 次の結論を得た。 ①クロールは水着の場合3泳法中最も速い0.69m/秒の泳速を示した。水着泳に対する着衣泳の泳速はTシャツ泳で12.2%(P<0.05), Tシャツ+長ズボン泳で26.7%(P<0.01)低下した。 ②背泳は水着の場合3泳法中最も遅い0.49m/秒の泳速を示した。水着泳に対する着衣泳の泳速はTシャツ泳で2.3%, Tシャツ+長ズボン泳で24.5%(P<0.001)低下した。 ③平泳は水着の場合3泳法中第2位の0.58m/秒の泳速を示した。水着泳に対する着衣泳の泳速はTシャツ泳で5.9%, Tシャツ+長ズボン泳で12.7%(P<0.01)低下した。 ④Tシャツ泳の泳速はクロール, 平泳, 背泳の順に高かった。Tシャツ+長ズボン泳の泳速はクロールと平泳の間に差はなかったが, 背泳はこれらより遅かった。 ⑤着衣泳の泳速の低下はクロールではストローク頻度の影響が大きく, 平泳ではストローク長の影響が大きく, 背泳では両者が影響した。 ⑥生理的運動強度としての心拍数はどの泳法においても150拍/分前後であり, 着衣泳と水着泳の間に差はなかった。The comparison of the effect of swimming in swimming wear and swimming in T-shirts or in T-shirts and pants to the swimming speed, frequency and length of strokes, and heart rate was made with a view to preventing children from drowning accidents. Ten children were allowed to devote all their energy to swim a span of 25m with the front crawl stroke, the breast stroke and the back crawl stroke. The results were as follows: (1) The front crawl stroke in swimming wear showed the fastest swimming speed of 0.69 m/s among the three swimming strokes. The swimming speed in T-shirts and in T-shirts and pants were 12.2% (p<0.05) and 26.7% (p<0.01) lower than that in swimming wear, respectively. (2) The back crawl stroke in swimming wear showed the slowest swimming speed of 0.49 m/s among the three swimming strokes. The swimming speed in T-shirts and in T-shirts and pants were 2.3% and 24.5% (p<0.001) lower than that in swimming wear, respectively. (3) The breast stroke in swimming wear showed the second swimming speed of 0.58 m/s among the three swimming strokes. The swimming speed in T-shirts and in T-shirts and pants were 5.9% and 12.7% (p<0.01) lower than that in the swimming wear, respectively. (4) In T-shirts, the descending order of the swimming speed were from the front crawl stroke to the breast stroke and the back crawl stroke. In swimming speed in T-shirts and pants, there was no difference between the front crawl stroke and the breast stroke, but the back crawl stroke was lower than those two strokes. (5) The declining tendency of swimming speed in clothes was remarkably affected by the frequency of stroke in the front crawl stroke, by the length of stroke in the breast stroke, and by both factors in the back crawl stroke. (6) The heart rate registered around 150 beats/min in any stroke. No major difference was noticed between swimming in clothes and swimming in swimming wear