INTRODUCTION: The aim of this study was to examine the relationship of the arm-stroke index (ASI) to some physical characteristics and performance in swimming. METHODS: The study was conducted on 36 (17 male age of; 14.6±2.1, height(cm); 167.7±11.4, weight(kg); 59.2±10.5 and 19 female age of; 14.8±1.9 height(cm); 159±7.5, weight(kg); 52.2±7.4) competitive swimmers. The subjects swam four different styles (Freestyle [FR], backstroke [BA], butterfly [FY], breaststroke [BR]) for 100 meters at their best speeds, with 15 minutes in between. for each style, the ASI was calculated by dividing the number of arm strokes by the swimming velocity in m/s. The relationship between the variables was studied through correlation analyses (Spearman). The Mann- Whitney U test was used to compare male and female swimmers. The Friedman test was used for differences between different swimming styles and Wilcoxon was used for the post-hoc evaluation. RESULTS: The hand length (cm), arm length (cm) and the hand grip (kg/f ) values of male and female swimmers were found 18.6±1.3 and 18.2±1, 66.6±4.9 and 64.9±3.6, 32.8±10.2 and 24.8±5.6 respectively. Important significant correlations of varying degrees between ASI and the physical characteristics of height (in males; r(FR)= -0.83, r(BA)= -0.84, r(BR)= -0.89; [p<0.001]), weight (in males; r(FR)= -0.96, r(FY)= -0.84, r(BR)= -0.84, in females; r(FY)= -0.78; [p<0.001]), the lengths of the arm (in males; r(BA)= -0.81, r(BR)= -0.83; [p<0.001]), hand grip (in males; r(BR)= -0.80, in females; r(BA)= -0.79; [p<0.001]). A significant decrease in ASI with age in both sexes was observed (p<0.01). Similar relationship was observed between ASI and swiming velocity (in males; r(BA)= -0.88, r(FY)= -0.86, in females; r(FR)= -0.82, r(FY)= -0.87, r(BR)= -0.86; [p<0.001]). DISCUSSION: This study shows that certain physical characteristics effect ASI, and that development of ASI is reflected in swimming velocity. It is important to note here that the mechanical effect of leg kicking must not be overlooked. Attention paid to these points in designing the training programs of competitive swimmers will play a positive role and help increase their performance levels.
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