The purpose of this study was to determine the relationships between swimming speed (SS), stroke length (SL), and stroke frequency (SF) for competitive single-arm amputee front crawl swimmers and assess their relationships with anthropometric characteristics. Thirteen highly trained swimmers (3 male, 10 female) were filmed underwater from a lateral view during seven increasingly faster 25-m front crawl trials. Increases in SS (above 75% of maximum SS) were achieved by a 5% increase in SF, which coincided with a 2% decrease in SL. At SSmax, interswimmer correlations showed that SF was significantly related to SS (r = .72; p < .01) whereas SL was not. Moderate but nonsignificant correlations suggested that faster swimmers did not necessarily use longer and slower strokes to swim at a common submaximal speed when compared with their slower counterparts. No correlations existed between SL and any anthropometric characteristics. Biacromial breadth, shoulder girth, and upper-arm length all significantly correlated with the SF used at SSmax. These findings imply that as a consequence of being deprived of an important propelling limb, at fast swimming speeds SF is more important than SL in influencing the performance outcome of these single-arm amputee swimmers.
Conor D. Osborough, Carl J. Payton and Daniel J. Daly
Carl J. Payton, James G. Hay and David R. Mullineaux
The aim of this study was to predict the effect of body roll on hand speed and hand path during the pull phase in front crawl swimming. An earlier three-segment model (Hay, Liu, & Andrews, 1993) was developed to enable the hand to move out of the plane through the shoulder parallel to the sagittal plane of the rotating trunk. Elbow flexion, shoulder abduction, and body roll angular velocities were modeled as sine or cosine functions. For a given elbow flexion, an increase in maximum body roll from 45° to 60° produced a marked increase in medial hand motion. For a given body roll, an increase in maximum elbow flexion from 60° to 90° increased medial hand motion and reduced downward hand motion. An increase in body roll increased hand speed in the plane perpendicular to the swimming direction, thus increasing the potential of the hand to develop propulsive lift forces.