Human Movement Science vol:29 issue:6 pages:921-931
The aims of this study were for competitive unilateral arm amputee front crawl swimmers to: (1) examine the changes in inter-arm coordination as a function of swimming speed; and the interrelationship between speed inter-arm coordination and other stroke parameters. Thirteen highly-trained swimmers (3 male, 10 female) were filmed underwater from a lateral view during seven increasingly faster 25 m front crawl trials. Stroke parameters and arm coordination were determined at 80%, 85%, 90%, 95% and 100% of SSmax. Arm coordination for both arms was quantified using an adapted version of the Index of Coordination (IdCadapt). Results showed that the IdCadapt of the amputees did not change with an increase in swimming speed up to maximum. At all speeds this conformed to the catch-up model (IdCadapt < 0%), All swimmers showed significantly more catch-up before their affected arm pull compared to their unaffected arm pull. At SSmax, the fastest swimmers used higher stroke frequencies and less catch-up before their affected arm pull, when compared to the slower swimmers. These findings imply that as a consequence of being deprived of an important propelling limb: (1) unilateral arm amputee front crawl swimmers use a different strategy for coordinating their affected arm relative to their unaffected one in maintaining the stable repetition of their overall arm stroke cycle; and (2) when sprinting, the attainment of a high stroke frequency is mainly influenced by the amount of catch-up coordination of the affected arm. Reducing the time delay before initiating the affected arm pull appears to be beneficial for successful swimming performance.