Ogura, Y., & Kasuga, K. (2015). The relationship between the operation of kick-start and isokinetic knee strength in swimmers. Medicine & Science in Sports & Exercise, 47(5), Supplement abstract number 1931.

This study examined the relationship between the operation of a kick-start and isokinetic knee strength in swimmers using three-dimensional (3D) analysis. Male university swimmers (N = 11) who normally used a kick-start were filmed using three high-speed cameras. Motion analysis was performed using Frame-DIASIV System (DKH) software. The 3D coordinates of 23 points on each S’s body were determined using direct linear transformation. Tests of isokinetic knee strength were performed using an isokinetic dynamometer. For each measurement, the angular velocity was set at 60, 180, and 300°/s, and repetitions were conducted 5, 10, and 15 times, respectively. In the analysis, muscle strength was divided by weight for each S.

There was a significant relationship between the average center of gravity, horizontal acceleration before take-off, and flexion muscle strength of the front knee at 60°/s (r = 0.718) and 180°/s (r = 0.636) and extension muscle strength of the rear knee at 300°/s (r = 0.500). Similarly, there was a significant relationship between the time from the start signal to take-off and flexion muscle strength of the front knee at 60°/s (r = -0.651) and 180°/s (r = -0.651) and extension muscle strength of the rear knee at 300°/s (r = -0.433).

Implication. Swimmers with high muscle strength of the front knee at flexion can obtain a high horizontal-acceleration in the acceleration phase because they can quickly move the body forward which should shorten the take-off time.

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