Nonlinear parameters and variability in competitive swimming

Abstract

Background: Linear parameters such as swimming kinematics have been the main method of assessing and characterizing competitive swimming strokes. New tools such as approximate entropy (ApEn) and fractal analysis can be a useful approach. The aim is to find out if there are significant differences between the strokes in the nonlinear parameters.

Hypothesis: It is hypothesized that there will be significant difference between the 4 strokes in terms of their fractal properties and approximate entropy.

Method: 29 healthy competitive swimmers (Mean age= 14.8 ± 1.4 years, Mass = 56.37 ± 8.9kg, Height= 1.65 ± 0.08m) with at least 4 years of swimming experience and participating on regular basis in at least national level competitions participated in this studying. Participants performed 4 x 25m swim with different strokes for each set, namely front crawl(FR), breast stroke(BR), backstroke(BS) and butterfly stroke(FLY), at maximal effort. Kinematic data will be collected using the Swim Speedo-meter.

Results: Results shown that there are significant differences (p<0.05) in the ApEn aspect between the 4 strokes. For fractal analysis, post-hoc test shown that breast stroke is significantly different (p<0.05) from the rest. Analysis of interaction between velocity, speed fluctuation, fractal properties and ApEn showed no significant relation between each other for all the four strokes (FR: p=0.132, BS: p=0.372, BR: p=0.363, FLY: p=0.261)

Conclusion There are significant differences between the strokes in terms of speed fluctuation, ApEn and fractal properties. There is lack of significant findings regarding the interaction between velocity, speed fluctuation, ApEn and fractal dimensions. Further research can be carried out on a larger sample group for results to be conclusive.