Analysis of unusual alternative patterns of breaststroke’s technique

Introduction. Breaststroke is a continuously evolving technique. Several studies have been carried out about its biomechanics and its complex coordinative structure, in particular analyzing continuity and frequency of propulsive actions (1, 2). The aim of this study was to analyze the efficiency of some unusual alternative patterns of breaststroke’s technique generally set by trainers during the training sessions, useful in elderly swimmers, people with disabilities, rehabilitation, leisure swimming. Material and methods. Nine swimmers (mean±SD, age 15.1±1.2 years, height 172.4±3.5 cm, body mass 61.5±3.4 kg) participated in the study. Firstly subjects experienced two alternative patterns of breaststroke’s coordination: DA stroke, with a double arm stroke per stroke cycle (without breathing between the two arm strokes); DK stroke, with a double kick per stroke cycle. Then swimmers performed 25, 100 and 400 meters flat breaststroke (FB) and in the alternatives DA and DK patterns. Performances were collected and an index of efficiency (IE = velocity swim cycle length) was calculated from video recordings. We compared: the performances, the IE means for each swim distance and the IE in the three distances for each swim pattern. Results. No differences were found between FB and DA performances, whereas swimmers achieved better results in FB compared to DK pattern in all distances: 426.7±28.3 to 442.9±32.5 s in the 400m (p=.011); 94.4±8.9 to 100.9±8.7 s in the 100m (p=.00); 20.4±1.8 to 23.2±1.9 in the 25m (p=.011). Flat breaststroke showed also a higher IE in every distance both in FB-DA comparisons (25m p=.005; 100m p=.00; 400m p=.00) and in FB-DK comparisons (25m p=.003; 100m p=.008; 400m p=.00). With regard to the IE within each distance of swim, significant differences were found between: i) 400m and 25m both in FB (1.67±0.3 vs. 2.09±0.3, p=.025) and in the DK pattern (3.04±0.6 vs. 4.09±1.0, p=.014); ii) 400m and 100m in the DA pattern (3.61±0.6 vs. 3.92±0.5, p=.011). Conclusion. DA pattern is nearly as efficient as FB, whereas worse results were found in the DK pattern, perhaps due to a longer non propulsive phase per stroke (the two gliding after the two kicks). Therefore it seems that the DA pattern is more suitable when an alternative breaststroke is required, such as in elderly swimmers or people with leg disabilities. However, it should be noticed that as distance increases the lack of rhythm occurs more frequently and the maintenance of the DA pattern becomes more difficult.