Research in Sport Medicine and Technology

The purpose of this study was to investigate the relationship between sprint performance of front-crawl swimming and muscle fascicle length in 23 male young swimmers. The sample was divided into two groups by 25-m sprint front-crawl swimming performance: 14.6-15.7 s (S1, n=11) and 15.8-17 s (S2, n=12). Muscle thickness and pennation angle and fascicle length of the Biceps Brachii (only muscle thickness) and Triceps Brachii and Vastus Lateralis and Gastrocnemius Medialis and Lateralis muscles were measured by B-mode ultrasonography. S1 had a significantly greater Vastus Lateralis, Gastrocnemius Lateralis, and Triceps Brachii muscle thickness. Pennation angle only in Triceps Brachii was significantly smaller in S1. S1 in Vastus Lateralis, Gastrocnemius Lateralis, and Triceps Brachii muscles had significantly absolute longer fascicle length and in Vastus Lateralis and Triceps Brachii muscles, had relatively (relative to limb length) longer fascicle length. There was a significant relationship between sprint performance of front-crawl and absolute and relative fascicle length in Vastus Lateralis (absolute: r = -0.49, relative: r = -0.43) and Gastrocnemius Lateralis (absolute: r = -0.47, relative: r = -0.42). It is concluded that muscle fascicle length is one of the effective factors on the sprint front-crawl swimming in young swimmers.

Youth swimming performance may be influenced by anthropometric,
physiology, and biomechanical factors. The purpose of this study was to
analyze the relationships between 50-m front-crawl swimming performance and
relevant anthropometrical (body height, body mass, body mass index, arm
span, shoulders width, thigh, leg and upper arm lengths), muscle architectural
(muscle thickness, pennation angle, and fascicle length) and biomechanical
(stroke rate, stroke length, and stroke index) parameters in male young
swimmers, with 13.86±0.86 years of age (n = 23). Multiple regression analysis
was used to examine the variance of the 50 meters front-crawl. Results indicate
that stroke index, muscle thickness of Vastus Lateralis, and stroke length
explained %89 (p < .01) of 50-m front-crawl swimming performance variability in
these young male swimmers, and stroke index was the best single predictor of
swimming performance (R2=0.519, p<0.001). To conclude, performance of
young male swimmers in the 50 meters front-crawl is determined predominantly
by biomechanical and muscle architectural factors, and must be considered
when predicting success in young swimmers