Abstract
Numerous studies have clarified that sprinters possess unique morphological characteristics of the thigh muscles compared with non-athletes. However, little evidence is available regarding the morphological differences between sprinters and rugby players. This study aimed to examine the morphological differences in the individual hamstrings and quadriceps femoris muscles between sub-elite sprinters and rugby players. Ultrasound images were acquired from the proximal, middle, and distal regions of the thigh. From the images, the anatomical cross-sectional areas were calculated for 14 sub-elite sprinters, 14 rugby players, and 14 non-athletes. The calculated anatomical cross-sectional areas were normalized to two-thirds power of the body mass, and the normalized values of all regions were averaged as those of the individual muscles. In the hamstrings, the sizes of the biceps femoris short head and semitendinosus were greater in the sprinters than in the rugby players and/or non-athletes (all p < 0.05). In contrast, in the quadriceps femoris, the sizes of the rectus femoris, vastus lateralis, and vastus intermedius were the greatest in the rugby players (all p < 0.05). In the middle region of the biceps femoris short head and the proximal-middle regions of the semitendinosus, the muscle sizes were greater in the sprinters than in the rugby players (all p < 0.05), and vice versa in the middle-distal regions of the rectus femoris (all p < 0.05). These results suggest that 1) sub-elite sprinters possess larger sizes of the biceps femoris short head and semitendinosus, whereas rugby players have larger sizes of the rectus femoris, vastus lateralis, and vastus intermedius, and 2) each of the athletes has different size distributions, especially along the lengths of BFsh, ST, and RF. The findings of the present study would be helpful for rugby players in designing training regimens aimed at enhancing sprint performance.
Highlights
Sprint running is a key component of performance in rugby [1,2]
The nACSA of the hamstrings was significantly greater in the sprinters than in the rugby players (p < 0.001, r = 0.66, 95% confidence interval (95% CI) = 0.45–0.80, %difference = 12.4%) and non-athletes (p < 0.001, r = 0.75, 95% CI = 0.52–0.88, %difference = 34.3%)
The nACSA of the quadriceps femoris was significantly greater in the rugby players than in the sprinters (p < 0.001, r = 0.69, 95% CI = 0.42–0.84, %difference = 15.9%) and non-athletes (p < 0.001, r = 0.79, 95% CI = 0.59–0.90, %difference = 32.2%)
Summary
Sprinters would be recognized as an ideal model to enhance sprint performance because they can generate a much faster running speed than other athletes [3]. It has been considered that the impressive running speed of sprinters is mainly achieved by the great joint moment of the lower limb [4]. Numerous studies have examined the morphological characteristics of sprinters to identify the muscles that are most important for achieving a high running sprint performance [4,6,7,8]. There is little information about the morphological differences between sprinters and rugby players; the muscle morphologies of sprinters have generally been compared with those of non-athletes in most studies [4,6,7,8]
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