Differences in morphology and force/velocity relationship between Senegalese and Italian sprinters.
In order to investigate whether the supremacy of African sprinters is related to the leg extensor force/velocity relationship or to leg morphology, two groups of elite sprinters originating respectively from Senegal (S) and Italy (I) were compared in this respect. The groups included 13 S and 15 I male sprinters. Their mean best performances over 100 m during the preceding track and field season were 10.66 (0.3) and 10.61 (0.3) s (NS), respectively. Age, height and mass were similar in the two groups. The force/velocity relationship of the leg extensors was assessed during maximal half-squats on a guided horizontal barbell with masses of 20-140 kg added on the shoulders. Leg morphology was assessed by relating the sub-ischial length to the standing height (L/H) and by measuring the inertia in the vertical (IZ in kg.cm2), antero-posterior (IY, kg.cm2) and medio-lateral (IX, kg.m2) planes. The two groups developed non-different force and power when lifting the heaviest loads. Inversely, the lighter the load, the lower the force and power developed by S, as compared to I (P<0.001). S demonstrated greater L/H (P<0.001), and 26% lower IZ (P<0.01), 15% lower IY (P=0.09), and 14% lower IX (P=0.10). These results suggest that S and I sprinters were similar as regards the muscle abilities involved in slow maximal contractions. However, S demonstrated lower values in muscle abilities related to high-speed contractions, suggesting that S sprinters had a lower percentage of fast twitch fibres. This is likely to be compensated for by the lower level of internal work due to longer and lighter legs.
Rahmani
Abderrehmane
A
Groupe de Physiologie et Biomécanique de l'Appareil Locomoteur, Faculté des Sciences et Techniques, Département STAPS, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans 9, France. arahm@univ-lemans.fr
Locatelli
Elio
E
Lacour
Jean-Rene
JR
D000328:Adult; D000349:Africa / Q000208:ethnology; D044383:Black People / Q000706:statistics & numerical data; D001824:Body Constitution / Q000208:ethnology* / Q000502:physiology*; D006801:Humans; D007558:Italy / Q000208:ethnology; D007866:Leg / Q000033:anatomy & histology / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology*; D015203:Reproducibility of Results; D012420:Running / Q000502:physiology* / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity; D013177:Sports / Q000502:physiology / Q000706:statistics & numerical data; D044465:White People / Q000706:statistics & numerical data