Force-velocity relationship on a cycle ergometer and knee-extensor strength indices

Maximal anaerobic power (P-max) is often measured on a friction loaded cycle ergometer by means of an all-out exercise against a single braking force or from the force-velocity relationship. The relationship between braking force (F) and peak velocity (V) in cycling is linear: V=V-0(1-F/F-0) where V-0 and F-0 correspond to the intercepts with the velocity axis and force axis, respectively. The aim of the present paper it-as to test the hypothesis that parameter F-0 expresses strength ability. The first study (12 male volleyball players) showed significant correlations between F-0 and maximal isometric voluntary force (MVF) or maximal isometric rate of force development (MRFD) during isometric knee extension with data expressed either in absolute units (0.66 < r < 0.81, P < 0.01) or related to quadriceps muscle mass kgQ or kgQ(2/3) (0.58 < r < 0.82, 0.05 < P < 0.001). In the second study (24 male athletes), F-0 was significantly correlated with the peak torques in isokinetic Biodex knee extension at four angular velocities (0, 1.57, 3.14 and 4.19 rad . s(-1)) with the values expressed in absolute units (0.49 < r < 0.83, 0.05 < P < 0.001). When the results were related to kgQ or kgQ(2/3) the correlation coefficients increased with velocity (0.22 < r < 0.69) and were significant (0.05 < P < 0.001) except at 0 rad . s(-1). Nevertheless, the interest of the determination of F-0 in addition to P-max is questionable because similar coefficients of correlation were obtained between P-max and strength performances.