The effects of different training programs on the force-velocity relation and the maximum power output from the elbow flexor muscles were examined in 12 male adults. The subjects were divided into two equal groups (G30 + 100 and G30 + 0). In the G30 + 100 group, training was performed with five repetitions at 30% maximum strength (Fmax) and five isometric contractions (100% Fmax), and in the G30 + 0 group with five repetitions at 30% Fmax and five contractions with no load (0% Fmax). Training was performed 3 days a week for 11 weeks. Maximum power increased significantly in both groups after training. The power increase was significantly greater in the G30 + 100 group. Maximum strength was significantly higher only in the G30 + 100 group, while maximum velocity increased in both groups. No significant difference in strength or velocity gain was observed between the two groups. These results suggest that isometric training at maximum strength (100% Fmax) is a more effective form of supplementary training to increase power production than no load training at maximum velocity.

The effect of training with a combination of different loads (multiple-load training) on the force-velocity and force-power relationships was examined with training programs that included maximal isometric contraction (Fmax) and concentric contraction of the elbow flexor muscles. Twenty-one male college students were placed into 3 equal training groups (G(30 + 60), G(30 + 100), and G(30 + 60 + 100)) and performed multiple-load training 3 days per week for 8 weeks. The training load was a set fraction of the maximal isometric strength (% Fmax). The G(30 + 60) group performed 6 repetitions of elbow flexion at 30 and 60% Fmax. The G(30 + 100) group performed 6 repetitions at 30% Fmax and six 5-second Fmax loads. The G(30 + 60 + 100) group performed 4 repetitions at 30 and 60% Fmax and four 5-second Fmax loads. After training, Fmax and maximal velocity significantly increased (p < 0.05) in all 3 training groups. The increases in maximal power were significantly (p < 0.05) different between the G(30 + 60 + 100) group (52.9%) and the G(30 + 100) group (24.2%). These results suggest that multiple-load training programs with 4-6 repetitions are effective for improving muscle power and velocity of the elbow flexors.

The effect of aging on muscular power development was investigated by determining the forcevelocity relationship. The muscle cross-sectional area (CSA) was estimated by the thickness of the elbow flexors. The subjects were 19 elderly males aged 69.1Ϯ3.7 years old (G-70 group), 15 middle-aged males aged 50.9Ϯ3.5 years old (G-50), and 19 young males aged 21.2Ϯ1.3 years old (G-20). The G-70 group had the slowest shortening velocities under various load conditions, resulting in the lowest force-velocity relationship. The maximum values for force (Fmax), velocity (Vmax), power (Pmax), dynamic constants (a, b), and the a/Fmax ratio were determined using Hill's equation. The a/Fmax ratio determines the degree of concavity in the forcevelocity curve. The a/Fmax ratio was greatest in G-70, followed by those in G-50 and G-20, while the maximum values for force (Fmax), velocity (Vmax), and power (Pmax) were significantly lower in G-70 than in the other groups. Fmax and Pmax per CSA were lowest in G-70, and Vmax per unit muscle length was also lowest in G-70 as compared to the other age groups. The ratio of G-70/G-20 was greatest in Pmax (69.6%), followed by Fmax (75.3%) and Vmax (83.4%). However, there were no significant differences in CSA among the 3 age groups. Our findings suggest that muscle force and shortening velocity may decline gradually in the process of aging attributed to declining muscle function rather than CSA.

Toji, H., and M. Kaneko. Effect of multiple-load training on the force-velocity relationship. J. Strength Cond. Res. 18(4):792-795. 2004.-The effect of training with a combination of different loads (multiple-load training) on the force-velocity and force-power relationships was examined with training programs that included maximal isometric contraction (Fmax) and concentric contraction of the elbow flexor muscles. Twenty-one male college students were placed into 3 equal training groups (G 30 ϩ 60 , G 30 ϩ 100 , and G 30 ϩ 60 ϩ 100 ) and performed multiple-load training 3 days per week for 8 weeks. The training load was a set fraction of the maximal isometric strength (% Fmax). The G 30 ϩ 60 group performed 6 repetitions of elbow flexion at 30 and 60% Fmax. The G 30 ϩ 100 group performed 6 repetitions at 30% Fmax and six 5-second Fmax loads. The G 30 ϩ 60 ϩ 100 group performed 4 repetitions at 30 and 60% Fmax and four 5-second Fmax loads. After training, Fmax and maximal velocity significantly increased (p Ͻ 0.05) in all 3 training groups. The increases in maximal power were significantly (p Ͻ 0.05) different between the G 30 ϩ 60 ϩ 100 group (52.9%) and the G 30 ϩ 100 group (24.2%). These results suggest that multiple-load training programs with 4-6 repetitions are effective for improving muscle power and velocity of the elbow flexors.

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