The effects of different training programs on the force-velocity relation and the maximum power output from the elbow flexor muscles were examined in eighteen male adults. The subjects were divided into three equal groups (G 30, G 30+0, G 30+ 100) . Training for G 30 was performed with ten repetitions at 30% P_o (P_o: maximum strength), for G30+0 with five repetitions at 30% P_o and five contractions with no load (0 % P_o), and for G 30+100 with five repetitions at 30% P_o and five isometric contractions (100% P_o) .
Maximum power was increased significantly in all groups after training. The amounts of power increase tended to be greatest for G 30+ 100, followed by G 30+0 and G 30. A significant difference was observed between G 30 + 100 and G 30 + 0. Maximum strength increased most in G 30 + 100, followed by G30 and G 30+0. The strength gain in G 30+100 was significantly greater than that in G 30. Maximum velocity increased significantly in all groups. No significant difference in velocity gain was observed between any pair of groups.
These results suggest that isometric training at maximum strength (100% P_o) appears to be a more effective form of supplementary training to increase power production than would no load training at maximum velocity.

The effects of different intensities of muscle training on the force, velocity and power relationship have been examined on human elbow flexor muscles. Twenty male subjects, 18-22 years of age, were divided into 4 different groups ; G₀, G₃₀, G₆₀, and G₁₀₀. Their training loads were prescribed by a fraction of isometric strength (P₀) measured at right angle of elbow joint : 0% P₀ (G₀ ; isotonic contraction without load), 30% P₀ (G₃₀), 60% P₀ (G₆₀), and 100% P₀ (G₁₀₀ ; isometric contraction) . The subject contracted his elbow flexors with maximum effort 10 times a day, 3 days a week for 12 weeks. The force-velocity relations and the resultant power output were determined, before and after training period, by a modified Wilkie's apparatus.
The training by maximum isotonic contraction without load (G₀) was found to be most effective for improving maximum velocity (V₀), while the isometric training improved isometric strength (P₀) most. For this, the P-V relations of these groups were specifically modified by greater velocity component (G₀) or greater force component (G₁₀₀) . The G₃₀ and G₆₀ groups showed such all-round improvements that the P-V relations shifted in parallel with those of pre-training period. The maximum power (PVmax), which calculated from P-V relationship, increased most in G₃₀, followed by G₁₀₀, G₆₀, and G₀ groups.
From these results it was concluded that the different training loads brought about specific effects on P-V relation, and that the most effective load for improving maximum power was 30% of isometric strength.