Muscle power is produced by strength and speed (Power = Force x Velocity). Strength, velocity, and power can be considered having the most important influence on an athlete's performance. Previous studies showed that strength and velocity can be enhanced by means of weight training, isokinetic exercise, plyometric training, etc. Recent findings indicated that rapid muscle contraction could produce the greatest explosive power during continuous impact training (Kuo et al., 2002). According to the concept of continuous impact, the purpose of this study was to design a successive impact device attached on traditional weight training machine. The comparison of the tension variation and the muscle neuromusclar activity between the successive impact and the traditional weight exercise was done using lower limbs knee extension with six loading conditions including 3 exercise loads (25% of maximal voluntary contraction only, 25% of maximal voluntary contraction and successive impact, as well as successive impact only) and 2 contraction velocities (fast and slow). Surface electromyography (EMG) and the load cell were used to assess the function of the successive impact device. During the continuous impact exercise, the muscle neuromusclar activity was higher than the traditional weight exercise in both fast and slow movement speeds. The results revealed that the successive impact exercise had innovated higher neuromuscular activity and recruited faster motors units. Thus, the design of a successive impact device attached on the traditional weight training machine can provide better mechanism for muscle strength and power training.