Estudiante

Fast contraction velocity in resistance exercise induces greater total volume load lifted and muscle strength loss in resistance-trained men
Abstract
Objective. To compare the influence of slow and fast contraction velocities in the total volume of load lifted in a resistance training bout with free weights exercises for upper limbs, and analyze the recovery time of the maximum muscle strengthpost-exercise in resistance-trained men.
Methods. Sixteen young men, who were experienced in resistance training were randomly divided into two groups: fast contraction velocity (FCV - n = 8) and slow contraction velocity (SCV - n = 8). Both groups performed bench press and incline bench press exercises (free weights) with 4 sets of 12 repetitions maximum. There was a 50 seconds rest intervalbetween each set, and 2 minutes interval between the exercises. The contraction velocity was 6 seconds for the SCV group and 1.5 seconds for the FCV group. The total volume of load was recorded during the exercise bout, and the one repetition maximum (1RM) was evaluated before (baseline) and for 96 hours after exercise to measure the neuromuscular function.
Results. The results demonstrated that theFCV group provide a higher (p < 0.05) volume of load lifted during the exercise bout, and had a significant decline (p < 0.05) in the neuromuscular performance post-exercise, when compared to the SCV group.
Conclusion. These data suggest that besides the contraction velocity, the total volume of load lifted determines the decline of neuromuscular function post-exercise inresistance-trained men.
Key words: Contraction velocity. Neuromuscular function. Free weight exercises. Total volume of load lifted.
Introduction
Resistance training is known as an effective method to enhance neuromuscular capacity. It is greatly used by various populations in order to increase the levels of strength, power and muscular hypertrophy1,2. The magnitude of adaptive responses in the continuousprocess of training depends on how the acute variables are manipulated, which include: muscle action, intensity, volume, choice and order of exercises, rest interval between sets and exercise, contraction velocity and weekly frequency3,4.
The impact of a resistance training bout of high intensity and/or volume resistance exercise results in muscle damage caused by metabolic and mechanical factors5,6.From functional point view, the muscle damage can cause alterations in neuromuscular function, as the decrease in maximal voluntary contraction post-exercise bout7-10.
However, when recovery times between bouts are inadequate for an extended period of time, they may contribute to a substantial decline in muscular performance and may also induce an overtraining state11,12. For this reason,studies investigating the influence of the manipulation in training variables on muscle performance, contribute to the prescription and elaboration of more efficient strategies for the development of training programs with appropriate recovery time.
Among the factors mentioned above, the contraction velocity may influence the magnitude of muscle damage and decline in neuromuscular function. However,this relation is not clear since there are studies that indicate greater muscle damage in fast movement velocity8,13,14, and other studies do not corroborate with these results15,16. However, these studies reported uses isokinetic dynamometers and individuals not trained to assess the impact of the contraction velocity. In addition, the results of these studies hamper their reproduction inresistance training routines using free-weights exercises, which shows a practical limitation for the trained population.
Ide et al10 were pioneers investigating the influence of contraction velocity in a resistance training bout with free weights exercises for lower limbs in resistance-trained men, equalizing the volume by the number of repetitions maximum (RM). The authors noted that the fast...