2009 Studies & Research Blog

Getting the right exercises, total set number, and number of reps in your workout is going to be vital so that you see continued results.  Far too often though people overlook the factor of tempo.  How fast or how slowly you lift a given weight will have a direct influence on how you progress as well, as it will factor into the total intensity of the weight lifting program.

As you may have already found out for yourself if you’ve experimented with different tempos, lifting a weight at a much slower pace does tend to be significantly more difficult than lifting it at the typical moderate pace instead.

Recently, researchers out of the Waseda University wanted to assess tempo and the resulting hormonal responses different protocols obtained.

The design of the study was set up so that nine men would perform knee extension exercises.  On one occurrence they would perform these at a low-intensity with a clow concentric contraction, with a rate of 5:1 seconds on the concentric to eccentric phase.  

On the second occurrence they would perform similar low-intensity exercise with slow eccentric contractions, reversing the ratio to 1:5 seconds for the up and down motion.

On the third trial, they were to maintain similar timing for both the eccentric and concentric contractions, with a 3:3 ratio.  

Finally, on the fourth trial they performed high-intensity exercise at the normal velocity of 1:1 for contraction speed.

After each trial the subjects were tested for lactate concentration, plasma ephinephrine, serum growth hormone, and free testosterone levels.  

The results of the study indicated that the lactate concentration in the body was significantly higher after the 5:1 exercise compared to the 1:5 exercise.  The slow movement exercises also showed a much higher level of serum growth hormone and free testosterone concentration compared to the faster paced tempo.  One interesting thing to note was that serum cortisol level was higher after the 5:1 tempo compared with the 1:5 or 1:1 tempo.

From this data we can conclude that there are some positive muscle building correlations between performing slower weight lifting contractions, however to avoid higher cortisol levels throughout the body you would be better off not just focusing on slowing down the concentric portions of the movement.

Reference:
Goto, K, et al. (2009) Hormonal and metabolic responses to slow movement resistance exercise with different durations of concentric and eccentric actions.  European Journal of Applied Physiology. May 10.