Almost every strength athlete is familiar with the dilemma: should I train 'properly' and therefore use a weight that is nothing special? Or should I go for the more impressive weights, which means I can't make full reps? Choose the first option, advise sports scientists at the Federal University of Rio Grande do Sul. This way you'll build more strength in the long run.
The researchers will soon publish in the Journal of Strength and Conditioning Research the results of an experiment they did with 40 males in their twenties. Ten men in the control group did nothing for ten weeks; thirty men trained their biceps twice a week on a sitting curl machine.
Fifteen of the thirty men trained their biceps with a weight at which they could make full reps [FULL]. The figure below shows what Full ROM means.
The other fifteen men [PART] trained their biceps by doing only a Partial ROM. The men in the PART group trained with 10 kg heavier weights than the men in the FULL group did.
At the end of the ten weeks the maximal strength of the FULL group had increased by 26 percent. The increase in the PART group was only 16 percent. The researchers could not detect an effect on muscle mass. There was no difference in the increase in muscle thickness [MT] between the two groups.
The researchers speculate that if you train your muscles with full reps they 'recruit' more muscle fibres for this, and therefore the training effect is greater. Another possibility is that full reps lead to better circulation of blood in the muscle, and therefore also to a better supply of oxygen and nutrients.
J Strength Cond Res. 2011 Oct 24. [Epub ahead of print].