Looks like the 'no pain, no gain' adage may not be so true after all. Sports scientists at Northern Arizona University have shown that workouts which lead to sore muscles are only as effective as workouts that don't do this. The study was done with strength athletes who had only just started to train.
The researchers did an experiment with 14 healthy students, who they divided into two groups. The first group started by doing nothing for three weeks; the other group started immediately on heavy strength training for the legs [Pre-trained group]. The first workout lasted five minutes, and was gradually extended throughout the preparation period. The group built up to twenty minutes of training.
After that, both groups of students trained for eight consecutive weeks, three times a week. Each session lasted twenty minutes, during which the students trained their legs using the leg-press with weights they couldn't lift by themselves, but which they could lower in a controlled fashion. This kind of eccentric movement is heavier on the muscles than regular, concentric movements.
The students who hadn't done the preparation [Naïve group] had more trouble with sore muscles during the training period. This was because their muscles were damaged. Their blood levels of the enzyme creatine kinase rose. This enzyme belongs in the muscle cells. The more creatine kinase there is in the blood, the more seriously the muscle cells are damaged.
In the eight week training period both groups of students had build up approximately the same amount of muscle mass [about 25 percent] and strength [about 7 percent] in their leg muscles.
The researchers draw two conclusions. One is that strength training schedules that prevent muscle pain and damage can be effective; the other is that the – extremely effective – eccentric forms of strength training can help keep muscles in condition in elderly people.
"If increases in muscle size and strength can be achieved independent of any symptoms of damage, chronic eccentric exercise regimes might be perfectly suited for these elderly exercise intolerant individuals because of the low energy requirements and high force-production abilities of eccentric muscle contractions", the researchers write.
J Exp Biol. 2011 Feb 15;214(Pt 4):674-9.