Effect of concentric or eccentric weight training on the expression of heat shock proteins in m. biceps brachii of very well trained males.

Increased HSP expression in response to acute exercise is well documented in animal studies, and there is growing evidence that similar responses occur in man. In general, many human exercise studies have investigated the HSP response to low force continuous activity, while the knowledge about the HSP response to high force intermittent type of activity, like weight training, is so far sparse. In addition, most studies have used untrained subjects, and a common observation is that acute low force continuous activity in untrained individuals increases the HSP expression in these individuals. The main scope of this study was to investigate the HSP response in very well trained males subjected to longitudinal high intensity exercise, and if this response was dependent on exercise modality [i.e. eccentric (ECC) or concentric (CON) contractions]. Very well trained males performed progressive strength training consisting of either high force ECC or high force CON elbow flexions 2-3 times a week for 12 weeks. Compared with pre-exercise levels, HSP72 expression decreased by 46.1% (P<0.05) after CON contractions. GRP75 expression was unchanged after ECC or CON contractions, while ubiquitin expression decreased by 19.9% (P<0.02) after ECC contractions. These findings imply that chronic, intensive exercise may attenuate the HSP response in well-trained males.