CHANGES IN URINARY 3-METHYLHISTIDINE, UREA-NITROGEN AND CREATININE IN THE INITIAL PERIOD OF WEIGHT TRAINING

Abstract

A study was couducted to determine the changes in urinary 3-methylhistidine (3-ME), urea-nitrogen (Urea-N) and creatinine (CR) in the initial period of weight training. The urinary excretion of 3-ME, Urea-N and CR over a 24-h period in nine human subjects was determined before and during (at one-day intervals) a weight training period of 11 days. Two periods of weight training at different work intensities were performed; experiment A (Exp. A) : three sets of 8 repetitions at 60% of maximal voluntary contraction (MVC) ; experiment B (Exp. B) : one set of 48 repetitions at 30% of MVC. Subjects in both Exp. A and Exp. B performed five kinds of weight lifting exercise (hyper extension, sit-up, bench press, leg curl, leg extension) every day during the weight training period.
The main results obtained were as follows;
1) Urine volume and urinary CR showed no clear changes in either Exp. A or Exp. B.
2) In Exp. A, urinary 3-ME increased significantly, and Urea-N tended to decrease during the weight training period. On the other hand in Exp. B, urinary Urea-N tended to increase, but the fluctuation of urinary 3-ME showed no clear tendency during the weight training period.
3) After the weight training period, girth of the chest, upper arm and thigh tended to be increased after Exp. A in comparison with those before the weight training period.
These results suggest that whole-body protein catabolism in the initial period of weight training is dependent on the aim and type of weight training.