Kd. Tipton et al., MUSCLE PROTEIN-METABOLISM IN FEMALE SWIMMERS AFTER A COMBINATION OF RESISTANCE AND ENDURANCE EXERCISE, Journal of applied physiology, 81(5), 1996, pp. 2034-2038
There is Little known about the responses of muscle protein metabolism
in women to exercise. Furthermore, the effect of adding resistance tr
aining to an endurance training regimen on net protein anabolism has n
ot been established in either men or women. The purpose of this study
was to quantify the acute effects of combined swimming and resistance
training on protein metabolism in female swimmers by the direct measur
ement of muscle protein synthesis and whole body protein degradation.
Seven collegiate female swimmers were each studied on four separate oc
casions with a primed constant infusion of ring-[C-13(6)]phenylalanine
(Phe) to measure the fractional synthetic rate (FSR) of the posterior
deltoid and whole body protein breakdown. Measurements were made over
a 5-h period at rest and after each of three randomly ordered workout
s: 1) 4,600 m of intense interval swimming (SW) 2) a whole body resist
ance-training workout with no swimming on that day (RW); and 3) swimmi
ng and resistance training combined (SR). Whole body protein breakdown
was similar for all treatments (0.75 +/- 0.04, 0.69 +/- 0.03, 0.69 +/
- 0.02, and 0.71 +/- 0.04 mu mol . min(-1). kg(-1) for rest, RW, SW, a
nd SR, respectively). The FSR of the posterior deltoid was significant
ly greater (P < 0,05) after SR (0.082 +/- 0.015%/h) than at rest (0.04
5 +/- 0.006%/h). There was no significant difference in the FSR after
RW (0.048 +/- 0.004%/h) or SW (0.064 +/- 0.008%/h) from rest or from S
R. These data indicate that the combination of swimming and resistance
exercise stimulates net muscle protein synthesis above resting levels
in female swimmers.