Resistance training reduces the acute exercise-induced increase in muscle protein turnover

Am J Physiol. 1999 Jan;276(1):E118-24. doi: 10.1152/ajpendo.1999.276.1.E118.


We examined the effect of resistance training on the response of mixed muscle protein fractional synthesis (FSR) and breakdown rates (FBR) by use of primed constant infusions of [2H5]phenylalanine and [15N]phenylalanine, respectively, to an isolated bout of pleiometric resistance exercise. Trained subjects, who were performing regular resistance exercise (trained, T; n = 6), were compared with sedentary, untrained controls (untrained, UT; n = 6). The exercise test consisted of 10 sets (8 repetitions per set) of single-leg knee flexion (i.e., pleiometric muscle contraction during lowering) at 120% of the subjects' predetermined single-leg 1 repetition maximum. Subjects exercised one leg while their contralateral leg acted as a nonexercised (resting) control. Exercise resulted in an increase, above resting, in mixed muscle FSR in both groups (UT: rest, 0.036 +/- 0.002; exercise, 0.0802 +/- 0.01; T: rest, 0.045 +/- 0.004; exercise, 0.067 +/- 0.01; all values in %/h; P < 0.01). In addition, exercise resulted in an increase in mixed muscle FBR of 37 +/- 5% (rest, 0.076 +/- 0.005; exercise, 0.105 +/- 0.01; all values in %/h; P < 0.01) in the UT group but did not significantly affect FBR in the T group. The resulting muscle net balance (FSR - FBR) was negative throughout the protocol (P < 0.05) but was increased in the exercised leg in both groups (P < 0.05). We conclude that pleiometric muscle contractions induce an increase in mixed muscle protein synthetic rate within 4 h of completion of an exercise bout but that resistance training attenuates this increase. A single bout of pleiometric muscle contractions also increased the FBR of mixed muscle protein in UT but not in T subjects.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Exercise / physiology*
  • Female
  • Humans
  • Male
  • Muscle Contraction / physiology
  • Muscle Proteins / metabolism*
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiology
  • Osmolar Concentration
  • Phenylalanine / blood
  • Phenylalanine / metabolism
  • Physical Education and Training*
  • Reference Values
  • Time Factors
  • Weight Lifting / physiology


  • Muscle Proteins
  • Phenylalanine