Effects of oral creatine and resistance training on myosin heavy chain expression

Med Sci Sports Exerc. 2001 Oct;33(10):1674-81. doi: 10.1097/00005768-200110000-00010.

Abstract

Purpose: This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression.

Methods: Twenty-two untrained male subjects were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after 12 wk of heavy resistance training. PLC and CRT trained thrice weekly using three sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk, whereas PLC consumed the equal concentration of placebo.

Results: There were no significant differences for percent body fat (P > 0.05). However, for total body mass, fat-free mass, thigh volume, muscle strength, and myofibrillar protein, CRT and PLC exhibited significant increases after training when compared to CON (P < 0.05), whereas CRT was also significantly greater than PLC (P < 0.05). For Type I, IIa, and IIx MHC mRNA expression, CRT was significantly greater than CON and PLC, whereas PLC was greater than CON (P < 0.05). For MHC protein expression, CRT was significantly greater than CON and PLC for Type I and IIx (P < 0.05) but was equal to PLC for IIa.

Conclusion: Long-term Cr supplementation increases muscle strength and size, possibly as a result of increased MHC synthesis.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Analysis of Variance
  • Anthropometry
  • Body Composition
  • Creatine / administration & dosage*
  • Creatine / blood
  • Dietary Supplements*
  • Double-Blind Method
  • Gene Expression / drug effects
  • Humans
  • Male
  • Muscle Proteins / biosynthesis*
  • Muscle, Skeletal / physiology
  • Myofibrils / metabolism*
  • Myosin Heavy Chains / genetics
  • Myosin Heavy Chains / metabolism*
  • Physical Education and Training / methods*
  • RNA, Messenger / metabolism
  • Time Factors

Substances

  • Muscle Proteins
  • RNA, Messenger
  • Myosin Heavy Chains
  • Creatine