Anabolic and catabolic hormones and energy balance of the male bodybuilders during the preparation for the competition

Jarek Mäestu, Alon Eliakim, Jaak Jürimäe, Ivo Valter, Toivo Jürimäe

Research output: Contribution to journalArticlepeer-review


The purpose of the study was to investigate simultaneous effects of energy balance, caloric intake, and the hormonal anabolic-catabolic balance in bodybuilders prior to competition. Fourteen male bodybuilders took part in an 11-week energy-restricted period to reduce body fat. The subjects were divided into the energyrestricted group (ERG) (n = 7), who were preparing for the competition, or the control group (CG) (n = 7) who continued to train regularly and did not change their dietary or training pattern. Participants were tested at 11 weeks (T1), 5 weeks (T2), and 3 days (T3) before competition for diet, body composition, and fasting hormonal assessment. Body mass and body fat percentage of ERG were significantly (p < 0.05) decreased during the study period. In ERG, insulinlike growth factor-1 (IGF-1) and insulin decreased significantly during the 11-week weight-reduction period (p < 0.05). Testosterone was decreased only from week 11 to week 5 (from 20.3 ± 6.0 to 18.0 ± 6.8 nmol/L). Changes in IGF-I concentration were significantly related to changes in insulin (r = 0.741), fat mass (r = 0.705), lean body mass (r = 0.696), and body mass (r = 0.652). Changes in insulin concentrations were significantly related to changes in fat mass (r = 0.630) and lean body mass (r = 0.725). These data indicate that severe energy restriction to extremely low body energy reserves decreases significantly the concentrations of 3 anabolic pathways despite high protein intake. Monitoring of insulin and IGF-1 concentration is suggested to prevent losses in muscle mass in energy-restricted conditions. Other nutritional strategies might be needed to prevent possible catabolic effect during preparation of bodybuilders to competition.

Original languageEnglish
Pages (from-to)1074-1081
Number of pages8
JournalJournal of Strength and Conditioning Research
Issue number4
StatePublished - Apr 2010


  • Anabolism
  • Energy expenditure
  • Energy intake
  • Muscle mass
  • Weight restriction


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