Int J Sports Med 2007; 28(12): 1070-1076
DOI: 10.1055/s-2007-965003
Nutrition

© Georg Thieme Verlag KG Stuttgart · New York

Dietary Intake, Serum Hormones, Muscle Mass and Strength During Strength Training in 49 - 73-Year-Old Men

J. Sallinen1 , A. Pakarinen2 , M. Fogelholm3 , M. Alen4 , J. S. Volek5 , W. J. Kraemer5 , K. Häkkinen1
  • 1Department of Biology of Physical Activity and Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
  • 2Department of Clinical Chemistry, University of Oulu, Oulu, Finland
  • 3The UKK Institute, Tampere, Finland
  • 4Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland
  • 5Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT, USA
Further Information

Publication History

accepted after revision November 14, 2006

Publication Date:
11 May 2007 (online)

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Abstract

Effects of dietary intake on serum hormones, muscle cross-sectional area (CSA) and strength during strength training were studied in two groups of men: 1) strength training + nutritional counseling (n = 22, 59.1 ± 6.1 yrs), and 2) strength training (n = 23, 58.5 ± 7.1 yrs). Both groups performed strength training twice a week for 21 weeks. Counseling increased carbohydrate (p < 0.01) and fiber intake (p < 0.001) and polyunsaturated/saturated fat-ratio (p < 0.05) and decreased fat intake (p < 0.01). Muscle strength and CSA increased by 16 - 20 % and by 5.4 - 5.9 % in both groups (p < 0.001). Changes in protein content of diet correlated with the changes in the acute postexercise concentrations of total (r = 0.64, p < 0.01) and free testosterone (r = 0.54, p < 0.05) after training in the counseling group. Moreover, changes in the free testosterone responses to heavy-resistance exercise correlated with the increases in the muscle CSA (r = 0.52, p < 0.05) in the counseling group. Serum basal testosterone/sex hormone-binding globulin-ratios correlated with the body mass normalized energy (kJ/kg: r = 0.54, p < 0.001), protein (g/kg: r = 0.42, p < 0.01) and fat (g/kg: r = 0.51, p < 0.01) intake in all participants during the training. The data indicate that protein and fat intake may influence serum testosterone concentrations and that the changes in exercise-induced testosterone responses may contribute to muscle mass development during strength training.