title: Musculoskeletal adaptations to 16 weeks of eccentric progressive resistance training in young women.
abstract: We investigated the musculoskeletal adaptations and efficacy of a whole-body eccentric progressive resistance-training (PRT) protocol in young women. Subjects (n = 37; mean age, 24.3) were randomly assigned to one of 3 groups: high-intensity eccentric PRT (HRT), low-intensity eccentric PRT (LRT), or control. Subjects performed 3 sets of 6 repetitions at 125% intensity or 3 sets of 10 repetitions at 75% intensity in the HRT and LRT groups, respectively, 2 times per week for 16 weeks. Strength was determined by the concentric 1-repetition maximum (1RM) standard. Bone mass and body composition were measured by dual-energy x-ray absorptiometry (DXA). Blood and urine samples were obtained for deoxypyridinoline, osteocalcin, creatine kinase, and creatinine. Data were analyzed by repeated-measures analysis of variance with post hoc comparisons. Strength increased 20-40% in both training groups. Lean body mass increased in the LRT (0.7 +/- 0.6 kg) and HRT (0.9 +/- 0.9 kg) groups. Bone mineral content increased (0.855 +/- 0.958 g) in the LRT group only. Deoxypyridinoline decreased and osteocalcin increased in the HRT and LRT groups, respectively. These findings suggest that submaximal eccentric training is optimal for musculoskeletal adaptations and that the intensity of eccentric training influences the early patterns of bone adaptation.
authors.affiliation: Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California 90089, USA. eschroed@usc.edu
authors.forename: E Todd
authors.initials: ET
authors.lastname: Schroeder
authors.forename: Steven A
authors.initials: SA
authors.lastname: Hawkins
authors.forename: S Victoria
authors.initials: SV
authors.lastname: Jaque
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000293:injuries / Q000378:metabolism / Q000502:physiology*; D009140:Musculoskeletal Diseases / Q000517:prevention & control*; D010806:Physical Education and Training / Q000379:methods*
chemical_list: D015415:Biomarkers