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Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone concentration.
Eur J Appl Physiol. 2006 Dec; 98(6):546-55.EJ

Abstract

We aimed to gain insight into the role that the transitory increases in anabolic hormones play in muscle hypertrophy with unilateral resistance training. Ten healthy young male subjects (21.8 +/- 0.4 years, 1.78 +/- 0.04 m, 75.6 +/- 2.9 kg; mean +/- SE) engaged in unilateral resistance training for 8 week (3 days/week). Exercises were knee extension and leg press performed at 80-90% of the subject's single repetition maximum (1RM). Blood samples were collected in the acute period before and after the first training bout and following the last training bout and analyzed for total testosterone, free-testosterone, luteinizing hormone, sex hormone binding globulin, growth hormone, cortisol, and insulin-like growth factor-1. Thigh muscle cross sectional area (CSA) and muscle fibre CSA by biopsy (vastus lateralis) were measured pre- and post-training. Acutely, no changes in systemic hormone concentrations were observed in the 90 min period following exercise and there was no influence of training on these results. Training-induced increases were observed in type IIx and IIa muscle fibre CSA of 22 +/- 3 and 13 +/- 2% (both P < 0.001). No changes were observed in fibre CSA in the untrained leg (all P > 0.5). Whole muscle CSA increased by 5.4 +/- 0.9% in the trained leg (P < 0.001) and remained unchanged in the untrained leg (P = 0.76). Isotonic 1RM increased in the trained leg for leg press and for knee extension (P < 0.001). No changes were seen in the untrained leg. In conclusion, unilateral training induced local muscle hypertrophy only in the exercised limb, which occurred in the absence of changes in systemic hormones that ostensibly play a role in muscle hypertrophy.

Authors+Show Affiliations

Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16972050

Citation

Wilkinson, Sarah B., et al. "Hypertrophy With Unilateral Resistance Exercise Occurs Without Increases in Endogenous Anabolic Hormone Concentration." European Journal of Applied Physiology, vol. 98, no. 6, 2006, pp. 546-55.
Wilkinson SB, Tarnopolsky MA, Grant EJ, et al. Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone concentration. Eur J Appl Physiol. 2006;98(6):546-55.
Wilkinson, S. B., Tarnopolsky, M. A., Grant, E. J., Correia, C. E., & Phillips, S. M. (2006). Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone concentration. European Journal of Applied Physiology, 98(6), 546-55.
Wilkinson SB, et al. Hypertrophy With Unilateral Resistance Exercise Occurs Without Increases in Endogenous Anabolic Hormone Concentration. Eur J Appl Physiol. 2006;98(6):546-55. PubMed PMID: 16972050.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone concentration. AU - Wilkinson,Sarah B, AU - Tarnopolsky,Mark A, AU - Grant,Emily J, AU - Correia,Caroline E, AU - Phillips,Stuart M, Y1 - 2006/09/14/ PY - 2006/08/28/accepted PY - 2006/9/15/pubmed PY - 2007/5/15/medline PY - 2006/9/15/entrez SP - 546 EP - 55 JF - European journal of applied physiology JO - Eur. J. Appl. Physiol. VL - 98 IS - 6 N2 - We aimed to gain insight into the role that the transitory increases in anabolic hormones play in muscle hypertrophy with unilateral resistance training. Ten healthy young male subjects (21.8 +/- 0.4 years, 1.78 +/- 0.04 m, 75.6 +/- 2.9 kg; mean +/- SE) engaged in unilateral resistance training for 8 week (3 days/week). Exercises were knee extension and leg press performed at 80-90% of the subject's single repetition maximum (1RM). Blood samples were collected in the acute period before and after the first training bout and following the last training bout and analyzed for total testosterone, free-testosterone, luteinizing hormone, sex hormone binding globulin, growth hormone, cortisol, and insulin-like growth factor-1. Thigh muscle cross sectional area (CSA) and muscle fibre CSA by biopsy (vastus lateralis) were measured pre- and post-training. Acutely, no changes in systemic hormone concentrations were observed in the 90 min period following exercise and there was no influence of training on these results. Training-induced increases were observed in type IIx and IIa muscle fibre CSA of 22 +/- 3 and 13 +/- 2% (both P < 0.001). No changes were observed in fibre CSA in the untrained leg (all P > 0.5). Whole muscle CSA increased by 5.4 +/- 0.9% in the trained leg (P < 0.001) and remained unchanged in the untrained leg (P = 0.76). Isotonic 1RM increased in the trained leg for leg press and for knee extension (P < 0.001). No changes were seen in the untrained leg. In conclusion, unilateral training induced local muscle hypertrophy only in the exercised limb, which occurred in the absence of changes in systemic hormones that ostensibly play a role in muscle hypertrophy. SN - 1439-6319 UR - https://www.unboundmedicine.com/medline/citation/16972050/Hypertrophy_with_unilateral_resistance_exercise_occurs_without_increases_in_endogenous_anabolic_hormone_concentration_ L2 - https://dx.doi.org/10.1007/s00421-006-0300-z DB - PRIME DP - Unbound Medicine ER -