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Growth Horm IGF Res. 2017 Feb;32:41-48. doi: 10.1016/j.ghir.2016.12.003. Epub 2016 Dec 15.

Endurance training-induced changes in the GH-IGF-I axis influence maximal muscle strength in previously untrained men.

Author information

1
Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, Al. Jana Pawla II 78, 31-571 Krakow, Poland.
2
Department of Physical Education and Corrective Gymnastics, Institute of Health Protection, The State Higher School of Vocational Education, Ul. Mickiewicza 8, 33-100 Tarnow, Poland.
3
Department of Clinical Biochemistry of Pediatric Institute, Faculty of Medicine, Jagiellonian University, Ul. Wielicka 265, 30-663 Krakow, Poland.
4
Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, Al. Jana Pawla II 78, 31-571 Krakow, Poland; Department of Nursing, Institute of Health Protection, The State Higher School of Vocational Education, Ul. Mickiewicza 8, 33-100 Tarnow, Poland.
5
Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, Al. Jana Pawla II 78, 31-571 Krakow, Poland. Electronic address: jerzy.zoladz@awf.krakow.pl.

Abstract

OBJECTIVE:

In this study we have determined the effects of 20weeks of endurance running training on the GH-IGF-I axis changes in the context of the skeletal muscle performance and physical capacity level.

DESIGN:

Before and after the endurance training program a maximal incremental exercise tests, a 1500m race and a muscle strength measurements were performed and the blood samples were taken to determine both resting as well as end-exercise serum growth hormone (GH), insulin-like growth hormone-I (IGF-I), insulin-like growth hormone binding protein-3 (IGFBP-3) and plasma interleukin-6 (IL-6) concentrations.

RESULTS:

20weeks of endurance running training improved power output generated at the end of the maximal incremental test by 24% (P<0.012), 1500m running time by 13% (P<0.012) and maximal muscle strength by 9% (P<0.02). End-exercise IGF-I/IGFBP-3 ratio was decreased by 22% after the training (P<0.04) and the magnitude of IGF-I/IGFBP-3 ratio decrease (ΔIGF-I/IGFBP-3ex) was 2.3 times higher after the training (P<0.04). The magnitude of the exercise-induced changes in IGFBP-3 concentration was also significantly higher (P<0.04) and there was a trend toward lower end-exercise IGF-I concentration (P=0.08) after the training. These changes were accompanied by a significantly higher (30%) end-exercise IL-6 concentration (P<0.01) as well as by a 3.4 times higher magnitude of IL-6 increase (P<0.02) after the training. Moreover, there were strong positive correlations between changes in resting serum IGF-I concentration (ΔIGF-Ires) and IGF-I/IGFBP-3 ratio (ΔIGF-I/IGFBP-3res) and changes in muscle strength (ΔMVC) (r=0.95, P=0.0003 and r=0.90, P=0.002, respectively).

CONCLUSIONS:

The training-induced changes in the components of the GH-IGF-I axis may have additive effects on skeletal muscle performance and physical capacity improvement.

KEYWORDS:

Insulin-like growth factor; Interleukin-6; Muscle strength; Running; Training

PMID:
28017505
DOI:
10.1016/j.ghir.2016.12.003
[Indexed for MEDLINE]

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