Atrophy/hypertrophy cell signaling in muscles of young athletes trained with vibrational-proprioceptive stimulation

Authors: Helmut Kern1,2, Laura Pelosi3, Luisa Coletto4, Antonio Musarò 3, Marco Sandri4,5, Michael Vogelauer1, Lukas Trimmel1, Jan Cvecka6, Dusan Hamar6, Josef Kovarik2, Stefan Löfler2, Nejc Sarabon7, Feliciano Protasi8, Nicoletta Adami9, Donatella Biral10, Sandra Zampieri9,11, Ugo Carraro5,9,10

Source: Neurological Research. 2011 Dec;33(10):998-1009.

Keywords: Cell signaling, Human muscle, IGF-1 muscle isoforms, Vibrational-proprioceptive stimulation

Abstract:

Objective: To compare the effects of isokinetic (ISO-K) and vibrational-proprioceptive (VIB) trainings on muscle mass and strength.
Methods: In 29 ISO-K- or VIB-trained young athletes we evaluated: force, muscle fiber morphometry, and gene expression of muscle atrophy/hypertrophy cell signaling.
Results: VIB training increased the maximal isometric unilateral leg extension force by 48.1%. ISO-K training improved the force by 24.8%. Both improvements were statistically significant (P(0.01). The more functional effectiveness of the VIB training in comparison with the ISO-K training was shown by the statistical significance changes only in VIB group in: rate of force development in time segment 0–50 ms (P,0.001), squat jump (P,0.05) and 30-m acceleration running test (P,0.05). VIB training induced a highly significant increase of mean diameter of fast fiber (z9%, P,0.001), but not of slow muscle fibers (23%, not significant). No neural cell adhesion molecule-positive (N-CAMz) and embryonic myosin heavy ; chain-positive (MHC-embz) myofibers were detected. VIB induced a significant twofold increase (P,0.05) of the skeletal muscle isoform insulin-like growth factor-1 (IGF-1) Ec mRNA. Atrogin-1 and muscle ring finger-1 (MuRF-1) did not change, but myostatin was strongly downregulated after VIB training (P,0.001). Peroxisome proliferator-activated receptor c coactivator-1a (PGC-1a) expression increased in post-training groups, but only in VIB reached statistical significance (z228%, P,0.05).
Discussion: We demonstrated that both trainings are effective and do not induce muscle damage. Only, VIB-trained group showed statistical significance increase of hypertrophy cell signaling pathways (IGF-1Ec and PGC-1a upregulation, and myostatin downregulation) leading to hypertrophy of fast twitch muscle fibers.

Affiliations:

1 Department of Physical Medicine and Rehabilitation, Wilhelminenspital, Wien, Austria
2 Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Wien, Austria
3 Department of Histology and Medical Embryology, Sapienza University of Rome, Italy
4 Venetian Institute of Molecular Medicine and Dulbecco Telethon Institute, Padova, Italy
5 Department of Biomedical Sciences, University of Padova, Italy
6 Faculty of Physical Education and Sport, Comenius University, Bratislava, Slovakia
7 University of Primorska, Science and Research Centre, Institute for Kinesilogical Research, Koper, Slovenia
8 CeSI – Department of Basic and Applied Medical Sciences; IIM – Interuniversitary Institute of Myology, University G. d’Annunzio, Chieti
9 Laboratory of Translational Myology, Interdepartmental Research Center of Myology, University of Padua,
Italy
10 Italian CNR Institute of Neuroscience, University of Padova, Italy
11 Division of Rheumatology, Department of Clinical and Experimental Medicine, University of Padova, Italy

PMID:22196751