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

• Published in: Neurological research (New York) Vol. 33; no. 10; pp. 998 - 1009
• Main Authors: Kern, Helmut, Pelosi, Laura, Coletto, Luisa, Musarò, Antonio, Sandri, Marco, Vogelauer, Michael, Trimmel, Lukas, Cvecka, Jan, Hamar, Dusan, Kovarik, Josef, Löfler, Stefan, Sarabon, Nejc, Protasi, Feliciano, Adami, Nicoletta, Biral, Donatella, Zampieri, Sandra, Carraro, Ugo
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01-12-2011
• Subjects: Adult; Cell signaling; Human muscle; Humans; Hypertrophy - etiology; Hypertrophy - pathology; IGF-1 muscle isoforms; Male; Muscle Fibers, Skeletal - cytology; Muscle Fibers, Skeletal - metabolism; Muscle Proteins - genetics; Muscle Proteins - metabolism; Muscular Atrophy - etiology; Muscular Atrophy - pathology; Resistance Training - methods; Signal Transduction - physiology; Sports - physiology; Vibrational-proprioceptive stimulation; Young Adult
• ISSN: 0161-6412; 1743-1328
• DOI: 10.1179/016164110X12767786356633

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 (+9%, P<0·001), but not of slow muscle fibers (−3%, not significant). No neural cell adhesion molecule-positive (N-CAM
+
) and embryonic myosin heavy chain-positive (MHC-emb
+
) 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 γ coactivator-1α (PGC-1α) expression increased in post-training groups, but only in VIB reached statistical significance (+228%, 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-1α upregulation, and myostatin downregulation) leading to hypertrophy of fast twitch muscle fibers.