Original articles  PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2010 June;50(2):113-20

Copyright © 2010 EDIZIONI MINERVA MEDICA

language: English

Deltoid muscle fiber characteristics in adolescent and adult wrestlers

Mandroukas A., Metaxas T., Kesidis N., Christoulas K., Vamvakoudis E., Stefanidis P., Heller J., Ekblom B., Mandroukas K. ✉

¹ Faculty of Physical Education and Sports, Charles University, Prague, Czech Republic; ² Laboratory of Ergophysiology-Ergometry, Department of Physical Education and Sports Science, Aristotle University of Thessaloniki, Thessaloniki, Greece; ³ Åstrand Laboratory of Work Physiology, The Swedish School of Health and Sports Science, Stockholm, Sweden

AIM: The aim of the present study was to examine the adaptation of myosin heavy chain (MHC) isoforms, capillary density and fiber cross sectional area (CSA) of deltoid muscle in adolescent and adult elite Greco-Roman wrestlers.
METHODS: Eighteen Greco-Roman wrestlers were divided into two groups: adolescents included 10 athletes (group A) between 14-18 years of age (15.4±1.3 yrs) and adults included 8 athletes (group B) between 20-27 years (23.5±2.6 yrs). Histochemical analyses were used to determine the muscle fiber type distribution and the muscle fiber cross sectional area. MHC isoform composition was determined with protein electrophoresis, while capillary density (capillary to fiber ratio and capillaries per mm2) analysis was performed with a-amylase Periodic and Schiff staining.
RESULTS: Adolescents demonstrated a significantly higher percentage of type I fibers (P<0.05) and type I fiber area (P<0.05) compared to the adults. The percentage of type IIa fiber area were significantly higher in adult wrestlers (P<0.05). MHC I isoforms was significantly higher in adolescents (P<0.05), whereas the MHC isoforms of IIa and IIx did not differ between groups. The capillary density (mm2) were significantly higher (P<0.05) in adolescents compared to adults.
CONCLUSION: Our findings suggest that the observed muscle fiber profile in the deltoid muscle of wrestlers may represent an adaptation based on the mechanical and biochemical demands of the long-term training. Such adaptations are linked to the specific characteristics of the training program, the level and the previous training experience of the wrestlers.