Specifity of the neck-muscles in Wrestlers and weightlifters from the perspective of isometric cervical extension strength and cross-sectional area of neck extensor muscles

12th Anmual Congress of the Europiean colledge of Sport Science.（Jyvaskyla,Finland ）（2007/07/11-14）

[Purpose]  Neck muscle strength of athletes have not enough studied compared with  limb muscle strength, especially there are very few studies of neck muscles in athletes from viewpoint of cross-sectional area (CSA) of neck muscles calculated from magnetic resonance imaging (MRI) image.  The purpose of study was to examine the specificity of the isometric cervical extension strength (ICES) and CSA of neck extensor muscles in wrestlers and weightlifters.      
[Methods]  The subjects comprised 18 wrestlers and 37 weightlifters from N. University in Japan.  Informed consent was obtained from all of them before participating in this study.  This study was approved by the Ethics of the Nippon Sport Science University.  The ICES was measured at eight angles using cervical extension machine (MedX, USA).  Transverse slices were obtained at the position of each intervertebral disc between C2 and C3, C3 and C4, C4 and C5 and C5 and C6 using MRI.  The CSA of neck extensor muscles between C4 and C5 were divided into three areas, which are the deepest, the intermediate and the superficial1).     
[Results]  The average values of the ICES at all the angles examined in wrestlers were significantly higher than those in weightlifters.  In muscle size, the total CSA values of neck extensor muscles in the wrestlers were significantly larger at all intervertebral levels examined than those in the weightlifters.  However, the CSA value in the superficial layer, trapezius muscle between C4 and C5 in weight lifters was significantly larger than that in wrestlers, although the CSA values of the deepest and intermediate layers were significantly larger in wrestlers.    
[Discussion]  The total CSA of wrestlers was significantly larger than that of weightlifters, which was similar to the results of previous study2).  In addition, it was found that the CSA in the superficial layer was significantly larger in weightlifters than that in wrestlers, although the CSA in deepest and intermediate layers were significantly larger in wrestlers.  It seemed that these results showed the specificity of neck muscles in each event. Weightlifters lift some heavy barbells many times in practice, thus it was inferred that their trapezius muscle was especially developed.  Conley et al.3) showed that neck extensor muscles in the deep layer are more activated during head extension.  Wrestlers frequently perform motion of neck extension and flexion in practice, therefore the deepest layer of neck extensor muscles in wrestlers was especially developed.       
[Conclusion]  It was shown that neck extensor muscles in wrestlers were especially developed in the deepest layer, while those in weightlifters were especially developed in the surface layer, trapezius muscle. 
[References]    
1.Tsuyama, K. et al.:  EJAP, 84, 487-491, 2001.
2.  Rezasoltani, A. et al.:  Scand. J. Med. Sci. Sports, 9, 214-218, 1999.
3.  Conley, M. S. et al.:  Spine, 20, 2505-2512, 1995.

Tsuyama K, Fujimoto H, Sekiguchi O, Kiyota H, Nakajima H

P567