Pages 423–428 Isometric cervical extension force and dimensions of semispinalis capitis muscle

Abstract—The anatomy of the human cervical region has a special complexity. Ultrasonography is a scanning technique, which has been successfully used to identify and measure the cervical muscle dimensions. The purpose of this study was to detect with the use of real-time ultrasonography the dimen-sional changes of the human semispinalis capitis muscle (SECM) during isometric cervical extension. Six junior ice hockey players took part in the study. We simultaneously mea-sured the values of estimates, such as breadth or anteroposte-rior dimension (APD) and width or lateral dimension (LD), of the SECM cross-sectional area during isometric cervical exten-sion at different maximum voluntary contraction (MVC) per-cent levels (0%, 20%, 40%, 60%, 80%, and 100%). The result of multiplication of the linear dimensions (APD × LD), considered as the size of the SECM, increased (p < 0.05) with increasing the level of the cervical extension force. The correlation between muscle size and extension force of 100% MVC was r = 0.79 (p = 0.05). The ultrasonography metho