A cross-sectional real-time ultrasound study into the size differences in the semispinalis capitis muscles, comparing front five rugby union players and a control group

Research into the rugby scrummage has centred on the rate and mechanisms of injury, with very little being done into the effects of the scrum on the cervical musculature. Marked increases in the cross sectional area of the neck extensor semi-spinalis capitis (SECM) in elite wrestlers was previously found and attributed to the increased demands on cervical musculature. Scrummaging causes a similar increase in demands on the cervical musculature and the study aim of this cross sectional study was to investigate the effects of those demands on the semi-spinalis capitis. Five props and second rows from the AECC Rugby Club and five controls who did not participate in contact sports were selected to participate in the study. All subjects were injury free and regularly participated in exercise. Any subjects with hearing disability or spinal abnormality were excluded. The linear dimension (LD), anterior–posterior dimension (APD) and cross sectional area (CSA) were measured bilaterally in a relaxed and contracted state using real-time ultrasound. Height, weight and neck-girth measurements were also taken. Results: no difference was found in APD (p = 0.318), LD (p = 0.078) and CSA (p = 0.419) of the SECM. There was no difference in the height of the subjects (p = 0.657). However, weight (p < 0.01) was found to be significantly increased in the rugby players. No significant increase in the dimensions of the muscles was found, possibly due to the small numbers of participants in the study. Some trends displayed in the results did indicate that there was a possibility that with larger numbers there may be more significant results. Further investigation using a larger population of subjects is therefore needed to fully investigate the effects of scrummaging on the cervical musculature.