The effect of a single versus multiple cervical spine manipulations on peak torque of the rotator cuff muscles in asymptomatic subjects with cervical spine fixation

Abstract

Aim: The aim of the study was to assess the effect of a single versus multiple cervical spine manipulations, over a two week period, on peak torque of the rotator cuff muscles utilizing the Cybex Orthotron II Isokinetic Rehabilitation System. This study was a pre and post experimental investigation. Method: Forty asymptomatic (in terms of neck and shoulder pain) male chiropractic students were stratified into two equal groups of twenty subjects to ensure that each group consisted of an equal number of subjects from each year of study. All subjects underwent a familiarisation session on the Cybex Orthotron II Isokinetic Rehabilitation System. Group One received a single manipulation. Rotator cuff peak torque was measured pre-manipulation, immediately post manipulation and at a two-week follow up. Group Two received four manipulations over a two week period. Rotator cuff peak torque was measured pre and immediately post the first manipulation. A third rotator cuff peak torque measurement was taken two weeks after the first manipulation. Results: There was no statistically significant effect of a single or multiple manipulations on rotator cuff peak torque (abduction, adduction, internal rotation and external rotation). Inter-group analysis revealed a trend of an effect for abduction as the single manipulation increased at the two-week follow up and the multiple manipulation group decreased; however, this was not statistically significant. Conclusion: No statistically significant results were found possibly due to small sample size and the fact that objective measurements were only taken at the beginning and the end of the research processes and not at regular intervals throughout the study.Further studies are needed to determine the effects of multiple manipulations on peripheral muscle activity, including the treatment of symptomatic patients with rotator cuff pathology. It is also recommended that EMG readings be done in conjunction with peak torque measures to determine muscle activity.