Forces and translation distance during an inferior glide of the shoulder in asymptomatic individuals measured with the novel pliance glove and ultrasound imaging

BACKGROUND:There has been limited research on how the variance of force affects manual therapy outcomes and what the best practices should be. No specific force threshold necessary to achieve a predetermined translational distance within the joint has been quantified within the literature. PURPOSE:To quantify the amount of force necessary to perform an inferior glide to the glenohumeral joint and reach to end range. A secondary aim was to determine the impact of co-variables, such as gender, height, weight, and age, on the amount of force required to translate the humeral head within the glenohumeral joint. METHODS:A convenience sample of 64 healthy subjects were recruited. Musculoskeletal ultrasound imaging using the GE LogiQe was used to measure the translation of the humeral head. The manipulation force was measured using the novel pliance glove device and software. The ANOVA was used to determine if there was a difference in translation distance and force between trials. The Pearson's correlation was used to correlate translation and force and between covariables. RESULTS:There was no significant difference in translation distance between trials (p = .14). There was no significant difference in the mean force for this translation (p = .45). There was a poor correlation between age and force (r = 0.28) and weight and force (r = 0.12). CONCLUSION:An average force of 14.27 N (n = 61) was needed to displace the humeral head to reach end range. This was the first study using the combination of a flexible force sensor technology and real-time ultrasound imaging to measure humeral head translation.