Investigation into the coefficient of friction of manual therapy products

Abstract

The ability to modulate friction is a vital aspect of manual therapy. Various mediums are utilised to assist with different techniques in the form of: lotions, oils and waxes. The aim of this research was to investigate the differences in the dynamic coefficient of friction between manual therapy mediums. A scientific testing rig with an interchangeable calibration weight (SE-8708, PASCO, USA) was pulled across the mediums and the force was recorded. Constant velocity was confirmed by monitoring acceleration via a wireless force-acceleration sensor (PS-3202, PASCO, USA). The coefficient of friction for each medium was calculated and recorded. Results showed the mean dynamic coefficient of friction for wax was 0.30 (95% CI, 0.26 - 0.35). This was significantly different from cream 0.16 (95% CI, 0.13 - 0.19) p=0.000 and oil 0.09 (95% CI, 0.07 - 0.12) p=000. There was also a statistically significant difference between cream and oil p=0.037. These results suggest that oil and wax produce the lowest and highest coefficient of frictions respectively. Therefore, if the intention of a technique were to increase friction, then wax may be the most effective medium. Alternatively, where less friction is required, oil may prove more efficient for the practitioner.