Effect of instrument type and one-handed versus two-handed grips on force application during simulated...

The purpose of this study was to examine whether the forces used by trained clinicians during a simulated instrument-assisted soft tissue mobilisation (IASTM) treatment varied across five different instruments during one-handed and two-handed IASTM grips.

Nine athletic trainers who previously completed IASTM training and used the technique in professional practice were included in the study. A skin simulant was attached to a force plate and used to evaluate force production during a simulated IASTM treatment scenario. Peak (F_peak) and mean (F_mean) forces were recorded for both one-handed and two-handed grips for each participant across the five instruments. Data were analysed using separate 2 (grip type) × 5 (IASTM instrument) repeated measures analysis of variance for both F_peak and F_mean.

Data for F_peak demonstrated a significant main effect for grip type (F_{(1, 8)}=46.39, p<0.001, $$ =0.34), instrument (F_{(4, 32)}=4.61, p=0.005, $$ =0.06) and interaction (F_{(2, 16)}=10.23, p=0.001, $$ =0.07). For F_mean, there was also a statistically significant main effect for grip type (F_{(1, 8)}=60.47, p<0.001, $$ =0.32), instrument (F_{(4, 32)}=4.03, p=0.009, $$ =0.06) and interaction (F_{(2, 19)}=7.92, p=0.002, $$ =0.06).

Clinicians produced greater IASTM forces when applying a two-handed grip than a one-handed grip. Instrument weight may matter less than instrument shape, size and bevelling for influencing force production as instrument length appears to influence force production when using one-handed or two-handed grips. Although the effects of IASTM force variation on patient outcomes remains unknown, these findings may be considered by clinicians when making instrument and grip choices.