To investigate the effects of continuous vs. intermittent compressions on MTrPs in humans and horses.To investigate the effects of continuous vs. intermittent compressions on MTrPs in humans and horses.
Intervention consisting in i) searching for MTrPs in the upper trapezius for Human (n=1 per side) but in neck, withers and back muscles in horses (n=3, 2 MTrPs and 1 control location) ; ii) treating by applying either a continuous compression (lasting 90s) or an intermittent compression (3 periods of 30s). Treatment was randomly chosen (i.e., side for human ; one of the MTrPS per side in horse). Primary outcome was the muscle stiffness measured by the Myoton. In human, we also measured pain during neck flexion (visual analogic scale VAS, 0-100). We included human with stroke during rehabilitation at hospital and horses at work, with no apparent pain, aged 4 to 20 years. We used linear mixed models to compare the before and after intervention effects (R 4.1.1) setting statistical significance to 5%.
We measured the effect of intervention in 40 human’s upper trapezius muscles (n=20 participants with stroke, mean age = 50y, 2 sides) and 72 horses’ erector spinae muscles (n=12 animals, mean age = 12y, 3 points, 2 sides). Intermittent ischemic compression significantly increased the muscle stiffness only in animals (i.e., non-significant trend in humans). There were no statistical changes in muscle stiffness after a continuous ischemic compression in both humans and horses. After both continuous and intermittent ischemic compression, humans showed a significant decreased of pain during neck flexion by 31 points (SE=5.5). In horse, untreated MTrPs showed a significant increase of muscle stiffness as compared to control position by 128 N.m-1.
This is the first human-animal study which suggest that continuous ischemic compression is effective to reduce pain during neck flexion in human and did not elicit an increase in muscle stiffness in both human and animals. Our results indicate that stiffness measurement is feasible and reproducible in horses. Future larger sampled studies are welcomed to confirm these results. In human, these studies could investigate difference between MTrPs type (always painful, i.e., active or only painful during compression i.e., latent) and other factors (i.e., stroke severity) and comparison with healthy subjects. In animals, studies could consider additional outcomes relevant for assessing horse function.
Continuous ischemic compression may be recommended over intermittent for the treatment of MTrPs.
Human
Animal
