Athlete compliance to therapist requested contraction intensity during proprioceptive neuromuscular facilitation

Contraction intensities between 10 and 100% maximal voluntary contraction (MVC) have been proposed in varying muscle energy technique (MET) and proprioceptive neuromuscular facilitation (PNF) post-isometric relaxation (PIR) protocols. The current study was undertaken to determine if athletes were able to comply with differing therapist requested contraction intensities during (PNF) stretching protocols. Thirty-six university athletes were recruited and MVC was established at hip extension, hip adduction, and horizontal shoulder adduction. Target PIR contractions were set at 20, 50 and 100% MVC and monitored throughout the contractions with a strain gauge dynamometer. Athletes were not able to match the target contraction values at 20 and 100% MVC (P ≤ 0.001). When examined for consistency across the three component contractions within each of the three PIR protocols, the athletes demonstrated widely variable scores (coefficient of variation (CV) = 23.2-36.4% at 20% MVC; CV = 19.3-29.4% at 50% MVC; and, CV = 9.4-14.5% at 100% MVC). Our findings indicate that this group of athletes displayed a poor level of compliance to varying therapist requested contraction intensities with respect to both accuracy and consistency.