The effectiveness of proprioceptive training in the ACL reconstructed knee
Creators: name: Liu, Teresa Yeong Lih
Publisher: name: University of British Columbia
Year: 2009

description: Purpose The main purpose of this study was to determine the effectiveness of proprioceptive training in the ACL reconstructed limb. The second purpose of this study was to determine the relative contribution of isokinetic strength and peak hamstring torque time to functional ability. Methods Ten subjects with unilateral ACL reconstructed limbs were randomly assigned to two experimental groups. Group One (Strength Training Group) consisted of five subjects who were placed on a 12 week general lower body strength training program. Group Two (Proprioceptive Group) consisted of five subjects who were placed on a 12 week proprioceptive training program for the lower extremities. Peak hamstring torque time (PTT) was measured using the protocol described by Small et al.¹. Average concentric and eccentric torques of the quadriceps and hamstring muscles were measured using the KIN-COM isokinetic dynamometer. Functional ability was determined by the one-legged single hop for distance (SLHD) and the one-legged timed hop. Subjective scores were obtained from the Lysholm and Gillquist Knee Scoring Scale and the Tegner and Lysholm Activity Scale. Results Both training protocols were found to influence peak hamstring torque time of the ACL reconstructed limb. No significant differences were found between or within the two experimental groups. However, a group by test occasion interaction effect on peak hamstring torque time was found. A curvilinear relationship between PTT and test occasion was evident for both experimental groups. The strength training group demonstrated a slowing of PTT at 6 weeks, while the proprioceptive training group demonstrated an improvement in PTT at 6 weeks. At the end of the 12 weeks, both experimental groups regressed toward their baseline PTT values, such as the strength training group demonstrated an improvement in PTT while the proprioceptive training group demonstrated a slowing of PTT in the latter six weeks. There was a significant group by test occasion interaction effect on isokinetic strength measures. The proprioceptive group demonstrated greater isokinetic strength gains than the strength training group after 12 weeks of training. Both experimental groups demonstrated similar significant gains in functional ability. Both groups also demonstrated similar significant gains in the subjective assessment (Lysholm and Gillquist Knee Scoring Scale) and the subjective analysis of physical function (Tegner and Lysholm Activity Scale) after 12 weeks of training. Regressional analyses indicated isokinetic strength of the quadriceps and the hamstring muscles to have significant effects on functional ability (SLHD). Average concentric hamstring torque was found to have the most significant effect on functional ability. Conclusion Both strength training and proprioceptive training have an influence on peak torque time. It is proposed that the two types of training influence PTT through different neuromuscular mechanisms. Strength training is proposed to positively influence PTT by increasing fast twitch/slow twitch (FT/ST) muscle area ratio and to negatively influence PTT by decreasing muscle spindle sensitivity. Proprioceptive training is proposed to positively influence PTT by improving coordination and neural activation of the appropriate muscles. Coordination relies on proprioception and kinesthesia. However, the effectiveness of proprioceptive training is dependent on appropriate progression and repetition. Early integration of speed, force, and complexity of movement into proprioceptive training may decrease the effectiveness of training. Thus, the integration of these components should only occur if precision of performing motor tasks is not compromised. Both strength training and proprioceptive training may have beneficial effects on subjective scores and functional ability. Greater isokinetic strength gains can be observed with proprioceptive training than with strength training as training occurs over time. These greater isokinetic strength gains are proposed to be secondary to improved muscle coordination and neural activation rather than actual muscular hypertrophy. The strength of the lower extremities contribute significantly to functional ability. The strength of the hamstring muscle appear to play a greater role in functional ability than the quadriceps. However, due to the small sample size used in this study, the ability to generalize these results may be limited.