Acute Effects of Kinesio Taping on Knee Extensor Peak eflex

Kinesio Tex tape (KT) is used to prevent and treat sportsrelated injuries and to enhance muscle performance. It has been proposed that the direction of taping may either facilitate or inhibit the muscle by having different effects on cutaneous receptors that modulate excitability of the motor neurons. This study had 2 goals. First, we wished to determine if KT application affects muscle performance and if the method of application facilitates or inhibits muscle performance. This was assessed by measuring isokinetic knee extension peak torque in the knee extensor. Second, we assessed neurological effects of taping on the excitability of the motor neurons by measuring the reflex latency and action potential by electromyography (EMG) in the patellar reflex. The study was a single-blind, placebo-controlled crossover trial with 28 healthy volunteers with no history of knee injuries. Participants received facilitative KT treatment, inhibitory KT treatment, or Hypafix taping of the knee extensor. There were significant differences in the peak torque between 3 treatments (F(2,54)1⁄4 4.873, P< 0.01). Post hoc analysis revealed that facilitative KT treatment resulted in higher knee extensor peak torque performance than inhibitory KT treatment (P1⁄4 0.036, effect size 0.26). There were, however, no significant differences in the reflex latency (F(2,54)1⁄4 2.84, P1⁄4 0.067) nor in the EMG values (F(2,54)1⁄4 0.18, P1⁄4 0.837) in the patellar reflex between the 3 taping applications. The findings suggest that the direction of KT application over the muscle has specific effects on muscle performance. Given the magnitude of effect is small, interpretation of clinical significance should be considered with caution. The underlying mechanism warrants further investigation. (Medicine 95(4):e2615) Abbreviations: EMG = electromyography, KT = Kinesio Tex tape, KTM = Kinesio Taping method, RF = rectus femoris. INTRODUCTION Ella W. Yeung, PhD means to prevent and treat sports-related injuries, as well as to enhance performance. According to its developer, Kenso Kase, KT was designed to mimic some of the qualities of the skin. KT is a thin elastic tape that can be stretched up to 55% to 60% of its resting length. It has approximately the same thickness as the epidermis and its degree of stretch approximates the elastic qualities of human skin. When applied as specified by its developer, it has been claimed to have beneficial effects on the skin, fascia, circulation, lymphatic system, muscles, and skeletal system, and to provide pain relief, resolve edema, improve muscle performance, and increased joint stability. The research evaluating these claims has recently been summarized in several reviews addressing the effectiveness of the KTM on muscle strength, the treatment and management of sports-related injuries, and musculoskeletal pain and injury. The authors of these reviews concluded that the information available was inadequate and stress the need for more rigorous investigation of the KTM before its effectiveness can be assessed. A common goal in the application of the KTM is to enhance muscle performance. The elastic recoil of KT has been proposed to alter the length–tension relationships of muscles. When KT is applied at the insertion of the muscle and extended to its origin, it is proposed that the recoil effect may inhibit motor neurons by stretching the Golgi tendon organs at the distal end of the muscle. In the reverse scenario, the application of KT from the origin to the insertion of the muscle may enhance the muscle spindle reflex contraction and facilitate contraction of the muscle. This concept is based on early neurological studies which demonstrate that cutaneous afferent signals, presumably associated with these proprioceptors, modify the excitability of slow and fast motor units differently and modulate the activity of the proprioceptive reflex loops. It has also been suggested that application of KT activates cutaneous mechanoreceptors, thereby alleviating pain (as predicted by the gate-control theory). Thus, if the application of KT affects afferent input, then motor neuron excitability should either be enhanced or inhibited, depending on the direction of application. No studies have specifically investigated the effect of KT on muscle strength via the monosynaptic reflex of the muscle concerned, but there are several studies which evaluated the effects of taping on cutaneous sensation and the associated changes in the muscle activity. For instance, Macgregor et al showed that when stretch was applied to the skin via taping over the vastus medialis obliquus muscle, which stimulates the cutaneous afferent receptors, this led to an increase in the muscle activity and the motor unit firing rate. Alexander et al evaluated the effect of taping on the monosynaptic reflex of the muscle concerned. Rigid sports tape was applied to the lower trapezius muscle on healthy individuals and the effect of the taping was assessed by H-reflex. The results g inhibited the electromyography (EMG) by 22%. Another study conducted by estigators evaluated the effects of rigid www.md-journal.com | 1 randomization.com) and the treatment was concealed from tape to the medial gastrocnemius muscle on healthy individuals, and the results indicated a decrease in the amplitude of the H-reflex, indicating a reduction in the excitability of the gastrocnemius muscle. However, it has to be noted that these 2 studies utilize traditional rigid sports tapes in which the material properties are very different from KT. Of importance, there are organizational differences between the H-reflex and the stretch reflex. The H-reflex is evoked by direct electrical stimulation of Ia afferent fibers. However, stretch reflex is elicited through activation of the muscle spindle primary endings, whose sensitivity is controlled by the activity of the g-efferent fibers. We hypothesize that the sensitivity of this reflex can be influenced by KT application to the skin. We have addressed these questions by measuring the reflex latency and the motor unit action potential with EMG in the patellar tendon reflex, and the peak torque in 1 of the quadriceps muscles. The first goal of this study was to determine if the KTM alters muscle performance and to evaluate the effect of the direction of taping. The second goal was to determine if motor neuron excitability is a contributing mechanism to the KTM effect through the activation of cutaneous receptors. The latter question should be evaluated in reflexive muscle action rather than voluntary actions and would be reflected in enhancement or inhibition of the reflex. The patellar reflex or knee-jerk reflex is a typical monosynaptic stretch reflex that is frequently used for neurophysiological examinations. Stretch reflexes are elicited through the activation of the primary endings of muscle spindles. The sensitivity of the muscle spindles is controlled by g-efferent neurons, which should be sensitive to the KT applied to the skin.