Decreased ability to voluntarily activate the entire motoneuron (MN) pool following joint injury is known as arthrogenic muscle inhibition (AMI), which is commonly quantified by measuring central activation ratio (CAR). AMI is not only observed immediately after joint injury, but has been shown to persist during and after rehabilitation. It is proposed that AMI, by negatively impacting neuromuscular factors such as muscle strength, muscle activation, and rate of torque development (RTD), contributes to a prolonged rehabilitation process and higher risk of re-injury. Unfortunately, AMI cannot be reduced by traditional rehabilitation interventions such as strength training alone. Therefore, it is necessary to identify an intervention that can effectively decrease AMI in order to facilitate improvements in muscle function in individuals with AMI.
Kinesio Tape® is commonly used to facilitate muscle contraction in athletic populations. This elastic therapeutic tape is popular in the athletic setting because it can be applied and used continually during exercise and activities of daily living for up to 2-3 days without restricting movement. It has been suggested that Kinesio Tape® facilitates muscle contraction by inducing increased sensory input via skin stimulation. The tape activates cutaneous mechanoreceptors with the greater afferent feedback thought to improve the efferent output from the central nervous system to the target muscles. While this technique is widely used in the clinical setting to improve muscle function, the facilitative effect of Kinesio Tape® has not been demonstrated- perhaps due to three key limitations of previous investigations. First, previous studies have predominantly recruited healthy participants without muscle function deficits. Therefore, there could have been a ceiling effect whereby there was no observable effect of Kinesio Tape® due to a lack of muscle dysfunction in these healthy individuals. Second, most investigators have generally taken outcome measurements immediately before Kinesio Tape® application and less than 24 hours later. This is much shorter than the 2-3 days that Kinesio Tape® is used clinically and may not be long enough to induce an observable, facilitative effect. Finally, the protocols utilized in previous investigations also failed to mimic clinical practice by not combining Kinesio Tape® application with a therapeutic exercise protocol targeting the inhibited muscle.
Therefore, the purpose of this study is to investigate the effects of prolonged application (\> 48hours) of Kinesio Tape® incorporated with a therapeutic exercise protocol on AMI and muscle function. To do so, we will use the peroneus longus muscle in individuals with functional ankle instability (FAI) as a model, given that AMI has been shown to exist in this muscle in individuals with FAI.
The following specific aims will be tested:
Aim#1. To investigate the effect of prolonged application (\> 48hours) of Kinesio Tape® incorporated with a therapeutic exercise protocol on AMI of the peroneus longus in individuals with FAI.
Aim#2. To investigate the effect of prolonged application(\> 48hours) of Kinesio Tape® incorporated with a therapeutic exercise protocol on peroneus longus muscle function in individuals with FAI.
Our central hypothesis is that prolonged application of Kinesio Tape® in combination with therapeutic exercise will diminish AMI and improve muscle function of the inhibited peroneus longus muscle.
