The mid – term effect of kinesio taping on peak power of quadriceps and hamstring muscles after anterior cruciate ligament reconstruction

Purpose: The aim of this study was to assess midterm effect of Kinesio tape on peak power of quadriceps and hamstrings muscles after ACL reconstruction 24 hours after taping. Material: Thirty six men who had undergone ACL reconstruction and completed physiotherapy periods (6 months) were assigned to no taping, placebo and taping groups. Peak power was tested before and 24 hours after taping by Isokinetic dynamometry. Data was analyzed by SPSS software 19. ANOVA and post hoc test (LSD) were used for interpretive analysis. Results: The results showed that the effect of Kinesio tape on peak power of quadriceps muscles at velocities of 180°/s and 300°/s was significant. In the hamstring muscles, significant effects were obtained at velocities of 60°/s,


Introduction
Rupture in ACL is very prevalent and its treatment is too costly and time-consuming [1]. Previous studies show that 80 to 250 thousand of ACL injuries occur yearly between ages 15 to 25 years [2]. Reconstruction of this ligament is the most common method of treatment for those who encounter with ACL tear. Special care and physiotherapy after surgical operation, together with the special exercise may help the athlete to return to competitions after some months [1]. The increased rate of ACL tears in youth athletes have been attributed to multiple factors including an increase in early sports specialization and competition, lack of free play and increased awareness of ACL injuries in children [3]. On the other hand, Quadriceps weakness persists after ACL reconstruction. Muscle atrophy and activation failure may contribute [4]. It has been mentioned that ACL reconstruction and injured limb decreased from 5% to 40% in strength of the quadriceps muscle [5,6,7]. It can be concluded that other factors (physical fitness) such as maximal power is affected by ACL reconstruction. So, Physiotherapist and sport therapists must plan and treat athletes to achieve all these factors in the shortest possible time and reach them to the peak level of their activity. Achieving to muscle maximal power factor is extremely important because it is infrastructure and basic foundation of athletes' skills training. Maximal power factor is considered in rehabilitation programs from 6 th month after reconstruction. Plyometric training is a specialized, high-intensity training method which aims to increase sport-specific explosive peak power and the rate of force development [8]. Plyometric training is applied as muscle peak power in rehabilitation protocols after the sixth month, because it's not only increasing muscle peak power but also neuromuscular coordination. For prevention, rehabilitation and modulating some physiological processes of ACL injury, different methods and tools such as "Kinesio-Tape" were used [9,10,1,11]. Taping is usually used to help recover from overuse and other injuries. Taping can support injuries at the muscletendon units by compressing and limiting movement and secure protective pads, dressings and splints [12]. KT gives support and stability to the joints and muscles without affecting circulation, range of motion and allows for the athletes to exercise with greater intensity [1]. Application of the tape allows the body to move normally, and reacts to the fascia via biomechanical or proprioceptive mechanisms [13]. Some of the researchers assumed that KT can facilitate and stimulate muscle function if its application starts at the origin of the muscle and ends at its insertion [12,13,14]. KT could stimulate the fascia and provide higher tension for facilitating the muscle contraction [12,14]. Before starting explosive exercise such as plyometric exercise, evaluation of the femur's muscles peak power can help to rehabilitator. Peak power of hamstring and quadriceps muscles can be considered as fair criteria and useful signal in the prevention of re-injury and promote a return to sport for injured athletes. Applying KT can help joint stability and increase the muscular power among athletes who underwent ACL reconstruction. Some studies have noted a positive effect of taping on explosive exercise and others have considered it ineffective [13,15,16]. Some of the studies have researched the effect models of taping in different area of the body. The most recent systematic reviews have concluded that there is little quality evidence to recommend the usage of KT to prevent or treat musculoskeletal injuries [17,18] and regarding efficacy of KT applications to promote strength gains has recently been reviewed (19). Since previous studies have been conducted on healthy people and athletes and on the other hand, few studies about applying mid -term KT on peak power of the femur's muscles have been done. So the aim of this study was studying mid -term effect (24 hours) of KT on peak power quadriceps and hamstring muscles among athletes who underwent ACL reconstruction.

Material and Methods
The method of this research was quasi experimental. Statistical population of present research included all of the athletes that had ACL reconstruction. The ACL surgery was performed by an orthopedic surgeon using a doublebundle method (allograft) followed by an effectively ACL reconstruction rehabilitation program that was performed about 6 months (see table 1). Inclusion criteria of the study were: (1) isolated ACL injuries; (2) unilateral arthroscopic ACL reconstruction; (3) age between 21 and 31 years; (4); regular attendance, missing no more than three sessions of ACL surgery rehabilitation in the first three months after ACL reconstruction. According to the aim of research, 36 men who had experienced ACL reconstruction randomly were divided into three groups: taping (N=12), non-taping (N=12) and placebo (N=12) groups. The instruments used were Siemens Isokinetic dynamometer (Iso 2 model, made in Italy), 3NS TEX (made by Korea) Kinesio tape, IKDCSKE form and SECA Scale (weight and height, made in Germany).Research procedure was explained verbally to the subjects. After adjusting isokinetic dynamometer for each subject, they performed 8 repetitions with a speed of 360°/s as a warm up set. The test protocols consisted of 2 repetitions in 3 sets with a speed of 300°/s, 2 repetitions in 3 sets with a speed of 180°/s and 2 repetitions in 3 sets with a speed of 60 °/s. They rested 10 seconds between each set and 120 seconds between stages 1 to 3.
According to study of Kase et al (2003) Kinesio tape is applied for both "muscle facilitation" and "muscle inhibition" technique. KT applying from the muscle origin to insertion with stronger tension (50 to 75%) of its original length may enhance muscle contraction. On the contrary, muscle contraction may be reduced by applying KT from the muscle insertion to origin with weaker, tension (15 to 25%) of its original length. So, Three different quadriceps taping modes were applied (no taping, placebo taping and taping) for three groups. The Tex was used from origin to insertion of the quadriceps muscle (50% tension by length), around and below the patella bone as KT (experimental) group (Fig1). According to the study of Vithoulka et al (2010), for placebo group two levels Tex were applied transverse on quadriceps muscle. One of Tex 5 cm above the middle distance of the femur and the other one 5 cm below were applied (Fig 2).As mentioned three groups (no taping, placebo taping and taping) performed testing protocol before and 24 hours after taping in the same room and environmental circumstances such as light, noise, temperature and wet. By using SPSS 19 data was analyzed. Descriptive statistics was used for measurement of Average, Standard Deviation, variance and interpretive analysis was applied for frequency tables and ANOVA and post hoc test (LSD) within three groups.

Results
According to the table 3 in the hamstring muscles, significant effects were obtained at velocities of 60°/s, 180°/s & 300°/s. Furthermore, there were significant effects in the quadriceps muscles at velocities of 180°/s and 300°/s 48 hours after taping (P˂0. 05).

Discussion
In quadriceps and hamstring muscles there were significant effects at velocities of 180°/s and 300°/s 24 hours after taping. Of course in quadriceps muscle, significant effects were obtained at velocity of 300°/s in the placebo group. Studies have used the output strength or peak torque but limited studies have directly evaluated the peak power of the femur's muscles among unhealthy athletes. However, peak power and torque in different angular velocities can be fair criteria for explosive movement of the femur's muscles. It has been reported that peak power is generated at velocities of 60°/s & 180°/s. It also has been found that measurements of power can be useful in describing the types of deficits seen in some patient types. Isoifidou et al (2000) found that increase in angular velocity lead to increase in peak power of the femur's muscles [20,21]. Herington et al (2004) figured out that use of tape is ineffective [22]. It seems that difference in the mentioned results and present study may be due to tension, type or method of taping and samples (healthy ans injured). Takey et al (2007) obtained significant differences in peak power between left and right leg among elderly females and suggested that peak torque is representative of work and power and may be the only necessary parameter for isokinetic muscle performance testing of the extensor muscles of the knee in the elderly [23]. Fu et al (2008) found no significant difference in muscle power among the three conditions and believed that KT on the anterior thigh neither decreased nor increased muscle strength in healthy non-injured young athletes [24]. They examined the possible delayed (12 hours after taping) effects of KT on muscle strength in the quadriceps and hamstring when taping is applied to the anterior thigh of 14 healthy young athletes in taping and control groups while in this study muscular power was assessed in athletes (men) who had ACL reconstruction and significant effects of KT on peak power at velocities of 180°/s and 300°/s 24 hours after taping in the quadriceps and hamstring muscles was observed. The inconsistency in the above results and present study may be attributed to difference in tension (30% vs 50%), type, method and time of taping (12h vs 24 h), samples (healthy and injured) and groups. Vithuolk et al (2010) taped their samples (nonathletic female) in different manner. Of course their taping had significant effect on peak torque. Nelson (2011) obtained significant decrease in maximum power post-intervention, and no significant differences in the average power, or average  and maximum speed and cadence measurements [24]. Forty asymptomatic trained amateur cyclists performed two 1.5 km time trials pre-and post-KT application and Peak power of quadriceps muscles was studied by him while this study was performed on men who had ACL reconstruction and obtained significant effect (mid -time) of KT on power. Wong et al (2012) showed that despite of taping, work out of samples (14 healthy male and 16 healthy female) were decreased by using KT [26]. In fact, type and stretching of taping (tension) can cause decrease of work out and peak power among healthy people. They reported that decreasing of peak power in extension is visible and more than flexion while in this research the result indicated in quadriceps and hamstring muscles there were significant effects at velocities of 180°/s and 300°/s at the 24 hours after taping. Subjects of Wong et al (2012) were healthy that had more decrease in extension than flexion whiles our subjects were men who had ACL reconstruction. Wong et al (2012) studied the effect of taping on output peak power at velocities of 60, 120 and 180 °/s while in the present study taping and its effect were studied at velocities of 60, 180 and 300 °/s. They evaluated peak power on quadriceps muscles and obtained decrease in power while the present study investigated the effect KT on peak power of hamstring and quadriceps muscles and obtained increase in peak power. With respect to these results it can be concluded that taping (our model and 50% tension) can improve peak power before plyometric exercise in rehabilitation protocols. So using tape in rehabilitation phase and starting of explosive exercises is suggested for improving of functional muscles, increasing in peak torque and strength and prevention of re-injury. Wong et al (2012) tested before and immediately after taping while this study tested before and 24 hours after taping. Lumbroso et al (2014) studied effect of KT (30% tension) application over hamstring on peak force among 36 physical therapy students (27) while our subjects were men who had ACL reconstruction and taped 50% tension. They found no immediate change of peak force in the hamstring group, however, two days later, peak force significantly increased that agrees with parts of the results of the present study. It has been figured out significant effects at 24 and 48 hours after taping compared with before taping in taping group [12]. They believed that using tape has a positive impact on explosive muscle performance and power in a vertical jump test that is compatible with the result of the present study. The isokinetic test (open chain exercise) involves one joint and segment, it limits the knee angular velocity and biarticular muscles (rectus femoris) are affected only by one joint (knee) since there is no simultaneous movement of adjacent joints. In contrast, the squat vertical jump test involves both legs, it is a closed chain exercise, the knee angular velocity is not limited and there is a transfer of energy from other joints so output power increases. However, according to reports of Nadali (2014), the positive effect of taping during the 24 and 48 hours after taping is effective on vertical jump or Sargent and results of the present study indicates increase of strength output of the femur's muscles among athletes who had ACL reconstruction. So, taping can cause psychological positive effects, knee stability and adaptability (proprioceptive receptors) of the knee joint. Sera et al (2015) has not found significant differences in the variables assessed between KT and Micropore conditions or among testing sessions (pre, post, and 24h after) and no statistical significance for interaction between tape conditions and testing session [28]. They evaluated the effects of KT on knee extension force in soccer players while the present study tested the peak power of the femur's muscles in athletes who had ACL reconstruction that agrees with the parts of the result of the present study. Guedes et al (2016) reported that there were no significant differences on time of taping at 24 and 48 hours and KT did not enhance knee extensor neuromuscular performance of healthy men at different muscle action velocities between 60 to 240°/s [29] but this study obtained significant effects of KT on muscular power in the quadriceps and hamstring muscles at velocities of 180°/s and 300°/s 24 hours after taping. It can be stated the difference in their results and present study may be due to tension (0% and 40% vs 50%), subjects (healthy vs Injured), type or method and time (duration) of taping. On the other hands, it has been verified that KT has positive effects in individual's post-ACL reconstruction during returning to pre-injury activity level and/or sport [30].

Conclusion
It seems that the use of KT has a positive impact on peak power of quadriceps and hamstring muscles at the start of the powers' program of the rehabilitation on unhealthy athletes who have ACL reconstruction. Apart from the psychological impact, taping by stabilizing the knee joint may result in significant impact. Use the proper tension of taping makes optimum traction to touch receptors, stimulating more skin deep motor neurons and thereby increase the torque and peak power of the femur's muscles. Increasing stability in the joint of athletes can cause more daring and courage among athletes who have injury and can reach them to higher muscular peak power during plyometric exercises or explosive activity. Therefore, using mid -term taping (24 hours later) with the proper tension (50%) like model of the present study can be recommended (Mehregan model) in the start of the power's program of the rehabilitation athletes who have ACL reconstruction. Other influences of KT among other injured athletes need to be addressed in further research efforts.