Study On Effects Of Gradient Compression Tights On Sports Performance In Pedaling

Tight-fit sportswear as a type of high-performance sportswear had become very popular with both athletes and sports enthusiasts.It also had attracted the wide attention of researchers because of its special functions.It was reported that wearing tight-fit sportswear during exercise may help to promote blood circulation,reduce muscle vibration,delay sports fatigue and so on.In this study focus on the lower limbs,special nylon grandient compression tights(GCT)developed by Toray Fibers&textiles Research laboratories(China)Co.Ltd.(TFRC)were chosen as samples,their pressure distribution and the influence on sports performance were investigated.8 male undergraduates majored physical education volunteered to participate in this study.The static pressure and the dynamic pressure were measured while subjects standing and pedaling respectively.Subjects were asked to wear special nylon grandient compression tights(GCT)or the same material loose tights(CONT),then pedaled on a the cycle ergometer under the high or moderate exercise intensity of constant speed(60rpm).The exercise continued until the subject couldn't maintain the pedal speed and his ratings of perceived exertion(RPE)reached 19 or 20.During the exercises,heart rate(HR)and surface electromyography(sEMG)of five lower limb muscles were measured simultaneously.The results were obtained as follow:1)GCT produced a gradient pressure distribution on lower limbs,gradually decreased from the ankle to the thigh,the dynamic pressure while pedaling fluctuated in cycles because of body surface deformation caused by muscle contractions;2)both in high and moderate intensity pedaling exercise,HR while wearing GCT increased more slowly than wearing CONT,and reached the maximum heart rate which was lower than that wearing CONT,the pedaling time period till exhaustion was longer;3)amplitude of EMG was smaller when wearing GCT,average EMG(aEMG)was smaller,mean power frequency(MPF)was higher.It could be concluded that the pressure generated by GCT accelerated blood circulation,promoted venous return,slowed down the rise of heart rate,delayed the development of fatigue.The gradient pressure changed the recruitment pattern of motor units,suppressed low-frequency motor units working,decreased muscle discharge and increased the frequency.