Effects Of Graded Compression Leg Sleeve On Running Economy And Biomechanical Characteristics Of Lower Limbs During Running

Purpose: Lower limb compression equipment is widely used in sports enthusiasts,occupying a certain sports equipment market,but its role has not been clearly established.The propose of this study is to compare the effects of fatigue and pressure on the biomechanical parameters and oxygen consumption of lower limbs during long-term running between the graded compression leg sleeve with different pressure levels and ordinary running socks and to explore the possible relationship between them.Methods: Twelve male runners were selected and compared with the control group wearing graded pressure leg sleeves with high and low pressure.Cortex gas metabolic analysis system(Metalyzer 3B,Cortex Biophysik,Leipzig,Germany)was used to test the maximum oxygen uptake on the h/p/cosmos Mercury 4.0 runway produced in Germany to determine the official test speed.The kinematics data of subjects during running were collected by using 8-lens infrared spot motion capture system(Qualisys-oqus 700+,Swede,200Hz).A Kistler 9281 CA three-dimensional dynamometer manufactured in Switzerland was used to collect dynamic data synchronously with a frequency of 1000 Hz.The formal test is divided into runway test and treadmill test.Firstly,after warm-up,the participants completed the kinematics and dynamics data collection on the runway,and monitored their speed using the portable speed measurement system(Newtest Powertimer,Finland).After that,the kinematics data and running economy data of 30 minutes were collected on the treadmill by wearing the gas acquisition device.Finally,return to the runway and repeat the initial test.The formal test was completed within a week,and all participants tried to ensure that each test lasted the same time.At the end of the test,the test process is repeated once for reliability and validity test of gas collection.Two-factor repeated measurement variance analysis was used to determine the effects of different pressure levels on biomechanical parameters and running economy.Pearson correlation analysis was used to explore the possible relationship between running economy and biomechanical parameters of lower limbs,and the repeatability of gas data.Results: In runway test,fatigue mainly affected the range of motion of hip joint(p = 0.036),knee flexion and joint force(p < 0.050,P = 0.001),ankle flexion,stiffness(p < 0.050,P = 0.026)and ground reaction force(p = 0.014).The degree of pressure changed knee joint angle and stiffness(p < 0.050,P = 0.021),ankle joint force(p = 0.027)and loading rate(p = 0.005).In treadmill test,fatigue showed significant difference in hip joint,knee joint and ankle joint(p < 0.050).Pressure mainly changed the angle and range of motion of knee(p = 0.018,P = 0.022).The repeatability of gas collection was statistically significant(r = 0.63,P = 0.000).In the Person correlation analysis,the maximum angular velocity of hip(r=-0.498,p=0.000),knee(r=-0.276,p=0.000),ankle(r=-0.623,p=0.000)and duty factor(r=-0.340,p=0.000)were negatively correlated with oxygen consumption.The angle of knee joint at toe-off time(r = 0.499,P = 0.000)and positive work(r = 0.349,P =0.003),the range of angular velocity of ankle(r = 0.547,P = 0.000)were positively correlated with oxygen consumption.Conclusions: During long-term running,? compression leg sleeve has no effect on running economy;with the accumulation of fatigue,the oxygen consumption increases and the running economy decreases.? the leg sleeve mainly affects the joint stiffness of the knee and ankle;the pressure of 34-46 mmHg at the ankle can increase the buffer period of braking and the stability of the knee.? fatigue increases the flexion/extension angles of the hip and knee,and promotes more energy absorption of the knee.? the increase of hip flexion angle at landingtime and knee flexion angle at toe-off time leads to the decrease of running economy;the same trend of duty factor and ankle angle at toe-off time can effectively improve the running economy;and the changes of joint angle velocity of lower limbs has a significant impact on running economy.