The Research On Muscle Characteristics In Different Angles And SEMG In Excellent Rock Climber

ObjeetiveRecently rock climber’s strength training has aroused widespread concern in the rock climbering. As the major joints of lower limb, knee has significance of practical guidance in different start and end point, different movement speed, under the conditions of different sports biomechanics characteristics of muscle strength,the improving of human exercise ability and technical levels. In this study, a rational detecting means of different starting angle of the rock climber knee flexion and extension isokinetic strength are adopted. It is combined with the surface EMG to evaluate the functional status of muscle. All these are in order to find the law of motion which a rock climber knee in different starting angles kicking. Then is more in line with modern rock climbing muscles work force training methods and means.MethodologyIt uses Germany Isomed2000Isokinetic System and Finland Mega6000EMG Measurement System and it should be general tested before system setting. Conner’s hip angle is fixed at about85°. Dominant leg respectively in concentric contraction testing under different starting point, and isokinetic exercise test angular velocity to the heart are set at:60°/s,120°/s. As testing, each complete flexion and extension is a motion cycle and each test is five cycles of flexion and extension in a different starting point and angular velocity. In the entire testing process, conners are asked to make every effort and they should rest5min after each test in order to avoid fatigue. Meanwhile each contraction process ought to be simultaneous recorded. Every angle and speed in the test is ordered randomly by drawing lots which is in order to avoid maximum "learning effect."Results(1) As isoknetic testing, the rock climber’s knee flexor peak torque is consistent with extensor peak torque variation, which is significant decrease in both with the increase of velocity and the starting point(movement of smaller). But extension peak torque is significantly greater than flexor peak torque. The two speed of flexion and extension peak torque is gradually increasing by the starting angle larger(motion amplitude decrease), and they are less changes in amplitude.(2) Rock climber’s knee extensor muscles of the relative peak torque, average power are significantly reduced with increasing starting angle. In the same rang of motion, the faster the speed, the higher the average power, while the smaller relative peak torque. Meanwhile extensor muscles of relative peak torque and average power trends is basically consistent with extensor.(3) Under the same condition of the end of the knee angle, rock climber’s extensor muscles peak torque angle is decreasing with the increasing of the sarting knee angle, as doing isokinetic flexion to heart, maximum knee extension peak torque angle is156.5°. Under the same condition of the initial knee, the knee muscle peak torque angle is decreasing with the increase of the end anglemaximum knee peak torque is136.5°-140.5°.(4) As doing isokinetic flexion to heart, rock climber’s extensor action is mainly completed by the quadriceps and tibialis anterior muscle. At the same time the antagonist muscle biceps femoris and gastrocnemius are in a good state oif relaxation and the flexion and extension muscle RMS is reducing with the increase of angle velocity. When the angle velocity is60°/s, the quadriceps RMS is significantly increasing with the increase of initial angle. When the angle velocity is120°/s, the quadriceps and tibialis anterior muscle RMS is increasing then decreasing with the increase of the initially angle, the maximum discharge capacity is both in the starting angle of90°, the minimum discharge capacity is in the initial angle of70°.(5) As doing isokinetic flexion to heart, rock climber’s knee action is mainly completed by the biceps femoris and gastrocnemius, and the antagonist quadriceps and tibial anterior muscles are relatively relaxed. When the angular velocity is60°/s, the RMS of biceps femoris and astrocnemius is increasing with the increase of initial angle, meanwhile the RMS of antagonistic muscles in the quadriceps and tibialis anterior muscle is decreasing. When the angular velocity is120°/s,the RMS of biceps femoris and tibialis anterior muscle is decreasing with the increase of initial angle, and the RMS of gastrocnemius and quadriceps is increasing then decreasing with the increase of initial angle. Compared the two angular velocity, the initial angle of90°, the flexor peak torque is decreasing, but the biceps femoris and gastrocnemius are in better discharge status.