A Study On The Biomechanical Characteristics Of Dominant And Non-dominant Legs In College Male Football Players Landing On One Leg

Aims: To investigate the biomechanical characteristics of the three joints of the lower limbs of male football players during the single-leg landing phase,to investigate whether there is any lateralisation of the dominant leg and the non-dominant leg during the single-leg landing phase,and to investigate the mechanisms that cause ACL injuries,and to provide a theoretical basis for the prevention of ACL injuries.Research technique: 1)There was no statistical difference in the Angle of the three joints of lower limbs between the dominant and non-dominant legs in sagittal plane and frontal plane at the moment of touchdown.The range of motion of the three joints of lower limbs,the range of motion of the sagittal plane joint of the knee joint of the dominant leg is smaller than that of the non-dominant leg,and there is a significant difference(P < 0.05),indicating that the dominant leg and the dominant leg have lateral characteristics in the landing stage.2)COP displacement and displacement velocity showed that the front and back displacement direction of the dominant leg was greater than the front and back displacement direction of the non-dominant leg,and the inside and outside displacement direction of the dominant leg was greater than the inside and outside displacement direction of the non-dominant leg.This indicates that the dominant leg is more likely to be injured than the non-dominant leg.3)In this study,both the GRF symmetry index and the shock rate symmetry index are greater than 10% of the reference index.This result indicates that the dynamic indexes of the three joints of the lower extremity of the dominant and non-dominant legs present asymmetry in this study.4)There were significant differences in peak joint power and peak moment between dominant and non-dominant legs when they completed single-leg landing.In terms of the peak power of the three joints of lower limbs,the peak power of the hips and knees of the non-dominant leg on the sagittal plane was greater than that of the hips and knees of the dominant leg on the sagittal plane,showing a significant difference(P < 0.05),and the peak power of the ankle of the non-dominant leg on the sagittal plane was greater than that of the ankle of the dominant leg on the sagittal plane.In terms of joint peak moment,the joint peak moment of the hip and knee of the non-dominant leg on the sagittal plane is greater than the joint peak moment of the hip and knee of the dominant leg on the sagittal plane,and the joint peak moment of the hip,knee and ankle of the dominant leg on the frontal plane is greater than the joint peak moment of the non-dominant leg on the frontal plane.There was no significant difference in the joint peak moment of the three joints of the lower extremity in sagittal plane and frontal plane between dominant leg and non-dominant leg.5)The total score of the non-dominant leg was lower than that of the dominant leg in the balancing ability test of male football players on one leg(dominant leg1747.23±768.69;Non-dominant leg 1466.55±475.86)The score of non-dominant leg was lower,indicating that the non-dominant leg had better stability.FB value represents the stability index of front and rear balance ability,the FB ratio of dominant leg is greater than that of non-dominant leg,and RL value represents the stability index of left and right balance ability,the RL ratio of dominant leg is greater than that of non-dominant leg.There were no significant differences in SCORE and FB ratio between dominant and non-dominant legs,but there were significant differences in RL ratio between dominant and non-dominant legs(P < 0.05).In the sagittal plane,the peak joint moment of the hip joint of the non-dominant leg was greater than that of the hip joint of the dominant leg in the sagittal plane;the peak joint moment of the knee joint of the non-dominant leg in the sagittal plane was greater than that of the knee joint of the dominant leg in the sagittal plane;the peak joint moment of the hip joint of the dominant leg in the frontal plane was greater than that of the hip joint of the non-dominant leg in the frontal plane;the peak joint moment of the knee joint of the dominant leg in the frontal plane was greater than that of the knee joint of the non-dominant leg in the frontal plane.The peak joint moment of the knee joint in the frontal plane,was greater than the peak joint moment of the ankle joint in the frontal plane of the dominant leg than the peak joint moment of the ankle joint in the frontal plane of the non-dominant leg;there was no significant difference between the peak joint moments of the ankle joint in the sagittal and frontal planes of the dominant and non-dominant legs.5)The total score of the non-dominant leg was lower than the total score of the dominant leg in the one-legged standing balance test for male football players,(dominant leg The FB value indicates the stability of the anterior-posterior balance(dominant leg FB ratio 0.66±0.28;non-dominant leg FB ratio 0.61±0.34)and the RL value indicates the stability of the left-right balance(dominant leg RL ratio was 0.8±0.26,and the non-dominant leg RL ratio was 0.7±0.28).There were no significant differences in SCORE and FB ratios between the dominant and non-dominant legs,but there were significant differences in RL ratios between the dominant and non-dominant legs(p<0.05).Conclusions: 1)In terms of symmetry index,the ASI index of the dominant and non-dominant legs of male football players was ≥10%,which was greater than the reference value indicating that the dominant and non-dominant legs did have laterality characteristics.2)In terms of angular range of motion of the lower limb joints,the knee and hip joints of the dominant leg were smaller than the range of motion of the non-dominant leg in the sagittal plane,and the dominant leg had a "stiff" 3)The hip and knee joints of the dominant leg produced greater valgus moments in the smaller range of motion,resulting in a higher risk of injury to the lower limb of the dominant leg.4)The ankle joint of the non-dominant leg was more prone to injury.5)In terms of peak joint moments and peak power,the hip,knee and ankle of the dominant leg all exhibited higher peak joint moments in the frontal plane,and the knee joint of the dominant leg produced greater valgus moments in the smaller range of motion.6)In the dynamic balance test,the non-dominant leg scored better and showed higher stability than the dominant leg.