The Effect Of Various Strength Training On Bilateral Force Deficit Of Lower Limb

Purpose:Bilateral force deficit (BFD) describes the phenomenon of a reduction in force during synchronous bilateral movements when compared to the sum of identical unilateral movements. BFD is the potential influencing factor of performance which is usually evaluated by bilateral limb ratio (BLR).The purpose of this study was to figure out the influence of various strength training on BFD of lower limb, and observe the characteristic of BFD of lower limb.Methods:(1) 205 healthy young subjects(include 71 athletes) have been tested maximal isometric force of BLR of keen extension or leg press, or the maximal isokinetic force of BLR of knee extension or leg press. (2) Research the influence of strength training after 8 weeks, 4 weeks, for once and acute vibration training on bilateral force deficit of lower limb respectively.Results:(1) The maximal force of BLR of isometric knee extension of male is 96.1%±8.8%, the isokinetic knee extension of that is 92.7% ±7.8%, the isokinetic leg press of that is 88.7%±9.8%; the maximal force of BLR of isokinetic knee extension of female is 91.5%±6.7%, BFD appears in all above; The isometric leg press of male is 96.8%±12.8%, no BFD appears (P<0.05). (2) Those who have BFD increase the maximal force of BLR of isometric knee extension with medium load squat training for 8 weeks (P<0.05), and the maximal force of BLR of isokinetic knee extension with medium load squat training for 4 weeks(P<0.05). (3) In the training group, the variation of maximal force of BLR of knee extension is in negative correlation with the maximal force of BLR before training (8 weeks squat:r=-0.929,P<0.05; 8 weeks lunge squat:r=-0.934,P<0.05; 4 weeks squat:r=-0.696,P=0.025). The BLR of vertical jump is in positive correlation with the distance of single leg hexagon jump (L:r=0.404, P<0.05; R:r=0.463, P<0.05). (4) The BLR of maximal isokinetic strength of knee extension after warming up in vibration way (97.0%±5.7%) is higher than that in traditional way (90.2%±7.9%, P<0.05).Conclusions:(1) BFD of lower limb exist generally in subjects. (2) Short-term medium load squat training can reduce FOD of lower limb, the more obvious the BFD is before training, the bigger the viration is. (4) Acute vibration training can reduce BFD of lower limb.