Study On The Effect Of Natural Walk And Carried Load On Human Gait

Objectives: Walking and loaded walking are common behaviors in human daily life,such as student schooling,shopping,work,physical exercise,labor behavior,military activities and other daily life will be related to walking and weight-bearing phenomenon.When long-distance walk and heavy load over walking,gait will change at some extent,and have a negative impact on the foot structure and lower limb joints.The objectives of this study was to analyze the changes of plantar pressure,surface electromyogrphy(sEMG)of the lower limbs’ muscles and joint motion under normal gait and loaded walking.To enrich the current Chinese normal gait characteristics database,provide a reference for clinical diagnosis,rehabilitation therapy and evaluation for exercise training.Quantification of the foot pathological state caused by deformity was also performed using plantar pressure detection,to provide accurate data for clinical diagnosis,treatment and rehabilitation.Methods:(1)Before and after a 30 minutes’ natural walk,plantar pressure and the sEMG of the lower limbs’ muscles were measured while barefoot walking by the foot pressure test system and the surface electromyrometer.(2)Ground reaction force(GRF),SEMG of lower limb muscles(left and right tibialis anterior,lateral gastrocnemius)and kinematics and dynamics parameters of joints(hip,knee and ankle)of ten healthy young men were measured in different weight forms(backpack,single hand)and weight(0%,5%,10%,15%,20% of subjects’ weight,respectively)during barefoot walking using three-dimensional force balance system,three-dimensional motion capture system and surface electromyography.(3)Plantar pressure distribution of patients with talipes cavus and hallux valgus was tested and analyzed by the plantar pressure test system.Results:(1)The peak pressure and impulse both performed difference between left and right side before and after 30-min natural walking.The difference between left and right side of different parameters reflected in different areas of foot respectively while different parameters in M3,M4 and M5 of left foot were all greater than right foot.The iEMG of sEMG for tibialis anterior,gastrocnemius,rectus femoris and biceps femoris in left side were greater than right side before and after 30-min walking.The MPF of sEMG for tibialis anterior,gastrocnemius in left side were greater than right side before and after 30-min walking.After 30-min walking,the peak pressure of right foot’s toe2-5 regions decreased,the iEMG of sEMG for all muscles remained unchanged,and the MPF of sEMG for left rectus femoris decreased.Peak pressure and height,weight has a weak correlation.(2)The characteristic parameters of the GRF Fz1,Fz2 and Fz3 were significantly increased with the increases of the load weight,and Fz1,Fz2 and Fz3 had no statistically difference between the backpack and the single hand hold,and Fz3 was greater than Fz1,and they were both greater than subjects’ weight.The integral electromyography iEMG of the tibialis anterior and gastrocnemius corresponding to the same side of single stance phase was significantly increased with the increase of the load,and there was no significant differences between different load form.The maximum flexion angle of the hip joint increases with the increase of the load while the maximum extension angle unchanged.The flexion angle of the knee joint is increased only at 20% weight;The plantarflexion angle of the ankle joint increases with the weight of load increases,the dorsiflexion angle did not change significantly.There was no significant difference in the angle of the lower limb joint motion between backpack and single hand.The moment of the hip,knee and ankle in the sagittal plane increases with the weight of load.(3)For the patient of talipes cavus,right foot valgus,peak force of right foot’s first metatarsal increased significantly;For the patient of hallux valgus,peak force of right foot’s first metatarsal significantly reduced on the right foot,both feet varus.Conclusions:(1)Plantar pressure and lower extremity’s surface electromyogram performed difference between left and right side during normal walking in this study.Natural walking of 30 minutes has not yet resulted in significant results of the plantar pressure in the apparent fatigue state.So we can maintain the stability of gait after 30-min natural walking.(2)GRF parameters,the SEMG of the lower limb and angle and moment of joints on the sagittal plane significantly increased with the increase of load of the backpack and the single-handed weight.In additional,there was no significant difference between the load forms.(3)Quantitative description and analysis of foot pressure distribution caused by deformity through plantar pressure detection can provide accurate data reference for clinical diagnosis and treatment and rehabilitation evaluation.