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Objective To estimate knee adduction moment (KAM) and knee flexion moment (KFM) under different gait test conditions via an inertial sensor network (ISN). Methods Twelve healthy young male subjects wore eight inertial sensors (located in the trunk, pelvis, both thighs, both shanks, both feet) and walked under different test conditions (changing foot progression angle, trunk sway angle, step width and walking speed). An ISN was used to extract biomechanical features as the input of recurrent neural network (RNN), so as to estimate the KAM and KFM. Results The overall KAM estimation accuracy: relative root mean square error (rRMSE) was 8.54% and r=0.84. The overall KFM estimation accuracy was rRMSE=6.40% and r=0.94. Conclusions The model can be used as the basis for load estimation of knee joints out of the lab and its potential application includes gait training and rehabilitation assessment after knee surgery.
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Objective To investigate the effects of shoes type (barefoot, ordinary running shoes, minimalist shoes) and walking speed (jogging, walking at normal speed) on biomechanical parameters of knee joint, so as to provide theoretical reference for scientific fitness. Methods Vicon three-dimensional （3D） motion capture system and Kistler 3D force plate were used to collect biomechanical parameters of lower limbs from 10 subjects during walking at different speed with different shoes. Two-way (2 walking conditions × 3 shoe conditions) repeated measures analysis of variance was used to statistically analyze each dependent variable. Results Compared with jogging, the lateral excursion of plantar center of pressure (COP) was greater, the moment arm in frontal plane, the adduction moment and peak loading rate of knee joint were smaller, but the angular impulse of knee joint in frontal plane was greater. Compared with ordinary running shoes, the stride length was decreased, the lateral excursion of COP was greater, and the moment arm of knee joint in frontal plane, the knee adduction moment, the peak load rate and the angular impulse of knee joint in frontal plane were smaller. Conclusions In order to reduce the angular impulse and peak loading rate of knee joint in frontal plane, it is recommended to jog with small strides for ordinary people with minimalist footwear.
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Knee osteoarthritis (KOA) is a common chronic degenerative joint disease. Hip muscle training, with the advantage of convenience and non-invasion, has been attached great importance by people gradually. Hip muscle training may affect keen medial compartment load, the strength and the electromyography signal of the muscle around the knee joint, and strong hip abductor can protect cartilage, which leads to change the load of the knee joint, and alleviate clinical symptoms. This article reviewed the mechanism of hip muscle training for knee osteoarthritis from the views of biomechanical simulation and electromyography.
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<p><b>OBJECTIVE</b>To observe the kinetic change that reflects joint loading in different planes during stair climbing in knee osteoarthritis (KOA) after electroacupuncture (EA) by three-dimensional motion analysis, so as to provide reference for its biomechanical mechanism treated with acupuncture.</p><p><b>METHODS</b>Forty KOA patients, in accordance with the random number table, were assigned into an observation group and a control group, 20 cases in each one and finally 18 cases completed. Acupoints in the observation group were Neixiyan (EX-LE 4), Dubi (ST 35), Yanglingquan (GB 34), Yinlingquan (SP 9), Xuehai (SP 10), Liangqiu (ST 34) and Zusanli (ST 36); points in the control groups were located about 2 cm next to the above acupoints with shallow acupuncture. EA was connected at Neixiyan (EX-LE 4) and Yinlingquan (SP 9), Liangqiu (ST 34) and Yanglingquan (GB 34). The frequency was 2 Hz with continuous wave in the observation group and there was no current in the control group for the corresponding points. All the treatment was given for 3 weeks, totally 11 times. Climbing stairs gait was measured before and after treatment. Velocities and kinetic parameters during ascending and descending stairs were analyzed, including flexion and extension peak torques of hip, knee, ankle on the vertical plane, external knee adduction moment on the coronal plane.</p><p><b>RESULTS</b>After treatment in the observation group, velocities during ascending and descending stairs significantly increased (<0.05,<0.01); maximal ankle plantar flexor moments during ascending and descending stairs and the second peak external knee adduction moment (PEKAM2) during ascending stairs significantly increased (<0.05,<0.01). After treatment in the control group, the first peak external knee adduction moment (PEKAM1) and PEKAM2 during descending stairs were less than those before treatment (<0.05,<0.01). In the observation group, the difference value (DV) of velocity before and after treatment was positively correlated to DV in the torque of ankle plantar flexors during ascending stairs in the observation group (=0.598，<0.01). Excluding the impact of velocity, the DV of the maximal torque of ankle plantar flexors during ascending stairs didn't show difference in the observation group (>0.05).</p><p><b>CONCLUSION</b>EA can increase the velocities of ascending and descending stairs of KOA patients. It improves the loading capacity of knee joint on both sagittal and coronary planes. But its effect during ascending may be correlated with the increase of velocity. The mechanism of different effects between EA and minimal acupuncture on joint moments is still unclear and warrants further study.</p>
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Objective To study the effect of lateral wedge insoles with different stiffness on the knee adduction moment (KAM) under walking condition. Methods The gait of 15 healthy males wearing lateral wedge insoles with different stiffness was tested. The kinetics and kinematics data were collected by optical motion capture system and ground reaction force platform. The KAM and its peak values were calculated by Visual 3D software. The differences in peak KAM under 3 walking conditions (shoes only, shoes with softer or harder lateral wedge insoles) were analyzed. Results Compared with walking with the softer lateral wedge insoles, walking with the harder lateral wedge insoles could reduce the 1st and 2nd peak KAM by 9.3% and 9.7%, respectively, with significant statistic differences. Conclusions Increasing some stiffness of lateral wedge insoles can further reduce the pressure and wear on medial compartment of the knee joint, which may relieve the symptom of knee osteoarthritis.
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Objective To study the effect of lateral wedge insoles with different stiffness on the knee adduction moment (KAM) under walking condition.Methods The gait of 15 healthy males wearing lateral wedge insoles with different stiffness was tested.The kinetics and kinematics data were collected by optical motion capture system and ground reaction force platform.The KAM and its peak values were calculated by Visual 3D software.The differences in peak KAM under 3 walking conditions (shoes only,shoes with softer or harder lateral wedge insoles) were analyzed.Results Compared with walking with the softer lateral wedge insoles,walking with the harder lateral wedge insoles could reduce the 1st and 2nd peak KAM by 9.3％ and 9.7％,respectively,with significant statistic differences.Conclusions Increasing some stiffness of lateral wedge insoles can further reduce the pressure and wear on medial compartment of the knee joint,which may relieve the symptom of knee osteoarthritis.
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Objective To study the effects of wedged insoles at different location on loads and motion of the knee joint. Methods Ten healthy female subjects participated in this experiment. Their gait patterns were assessed as six different wedged insoles and one controlled flat insole. The gait was monitored to study the kinetic changes in joint by using Motion Analysis System and force platforms. One way repeated measurement ANOVA was used to analyze the influences. Results Compared with the control group, the first peak of knee adduction moment was significant reduced by using medial forefoot wedged insole (P<0.05). The second peak of knee adduction moment was significantly reduced by both lateral forefoot wedged insole (P<0.05) and full-length lateral wedged insole (P<0.05). Conclusions The wedged insoles can effectively decrease the knee adduction moment in stance phase during walking, which will help to design an appropriate insole to reduce the knee pain due to osteoarthritis.