In response to the problem that the traditional lower limb rehabilitation scale assessment method is time-consuming and difficult to use in exoskeleton rehabilitation training, this paper proposes a quantitative assessment method for lower limb walking ability based on lower limb exoskeleton robot training with multimodal synergistic information fusion. The method significantly improves the efficiency and reliability of the rehabilitation assessment process by introducing quantitative synergistic indicators fusing electrophysiological and kinematic level information. First, electromyographic and kinematic data of the lower extremity were collected from subjects trained to walk wearing an exoskeleton. Then, based on muscle synergy theory, a synergistic quantification algorithm was used to construct synergistic index features of electromyography and kinematics. Finally, the electrophysiological and kinematic level information was fused to build a modal feature fusion model and output the lower limb motor function score. The experimental results showed that the correlation coefficients of the constructed synergistic features of electromyography and kinematics with the clinical scale were 0.799 and 0.825, respectively. The results of the fused synergistic features in the K-nearest neighbor (KNN) model yielded higher correlation coefficients ( r = 0.921, P < 0.01). This method can modify the rehabilitation training mode of the exoskeleton robot according to the assessment results, which provides a basis for the synchronized assessment-training mode of "human in the loop" and provides a potential method for remote rehabilitation training and assessment of the lower extremity.
Humans ; Exoskeleton Device ; Reproducibility of Results ; Walking/physiology* ; Lower Extremity ; Algorithms ; Stroke Rehabilitation/methods*

OBJECTIVES: To investigate the effect of torso training on unstable surface on lower limb motor function in patients with incomplete spinal cord injury. METHODS: A total of 80 patients with incomplete spinal cord injury caused by thoracolumbar fracture admitted in Ningbo Yinzhou No.2 Hospital from April 2020 to December 2021 were randomly divided into control group and study group, with 40 cases in each group. In addition to routine training, the control group received torso training on stable surface and the study group received torso training on unstable surface. The gait, lower limb muscle strength, balance function, lower limb function, mobility and nerve function of the two groups were compared. RESULTS: After treatment, the stride length, stride frequency and comfortable walking speed improved in the two groups (all P<0.05), and the improvements in study group were more significant (all P<0.05). The muscle strength of quadriceps femoris, gluteus maximus, hamstring, anterior tibialis and gastrocnemius were improved in the two groups (all P<0.05), and the improvements in study group were more significant (all P<0.05); the total trajectories of static eye opening and static eye closing gravity center movement in the two groups were significantly shorter (all P<0.05), and the improvements in the study group were more significant (all P<0.05). The dynamic stability limit range and the American Spinal Injury Association (ASIA) lower extremity motor score, Berg balance scale, modified Barthel index scale in the two groups were significantly higher (all P<0.05), and these scores in study group were significantly higher than those in the control group (all P<0.05). Both groups showed a significant improvement in ASIA grade (all P<0.05), and the improvement in the study group was significantly better (P<0.05). CONCLUSIONS Torso training on unstable surface can effectively improve the gait and lower limb muscle strength of patients with incomplete spinal cord injury and improve the lower limb motor function.
Humans ; Walking/physiology* ; Spinal Cord Injuries ; Gait/physiology* ; Lower Extremity ; Torso

Iliotibial band syndrome (ITBS), as an overused injury of the lower extremities, has developed into a common cause of lateral knee pain. At present, the treatment of ITBS includes drug therapy, muscle strength training, physical therapy, and surgical treatment. Among these methods, physical therapy, drug therapy, and surgical treatment can only alleviate the symptoms of patients. As a safe and effective treatment, lower limb muscle strength training can improve patients' muscle strength, correct abnormal gait, and reduce the recurrence rate of the disease by paying attention to the dynamic changes of patients' recovery process. At present, the pathogenesis of ITBS remains unclear, and the treatment methods are not unified. It is necessary to further study the biomechanical factors related to the lower extremities and develop more scientific and comprehensive muscle strength training methods.
Humans ; Resistance Training ; Running/physiology* ; Iliotibial Band Syndrome/diagnosis* ; Lower Extremity ; Physical Therapy Modalities/adverse effects* ; Knee Joint ; Muscle Strength/physiology* ; Muscles/injuries* ; Biomechanical Phenomena

Objective: To study the protective effect of parachute ankle brace on ankle joint during simulated parachuting landing. Methods: In August 2021, 30 male paratroopers were selected as the test subjects by simple random sampling method. They jumped from the 1.5 m and 2.0 m height platforms respectively with and without parachute ankle brace, and landed on the sandy ground in a semi-squat parachute landing position. The experiment was divided into 1.5 m experimental group and control group and 2.0 m experimental group and control group. Angle sensor and surface electromyograph were used to measure and analyze the coronal tilt range of the ankle joint and the percentage of maximal voluntary contraction (MVE%) of the muscles around the ankle joint, respectively, to evaluate the protective effect of the parachute ankle brace. Results: At the same height, the tilt range of coronal plane of ankle in experimental group was significantly reduced compared with control group, and the difference was statistically significant (P<0.05). Under the same protection state, the tilt range of the coronal plane of the ankle in the 1.5 m group was significantly reduced compared with that in the 2.0 m group, and the difference was statistically significant (P<0.05). The coronal plane inclination range of the ankle in 2 m experimental group was significantly lower than that in 1.5 m control group, and the difference was statistically significant (P<0.05). Compared with 1.5 m control group, MVE% of right tibialis anterior muscle and bilateral lateral gastrocnemius decreased in 1.5 m experimental group, while MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle and right lateral gastrocnemius decreased in 2.0 m experimental group, while the MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). The MVE% of bilateral tibialis anterior muscle, bilateral lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m experimental group decreased compared with 2.0 m experimental group, and the differences were statistically significant (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle, right lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m control group decreased, and the differences were statistically significant (P<0.05) . Conclusion: Wearing parachute ankle brace can effectively limit the coronal plane inclination range of ankle joint, improve the stability of ankle joint and reduce the load on the muscles around ankle joint by landing. Reducing the height of the jumping platform can reduce the coronal plane incline range of the ankle and the muscle load around the ankle during landing.
Humans ; Male ; Ankle ; Ankle Joint/physiology* ; Lower Extremity/physiology* ; Muscle, Skeletal/physiology* ; Electromyography

It has been found that the incidence of cardiovascular disease in patients with lower limb amputation is significantly higher than that in normal individuals, but the relationship between lower limb amputation and the episodes of cardiovascular disease has not been studied from the perspective of hemodynamics. In this paper, numerical simulation was used to study the effects of amputation on aortic hemodynamics by changing peripheral impedance and capacitance. The final results showed that after amputation, the aortic blood pressure increased, the time averaged wall shear stress of the infrarenal abdominal aorta decreased and the oscillatory shear index of the left and right sides was asymmetrically distributed, while the time averaged wall shear stress of the iliac artery decreased and the oscillatory shear index increased. The changes above were more significant with the increase of amputation level, which will result in a higher incidence of atherosclerosis and abdominal aortic aneurysm. These findings preliminarily revealed the influence of lower limb amputation on the occurrence of cardiovascular diseases, and provided theoretical guidance for the design of rehabilitation training and the optimization of cardiovascular diseases treatment.
Amputation ; Aorta, Abdominal/surgery* ; Aortic Aneurysm, Abdominal/surgery* ; Blood Flow Velocity/physiology* ; Hemodynamics/physiology* ; Humans ; Lower Extremity ; Models, Cardiovascular ; Stress, Mechanical

Aged ; Humans ; Lower Extremity ; Middle Aged ; Muscle, Skeletal/physiology* ; Vibration

The purpose of this paper was to investigate the effects of wearable lower limb exoskeletons on the kinematics and kinetic parameters of the lower extremity joints and muscles during normal walking, aiming to provide scientific basis for optimizing its structural design and improving its system performance. We collected the walking data of subjects without lower limb exoskeleton and selected the joint angles in sagittal plane of human lower limbs as driving data for lower limb exoskeleton simulation analysis. Anybody (the human biomechanical analysis software) was used to establish the human body model (the human body model without lower limb exoskeleton) and the man-machine system model (the lower limb exoskeleton model). The kinematics parameters (joint force and joint moment) and muscle parameters (muscle strength, muscle activation, muscle contraction velocity and muscle length) under two situations were compared. The experimental result shows that walking gait after wearing the lower limb exoskeleton meets the normal gait, but there would be an occasional and sudden increase in muscle strength. The max activation level of main lower limb muscles were all not exceeding 1, in another word the muscles did not appear fatigue and injury. The highest increase activation level occurred in rectus femoris (0.456), and the lowest increase activation level occurred in semitendinosus (0.013), which means the lower limb exoskeletons could lead to the fatigue and injury of semitendinosus. The results of this study illustrate that to avoid the phenomenon of sudden increase of individual muscle force, the consistency between the length of body segment and the length of exoskeleton rod should be considered in the design of lower limb exoskeleton extremity.
Biomechanical Phenomena ; Exoskeleton Device ; Gait ; Humans ; Lower Extremity ; physiology

To compare the effect of cold or room temperature of tumescence anesthesia solution on pain perception during and after endovenous laser ablation (EVLA) for varicose veins of lower limb.
 Methods: A total of 51 patients with lower extremity varicose vein were treated by EVLA with tumescence anesthesia solution. All patients were used for local anesthesia and randomly divided into 2 groups according to the temperature of tumescence anesthesia solution: Group A (n=26) with room temperature (24 ℃) of tumescence anesthesia solution and Group B (n=25) with cold (4 ℃) tumescence anesthesia solution. Number rating scale (NRS) was recorded immediately after the procedure and postoperative 1, 2, 3 day. Patients were asked to register pain scores during the week.
 Results: The mean linear endovenous energy density (LEED) in the 2 groups was not significantly different (P>0.05). The ratio of patients without pain during the operation in the Group A was lower than that in the Group B (30.8% vs 64%, P<0.05). On the day of operation and postoperative day 1, 2, 3, the average number rating scale (NRS) scores in the Group A were greater than those in the Group B (P<0.05). Postoperative day 1, only 30.8% of the patients in the Group A resumed daily activities, which was lower than that (68% of the patients) in the Group B.
 Conclusion: In the process of EVLA for varicose veins of lower limb, there is less pain during operation and post-operation using cold tumescence anesthesia solution comparing room temperature tumescence anesthesia solution.
Anesthesia ; methods ; Cold Temperature ; Humans ; Intraoperative Complications ; physiopathology ; Laser Therapy ; Lower Extremity ; Pain Measurement ; Pain Perception ; physiology ; Pain, Postoperative ; physiopathology ; Treatment Outcome ; Varicose Veins ; physiopathology ; surgery

BACKGROUNDFor a child with osteosarcoma, prediction of the limb length discrepancy at maturity is important when planning for limb salvage surgery. The purpose of this study was to provide a reliable prediction method.

METHODSA retrospective review of Chinese children receiving chemotherapy for osteosarcoma before skeletal maturity was conducted. Standing full-length radiographs of the lower extremity were used for length measurements. Length-for-age curves were constructed using the LMS method. The lower limb multiplier for a specific age and gender was calculated using the formula M = Lm/L, where M was the gender- and age-specific multiplier, Lmwas the bone length at maturity, and L was the age-specific bone length. Prematurity and postmaturity radiographs were used to assess the accuracy of the prediction methods.

RESULTSA total of 513 radiographs of 131 boys and 314 radiographs of 86 girls were used to calculate the coefficients of the multiplier. The multipliers of 8-, 9-, 10-, 11-, 12-, 13-, 14-, 15-, 16-, 17-, and 18-year-old boys after chemotherapy for osteosarcoma were 1.394, 1.306, 1.231, 1.170, 1.119, 1.071, 1.032, 1.010, 1.004, 1.001, and 1.000, respectively; while for girls at the same ages, the multipliers were 1.311, 1.221, 1.146, 1.092, 1.049, 1.021, 1.006, 1.001, 1.000, 1.000, and 1.000, respectively. Prematurity and postmaturity femoral and tibial lengths of 21 patients were used to assess the prediction accuracy. The mean prediction error was 0 cm, 0.8 cm, and 1.6 cm for the multiplier method using our coefficients, Paley's coefficients, and Anderson's method, respectively.

CONCLUSIONSOur coefficients for the multiplier method are reliable in predicting lower limb length growth of Chinese children with osteosarcoma.

Adolescent ; Body Height ; physiology ; Bone Neoplasms ; surgery ; Child ; Female ; Femur ; anatomy & histology ; Humans ; Limb Salvage ; Lower Extremity ; anatomy & histology ; Male ; Models, Theoretical ; Osteosarcoma ; surgery ; Radiography ; Retrospective Studies ; Tibia ; anatomy & histology

OBJECTIVEAging is associated with a progressive decline in muscle strength, muscle mass and impaired physical function, which reduces mobility and impairs quality of life in the elderly population. The 6-12 months of exercise can enhance the muscle strength, but these improvements can only be maintained for a short period. In this study, we investigated the effects of long-term Tai Chi (TC) exercise on muscle strength of lower extremities.

METHODSA cross-sectional study was conducted in 205 long-term TC practitioners (age: 60-89 years) and 205 age and gentle matched controls who did not practice TC. Each of the activity group was further divided into three distinct age groups: G1, 60-69 years; G2, 70-79 years; and G3, 80-89 years. Hand-held dynamometery was used to measure the maximum isometric strength of iliopsoas, quadriceps femoris, tibialis anterior and hamstrings in both sides of the participants. Unpaired t tests were performed to compare the difference of strength between the TC and non-Tai Chi (NTC) groups. Multivariate analysis of variance (MANOVA) was used to compare the lower muscle strengths among the different age groups in the TC and NTC groups. Pearson's correlations were used to quantify the linear relationship between the months of TC practice and lower limbs muscle strength.

RESULTSThe inter-rater reliabilities of iliopsoas, quadriceps femoris, tibialis anterior and hamstrings were intraclass correlation coeffificient (ICC) (1,1) = 0.895 (0.862-0.920), ICC (2,2) = 0.905 (0.874-0.928), ICC (3,3) = 0.922 (0.898-0.941) and ICC (4,4) = 0.930 (0.908-0.947). The strength of the muscles in the TC group did not differ among different age groups (P>0.05). The strength of iliopsoas, quadriceps femoris, tibialis anterior and hamstrings in TC group was higher than that in the NTC group (P<0.05). A correlation between muscle strength and extension of the exercise period was positive (P<0.05).

CONCLUSIONSResults shed light on the orientation and magnitude of long-term TC in preventing muscle strength loss with aging. TC might be a good form to slow down the trend of age-related decline in muscle strength in community-dwelling population.

Aged ; Aged, 80 and over ; Aging ; physiology ; Female ; Humans ; Lower Extremity ; physiology ; Male ; Muscle Strength ; physiology ; Reproducibility of Results ; Tai Ji