An in-depth understanding of the mechanism of lower extremity muscle coordination during walking is the key to improving the efficacy of gait rehabilitation in patients with neuromuscular dysfunction. This paper investigates the effect of changes in walking speed on lower extremity muscle synergy patterns and muscle functional networks. Eight healthy subjects were recruited to perform walking tasks on a treadmill at three different speeds, and the surface electromyographic signals (sEMG) of eight muscles of the right lower limb were collected synchronously. The non-negative matrix factorization (NNMF) method was used to extract muscle synergy patterns, the mutual information (MI) method was used to construct the alpha frequency band (8-13 Hz), beta frequency band (14-30 Hz) and gamma frequency band (31-60 Hz) muscle functional network, and complex network analysis methods were introduced to quantify the differences between different networks. Muscle synergy analysis extracted 5 muscle synergy patterns, and changes in walking speed did not change the number of muscle synergy, but resulted in changes in muscle weights. Muscle network analysis found that at the same speed, high-frequency bands have lower global efficiency and clustering coefficients. As walking speed increased, the strength of connections between local muscles also increased. The results show that there are different muscle synergy patterns and muscle function networks in different walking speeds. This study provides a new perspective for exploring the mechanism of muscle coordination at different walking speeds, and is expected to provide theoretical support for the evaluation of gait function in patients with neuromuscular dysfunction.
Humans ; Walking Speed ; Muscle, Skeletal/physiology* ; Electromyography ; Gait/physiology* ; Walking/physiology*

Energy Metabolism ; Humans ; Oxygen Consumption ; Walking ; physiology ; Weight-Bearing ; physiology

Wearing transfemoral prosthesis is the only way to complete daily physical activity for amputees. Motion pattern recognition is important for the control of prosthesis, especially in the recognizing swing phase and stance phase. In this paper, it is reported that surface electromyography (sEMG) signal is used in swing and stance phase recognition. sEMG signal of related muscles was sampled by Infiniti of a Canadian company. The sEMG signal was then filtered by weighted filtering window and analyzed by height permitted window. The starting time of stance phase and swing phase is determined through analyzing special muscles. The sEMG signal of rectus femoris was used in stance phase recognition and sEMG signal of tibialis anterior is used in swing phase recognition. In a certain tolerating range, the double windows theory, including weighted filtering window and height permitted window, can reach a high accuracy rate. Through experiments, the real walking consciousness of the people was reflected by sEMG signal of related muscles. Using related muscles to recognize swing and stance phase is reachable. The theory used in this paper is useful for analyzing sEMG signal and actual prosthesis control.
Artificial Limbs ; Electromyography ; Humans ; Leg ; Muscle, Skeletal ; physiology ; Walking ; physiology

The present paper is to study the center line of the plantar pressure of normal young people, and to find the relation between center line of the plantar pressure and gait stability and balance. The paper gives the testing principle and calculating methods for geometric center of plantar pressure distribution and the center of pressure due to the techniques of footprint frame. The calculating formulas in both x direction and y direction are also deduced in the paper. In the experiments carried out in our laboratory, the gait parameters of 131 young subjects walking as usual speed were acquired, and 14 young subjects of the total were specially analyzed. We then provided reference data for the walking gait database of young people, including time parameters, space parameters and plantar pressure parameters. We also obtained the line of geometry center and pressure center under the foot. We found that the differences existed in normal people's geometric center line and the pressure center line. The center of pressure trajectory revealed foot movement stability. The length and lateral changes of the center line of the plantar pressure could be applied to analysis of the plantar pressure of all kinds of people. The results in this paper are useful in clinical foot disease diagnosis and evaluation of surgical effect.
Foot ; physiology ; Gait ; Humans ; Pressure ; Reference Values ; Walking

The first metatarsophalangeal joint bending plays an important role in the foot movement. However, the existing researches mainly focused on the movement scope of the joint and the clinical treatments of related foot diseases. In order to investigate the effects of the first metatarsophalangeal joint bending on human walking gait stability, the present researchers recruited 6 healthy young men to perform the first metatarsophalangeal joint constraint (FMJC) and barefoot (BF) walking tests. Data of the temporal and spatial parameters, the joint angles of lower limbs, the ground reaction forces (GRF) and utilized coefficients of friction (UCOF) were collected and analyzed. The results showed that, since hip and knee could produce compensation motions, the FMJC had no significant effects on waking gait, but the slip and fall probability increased significantly.
Friction ; Gait ; Humans ; Male ; Metatarsophalangeal Joint ; physiology ; Walking

The purpose of this study was to investigate the effect of different backpack load on the plantar pressure of people during walking. By using three-dimensional force platform system, we collected the ground reaction force data from 20 college students, who were carrying different loads on their backs, and then we transformed the data into a characteristic two-peak curve. Seven characteristic parameters on the curve were selected and analyzed by using statistical methods. The results indicated that the peak ground reaction forces increased as the loads increased. Furthermore, in consideration of different genders, the amount increased was different. For the male subjects, when backpack load reached 17% body weight, changes in ground reaction force began to take place until the backloads reached 20% body weight changes in ground reaction force induced a significant difference. Por the female subjects, changes in ground reaction force began to take place with loads up to 14% body weight and while it reached 15% body weight it induced a significant difference.
Back ; physiology ; Biomechanical Phenomena ; physiology ; Female ; Foot ; physiology ; Humans ; Male ; Pressure ; Stress, Mechanical ; Walking ; physiology ; Weight-Bearing ; physiology ; Young Adult

It has been shown from medical researches that many diseases are major causes of foot morbidity, which are deeply related to the abnormality of the plantar pressure distribution. In this respect, we made a new type of conductive rubber sensor and designed a dynamic contact pressure measuring system of plantar-pressure distribution with 251 testing points successfully. It includes the multipoint conductive rubber sensor, the interface circuit and the computer data collecting and progressing system. The measuring system can give the intuitional and full-scale image results with the full-court, real time testing. Also in this paper are introduced the design of the system, the testing results, and its applications in primary medical studies.
Biomechanical Phenomena ; Equipment Design ; Foot ; anatomy & histology ; physiology ; Humans ; Pressure ; Stress, Mechanical ; Transducers, Pressure ; Walking ; physiology

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

Lower limb ankle exoskeletons have been used to improve walking efficiency and assist the elderly and patients with motor dysfunction in daily activities or rehabilitation training, while the assistance patterns may influence the wearer's lower limb muscle activities and coordination patterns. In this paper, we aim to evaluate the effects of different ankle exoskeleton assistance patterns on wearer's lower limb muscle activities and coordination patterns. A tethered ankle exoskeleton with nine assistance patterns that combined with differenet actuation timing values and torque magnitude levels was used to assist human walking. Lower limb muscle surface electromyography signals were collected from 7 participants walking on a treadmill at a speed of 1.25 m/s. Results showed that the soleus muscle activities were significantly reduced during assisted walking. In one assistance pattern with peak time in 49% of stride and peak torque at 0.7 N·m/kg, the soleus muscle activity was decreased by (38.5 ± 10.8)%. Compared with actuation timing, the assistance torque magnitude had a more significant influence on soleus muscle activity. In all assistance patterns, the eight lower limb muscle activities could be decomposed to five basic muscle synergies. The muscle synergies changed little under assistance with appropriate actuation timing and torque magnitude. Besides, co-contraction indexs of soleus and tibialis anterior, rectus femoris and semitendinosus under exoskeleton assistance were higher than normal walking. Our results are expected to help to understand how healthy wearers adjust their neuromuscular control mechanisms to adapt to different exoskeleton assistance patterns, and provide reference to select appropriate assistance to improve walking efficiency.
Aged ; Ankle/physiology* ; Ankle Joint/physiology* ; Biomechanical Phenomena/physiology* ; Electromyography ; Exoskeleton Device ; Gait/physiology* ; Humans ; Muscle Contraction ; Muscle, Skeletal/physiology* ; Walking/physiology*

BACKGROUNDDepression is a common problem impeding post-stroke rehabilitation. Up to 70% of patients show depression symptoms during the first twelve months after stroke onset. However, the depression and its effect on functional recovery can be difficult to diagnose. The purpose of this study was to use gait analysis as a tool to compare the recovery after stroke in patients with and without depression and to assess the impact of the initiation time of rehabilitation after stroke onset.

METHODSOne hundred and forty five consecutive patients after first ever stroke admitted for designed rehabilitation program within 2 to 31 months after stroke onset participated. All patients received 4 weeks treatment program included comprehensive rehabilitation consisted of multipurpose activities 5 days a week. These included individual and group exercises, physiotherapy, occupational therapy and gait training. Gait analysis with Kistler force plates was employed to assess gait pattern symmetry before and after the treatment. Gait symmetry was evaluated based on seven gait parameters. Regaining of gait pattern symmetry was assumed as a measure of rehabilitation outcome.

RESULTSAfter rehabilitation program gait symmetry was regained in patients without depression. Gait asymmetry remained unchanged in patients diagnosed with depression. No major differences in outcome from rehabilitation were noted in regards to the initiation time of rehabilitation after the stroke onset.

CONCLUSIONSDepression limits gait recovery after stroke. The time of initiation of rehabilitation after stroke onset does not limit the motor recovery after rehabilitation program.

Adult ; Aged ; Depression ; physiopathology ; Female ; Gait ; physiology ; Humans ; Male ; Middle Aged ; Recovery of Function ; physiology ; Stroke ; physiopathology ; psychology ; Walking ; physiology