This study was designed to determine the effect of backpack loading on the gait pattern and corresponding compensatory strategy, which is important to the balance control of biped robot and military training. Five healthy subjects were instructed to walk at their preferred speed on level pathway taking three different loads i.e. 6 kg, 12 kg and 25 kg, on their backs. The results showed that the gait pattern was apparently influenced, and the dominant effects were found to be the flexion of hip, knee joints and pitch angle of torso. The stride speed decreased apparently with loading on their backs, but the stride length showed less changes. Besides, the responses to taking loads might be influenced by the strength of body. An apparent multi-joints coordination motor mode was employed to compensate the influences of loading, however, their contributions are different; hip, knee joints and torso pitch made dominant contributions to the compensation while ankle joints made minor. The anterior pitch of upper torso could be employed to adjust the overall center of mass while loading on their backs, the larger the magnitude of loading on their backs, the larger the anterior pitch angle of torso. After the heel touched the ground, the flexion of hip and knee joints were effective for the shock absorption, which means that the stiffness of hip and knee joints can be used to absorb the shock and avoid the trauma of each joints.
Adult ; Ankle Joint ; physiology ; Back ; physiology ; Gait ; physiology ; Hip Joint ; physiology ; Humans ; Knee Joint ; physiology ; Male ; Weight-Bearing ; physiology

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

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*

BACKGROUNDRestoration of both normal movement of the pelvis and centre of mass is a primary goal of walking rehabilitation in post-stroke patients because these movements are essential components of effective gait. The aim of this study is to quantitatively analyze the effect of ankle-foot orthosis on walking ability, and to investigate the correlation between improvements in trunk motion and walking capacity.

METHODSWalking speed, centre of mass displacement, and pelvic movements were examined in 20 post-stroke hemiparetic patients with and without ankle-foot orthosis using three-dimensional motion analysis.

RESULTSUsing ankle-foot orthosis improved walking speed, pelvic rotation and tilt, and lateral and vertical displacements of the centre of mass (P < 0.01). Moreover, the gait asymmetry index was significantly decreased (P < 0.01), and the Functional Ambulation Categories score improved significantly when patients used an ankle-foot orthosis (P < 0.05). There was significant correlation between improvements in the walking capacity and the displacement of the centre of mass in both vertical and lateral directions (P < 0.01).

CONCLUSIONSUsing ankle-foot orthosis improves the walking capacity by improving the stability and concordant of the trunk in hemiplegic patients. The improvement in the walking capacity from using an ankle-foot orthosis may be attributed to its prevention of foot drop and compensation for the instability of the ankle joint.

Adult ; Aged ; Ankle ; physiology ; physiopathology ; Ankle Joint ; physiology ; physiopathology ; Female ; Foot Orthoses ; Gait ; physiology ; Humans ; Male ; Middle Aged ; Stroke ; physiopathology ; Walking ; physiology

DLUT4060 piezoelectric multi-component force platforms and DVM8820 three-dimensional infrared image capture system were used to test the sit-to-walk (STW) movements of 11 healthy elderly (72. 6 +/- 12. 2 years old) and 11 healthy young (19. 7 +/-1. 3 years old) individuals. Firstly, we studied the effects of seat-heights on the ground reaction forces, the velocity of the center of mass, and action time duration. Then we discussed the movement strategies and falling risks of the persons in the two age groups respectively. Finally, we decided the best seat height for the two age groups. It was found that the best seat heights for both the two age groups were 100% popliteal height. This height may make the subject get the greatest biomechanical advantages and the lowest falling risks. The popliteal height must be concerned when designing and fixing up the public activity area facilities and daily life of the elderly. To some extent, it can reduce the falling risk of the elderly.
Accidental Falls ; prevention & control ; Aged ; Aged, 80 and over ; Ankle Joint ; physiology ; Buttocks ; physiology ; Hip Joint ; physiology ; Humans ; Interior Design and Furnishings ; Knee Joint ; physiology ; Leg ; anatomy & histology ; physiology ; Male ; Middle Aged ; Movement ; physiology ; Posture ; Weight-Bearing ; physiology ; Young Adult

OBJECTIVETo compare balance ability between elderly individuals who practiced Tai-Chi-Chuan (TCC) for average 9.64 years and elderly individuals who did not practice TCC and its relationship with lower extremity muscle strength and ankle proprioception.

METHODSTwenty-five elderly volunteers were divided into two groups according to their TCC practcing experience. Sixteen were TCC group and the other nine were control population. Subjects completed a static balance test and ankle proprioception test using a custom-designed evaluation system, and concentric and eccentric knee extensor and flexor muscle strength tests. Subjects stood on the plate form to measure the proprioception in functional standing position which was differed from the previous studies. Multiple linear regressions were also used to predict the important factor affecting balance.

RESULTSTCC group performed better than the control group in balance, proprioception, and muscle strength of lower extremity. The proprioception was the most important factor related to balance ability and it can be accounted for explaining 44% of variance in medial-lateral sway direction, and 53% of variance in antero-posterior sway direction. The proprioception may be a more important factor which affecting the balance ability.

CONCLUSIONTCC training is recommended to the elders; as it can improve balance ability through better proprioception.

Aged ; Ankle Joint ; physiology ; Female ; Humans ; Kinesthesis ; Linear Models ; Male ; Middle Aged ; Muscle Strength ; physiology ; Postural Balance ; physiology ; Posture ; physiology ; Proprioception ; physiology ; Tai Ji

OBJECTIVETo explore therapeutic effects of bone setting manipulation for the treatment of over degree II supination-eversion fractures of ankle,and analyze manipulative reduction mechanism.

METHODSFrom 2005 to 2008, 95 patients with over degree II supination-eversion fractures of ankle were treated respectively by manipulation and operation. There were 43 cases [11 males and 32 females with an average age of (44.95 +/- 12.65) years] in manipulation group, and 2 cases were degree II, 11 cases were degree III, and 30 cases were degree IV. There were 52 cases [21 males and 31 females with an average age of (39.96 +/- 13.28) years] in operative group,and 6 cases were degree II, 18 cases were degree III, and 28 cases were degree IV. Bone setting manipulation and hard splint external fixation were applied to manipulative group. Operative reduction internal fixation was performed in operative group. X-ray was used to evaluate reduction of fracture before and after treatment, 2 months after treatment. Ankle joint function was evaluated according to Olerud-Molander scoring system after 6 months treatment.

RESULTSAll patients were followed up with good reduction. Three cases occurred wound complication in operative group, but not in manipulative group. In manipulation group, 19 cases got excellent results, 20 cases good and 4 cases fair; while in operative group, 30 cases got excellent results, 20 cases good and 2 cases poor. There were no significant differences in fracture reduction and ankle joint function recovery between two groups (P > 0.05). Efficacy of operative treatment was better than that of manipulative treatment at degree IV fracture (P < 0.05).

CONCLUSIONBone setting manipulation is a good method for treating supination-eversion ankle joint fractures, which has advantages of simple and safe operation, reliable efficacy. For ankle join fracture at degree IV, manipulative reduction should be adopted earlier, and operative treatment also necessary

Adult ; Ankle Injuries ; physiopathology ; therapy ; Ankle Joint ; physiology ; Case-Control Studies ; Female ; Fractures, Bone ; physiopathology ; therapy ; Humans ; Male ; Manipulation, Orthopedic ; methods ; Supination

PURPOSE: To identify the characteristics of static standing balance and its postural control mechanisms during quiet side-by-side standing and the changes in these measures whilst wearing hinged ankle-foot orthoses (AFOs) in children with bilateral spastic cerebral palsy (CP). MATERIALS AND METHODS: Twenty-one children with bilateral spastic CP (6.10 +/- 1.09 year-old) and 22 typically developing (TD) children (5.64 +/- 0.49 year-old) were recruited. Pressure data were recorded while subjects with or without AFOs stood on dual force platforms and net body center of pressure (CoP) coordinates were calculated from this data. Net body CoP was traced for measuring mediolateral (ML) and anteroposterior (AP) displacement and path length per second. Correlation coefficients between parameters representing ankle, hip, and transverse body rotation strategies were also analyzed. RESULTS: ML and AP displacement and path length per second of the CoP trajectory were higher in children with CP compared to TD children (p < 0.05). There were no significant improvements in these parameters whilst wearing hinged AFOs. Compared to TD children, children with CP used less ankle strategy though more hip and transverse rotation strategies for postural control during quiet standing. Whilst wearing hinged AFOs, the contribution of ankle strategy was significantly increased for ML balance control in children with CP (p < 0.05). CONCLUSION: Hinged AFOs for children with CP may be helpful in improving the postural control mechanisms but not the postural stability in quiet side-by-side standing.
Ankle Joint/*pathology ; Cerebral Palsy/rehabilitation/*therapy ; Child ; Child, Preschool ; Humans ; Male ; *Orthotic Devices ; Postural Balance/*physiology

OBJECTIVETo analyze micromovement of distal tihiofihular joints in different motion range of ankle joint ,and define the micromovement characteristic and range of distal tibiofihular joints.

METHODSTwelve normal Chinese were chosen. There were 9 males and 3 females, aged from 19 to 37 years old with an average (26.5 +/- 0.5) years. Detection terminals of laser photographic scanner were installed near the highest point between medial malleolus and lateral malleolos, the change of detection terminals on the position of dorsiflex, extension, introversion and eversion of ankle joint were scanned by 3D-laser scanner. The displacement of two detection terminals on the X ,Y and Z-axis (X-axis stands for the vertical-axis between coronal plane and Z-axis Y-axis stands for the vertical-axis between sagittal plane and Z-axis Z-axis stands for macroaxis of tibia).

RESULTSAlong with increased range of motion on the position of dorsiflex ,extension, introversion and eversion of ankle joint, the range of micromovement of distal tibiofibolar joints increased too. The max-displacement of X, Y and Z were respectively (1.04 +/- 0.12) mm, (1.70 +/- 0.16) mm and--(0.87 +/- 0.10) mm.

CONCLUSION3D-laser scanner can be used to determine the detailed displacement of distal tibiofibolar joint on the X , Y and Z, and measure the motion of distal tibiofibular joint. The method can be used to study the pathologic change of distal tibiofibular joint ,and provide basic biomechnics data for internal fixtor fitting for the characteristic of distal tibiofibular joint.

Adult ; Ankle Joint ; physiology ; Asian Continental Ancestry Group ; Female ; Fibula ; Humans ; Male ; Movement ; Range of Motion, Articular ; Tibia ; Young Adult

OBJECTIVETo evaluate the effects of lower limb rehabilitation training of the patients with free fibula flap.

METHODSFifth-nine patients with free fibula flap were assigned to the intervention group (28 cases) and control group (31 cases). The patients in the intervention group underwent the lower limb rehabilitation training, but there was no training plan for the control group. The function of lower limbs were evaluated by Enneking questionnaire and physical examinations before operation, and 2 weeks and each month after operation till six months.

RESULTSThe rate of ankle swelling in the intervention group (61%) was significantly lower than in the control group (84%) at the 3rd month after operation (P < 0.05). In the intervention group, the scores of ankle varus, valgus, muscle power of the great toe, the Enneking scores of self-feeling, walking ability and total scores were significantly higher than in the control group (P < 0.05).

CONCLUSIONSPostoperative rehabilitation training can promote the recovery of lower limb function for the patients with free fibula flap.

Ankle Joint ; pathology ; physiology ; Exercise Therapy ; Female ; Fibula ; transplantation ; Free Tissue Flaps ; Hallux ; physiology ; Humans ; Lower Extremity ; physiology ; Male ; Mandibular Diseases ; surgery ; Range of Motion, Articular ; Recovery of Function ; physiology ; Walking ; physiology