The metatarsophalangeal (MTP) joint is not considered in most current walking assistive devices e... more The metatarsophalangeal (MTP) joint is not considered in most current walking assistive devices even though it plays an important role during walking. The purpose of this study was to develop a new MTP assistive device and investigate its effectiveness on the muscle activities of the lower extremities during walking while wearing the device. The MTP assistive device is designed to support MTP flexion by transmitting force through a cable that runs parallel with the plantar fascia. Eight participants were instructed to walk at a constant speed on a treadmill while wearing the device. The muscle activities of their lower extremities and MTP joint kinematics were obtained during walking under both actuated and non-actuated conditions. Paired t-tests were performed to compare the differences in each dependent variable between the two conditions. The muscle activity of the MTP flexor was significantly reduced during walking under actuated conditions (p = 0.013), whereas no differences we...
Journal of Mechanical Science and Technology, 2016
We investigated 3D kinematic and kinetic changes of knee and ankle during downhill walking as the... more We investigated 3D kinematic and kinetic changes of knee and ankle during downhill walking as the slope angle increased and evaluated biomechanical injury risk factors related to non-contact ACL injury. Fifteen male subjects performed level walking and 15° and 25° downhill walking. For the kinetic and kinematic parameters, one-way ANOVA and post-hoc tests were performed at a significance level of 0.05. This study revealed significant differences in 3D knee and ankle kinematics and kinetics among 0°, 15° and 25° downhill walking. The peak posterior ground reaction force, the peak knee anterior force and the knee valgus moment (0° vs. 15°: p < 0.05; 0° vs. 25°: p < 0.05) in the early stance phase increased as the slope angle increased. The peak knee internal tibial rotation moments in the late stance also increased (0° vs. 15°: p < 0.05; 0° vs. 25°: p < 0.05; 15° and 25°: p < 0.05) as the slope angle increased. These results showed the risk for ACL injuries may be increased during downhill walking with a greater slope angle.
International Journal of Precision Engineering and Manufacturing, 2020
The movement pattern during stair descent differs by gender, and this difference may be associate... more The movement pattern during stair descent differs by gender, and this difference may be associated with gender differences in muscle strength or activation. The purpose of this study was to determine whether a gender difference in muscle activation exists by comparing the muscle activation amplitude and co-activation of lower extremity muscles during the stair-to-ground descent transition. Fifteen men and thirteen women descended stairs and the muscle activation was measured. Women showed a significantly lower peak normalized electromyography amplitude of the vastus lateralis (women: 171.7% peak EMG activation amplitude for level walking (PEALW), men: 297.0%PEALW, p < 0.05). Additionally, women showed significantly elevated co-activation of the vastus lateralis and biceps femoris compared to men (p < 0.05). The lower amplitude of the vastus lateralis in women indicates lower recruitment of knee extensor. In conclusion, the significantly higher co-activation of the vastus later...
Classification of terrain is a vital component in giving suitable control to a walking assistive ... more Classification of terrain is a vital component in giving suitable control to a walking assistive device for the various walking conditions. Although surface electromyography (sEMG) signals have been combined with inputs from other sensors to detect walking intention, no study has yet classified walking environments using sEMG only. Therefore, the purpose of this study is to classify the current walking environment based on the entire sEMG profile gathered from selected muscles in the lower extremities. The muscle activations of selected muscles in the lower extremities were measured in 27 participants while they walked over flat-ground, upstairs, downstairs, uphill, and downhill. An artificial neural network (ANN) was employed to classify these walking environments using the entire sEMG profile recorded for all muscles during the stance phase. The result shows that the ANN was able to classify the current walking environment with high accuracy of 96.3% when using activation from all...
The metatarsophalangeal (MTP) joint is not considered in most current walking assistive devices e... more The metatarsophalangeal (MTP) joint is not considered in most current walking assistive devices even though it plays an important role during walking. The purpose of this study was to develop a new MTP assistive device and investigate its effectiveness on the muscle activities of the lower extremities during walking while wearing the device. The MTP assistive device is designed to support MTP flexion by transmitting force through a cable that runs parallel with the plantar fascia. Eight participants were instructed to walk at a constant speed on a treadmill while wearing the device. The muscle activities of their lower extremities and MTP joint kinematics were obtained during walking under both actuated and non-actuated conditions. Paired t-tests were performed to compare the differences in each dependent variable between the two conditions. The muscle activity of the MTP flexor was significantly reduced during walking under actuated conditions (p = 0.013), whereas no differences we...
Journal of Mechanical Science and Technology, 2016
We investigated 3D kinematic and kinetic changes of knee and ankle during downhill walking as the... more We investigated 3D kinematic and kinetic changes of knee and ankle during downhill walking as the slope angle increased and evaluated biomechanical injury risk factors related to non-contact ACL injury. Fifteen male subjects performed level walking and 15° and 25° downhill walking. For the kinetic and kinematic parameters, one-way ANOVA and post-hoc tests were performed at a significance level of 0.05. This study revealed significant differences in 3D knee and ankle kinematics and kinetics among 0°, 15° and 25° downhill walking. The peak posterior ground reaction force, the peak knee anterior force and the knee valgus moment (0° vs. 15°: p < 0.05; 0° vs. 25°: p < 0.05) in the early stance phase increased as the slope angle increased. The peak knee internal tibial rotation moments in the late stance also increased (0° vs. 15°: p < 0.05; 0° vs. 25°: p < 0.05; 15° and 25°: p < 0.05) as the slope angle increased. These results showed the risk for ACL injuries may be increased during downhill walking with a greater slope angle.
International Journal of Precision Engineering and Manufacturing, 2020
The movement pattern during stair descent differs by gender, and this difference may be associate... more The movement pattern during stair descent differs by gender, and this difference may be associated with gender differences in muscle strength or activation. The purpose of this study was to determine whether a gender difference in muscle activation exists by comparing the muscle activation amplitude and co-activation of lower extremity muscles during the stair-to-ground descent transition. Fifteen men and thirteen women descended stairs and the muscle activation was measured. Women showed a significantly lower peak normalized electromyography amplitude of the vastus lateralis (women: 171.7% peak EMG activation amplitude for level walking (PEALW), men: 297.0%PEALW, p < 0.05). Additionally, women showed significantly elevated co-activation of the vastus lateralis and biceps femoris compared to men (p < 0.05). The lower amplitude of the vastus lateralis in women indicates lower recruitment of knee extensor. In conclusion, the significantly higher co-activation of the vastus later...
Classification of terrain is a vital component in giving suitable control to a walking assistive ... more Classification of terrain is a vital component in giving suitable control to a walking assistive device for the various walking conditions. Although surface electromyography (sEMG) signals have been combined with inputs from other sensors to detect walking intention, no study has yet classified walking environments using sEMG only. Therefore, the purpose of this study is to classify the current walking environment based on the entire sEMG profile gathered from selected muscles in the lower extremities. The muscle activations of selected muscles in the lower extremities were measured in 27 participants while they walked over flat-ground, upstairs, downstairs, uphill, and downhill. An artificial neural network (ANN) was employed to classify these walking environments using the entire sEMG profile recorded for all muscles during the stance phase. The result shows that the ANN was able to classify the current walking environment with high accuracy of 96.3% when using activation from all...
Uploads