The strategies to regulate and to modulate the propulsive forces during gait initiation in lower limb amputees

Michel, Véronique; Do, M.C.; Chong, Raymond

doi:10.1007/s00221-004-2001-3

Cited by 3 publications

(4 citation statements)

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“…Interestingly, replacement of one lower limb by a prosthesis does not affect the speed of progression, regardless of whether the stance limb was prosthetic or not. Most likely, other muscles take over the control of the duration of the stance phase of gait and of the BM CoM momentum (Michel and Do ; Michel and Chong ; Wentink et al. ).…”

Section: Resultsmentioning

confidence: 99%

By counteracting gravity, triceps surae sets both kinematics and kinetics of gait

et al. 2014

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In the single‐stance phase of gait, gravity acting on the center of mass (CoM) causes a disequilibrium torque, which generates propulsive force. Triceps surae activity resists gravity by restraining forward tibial rotation thereby tuning CoM momentum. We hypothesized that time and amplitude modulation of triceps surae activity determines the kinematics (step length and cadence) and kinetics of gait. Nineteen young subjects participated in two experiments. In the gait initiation (GI) protocol, subjects deliberately initiated walking at different velocities for the same step length. In the balance‐recovery (BR) protocol, subjects executed steps of different length after being unexpectedly released from an inclined posture. Ground reaction force was recorded by a large force platform and electromyography of soleus, gastrocnemius medialis and lateralis, and tibialis anterior muscles was collected by wireless surface electrodes. In both protocols, the duration of triceps activity was highly correlated with single‐stance duration (GI, R2 = 0.68; BR, R2 = 0.91). In turn, step length was highly correlated with single‐stance duration (BR, R2 = 0.70). Control of CoM momentum was obtained by decelerating the CoM fall via modulation of amplitude of triceps activity. By modulation of triceps activity, the central nervous system (CNS) varied the position of CoM with respect to the center of pressure (CoP). The CoM‐CoP gap in the sagittal plane was determinant for setting the disequilibrium torque and thus walking velocity. Thus, by controlling the gap, CNS‐modified walking velocity (GI, R2 = 0.86; BR, R2 = 0.92). This study is the first to highlight that by merely counteracting gravity, triceps activity sets the kinematics and kinetics of gait. It also provides evidence that the surge in triceps activity during fast walking is due to the increased requirement of braking the fall of CoM in late stance in order to perform a smoother step‐to‐step transition.

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Section: Resultsmentioning

confidence: 99%

By counteracting gravity, triceps surae sets both kinematics and kinetics of gait

et al. 2014

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“…Muscles in the trailing limb stabilize the body, during swing of the leading limb, and generate push-off. The execution phase ends at heel-strike of the leading limb [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…In TFA these two phases are similar, but the duration differs depending on which leg is leading, the prosthetic leg or the sound leg. It appears that TFA have the tendency to stand on their sound leg for as long as possible and load the prosthesis as short as possible [1,2,5].…”

Section: Introductionmentioning

confidence: 99%

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Intention detection of gait initiation using EMG and kinematic data

et al. 2013

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Gait initiation in transfemoral amputees (TFA) is different from non-amputees. This is mainly caused by the lack of stability and push-off from the prosthetic leg. Adding control and artificial push-off to the prosthesis may therefore be beneficial to TFA. In this study the feasibility of real-time intention detection of gait initiation was determined by mimicking the TFA situation in non-amputees. EMG and inertial sensor data was measured in 10 non-amputees. Only data available in TFA was used to determine if gait initiation can be predicted in time to control a transfemoral prosthesis to generate push-off and stability. Toe-off and heel-strike of the leading limb are important parameters to be detected, to control a prosthesis and to time push-off. The results show that toe-off and heel-strike of the leading limb can be detected using EMG and kinematic data in non-amputees 130-260 ms in advance. This leaves enough time to control a prosthesis. Based on these results we hypothesize that similar results can be found in TFA, allowing for adequate control of a prosthesis during gait initiation.

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Evaluation of the risk of falling in institution-dwelling elderly: clinical tests versus biomechanical analysis of stepping-up

Michel-Pellegrino

Hewson

Drieux

et al. 2007

2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Falls in the elderly constitute a major socio-economic problem for modern healthcare. The aim of the study was to extract biomechanical parameters to indicate balance level and the risk of falling in the elderly. It is a preliminary work as part of the development of a home-test based on force-plate technology. Seven faller and 12 non-faller elderly subjects performed stepped up onto a forceplate. Each subject was tested once per weekday for three weeks. Tinetti, Mini Mental Scale test (MMS) and the Geriatric Depression Scale (GDS) scores were measured before the experimentations. Temporal and ground reaction force parameters were measured. The Tinetti test was not correlated with falls in the following six-month period. In contrast, the biomechanical parameters related to the forces measured at foot-contact and to the durations of the phases of the stepping-up were correlated with fall, as well as with MMS and GDS. These results demonstrated that biomechanical parameters could be used as indicators of balance and risk of fall.

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The strategies to regulate and to modulate the propulsive forces during gait initiation in lower limb amputees

Cited by 3 publications

References 0 publications

By counteracting gravity, triceps surae sets both kinematics and kinetics of gait

By counteracting gravity, triceps surae sets both kinematics and kinetics of gait

Intention detection of gait initiation using EMG and kinematic data

Evaluation of the risk of falling in institution-dwelling elderly: clinical tests versus biomechanical analysis of stepping-up

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