Stair ascent kinematics and kinetics with a powered lower leg system following transtibial amputation
ABSTRACT During stair ascent (STA) persons with transtibial amputation (TTA) typically adopt a hip strategy to compensate for the limited ankle motion and joint power that is characteristic of conventional energy storing and returning (ESR) prosthetic feet. The purpose of this investigation was to determine if providing ankle power via a powered prosthetic device (BiOM) normalized STA kinematics and kinetics. Eleven individuals with TTA participated in two STA gait analysis sessions: (1) using an ESR foot, and (2) using the BiOM. Eleven height and weight matched able-bodied controls (CONT) were also assessed. Lower extremity peak kinematic and kinetic values were calculated at a self-selected and controlled cadence (80 steps/min). Increased prosthetic limb peak ankle plantarflexion and push-up power were observed while using the BiOM as compared to ESR. Peak ankle power was not significantly different between BiOM and CONT indicating normalization of ankle power generation. However, peak ankle plantarflexion was significantly lower than CONT. Limb asymmetries including greater prosthetic limb hip flexion and power during stance, and decreased prosthetic limb knee power during stance were observed in the BiOM and ESR conditions. The results suggest that the BiOM successfully increased ankle motion and restored ankle power during STA. These differences did not, however, reduce the use of a hip strategy while ascending stairs. Additional device specific training may be necessary to utilize the full benefits of the device.
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- "However , investigations into LLA function during challenging motor tasks similar to stepping gait, such as stair negotiation and obstacle crossing, have outlined specific biomechanical adaptations which may also be adopted during LLA stepping gait. For example, during stair descent, transtibial amputees (TTA) maintain the affected lead limb in an extended position in an attempt to reduce the demands on the knee extensor musculature, avoiding potential limb buckling, whilst during stair ascent intact trail limb ankle plantarflexion and knee extension during stance aids the elevation of the COM in preparation for affected limb stance (Aldridge et al., 2012; Alimusaj et al., 2009; Jones et al., 2006; Powers et al., 1997; Ramstrand and Nilsson, 2009; Schmalz et al., 2007; Vanicek et al., 2010; Winter and Sienko, 1988). When "
ABSTRACT: Background: Negotiating a raised surface during continuous gait is an important activity of daily living and is a potentially hazardous task with regards to trips, falls and fall-related injury. However, it is not known how recent transtibial amputees adapt to performing stepping gait tasks in the 6-month period following discharge from rehabilitation. Methods: Recent transtibial amputees performed continuous gait trials, stepping onto and from a raised surface walkway representing the height of a street kerb, whilst kinematic and kinetic data were recorded at one, three and six months post-discharge from rehabilitation. Findings: Walking speed increased when stepping down (p = 0.04) and was invariant across the study period when stepping up. At one month post-discharge, participants displayed an affected lead limb preference (90.8%) when stepping down and an intact lead limb preference (70.0%) when stepping up, although these lead limb preferences diminished over time. Participants spent more time in stance on the intact limb compared to the affected limb in both stepping down (trail limb) (p = 0.01) and stepping up (lead and trail limbs) (p = 0.05). Participants displayed significantly greater joint mobility and power bursts in the intact trail limb when stepping down and in the intact lead limb when stepping up. Interpretation: Transtibial amputees prefer to exploit intact limb function to a greater extent, although over time, the means by which this occurs changes which affects the initial lead limb preferences. The results from the current study enable future evidence-based therapeutic and prosthetic interventions to be designed that improve transtibial amputee stepping gait.Clinical biomechanics (Bristol, Avon) 06/2014; 29(7). DOI:10.1016/j.clinbiomech.2014.05.012 · 1.88 Impact Factor
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- "Load patterns in this study were similar to those observed in the gait analysis literature for corresponding tasks, points and anatomical planes, both in healthy subjects (Protopapadaki et al., 2007; Beaulieu et al,. 2008) and in individuals with transtibial amputation (Sanderson and Martin, 1997; Powers et al., 1998; Schmalz et al., 2007; Alimusaj et al., 2009; Vanicek et al., 2010; Aldridge et al., 2012; Sinistski et al., 2012; Rueda et al., 2013). Fig. 5. Same selection of plots of Fig. 4 "
ABSTRACT: External load at the tibia during activities of daily living provides baseline measures for the improvement of the design of the bone–implant interface for relevant internal and external prostheses. A motion analysis system was used together with an established protocol with skin markers to estimate three-dimensional forces and moments acting on ten equidistant points along the tibial shaft. Twenty young and able-bodied volunteers were analysed while performing three repetitions of the following tasks: level walking at three different speeds, in a straight-line and with sudden changes of direction to the right and to the left, stair ascending and descending, squatting, rising from a chair and sitting down. Moment and force patterns were normalised to the percentage of body weight per height and body weight, respectively, and then averaged over all subjects for each point, about the three tibial anatomical axes, and for each task. Load patterns were found to be consistent over subjects, but different among the anatomical axes, tasks and points. Generally, moments were higher in the medio/lateral axis and influenced by walking speed. In all five walking tasks and in ascending stairs with alternating feet, the more proximal the point was the smaller the mean moment was. For the remaining tasks the opposite trend was observed. The overall largest value was observed in the medio/lateral direction at the ankle centre in level walking at high speed (9.1% body weight * height on average), nearly three times larger than that of the anterior/posterior axis (2.9) during level walking with a sidestep turn. The present results should be of value also for in-vitro mechanical tests and finite element models.Journal of Biomechanics 03/2014; 47(5):2014. DOI:10.1016/j.jbiomech.2014.01.045 · 2.50 Impact Factor
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ABSTRACT: BACKGROUND: Recent research has focused on the design of intelligent prosthetic ankle devices with the goal of adapting behavior of the device to accommodate all walking surfaces that an individual encounters in daily life. To date, no studies have looked at how such devices perform on uneven terrain. METHODS: 11 young adults with unilateral transtibial amputation participated in two data collection sessions spaced approximately 3weeks apart. In each session they walked across a loose rock surface at three controlled speeds. In the first session, they wore a passive, energy storage and return prosthesis and in the second, they wore a powered prosthesis (BiOM, iWalk, Bedford, MA, USA). FINDINGS: Subjects had a 10% faster self-selected walking speed when wearing the powered (1.16m/s) compared to unpowered prosthesis (1.05m/s; p=0.031). They walked with increased ankle plantarflexion on their prosthetic limb throughout the gait cycle when wearing the powered compared to unpowered prosthesis. This was especially evident in the increased plantarflexion during push-off (p<0.001). There was a small (<3°), but statistically significant decrease in knee flexion during early stance when wearing the powered device (p=0.045). Otherwise, the kinematics of the knee and hip were nearly identical when wearing the different devices. Subjects had decreased medial-lateral motion of their center of mass when wearing the powered prosthesis (p=0.020), but there were no differences in medial-lateral margins of stability between the devices (p=0.662). INTERPRETATION: Subjects did not significantly alter their proximal joint kinematics on this irregular surface as a result of the addition of power.Clinical biomechanics (Bristol, Avon) 04/2013; 28(4). DOI:10.1016/j.clinbiomech.2013.03.005 · 1.88 Impact Factor