People experiencing mobility deficiencies in their lower limbs caused by genetics, injuries, diseases, etc. struggle with their physical and mental health. The goal of this research is to design an exoskeleton that will connect the upper limb (e.g., arm extension) to the ankle joint during walking movements. We advanced the first prototype of the Workshare Upper Lower Limb (WULL) by only targeting the ankle joint as the lower limb component. We found that this change would have the biggest impact on an individual's walking movements. The benefit of this research will be found in answering the question: will harnessing the kinetic energy from a person's upper limb (e.g., arm extension or arm flexion) to transfer into the ankle joint for gait assistance reduce the lower limb muscle activation during walking movements? A series of experiments were run to test the efficacy of the wearable device. Six participants were fitted to the device and six electromyography (EMG) sensors to track the muscle activation during a comfortable walking pace. This gait analysis study used pressure insoles to calculate ground reaction forces and multiple IMUs to track the individuals' limbs and joints kinetic motion. The overall effectiveness of the device was explored based on the data collected in this study. This device decreased muscle activation of the gastrocnemii medialis and increased the anterior deltoid activation. These results support the goal of the experiment to utilize the upper limbs (anterior deltoid) to assist the lower limbs (ankle joint) during walking.

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Electromyography (EMG) is a common tool in electrical muscle activity measurement and can be used in multiple areas of clinical and biomedical applications, mainly in identifying neuromuscular diseases, analyzing movement or in human machine interfaces. Traditionally a pair of electrodes were used to measure the signals, but in recent years the use of high density surface EMG (HD-sEMG) gained more popularity as it can sample myoelectric activities from multiple electrodes in an array on a single muscle and provide more information. In this thesis a measurement setup and protocol is proposed that can provide a reliably measurement, furthermore multiple features are extracted from the collected signals to characterise the major muscles around the ankle. 5 healthy subjects were tested using an ankle dynamometer with 5 HD-sEMG placed on the Tibialis Anterior, the Gastrocnemius Medialis, the Soleus, the Gastrocnemius Lateralis, and on the Peroneus Longus. Several tests were conducted using different initial angle of the ankle joint and different percentages of the maximum voluntary contraction. The reliability of the setup was assessed by comparing the variance between the collected signals of the same subject in a repeated test, and by comparing different subjects to each other. Results show a reasonably good reliability with less than $10\%$ variance, and adequate selectivity as well. To examine the muscle characteristics, 7 features were extracted from the collected and processed signals, then the features were plotted and compared to signs for muscle characteristics such as muscle fatigue, activation, and spatial distribution of activation. Correlations between features of mean average value (MAV) and zero crossing (ZC), and different muscle characteristics could be observed.

No / Unilateral lower-limb amputees lead with their intact limb when stepping up and with their prosthesis when stepping down; the gait initiation process for the different stepping directions has not previously been investigated. Ten unilateral amputees (5 transfemoral and 5 transtibial) and 8 able-bodied controls performed single steps up and single steps down to a new level (73 and 219 mm). Duration, a-p and m-l centre of mass and centre of pressure peak displacements and centre of mass peak velocity of the anticipatory postural adjustment and step execution phase were evaluated for each stepping direction by analysing data collected using a Vicon 3D motion analysis system. There were significant differences (in the phase duration, peak a-p and m-l centre of pressure displacement and peak a-p and m-l centre of mass velocity at heel-off and at foot-contact) between both amputee sub-groups and controls (P<0.05), but not between amputee sub-groups. These group differences were mainly a result of amputees adopting a different gait initiation strategy for each stepping direction. Findings indicate the gait initiation process utilised by lower-limb amputees was dependent on the direction of stepping and more particularly by which limb the amputee led with; this suggests that the balance and postural control of gait initiation is not governed by a fixed motor program, and thus that becoming an amputee will require time and training to develop alternative neuromuscular control and coordination strategies. These findings should be considered when developing training/rehabilitation programs.

Yes / /Aims: Partial weight-bearing protocols are commonly incorporated into hospital, clinical and field-based rehabilitation to enhance recovery, particularly in patients following cartilage surgeries. Overloading can affect healing time and the stability or integrity of the healing structure, however underloading can also be detrimental, as adequate weight bearing encourages the healing process—for example, osteoblastic stimulation. Therefore, accurate reproducibility of these protocols could be considered essential to the rehabilitation process. The aim of this study was to determine the accuracy with which weight-bearing protocols (20%, 50% or 80% of body weight) could be reproduced shortly after being taught. Methods: Thirty participants were taught three partial weight-bearing protocols (20%, 50% and 80% of body weight), using bathroom scales. Participants ability to reproduce their target load for each protocol was assessed statically using bathroom scales and dynamically with a force plate using a three-point elbow crutch-assisted gait. Participants were assessed 10 minutes after being taught. Errors between actual and target load during these trials was calculated. Findings: Accuracy assessed with scales was comparatively good for all target loads, however dynamic trials using the force plate showed an inverse relationship between all error measures and target loads (i.e. 20% > 50% > 80% body weight; all P<0.01). The peak error was double the intended load at 20% of body weight (95% CI: 11.9% body weight, 24.1% body weight). At 80% of body weight, the peak error was not significantly different from zero. Conclusions: The static method of instruction of partial weight-bearing protocols, using bathroom scales, does not seem to translate accurately to dynamic motion, and therefore affects adherence to medical instruction. Practitioners should be aware of the potential errors in reproducing these loads and the potential effect on rehabilitation. These results would suggest that practitioners should be cautious when using bathroom scales to teach partial weight-bearing protocols and not to rely on them to assess reproduction accuracy during gait

Yes / Partial weight bearing protocols are commonly incorporated into rehabilitation to enhance recovery. Patients are often prescribed protocols that refer to a percentage of their body weight, such as 20% weight bearing, that should be placed through the healing limb during activities such as walking (gait). In order to achieve these partial weight baring protocols patients are usually provided with walking aids such as crutches. Accurate reproducibility of and compliance with these protocols could be considered essential to the rehabilitation process, however poor reproducibility of partial weight bearing protocols during crutch assisted gait using a current method of instruction has been shown. Aims: The aim of this study was to determine whether a more dynamic method of partial weight bearing protocol instruction, was more accurately reproduced. Methods: In total, 16 participants were randomly allocated to one of two groups and were taught 20% partial weight bearing using two different methods of instruction. A participant’s ability to reproduce their target load using crutch assisted gait was assessed using a force plate. Findings: The mean error for the static method of instruction was significantly greater than the more dynamic method. Conclusion: As seen previously, the static method of instruction of partial weight bearing protocols, using bathroom scales, does not seem to translate accurately to dynamic motion; however, the more dynamic method assessed in this study appears to result in more accurate reproducibility.

L’objectif de ce travail de thèse est de caractériser, chez les amputés unilatéraux du membre inférieur, les modalités posturales qui interviennent dans la régulation de l’équilibre orthostatique et d’étudier l’impact de l’amputation sur la production de force à la cheville physiologique. Une première étude a révélé la présence de trois modalités posturales afin de réguler le contrôle postural : les amputés transfémoraux adoptent une modalité posturale basée sur les paramètres de stabilité, les amputés transtibiaux optent pour une modalité posturale mixte et les non amputés se réfèrent aux paramètres de l’attitude posturale. Etant donné que l’articulation de la cheville joue un rôle essentiel dans la régulation de l’équilibre postural, il était alors pertinent d’investiguer la production de force à la cheville physiologique. Toutefois, les ergomètres permettant d’étudier l’articulation de la cheville présentent des biais de mesure majeurs. Dans ce cadre, une deuxième étude a été menée afin de développer et valider un nouvel ergomètre pour cheville : le B.O.T.T.E. Parallèlement, la mise en place d’une méthode de mesure basée sur le retour visuel permettant une quantification fiable du couple de force a fait l’objet d’une troisième étude. Ensuite, une quatrième étude visait à utiliser le B.O.T.T.E. pour investiguer l’impact de l’amputation sur la production de force à la cheville physiologique. Les résultats de cette étude confirment la présence d’un déficit au niveau du couple de force généré en flexion plantaire (conditions maximale et sous maximale) chez les amputés transfémoraux. Enfin, ce travail de thèse vise à aider les rééducateurs et les cliniciens à optimiser la prise en charge des patients amputés. / This Ph.D. thesis aims to evaluate the standing posture modalities and the ankle joint torque in the intact limb in unilateral lower limb amputees. A first study shows the presence of three posture modalities: the non-amputee group relied on standing erect, the transfemoral amputees’ stance depended on balance control and the transtibial amputees exhibited a mixed modality of simultaneously maintaining an upright stance and standing balance. Since the ankle muscles have a functional importance in standing posture modalities, it is imperative to investigate the ankle joint torque in the intact limb. However, the current devices used to assess the ankle joint present substantial limitations for the measurement. Thus, a second study was designed to develop and to validate a new ankle ergometer B.O.T.T.E. Moreover, a third study was achieved in order to estimate the effect of visual feedback on enhancing isometric maximal voluntary contractions. A fourth study was realized to investigate the ankle joint torque in the intact leg of unilateral lower limb amputees. The results show that transfemoral amputees produce less torque and are less steady compared to transtibial amputees and able-bodied individuals. Overall, the present findings of this Ph.D. thesis could have implications for clinical practice and for rehabilitation of patients with a lower limb amputation.

The purpose of the present investigation was to: 1) Determine the relationship between cardiac output (estimated using the acetylene rebreathing methodology) and oxygen consumption in a homogeneous group of men who are paraplegic. 2) Investigate whether lower limb elevation increases stroke volume and decreases heart rate at rest and during submaximal arm exercise. 3) Investigate whether the application of constant circumferential pneumatic pressure applied to dependent lower limbs increases stroke volume and decreases heart rate at rest and during submaximal arm exercise.