The implication of backward walking in the rehabilitation of neuro-musculoskeletal conditions: systematic reviews and a biomechanical movement analysis

A thesis submitted to the Faculty of Health Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy in Physiotherapy, Johannesburg, South Africa 2018The neuro-musculoskeletal gait impairments have an enormous and growing impact in the world. Estimation shows that one in four people suffer from gait impairments as a major limitation. It reduces the quality of life with poor balance, muscle fatigue, joint stiffness and deformity. To treat neuromuscular gait impairments proper rehabilitation training is crucial. Walking is one of the functional training used by therapist for rehabilitation. Though, walking refers a forward walking (FW) in our daily life backward walking (BW) was reported for an effective functional exercise in rehabilitation. The underlying biomechanical characteristics such kinetic and kinematic parameters of both FW and BW were studied to understand and predict the clinical benefits. Biomechanical characteristics of FW were studied extensively with respect to speed, inclination, and surface. Whereas, limited reports on BW were found with level and uphill walking with comfortable/fixed speed on both ground and treadmill. It is important to study biomechanical characteristics with respect to speed and inclination to understand neural control strategies and musculoskeletal activities during BW. This helps to evaluate their clinical worthiness before implementing on patients. The comparison of FW with BW as a systematic review is an optimum way to reveal their clinical benefits and unique changes in locomotion task. As there is no systematic review is available in the literature, the present thesis designed with two systematic reviews and an experimental study. In brief the methodologies followed in this thesis were as follow: The two systematic reviews identified existing literature based on a structured search strategy applied to various databases. The outcomes were statistically analysed by RevMan software. For experimental study, 3Dkinematic movements were tracked by reflective markers using Qualisys cameras. Force plate integrated treadmill was used to measure GRF and muscle activities were recorded by wireless EMG. These Qualisys camera, treadmill and EMG were synchronised with QTM software. The collected data were analysed and processed through Visual3D software. The processed data were used to simulate an anthropometric model via OpenSim software. This software was used to calculate the kinematic and kinetic parameters. The first systematic review in Chapter-3 explores the clinical effectiveness of BW as a functional training for neuro-musculoskeletal gait impairment condition. This review dealt with six types of comparison with BW as an experimental group. The systematic search strategy finalises the eight trials with three conditions such as knee osteoarthritis (OA), stroke, and diabetic peripheral neuropathy. The primary outcome measures were the pain, functional disability, muscle strength, gait parameters, balance and plantar pressure. The results show BW with CPT was significantly effective in reducing knee OA pain (total SMD: -0.87), lowering functional difficulties (total SMD: -1.39) and improving muscle strength (SMD: 1.51). In conclusion BW with CPT is an effective and clinically worthwhile training for rehabilitation of knee OA. The second systematic review in Chapter-4 deals with biomechanical characteristics BW through comparison of FW for healthy participants to understand neuromuscular contributions. Twenty trials were found through systematic search strategy for kinematic and kinetic outcomes. The results show that BW significantly different from FW with lower hip flexion, knee flexion, tibiofemoral joint reaction force, ankle joint power, hip joint power, GRF and temporal gait parameters. The muscles GM, BF, RF, and LGAS are more active in BW than FW. Hence, the modified neural control strategies were required to produce BW from FW. The absence of visual cues in BW improves the neuromuscular control, proprioception and protective reflexes. Among the trials, BW in water found to be safer and yields better results than ground and treadmill. The experimental study in Chapter-5 analysed biomechanical characteristics of FW and BW with controlled speed and inclination. Ten healthy participant were chosen for FW and BW in three inclinations (-5%, 0% and +5%) and speeds (0.28 m/s, 0.69 m/s and 1.11 m/s). The study concludes that, walking speed is directly related to energy requirements. Increasing the speed requires higher magnitudes of the joint moment, joint power and muscle activity irrespective of inclination and direction. In FW and BW, uphill and downhill task produces opposite joint moment with a variety of flexor and extensor muscles contributions. These indicate that the motor control task requires different control strategies for inclined walking. The anatomical constraint and visual cues give additional features in biomechanical parameters of BW. Hence, a simple time reversal is not sufficient to distinguish between BW and FW. Interestingly, the similarities were observed between FW uphill and BW downhill or FW downhill and BW uphill in hip/knee joint moment and muscle activities. Such as during FW uphill and BW downhill an extension moment was present at the hip joint and a flexion moment at the knee joint. Here, the biarticular muscles BF was active in both types of walking. But we cannot conclude both types of walking were controlled by the same neural network as power patterns were distinctly different. The distributions of total power flow among joints were found to be related to the posture associated with the inclination in both FW and BW. Ankle contribution is more in both FW uphill and BW downhill (leaned trunk) whereas hip contributes for FW downhill and BW uphill (erected trunk). In level walking ankle dominates in both FW and BW irrespective of speeds. The ankle joint had main propulsion at all inclination and speed during FW and BW except FW uphill.XL201

How are human gait and energetics modified when walking over substrates of varying compliance?

Locomotion in the real-world requires humans to negotiate a variety of surfaces that have different material and mechanical properties and thus, require gait adjustments to maintain stability and efficiency. However, our current understanding of human gait and energetics is dominated by studies on hard, level surfaces in a laboratory environment. Previous research has shown that when walking on more irregular terrains such as loose rock surfaces, uneven surfaces and compliant substrates such as snow, grass and sand, there is an increase in energy expenditure. However, the primary mechanistic causes of this increase in energy costs is unclear. Previous studies suggest various biomechanical mechanisms including disruption to pendular energy recovery, increased muscle work, decreased muscle-tendon efficiency and increased gait variability. Yet, comparisons between studies is hindered by the measurement of different variables across studies and variation in substrates used. In this thesis, I focus on human walking over compliant substrates. This thesis aims to improve our understanding of the relationship between energetic costs, substrate properties, gait biomechanics and muscle activities. This is done by presenting a large experimental data set of human walking on both artificial (foam) and natural (sand) compliant substrates. The studies showed that compliant substrates had a considerable effect on gait biomechanics, muscle activation and energetics. On foam, there was greater energetic expenditure on more compliant substrates. On all compliant substrates, participants displayed greater ankle dorsiflexion during stance and greater knee and hip flexion during swing, increased muscle activation and changes to spatiotemporal parameters such as increased cycle time, stance time and swing time and decreased walking speed. The findings of this thesis suggests that overall gross adaptations like sagittal kinematics, spatiotemporal parameters and muscle activation are adopted in response to the depth of depression into a compliant substrate. However, there are specific gait changes due to substrate properties. Further research is required to explore gait adaptations on substrates with different material and mechanical properties. Furthermore, some of our results suggest there is large participant variability even in a relatively homogeneous study population. Therefore, future work should not only look at other demographic groups but also explore individual participant differences such as gender effects and variations in anatomical parameters

Biomechanical, muscle activation and clinical characteristics of chronic exertional compartment syndrome

Chronic exertional compartment syndrome (CECS) is a common problem within both military and athletic populations that can be difficult to diagnose. Furthermore, it is unclear what causes the development of CECS, particularly in the military population, as personnel undertake a variety of activities that can cause pain with CECS such as fast walking, marching and running. Chronic exertional compartment syndrome has been hypothesised to develop due to excessive muscle activity, foot pronation and abnormal biomechanics predominantly at the ankle. Treatment of CECS through running re-education to correct these abnormalities has been reported to improve symptoms. However no primary research has been carried out to investigate the biomechanical, muscle activation and clinical characteristics of military patients with CECS. The purpose of this thesis was to provide an original contribution to the knowledge through the exploration of these characteristics; and the development of insights into the development of CECS, with implications for prevention and treatment. Study one investigated the clinical characteristics of 93 service personnel with CECS. Plantar pressure variables, related to foot type and anterior compartment muscle activity, and ankle joint mobility were compared during walking between 70 cases and 70 controls in study two. Study three compared three-dimensional whole body kinematics, kinetics and lower limb muscle activity during walking and marching between 20 cases and 20 controls. Study four compared kinematics and lower limb muscle activity during running in a separate case-control cohort (n=40). Differences in electromyography (EMG) intensity during the gait cycle were compared in the frequency and time domain using wavelet analysis. All studies investigated subject anthropometry. Cases typically presented with bilateral, ‘tight’ or ‘burning’ pain in the anterior and lateral compartments of the lower leg that occurred within 10 minutes of exercise. This pain stopped all cases from exercising during marching and/or running. As such subsequent studies investigated the biomechanics of both ambulatory and running gaits. Cases in all case-control studies were 2-10 cm shorter; and were typically overweight resulting in a higher body mass index (BMI) than controls. There was strong evidence from study 3 that cases had greater relative stride lengths than controls during marching gait. This was achieved through an increase in ankle plantarflexion during late stance and a concomitant increase in the gastrocnemius medialis contraction intensity within the medium-high frequency wavelets. Given the differences in height observed, this may reflect ingrained alterations in gait resulting from military training; whereby all personnel are required to move at an even cadence and speed. These differences in stride length were also observed in walking and running gaits although to a lesser extent. There was no evidence from the EMG data that cases had greater tibialis anterior activation than controls during any activity tested, at any point in the gait cycle or in any frequency band. In agreement, there was also no evidence of differences between groups in plantar pressure derived measures of foot type, which modulate TA activity. Toe extensor - related plantar pressure variables also did not differ between groups. In summary, contrary to earlier theories, increased muscle activity of the anterior compartment musculature does not appear to be associated with CECS. The kinematic differences observed during running only partially matched the clinical observations previously described in the literature. Cases displayed less anterior trunk lean and less anterior pelvic tilt throughout the whole gait cycle and a more upright shank inclination angle during late swing (peak mean difference 3.5°, 4.1° and 7.3° respectively). However, no consistent differences were found at the ankle joint suggesting that running is unlikely to be the cause of CECS in the military; and that the reported success of biomechanical interventions may be due to reasons other than modifying pathological aspects of gait. In summary, the data presented in the thesis suggest that CECS is more likely to develop in subjects of shorter stature and that this is associated with marching at a constant speed and cadence. Biomechanical interventions for CECS, such as a change in foot strike or the use of foot orthotics, are unlikely to be efficacious for the military as personnel will continue to be required to march at prescribed speeds to satisfy occupational requirements. Preventative strategies that allow marching with a natural gait and/or at slower speeds may help reduce the incidence of CECS. The lack of association with foot type or muscle activity suggests that foot orthoses would not be a useful prevention strategy or treatment option for this condition.Headley Court Trustees - funding of student fee

Effects of the use of occlusal splints on the neuromuscular function

Dispositivos orais, tais como as goteiras, têm sido promovidos como um meio para aumentar a performance desportiva. As goteiras promovem variações na posição do maxilar e como conseguinte criam alterações na articulação temporomandibular (ATM) e nos músculos masticatórios. Estudos têm sido feitos sobre os seus efeitos, a nível neuromuscular e fisiológico, para determinar as mudanças causadas pela sua utilização. Contudo, devido à escassez de estudos nesta área, bem como a lacunas nas metodologias usadas, não é possível dar uma resposta definitiva sobre a possível influência das goteiras na capacidade neuromuscular e na performance desportiva. Deste modo, o objetivo desta tese foi determinar os efeitos agudos da utilização de goteiras em diferentes aspetos da função neuromuscular. Para tal, cinco estudos foram realizados: 1) Uma revisão sistemática, que revelou evidências do efeito positivo das goteiras em tarefas isométricas do trem superior, para sujeitos destreinados; 2) Um estudo que demonstrou que as goteiras melhoram a força e atividade muscular em tarefas isocinéticas do trem superior, para sujeitos destreinados; 3) Um estudo que determinou que, em jogadores de rugby, as goteiras não aumentaram a força do trem superior num movimento balístico, mas com protetores bocais customizados aumentavam o pico de força e o pico de aceleração, embora outros parâmetros de força e potência não tenham sido afetados; 4) Um estudo que analisou a oscilação do corpo na marcha e corrida através da análise cinemática e não encontrou diferenças em função da utilização de goteiras; e 5) Um estudo que observou a oscilação do centro de pressão, a atividade EMG de músculos do membro superior e a precisão no alvo de atletas do tiro enquanto utilizavam goteiras e não encontrou diferenças em nenhum dos parâmetros. O efeito ergogénico das goteiras, ocorreu de forma clara em ações de força dinâmica do trem superior e em sujeitos destreinados. Protetores bocais customizados, que reposicionam em atletas treinados a ATM numa posição idêntica ás goteiras, melhoraram alguns parâmetros de força e aceleração em movimentos balísticos do trem superior, mas não afetaram outros parâmetros. Futuras investigações devem confirmar estas hipóteses, bem como averiguar o efeito a longo prazo da utilização de goteiras.Oral appliances, such as occlusal splints (OS), have been advocated as a mean to improve high-level sports performance. OS promote variations in jaw position and therefore create a change in the temporomandibular joint (TMJ) and on the masticatory muscles. They have been a subject of research, at neuromuscular and physiological level, to determined changes derived from the use of such devices. However, due to a paucity of research studies, and limitations on the used methods in the performed studies, it is not possible to give a correct and definite answer to the possible influence of OS on neuromuscular function and in the human sports performance. Therefore, this thesis aimed to ascertain the acute effects of occlusal splints on neuromuscular function. Five studies were conducted to achieve this purpose: 1) a systematic review, which revealed evidence of the effects of OS in upper body isometric tasks, for untrained healthy subjects; 2) a study that showed that OS enhance strength and muscle activity in upper body isokinetic tasks for untrained subjects; 3) a study which determined that for rugby athletes, OS did not increase strength in an upper body power movement, but a customized mouthguard increased peak force and peak acceleration despite other force and power did not change; 4) a study that analyzed kinematic body oscillation in gait and running and found no changes when using OS; and 5) a study that found no changes in body sway, EMG from upper limb muscles and shooting accuracy in pistol shooters while using OS. The ergogenic effect of OS was found in the dynamic strength performed by untrained subjects. Customized mouthguards, that reposition, for trained athletes, TMJ in an identical position as OS, increased some parameters of strength and acceleration but did not change other parameters. Future research should confirm these findings, while also determining the long-term effect of using OS

A randomised control trial for the restoration of functional ability in patients post total knee arthroplasty: Eccentric versus concentric cycling ergometry

Introduction: While the total knee arthroplasty procedure improves joint-specific outcomes, including pain and range of movement, functional deficits post-surgery has been noted. Movement abnormalities and quadriceps weakness of the operated limb, as well as a decrease in strength on the non-operated have been widely reported. Recovery of strength and function to normal levels is also rare, thereby predisposing patients to future disability with increasing age. The purpose of this study was to determine the effects of an eight-week eccentric cycling ergometry exercise intervention versus a concentric cycling ergometry exercise intervention in total knee arthroplasty recipients three to nine months post-surgery. This study aimed to a) investigate the change in joint kinetics, kinematics and muscle activity during the phases of gait, between the eccentric and concentric groups over time and b) To determine if an eccentric cycling exercise intervention produces greater improvements in knee function when compared to concentric cycling exercise. Methods: Eighteen participants, three to nine months post total knee arthroplasty were recruited and randomly assigned to either an eccentric or concentric cycling exercise intervention group. Participants performed three exercise sessions weekly over a progressive eight-week period on the Grucox Isokinetic Ergometer. Walking gait analyses and functional outcomes, as measured by the six-minute walk test and validated knee scores (Knee Injury and Osteoarthritis Outcome Score, SF-36 Health Survey and Tegner Activity Scale) were recorded pre- and post-intervention. Results: The concentric group knee flexion range of movement increased significantly during the swing phase of gait (p=0.021) post-intervention together with a significant increase in the peak knee flexion angle during swing (p=0.038). The concentric group showed significant differences between pre and post-rehabilitation in knee flexion range of movement during the swing phase of gait (p=0.030). Significant correlations between knee joint stiffness and the quadriceps:hamstring co-activation ratio were observed in the concentric intervention group pre-intervention: during the pre-activation phase of gait between knee joint stiffness and vastus medialis / biceps femoris (r=-0.68; p=0.042) and during load acceptance phase of gait between knee joint stiffness and vastus lateralis / biceps femoris (r=0.07; p=0.036). The eccentric group recorded neuromuscular changes post-intervention with a significant decrease in the muscle activity of the biceps femoris during load acceptance phase of gait (p=0.021). The eccentric group had significantly better functional outcomes in the overall score of Knee injury and Osteoarthritis Outcome post-intervention (p=0.008) with a significant increase in function seen in the Sports and Recreation subgroup (p=0.008) and a significant increase in the level of activity as measure by the Tegner Activity Scale post-intervention (p=0.028), despite not showing any significant changes in the knee joint kinetics and kinematics. The concentric group only reported a significant increase in the overall score of the of the SF-36 Health Survey (p=0.011) with significant increases in three of the subgroups post-intervention: Bodily pains had improved (p=0.042), the role limitations due to physical heath had improved (p=0.028) and the role limitations due to emotional health had also improved (p=0.009). The concentric group also showed significant improvement in the emotional health over the intervention in comparison to the eccentric intervention group (p=0.020). Both intervention groups reported a similar significant increase in the distance covered during the six-minute walk test post-intervention (p=0.038). Conclusion: The results of this exploratory study did not find the eccentric cycling rehabilitation intervention exclusively more effective than the concentric cycling intervention in the restoration of functional ability in patients post-TKA. The eccentric intervention did however result in neuromuscular adaptations consistent with a move towards a more typical asymptomatic gait pattern and participants reported greater functional improvements on validated knee functional assessments and levels of activity scores. The concentric intervention yielded kinematic changes and participants reported improvements in their emotional and physical health post-intervention. Eccentric training and its role in early stage post-operative rehabilitation is limited. Based on the findings from this exploratory study, the benefit of eccentric training as an adjunct to rehabilitation and its role in contributing to greater improvements in the restoration of functional ability post-TKA needs to be further explored

The Association Between Quadriceps Activity and Loading Variables During Walking Gait in Individuals with ACL-R

Quadriceps dysfunction following ACL-R may contribute to the development of OA due to the inability of the muscles to attenuate impact forces. Both the timing and amplitude of quadriceps activity early in the gait cycle appear to be important factors in decreasing loading rates. Because gait is a repetitive and perpetual task, slight changes in loading rates may have substantial effects on the articular cartilage of the knee joint. However, the influence of quadriceps activation characteristics on impulsive loading during gait has yet to be evaluated in individuals with ACL-R. Therefore, the purpose of this investigation was to evaluate associations between the timing and amplitude of quadriceps EMG activity and impulsive loading during walking gait. Research Questions • What is the relationship between the onset of quadriceps activity (EMG) relative to heel strike and vertical ground reaction force (vGRF) loading rate and magnitude during the first 50% of the stance phase during walking gait in individuals with ACL-R? o H1: Earlier onset of quadriceps activity will be associated with lower vGRF loading rate and peak vGRF. • What is the relationship between the amplitude of quadriceps activity prior to heel strike and vGRF loading rate and magnitude during the first 50% of the stance phase during walking gait in individuals with ACL-R? o H2: Greater quadriceps activity prior to heel strike will be associated with lower vGRF loading rate and peak vGRF. • What is the relationship between the amplitude of quadriceps activity during the load acceptance phase of walking gait and vGRF loading rate and magnitude during the first 50% of the stance phase in individuals with ACL-R? o H3: Greater quadriceps activity during the load acceptance phase will be associated with lower vGRF loading rate and peak vGRF.Bachelor of Art