The immediate effects of Kinesio Taping on running biomechanics, muscle activity, and perceived changes in comfort, stability and running performance in healthy runners, and the implications to the management of Iliotibial band syndrome.

BACKGROUND: Kinesio Taping is frequently used in the management of lower limb injuries, and has been shown to improve pain, function, and running performance. However, little is known about the effects of Kinesio Taping on running biomechanics, muscle activity, and perceived benefits. RESEARCH QUESTION: This study aimed to explore the immediate effects of Kinesio Taping on lower limb kinematics, joint moments, and muscle activity, as well as perceived comfort, knee joint stability, and running performance in healthy runners. METHODS: Twenty healthy participants ran at a self-selected pace along a 20-metre runway under three conditions; no tape (NT), Kinesio Tape with tension (KTT), and Kinesio tape without tension (KTNT). Comparisons of peak hip, knee angles and moments, and EMG were analysed during the stance phase of running. RESULTS: KTT exhibited significant increases in peak hip flexion, peak hip abduction and hip external rotation compared to NT. Moreover, the KTT condition showed a trend towards a decrease in peak hip internal rotation and adduction angle compared to the NT condition. EMG results showed that Tensor Fascia Latae activity decreased with KTT compared with NT, and Gluteus Maximus activity reduced with KTNT when compared with NT. Ten of the 20 participants indicated important improvements in the comfort score, six participants in the knee stability score, and seven participants in the running performance score when using KTT. SIGNIFICANCE: These results suggest that changes in running biomechanics previously associated with ITBS can be improved with the application of kinesio tape, with the greatest effect seen with the application of kinesio tape with tension. Perceived improvements were seen in comfort, stability and running performance, however these benefits were only seen in half the participants. Further work is required to explore the biomechanical effects and perceived benefits in different patient groups.

Frontal plane knee alignment mediates the effect of frontal plane rearfoot motion on knee joint load distribution during walking in people with medial knee osteoarthritis.

OBJECTIVE: To examine the nature of differences in the relationship between frontal plane rearfoot kinematics and knee adduction moment (KAM) magnitudes. DESIGN: Cross-sectional study resulting from a combination of overground walking biomechanics data obtained from participants with medial tibiofemoral osteoarthritis at two separate sites. Statistical models were created to examine the relationship between minimum frontal plane rearfoot angle (negative values = eversion) and different measures of the KAM, including examination of confounding, mediation, and effect modification from knee pain, radiographic disease severity, static rearfoot alignment, and frontal plane knee angle. RESULTS: Bivariable relationships between minimum frontal plane rearfoot angle and the KAM showed consistent negative correlations (r = -0.411 to -0.447), indicating higher KAM magnitudes associated with the rearfoot in a more everted position during stance. However, the nature of this relationship appears to be mainly influenced by frontal plane knee kinematics. Specifically, frontal plane knee angle during gait was found to completely mediate the relationship between minimum frontal plane rearfoot angle and the KAM, and was also an effect modifier in this relationship. No other variable significantly altered the relationship. CONCLUSIONS: While there does appear to be a moderate relationship between frontal plane rearfoot angle and the KAM, any differences in the magnitude of this relationship can likely be explained through an examination of frontal plane knee angle during walking. This finding suggests that interventions derived distal to the knee should account for the effect of frontal plane knee angle to have the desired effect on the KAM.

Patient characteristics affect hip contact forces during gait.

OBJECTIVE: To examine hip contact force (HCF), calculated through multibody modelling, in a large total hip replacement (THR) cohort stratified by patient characteristics such as body mass index (BMI), age and function. METHOD: 132 THR patients undertook one motion capture session of gait analysis at a self-selected walking speed. HCFs were then calculated using the AnyBody Modelling System. Patients were stratified into three BMI groups, five age groups, and finally three functional groups determined by their self-selected gait speed. By means of statistical parametric mapping (SPM), statistical analyses of the 1-dimensional time series were performed to separately evaluate the influence of age, BMI and functionality on HCF. RESULTS: The mean predicted HCFs were comparable to HCFs measured with instrumented prostheses reported in the literature. The SPM analysis revealed a statistically significant positive linear correlation between BMI and HCF, indicating that obese patients are more likely to experience higher HCF during most of the stance phase, while a statistically significant negative correlation with age was found only during the late swing-phase. Patients with higher functional ability exhibited significantly increased peak HCF, while patients with lower functional ability demonstrated lower HCFs overall and a pathological flattening of the typical double hump force profile. CONCLUSION: HCFs experienced at the bearing surface are highly dependent on patient characteristics. BMI and functional ability were determined to have the biggest influence on contact forces. Current preclinical testing standards do not reflect this.

The feasibility of a modified shoe for multi-segment foot motion analysis: a preliminary study.

BACKGROUND: The majority of multi-segment kinematic foot studies have been limited to barefoot conditions, because shod conditions have the potential for confounding surface-mounted markers. The aim of this study was to investigate whether a shoe modified with a webbed upper can accommodate multi-segment foot marker sets without compromising kinematic measurements under barefoot and shod conditions. METHODS: Thirty participants (15 controls and 15 participants with midfoot pain) underwent gait analysis in two conditions; barefoot and wearing a shoe (shod) in a random order. The shod condition employed a modified shoe (rubber plimsoll) with a webbed upper, allowing skin mounted reflective markers to be visualised through slits in the webbed material. Three dimensional foot kinematics were captured using the Oxford multi-segment foot model whilst participants walked at a self-selected speed. RESULTS: The foot pain group showed greater hindfoot eversion and less hindfoot dorsiflexion than controls in the barefoot condition and these differences were maintained when measured in the shod condition. Differences between the foot pain and control participants were also observed for walking speed in the barefoot and in the shod conditions. No significant differences between foot pain and control groups were demonstrated at the forefoot in either condition. CONCLUSIONS: Subtle differences between pain and control groups, which were found during barefoot walking are retained when wearing the modified shoe. The novel properties of the modified shoe offers a potential solution for the use of passive infrared based motion analysis for shod applications, for instance to investigate the kinematic effect of foot orthoses.

Ankle motion influences the external knee adduction moment and may predict who will respond to lateral wedge insoles?: an ancillary analysis from the SILK trial.

OBJECTIVE: Lateral wedge insoles are a potential simple treatment for medial knee osteoarthritis (OA) patients by reducing the external knee adduction moment (EKAM). However in some patients, an increase in their EKAM is seen. Understanding the role of the ankle joint complex in the response to lateral wedge insoles is critical in understanding and potentially identifying why some patients respond differently to lateral wedge insoles. METHOD: Participants with medial tibiofemoral OA underwent gait analysis whilst walking in a control shoe and a lateral wedge insole. We evaluated if dynamic ankle joint complex coronal plane biomechanical measures could explain and identify those participants that increased (biomechanical non-responder) or decreased (biomechanical responder) EKAM under lateral wedge conditions compared to the control shoe. RESULTS: Of the 70 participants studied (43 male), 33% increased their EKAM and 67% decreased their EKAM. Overall, lateral wedge insoles shifted the centre of foot pressure laterally, increased eversion of the ankle/subtalar joint complex (STJ) and the eversion moment compared to the control condition. Ankle angle at peak EKAM and peak eversion ankle/STJ complex angle in the control condition predicted if individuals were likely to decrease EKAM under lateral wedge conditions. CONCLUSIONS: Coronal plane ankle/STJ complex biomechanical measures play a key role in reducing EKAM when wearing lateral wedge insoles. These findings may assist in the identification of those individuals that could benefit more from wearing lateral wedge insoles.

Evidence that older adult fallers prioritise the planning of future stepping actions over the accurate execution of ongoing steps during complex locomotor tasks.

Previous research has highlighted differences between older adults determined to be at a low-risk of falling (low-risk) and older adults prone to falling (high-risk) in both where and when they look at stepping targets and the precision with which they subsequently step. On the basis of these findings, we proposed that high-risk older adults prioritise the planning of future stepping actions over the accurate execution of ongoing movements and that adoption of this strategy contributes to increased likelihood of falls. The present experiment was designed to test this hypothesis by manipulating the complexity of the required walking conditions and comparing gaze and stepping performance between young, high-risk and low-risk older adults. Participants walked at a self-selected pace along a 7-m pathway and encountered one of three obstacle conditions: (1) a single stepping target, (2) two stepping targets, (3) two stepping targets separated by a raised obstacle. On average, when there was a single target (Target 1) in the travel path, all groups fixated the target until after heel contact. However, when challenged with additional impending stepping constraints, high-risk older adults transferred their gaze significantly sooner from Target 1 prior to heel contact. On average, low-risk older adults and younger adults maintained gaze on Target 1 until after heel contact, irrespective of future constraints. Premature gaze transfer was associated with decline in stepping accuracy and precision. Our findings suggest that high-risk older adults choose a potentially hazardous gaze strategy when challenged with multiple obstacles. Putative mechanisms underlying this behaviour are discussed.

Age-related differences in stepping performance during step cycle-related removal of vision.

The aim of the present study was to investigate whether there are age-related changes in the ability of individuals to use vision to plan (feedforward control) and guide (on-line control) foot placement during locomotion. This aim was achieved by constraining the availability of vision and comparing the effects on the stepping performances of older and young adults during a precision stepping task. We experimentally controlled the availability of visual information such that: (1) vision was only available during each stance phase of the targeting limb, (2) vision was only available during each swing phase of the targeting limb or (3) vision was always available. Our visual manipulations had relatively little effect on younger adults' stepping performance as demonstrated by their missing the target on less than 10% of occasions. However, there were clear visual condition-related differences in older adults' stepping performance. When vision was only available during the stance phase of the targeting limb, older adults demonstrated significantly larger foot placement error and associated task failure rate (23%) than trials in which vision was always available (10%). There was an even greater increase in older adults' foot placement error and task failure rate (42%) during trials in which vision was only available in the swing phase than the other visual conditions. These findings suggest that older adults need vision at particular times during the step cycle, to effectively pre-plan future stepping movements. We discuss the evidence that these age-related changes in performance reflect decline in visual and visuomotor CNS pathways.

Evidence for a link between changes to gaze behaviour and risk of falling in older adults during adaptive locomotion.

There is increasing evidence that gaze stabilization with respect to footfall targets plays a crucial role in the control of visually guided stepping and that there are significant changes to gaze behaviour as we age. However, past research has not measured if age-related changes in gaze behaviour are associated with changes to stepping performance. This paper aims to identify differences in gaze behaviour between young (n=8) adults, older adults determined to be at a low-risk of falling (low-risk, n=4) and older adults prone to falling (high-risk, n=4) performing an adaptive locomotor task and attempts to relate observed differences in gaze behaviour to decline in stepping performance. Participants walked at a self-selected pace along a 9m pathway stepping into two footfall target locations en route. Gaze behaviour and lower limb kinematics were recorded using an ASL 500 gaze tracker interfaced with a Vicon motion analysis system. Results showed that older adults looked significantly sooner to targets, and fixated the targets for longer, than younger adults. There were also significant differences in these measures between high and low-risk older adults. On average, high-risk older adults looked away from targets significantly sooner and demonstrated less accurate and more variable foot placements than younger adults and low-risk older adults. These findings suggest that, as we age, we need more time to plan precise stepping movements and clearly demonstrate that there are differences between low-risk and high-risk older adults in both where and when they look at future stepping targets and the precision with which they subsequently step. We propose that high-risk older adults may prioritize the planning of future actions over the accurate execution of ongoing movements and that adoption of this strategy may contribute to an increased likelihood of falls.

An elbow extension neuroprosthesis for individuals with tetraplegia.

Functional electrical stimulation (FES) of the triceps to restore control of elbow extension was integrated into a portable hand grasp neuroprosthesis for use by people with cervical level spinal cord injury. An accelerometer mounted on the upper arm activated triceps stimulation when the arm was raised above a predetermined threshold angle. Elbow posture was controlled by the subjects voluntarily flexing to counteract the stimulated elbow extension. The elbow moments created by the stimulated triceps were at least 4 N.m, which was sufficient to extend the arm against gravity. Electrical stimulation of the triceps increased the range of locations and orientations in the workspace over which subjects could grasp and move objects. In addition, object acquisition speed was increased. Thus elbow extension enhances a person's ability to grasp and manipulate objects in an unstructured environment.

Stimulus artifact removal in EMG from muscles adjacent to stimulated muscles.

When stimulating muscles, EMG signals recorded in neighboring muscles can be contaminated by stimulus artifacts, and artifact deletion is necessary. We have devised a digital technique for removing stimulus artifacts from rectified EMG recordings in muscles which lie close to a stimulated muscle. This artifact deletion method replaces the rectified EMG during the artifact interval with an estimate of the rectified EMG. Our research requires detection of very small changes in EMG levels. Therefore, the artifact deletion technique described in this paper was designed to leave less than 10 microV of artifact in the rectified EMG post-processing. This technique relies on being able to estimate the artifact duration. Since stimulated muscles have M-waves that can overlap with artifacts, our technique is only appropriate for removing artifacts in muscles which are not being stimulated. Unlike other artifact elimination techniques, our technique does not change the mean value of the rectified EMG, regardless of artifact width. In addition, it provides a more accurate estimate of the rectified EMG during the artifact interval as opposed to sample-and-hold techniques.

Automated tuning of a closed-loop hand grasp neuroprosthesis.

An automated tuning algorithm was developed to reduce the time and skill required to tune a closed-loop hand grasp neuroprosthesis. The time reduction results from simultaneous tuning of four gain parameters controlling the dynamic response of the system, and from automation of the calculation and decision processes. The new tuning method is therefore an automated parallel tuning method, replacing a manual sequential method in which only one parameter at a time was tuned. RMS error between the step input and the grasp output is minimized, with absence of oscillation as a constraint. The difference between the system's RMS ramp tracking errors for the two tuning methods was less than 1% of the ramp size regardless of the initial values of the parameters, implying that the tuning methods were equivalent. However, the parallel tuning method was faster and required fewer trials than the sequential method. The capability of the closed-loop system to regulate grasp output in the presence of disturbances was compared with the capability without feedback. Patients were instructed to either grasp an object at a certain force level or to match a certain grasp opening. They would then lock their command at a fixed value, and either remain immobile to test time dependence or pronate and supinate their forearm to test postural disturbances. With closed-loop control, the grasp output was better regulated in the presence of disturbances, with an average output variance 60% lower than without feedback control.