Feasibility and acceptability study on the use of a smartphone application to facilitate balance training in the ageing population.

OBJECTIVES: This study aims to investigate the feasibility and acceptability of using an app-based technology to train balance in the older population. DESIGN: Prospective feasibility study. SETTING: The study was conducted in a university setting and participants' homes. PARTICIPANTS: Thirty-five volunteers ≥55 years old were recruited. INTERVENTION: Participants were asked to follow a balance exercise programme 7 days a week for 3 weeks using a phone application. Seventeen participants trained for a further 3 weeks. OUTCOME MEASURES: Postural sway measures during quiet standing with feet at shoulder width apart and feet together, one leg standing and tandem stance were measured at baseline, and at the end of the 3 and 6 training weeks; the International Physical Activity Questionnaire (IPAQ) assessed participants' physical activity level before training; and app acceptability was recorded using a user experience questionnaire. RESULTS: Participants on the 3 and 6-week programme on average completed 20 (±5) and 38 (±11) days of training, respectively, and all scored moderate to high on the IPAQ. Between baseline and the 3-week assessments, statistically significant improvements were observed for anteroposterior sway, mediolateral sway, sway area during tandem stance, for anteroposterior sway during one leg standing and for sway area during feet together stance. Improvements were observed at 6 week compared with baseline but those between 3 and 6 weeks were not significant. Based on the questionnaire, participants reported that the app is an appropriate tool for balance training (77%), they reported benefits from the training (50%) and found it easy to fit it into daily routine (88%). CONCLUSION: The high level of adherence and improvements observed in the analysed measures demonstrate the feasibility of using an app to train balance in moderately to highly physically active older participants. This demonstrates that given appropriate tools the older population is positive towards and receptive of digital interventions aimed to improve balance.

Assessment of chest wall movement following thoracotomy: a systematic review.

Thoracotomy is a major cause of respiratory impairment, increasing the risk of postoperative pulmonary complications (PPC). Systems assessing ribcage kinematics may detect changes in chest expansion following thoracotomy and may thus aid in the development of patient-tailored chest physiotherapy. Hence, we aimed to identify studies assessing changes in chest wall movement following thoracotomy using objective measures. The Cochrane library, MEDLINE, EMBASE, Scopus and Web of Science databases were searched to find relevant articles providing an objective assessment of chest wall movement following thoracotomy. Methodological quality of included studies concerning chest wall movement following thoracotomy was assessed by use of QUADAS-2 tool. A total of 12 articles were included for the assessment of chest wall changes following thoracotomy using objective measures. Four studies measured changes in the cross-sectional area of the ribcage and abdomen using the respiratory inductive plethysmography (RIP), 1 study computed the chest wall compliance by monitoring the intra-pleural pressure, 3 studies measured changes in chest circumference with a simple tape measure and 4 articles performed a compartmental analysis of the chest wall volume by means of an optoelectronic plethysmography (OEP). There was no delay in the collection of data of the index test and reference standard, resulting in a low risk of bias for the flow and timing domain. Across all studies, participants underwent the same reference standard, resulting in a low risk of verification bias. Several objective measures were able to detect changes in chest wall displacement following thoracotomy and differed in the practical use and invasive nature. OEP allows a compartmental analysis of the chest wall volume. Hence, this system allows to assess chest wall movement changes following thoracotomy and the impact of different types of surgical approach. Furthermore, it could aid in the development of tailored physiotherapy.

Alteration of movement patterns in low back pain assessed by Statistical Parametric Mapping.

Changes in movement pattern in low back pain (LBP) groups have been analysed by reporting predefined discrete variables. However, this approach does not consider the full kinematic data waveform and its dynamic information, potentially exposing the analysis to bias. Statistical Parametric Mapping (SPM) has been introduced and applied to 1 dimensional (D) kinematic variables allowing the assessment of data over time. The aims of this study were to assess differences in 3D kinematics patterns in people with and without LBP during functional tasks by using SPM and to investigate if SPM analysis was consistent with standard 3D range of motion (RoM) assessments. 3D joints kinematics of the spine and lower limbs were compared between 20 healthy controls and 20 participants with non-specific LBP during walking, sit-to-stand and lifting. SPM analysis showed significant differences in the 3Dkinematics of the lower thoracic segment, upper and lower lumbar segment and knee joint during walking and lifting mostly observed at the beginning and/or towards the end of the tasks. ROMs differed between groups in the lower thoracic segment (walking/sit-to-stand), upper and lower lumbar segments (walking/sit-to-stand/lifting), hip and knee (sit-to-stand/lifting). Based on these results, the two approaches can yield different data interpretations. SPM analysis allows the identification of differences in movement that occur over time. This adds value to LBP movement analysis as it allows an understanding of the LBP strategies adopted during motion that may not be conveyed by simple discrete parameters such as ROMs.

Exploring the Role of Wearable Technology in Sport Kinematics and Kinetics: A Systematic Review.

The aim of this review was to understand the use of wearable technology in sport in order to enhance performance and prevent injury. Understanding sports biomechanics is important for injury prevention and performance enhancement and is traditionally assessed using optical motion capture. However, such approaches are limited by capture volume restricting assessment to a laboratory environment, a factor that can be overcome by wearable technology. A systematic search was carried out across seven databases where wearable technology was employed to assess kinetic and kinematic variables in sport. Articles were excluded if they focused on sensor design and did not measure kinetic or kinematic variables or apply the technology on targeted participants. A total of 33 articles were included for full-text analysis where participants took part in a sport and performed dynamic movements relating to performance monitored by wearable technologies. Inertial measurement units, flex sensors and magnetic field and angular rate sensors were among the devices used in over 15 sports to quantify motion. Wearable technology usage is still in an exploratory phase, but there is potential for this technology to positively influence coaching practice and athletes' technique.

Exploring the clinical context of adopting an instrumented insole: a qualitative study of clinicians' preferences in England.

OBJECTIVES: This study explores clinicians' views of the clinical uptake of a smart pressure-sensing insole, named Flexifoot, to enhance the care and management of patients with osteoarthritis (OA). Clinicians are key users of wearable technologies, and can provide appropriate feedback for a specific device for successful clinical implementation. DESIGN: Qualitative study with in-depth, semi-structured interviews, analysed using inductive analysis to generate key themes. SETTING: Conducted in a University setting. PARTICIPANTS: 30 clinicians were interviewed (11 physiotherapists, 11 orthopaedic surgeons, 5 general practitioners, 3 podiatrists). RESULTS: All clinicians regarded Flexifoot to be useful for the care and management of patients in adjunction to current methods. Responses revealed four main themes: use, data presentation, barriers to use and future development. Flexifoot data were recognised as capable of enhancing information exchange between clinicians and patients, and also between clinicians themselves. Participants supported the use of feedback for rehabilitation, screening and evaluation of treatment progress/success purposes. Flexifoot use by patients was encouraged as a self-management tool that may motivate them by setting attainment goals. The data interface should be secure, concise and visually appealing. The measured parameters of Flexifoot, its duration of wear and frequency of data output would all depend on the rationale for its use. The clinicians and patients must collaborate to optimise the use of Flexifoot for long-term monitoring of disease for patient care in clinical practice. Many identified potential other uses for Flexifoot. CONCLUSIONS: Clinicians thought that Flexifoot may complement and improve current methods of long-term patient management for OA or other conditions in clinical settings. Flexifoot was recognised to be useful for objective measures and should be tailored carefully for each person and condition to maximise compliance. Adopting the device, and other similar technologies, requires reducing the main barriers to use (time, cost, patient compliance) before its successful implementation.

Spinal segments do not move together predictably during daily activities.

BACKGROUND: Considering the thoracic, lumbar spine or whole spine as rigid segments has been the norm until recent studies highlighted the importance of more detailed modelling. A better understanding of the requirement for spine multi-segmental analysis could guide planning of future studies and avoid missing clinically-relevant information. RESEARCH QUESTION: This study aims to assess the correlation between adjacent spine segments movement thereby evaluating segmental redundancy in both healthy and participants with low back pain (LBP). METHODS: A 3D motion capture system tracked the movement of upper and lower thoracic and lumbar spine segments in twenty healthy and twenty participants with LBP. Tasks performed included walking, sit-to-stand and lifting, repeated 3 times. 3D angular kinematics were calculated for each spine segment. Segmental redundancy was evaluated through cross-correlation (Rxy) analysis of kinematics time series and correlation of range of motion (RROM) of adjacent spine segments. RESULTS: The upper/lower lumbar pairing showed weak correlations in the LBP group for all tasks and anatomical planes (Rxyrange:0.02-0.36) but moderate and strong correlations during walking (Rxy _frontalplane:0.4) and lifting (Rxy _sagittalplane:0.64) in the healthy group. The lower thoracic/upper lumbar pairing had weak correlations for both groups during lifting and sit-to-stand in the frontal plane and for walking (Rxy:0.01) in the sagittal plane only. The upper/lower thoracic pairing had moderate correlations during sit-to-stand in sagittal and transverse plane in patients with LBP (Rxy _sagittalplane:0.41; Rxy _transverse plane:-0.42) but weak in healthy (Rxy _sagittalplane:0.23; Rxy _transverseplane:-0.34); the contrary was observed during lifting. The majority of RROM values (55/72) demonstrated weak correlations. SIGNIFICANCE: The results suggest that multi-segmental analysis of the spine is necessary if spine movement characteristics are to be fully understood. We cannot establish a priori where redundancy occurs based on healthy data, therefore extra consideration should be made when planning studies with pathological cohorts.

Is there evidence to use kinematic/kinetic measures clinically in low back pain patients? A systematic review.

BACKGROUND: Currently, there is a widespread reliance on self-reported questionnaires to assess low back pain patients. However, it has been suggested that objective measures of low back pain patients' functional status should be used to aid clinical assessment. The aim of this study is to systematically review which kinematic /kinetic parameters have been used to assess low back pain patients against healthy controls and to propose clinical kinematic/kinetic measures. METHODS: PubMed, Embase and Scopus databases were searched for relevant studies. Reference lists of selected studies and hand searches were performed. Studies had to compare people with and without non-specific low back pain while performing functional tasks and report body segment/joint kinematic and/or kinetic data. Two reviewers independently identified relevant papers. FINDINGS: Sixty-two studies were included. Common biases identified were lack of assessor blinding and sample size calculation, use of samples of convenience, and poor experimental protocol standardization. Studies had small sample sizes. Range of motion maneuvers were the main task performed (33/62). Kinematic/kinetic data of different individual or combination of body segments/joints were reported among the studies, commonest was to assess the hip joint and lumbar segment motion (13/62). Only one study described full body movement. The most commonly reported outcome was range of motion. Statistically significant differences between controls and low back pain groups were reported for different outcomes among the studies. Moreover, when the same outcome was reported disagreements were noted. INTERPRETATION: The literature to date offers limited and inconsistent evidence of kinematic/kinetic measures in low back pain patients that could be used clinically.

A flexible wearable sensor for knee flexion assessment during gait.

BACKGROUND: Gait analysis plays an important role in the diagnosis and management of patients with movement disorders but it is usually performed within a laboratory. Recently interest has shifted towards the possibility of conducting gait assessments in everyday environments thus facilitating long-term monitoring. This is possible by using wearable technologies rather than laboratory based equipment. RESEARCH QUESTION: This study aims to validate a novel wearable sensor system's ability to measure peak knee sagittal angles during gait. METHODS: The proposed system comprises a flexible conductive polymer unit interfaced with a wireless acquisition node attached over the knee on a pair of leggings. Sixteen healthy volunteers participated to two gait assessments on separate occasions. Data was simultaneously collected from the novel sensor and a gold standard 10 camera motion capture system. The relationship between sensor signal and reference knee flexion angles was defined for each subject to allow the transformation of sensor voltage outputs to angular measures (degrees). The knee peak flexion angle from the sensor and reference system were compared by means of root mean square error (RMSE), absolute error, Bland-Altman plots and intra-class correlation coefficients (ICCs) to assess test-retest reliability. RESULTS: Comparisons of knee peak flexion angles calculated from the sensor and gold standard yielded an absolute error of 0.35(±2.9°) and RMSE of 1.2(±0.4)°. Good agreement was found between the two systems with the majority of data lying within the limits of agreement. The sensor demonstrated high test-retest reliability (ICCs>0.8). SIGNIFICANCE: These results show the ability of the sensor to monitor knee peak sagittal angles with small margins of error and in agreement with the gold standard system. The sensor has potential to be used in clinical settings as a discreet, unobtrusive wearable device allowing for long-term gait analysis.

Wearable technology for spine movement assessment: A systematic review.

Continuous monitoring of spine movement function could enhance our understanding of low back pain development. Wearable technologies have gained popularity as promising alternative to laboratory systems in allowing ambulatory movement analysis. This paper aims to review the state of art of current use of wearable technology to assess spine kinematics and kinetics. Four electronic databases and reference lists of relevant articles were searched to find studies employing wearable technologies to assess the spine in adults performing dynamic movements. Two reviewers independently identified relevant papers. Customised data extraction and quality appraisal form were developed to extrapolate key details and identify risk of biases of each study. Twenty-two articles were retrieved that met the inclusion criteria: 12 were deemed of medium quality (score 33.4-66.7%), and 10 of high quality (score >66.8%). The majority of articles (19/22) reported validation type studies. Only 6 reported data collection in real-life environments. Multiple sensors type were used: electrogoniometers (3/22), strain gauges based sensors (3/22), textile piezoresistive sensor (1/22) and accelerometers often used with gyroscopes and magnetometers (15/22). Two sensors units were mainly used and placing was commonly reported on the spine lumbar and sacral regions. The sensors were often wired to data transmitter/logger resulting in cumbersome systems. Outcomes were mostly reported relative to the lumbar segment and in the sagittal plane, including angles, range of motion, angular velocity, joint moments and forces. This review demonstrates the applicability of wearable technology to assess the spine, although this technique is still at an early stage of development.

Predicting knee osteoarthritis risk in injured populations.

BACKGROUND: Individuals who suffered a lower limb injury have an increased risk of developing knee osteoarthritis. Early diagnosis of osteoarthritis and the ability to track its progression is challenging. This study aimed to explore links between self-reported knee osteoarthritis outcome scores and biomechanical gait parameters, whether self-reported outcome scores could predict gait abnormalities characteristic of knee osteoarthritis in injured populations and, whether scores and biomechanical outcomes were related to osteoarthritis severity via Spearman's correlation coefficient. METHODS: A cross-sectional study was conducted with asymptomatic participants, participants with lower-limb injury and those with medial knee osteoarthritis. Spearman rank determined relationships between knee injury and outcome scores and hip and knee kinetic/kinematic gait parameters. K-Nearest Neighbour algorithm was used to determine which of the evaluated parameters created the strongest classifier model. FINDINGS: Differences in outcome scores were evident between groups, with knee quality of life correlated to first and second peak external knee adduction moment (0.47, 0.55). Combining hip and knee kinetics with quality of life outcome produced the strongest classifier (1.00) with the least prediction error (0.02), enabling classification of injured subjects gait as characteristic of either asymptomatic or knee osteoarthritis subjects. When correlating outcome scores and biomechanical outcomes with osteoarthritis severity only maximum external hip and knee abduction moment (0.62, 0.62) in addition to first peak hip adduction moment (0.47) displayed significant correlations. INTERPRETATION: The use of predictive models could enable clinicians to identify individuals at risk of knee osteoarthritis and be a cost-effective method for osteoarthritis screening.

Clinical assessment of antero-medial rotational knee laxity: a systematic review.

PURPOSE: To inventory the examination methods available to assess antero-medial rotational laxity (AMRL) of the knee following medial collateral ligament injury. METHODS: Searches were conducted in accordance with the PRISMA guidelines and using four online databases: WEB OF SCIENCE, MEDLINE, EMBASE, and AMED. The Critical Appraisal Skills Programme guidelines for Diagnostic Test Studies were used for the quality assessment of the articles. RESULTS: A total of 2241 articles were identified from the database searches. From this, four articles were included in the final review. All were case-control studies, considered a combined ACL/MCL injury and had small study populations. Specialised equipment was required in all studies, and one needed additional imaging support before measurements could be taken. Two employed commercially available measuring equipment as part of the assessment process. CONCLUSION: Clinical assessment of AMRL in relation to a MCL injury remains challenging. Although methods have been developed to support clinical examination, they are limited by a number of factors, including the need for additional time in the clinical environment when setting up equipment, the need for specific equipment to produce and measure rotational movement and imaging support. In addition, there are patient safety concerns from the repeated imaging. A reliable and valid clinical examination remains to be found to truly assess antero-medial rotational laxity of the knee. LEVEL OF EVIDENCE: IV.

Impact of wearable technology on psychosocial factors of osteoarthritis management: a qualitative study.

OBJECTIVES: To identify the impact the use of wearable technology could have in patients with osteoarthritis in terms of communication with healthcare providers and patients' empowerment to manage their condition. DESIGN: Qualitative study using focus groups with patients with osteoarthritis; data from patients' responses were analysed using Framework Methodology. PARTICIPANTS: 21 patients with knee osteoarthritis from the London area (age range 45-65 years) participated in a total of four focus groups. Recruitment continued until data saturation. SETTING: The study was conducted in a university setting. RESULTS: Patients' responses suggested a positive attitude on the impact wearable technology could have on the management of osteoarthritis. It was perceived that the use of wearable devices would benefit patients in terms of feeling in control of their condition, providing them with awareness of their progress, empowering in terms of self-management and improving communication with their clinician. CONCLUSIONS: This paper suggests positive patient perspectives on the perceived benefits wearable technology could have on the management of osteoarthritis. The data that could be collected with the use of wearable technology could be beneficial both to patients and clinicians. The information obtained from this study suggests that introducing wearable technology into patient-centred care could enhance patient experience in the field of osteoarthritis and beyond.

Wearable technologies in osteoarthritis: a qualitative study of clinicians' preferences.

OBJECTIVE: This study investigates clinicians' views of health-related wearable technologies in the context of supporting osteoarthritis (OA) long-term management. Clinicians' preferences are critical in identifying realistic implementation strategies for such technologies. DESIGN: Qualitative study incorporating an inductive thematic analysis applied to identify key themes from clinicians' responses. PARTICIPANTS: Clinicians, including 4 general practitioners, 4 physiotherapists and 5 orthopaedic surgeons were interviewed. SETTING: The study was conducted in a University setting. RESULTS: Participants all agreed wearable technologies could positively complement their role and enhance their relationship with patients. Perceived benefits of wearable technologies included monitoring patients' progress, treatment evaluation, monitoring compliance and informing clinical decision-making. The device should be designed to provide objective data of patients' locomotion capability in an easy and timely fashion via a simple interface. Data should be available to both clinicians and patients to provide them with the motivation to achieve clinical goals and allow them to take ownership of their treatment. The use of technology was also seen as a way to more effectively plan treatment and manage patients' contact time saving time and cost. CONCLUSIONS: Findings support the use of wearable technologies to enhance current OA management and suggest clinical uses. Adoption of technologies could have implications on the effectiveness of treatment provided overcoming current barriers, in particular compliance with treatment.

A knee monitoring device and the preferences of patients living with osteoarthritis: a qualitative study.

OBJECTIVES: To identify perspective of patients with osteoarthritis, in particular design requirements and mode of use, of wearable technology to support the rehabilitation pathway. This study is part of a user-centred design approach adopted to develop a rehabilitation tool for patients with osteoarthritis. DESIGN: Qualitative study using a focus group approach; data management via a thematic analysis of patients' responses. PARTICIPANTS: 21 patients with osteoarthritis (age range 45-65 years) participated in 1 of the 4 focus groups. Recruitment continued until data saturation. SETTING: The study was conducted in a university setting. RESULTS: Main determinants of user acceptance of a wearable technology were appearance and comfort during use. Patients were supportive of the use of wearable technologies during rehabilitation and could recognise their benefit as monitors for their progress, incentives to adhere to exercise, and tools for more informed interaction with clinicians. CONCLUSIONS: This paper should encourage adoption and development of wearable technology to support rehabilitation of patients with osteoarthritis. It is pivotal that technological development takes into account patients' views in that it should be small, light, discrete, not 'appear medical' or challenge the identity of the user. Derived data should be available to patients and clinicians. Furthermore, wearable technologies should be developed to operate in two modes: for exercise guidance and assessment only, and for unobtrusive everyday monitoring. The information obtained from this study should guide the design of new technologies and support their use in clinical practice.

Use of wearable technology for performance assessment: a validation study.

The prevalence of osteoarthritis is increasing globally but current compliance with rehabilitation remains poor. This study explores whether wearable sensors can be used to provide objective measures of performance with a view to using them as motivators to aid compliance to osteoarthritis rehabilitation. More specifically, the use of a novel attachable wearable sensor integrated into clothing and inertial measurement units located in two different positions, at the waist and thigh pocket, was investigated. Fourteen healthy volunteers were asked to complete exercises adapted from a knee osteoarthritis rehabilitation programme whilst wearing the three sensors including five times sit-to-stand test, treadmill walking at slow, preferred and fast speeds. The performances of the three sensors were validated against a motion capture system and an instrumented treadmill. The systems showed a high correlation (r(2) > 0.7) and agreement (mean difference range: -0.02-0.03 m, 0.005-0.68 s) with gold standards. The novel attachable wearable sensor was able to monitor exercise tasks as well as the inertial measurement units (ICC > 0.95). Results also suggested that a functional placement (e.g., situated in a pocket) is a valid position for performance monitoring. This study shows the potential use of wearable technologies for assessing subject performance during exercise and suggests functional solutions to enhance acceptance.

Determination of loads carried by polypropylene ankle-foot orthoses: a preliminary study.

Ankle-foot orthoses (AFOs) are prescribed for the management of gait-related problems. Prescription of AFOs is based on empirical techniques due to the low level of evidence-based research on their efficacy, but primarily poor understanding of their mechanical characteristics. This study aimed to establish a method that would allow the quantification of the contribution of AFOs in the control of the ankle joint during gait. A possible way of achieving this aim would be to measure strain on the AFO during walking by the use of strain gauges. Following successful experimentation with the application of strain gauges to polypropylene tensile specimens, an AFO was instrumented by attaching strain gauges to it so as to allow the moment generated on the AFO in the sagittal plane about the ankle to be measured. Walking trials using this AFO on an able-bodied subject indicated good step-to-step repeatability. The use of an instrumented AFO in conjunction with kinematic and kinetic data acquisition would allow the contribution of the AFO and the residual anatomical loads to be determined. The advantage of such procedure over previously reported ones resides on the use of the actual orthosis being worn by patients thereby conducting tests under real-life situations. It is believed that such analysis of the load actions of an orthosis, which may in future be carried out in three dimensions, would allow a better understanding of the interaction between the leg and the orthosis. This should ultimately enhance AFO prescription criteria and help in optimising patient/device matching.

Analysis of gait within the uncontrolled manifold hypothesis: stabilisation of the centre of mass during gait.

This study investigated the feasibility of the uncontrolled manifold approach (UCM) to analyse gait data variability in relation to the control of the centre of mass (COM) in adults with and without neuropathology. The proposed method was applied to six able-bodied subjects to characterise mechanisms of normal postural control during stance phase. This approach was repeated on an early stroke patient, who attended the laboratory three times at three monthly intervals, to characterise the variability of COM movement during walking with and without an orthosis. Both able-bodied subjects and the stroke participant controlled COM movement during stance but utilized a different combination of lower limb joint kinematics to ensure that the COM trajectory was not compromised. Interestingly, the stroke subject, despite a higher variability in joint kinematics, was able to maintain a stable COM position throughout stance phase. The stabilisation of the COM decreased when the patient walked unaided without the prescribed orthosis but increased over the six months of study. The UCM analysis demonstrated how a stroke patient used a range of lower limb motion pattern to stabilise the COM trajectory. It is suggested that this analysis can be used to track changes in these movement patterns in response to rehabilitation. As such we propose that this approach could have clinical utility to evaluate and prescribe rehabilitation in stroke patients.

The evaluation of an inexpensive, 2D, video based gait assessment system for clinical use.

The purpose of this study was to investigate the clinical potential of an augmented-video-based-portable-system (AVPS). The AVPS included a walkway grid mat made of vinyl flooring, flat paper bull's eye markers, four photoswitches mounted on tripods, a light-indicator, a video camera, and a computer with ProTrainer System software. The AVPS output was compared to a "gold standard" 3D Vicon Motion Analysis System both statically and dynamically over a fixed range (-90° to +90°) using a two-segment-goniometric-rig marked with both bull's eye and retroreflective markers. At each segment angle position, three trials of data were captured. The reliability of the AVPS was also tested using three raters. Further twelve, young, healthy subjects participated in a concurrent validity study in which they performed six gait trials which were simultaneously recorded by both systems. Both motion analysis systems showed low levels of intra subject variability in all kinematic variables indicated by the size of the standard deviations across the six trials. There were no significant differences between the motion systems with respect to the kinematic variables (P>0.05). The results showed a high intra- and inter-rater reliability for both the kinematic and temporo-spatial parameters. With respect to gait events the lowest ICC value for the intra-rater reliability test was 0.993 for the kinematic variables, and ranged from 0.941 to 0.956 for the temporo-spatial variables and 0.731 to 0.954 for the tibia inclination angles. The validation data suggest the AVPS is capable of generating highly reliable and repeatable data when applied to normal subjects and could be used within the clinical setting.