MEASUREMENT ERROR IN SIMULATED 20 GAIT DATA EXTRACTED BY A VIDEO-BASED MOTION MEASUREMENT SYSTEM

An instrument reliability study was conducted in order to quantify the measurement error contained in 2D spatial data (linear and angular) commonly collected in gait and long jump studies (e.g. footfall position, toe-board-distance or limb orientation) by video-based motion measurement systems. Three experiments examined the effect of camera-to-object distance (5 to 10 m) and field of view (2.5 to 4.5 m) upon marker sets (stationary) representative of walking or running motion. The results show 7 to 10 m camera-to-object distances to be associated with the least error (mean absolute error = 0.59 cm) or about a third of the error found for the 5 m distance (mean absolute error = 1.5 cm). No systematic changes in measurement error were found across the differing camera fields of view with the mean absolute error falling below 0.66 cm and 0.6

CHANGES IN LOWER-LIMB MUSCLE FORCES WITH PROPHYLACTIC KNEE BRACING DURING LANDING AND STOP-JUMP TASKS

Prophylactic knee braces are designed to prevent knee injuries, which often occur during sports such as basketball and volleyball, but their efficacy is debated. The purpose of this study is to calculate and compare lower-limb muscle forces in braced and unbraced recreational athletes during landing and stop-jump tasks. Experimental motion capture and ground reaction force data were collected from five participants with and without a knee brace. Subject-specific musculoskeletal models were created in OpenSim and were used to calculate muscle forces. Preliminary results indicated that knee bracing altered both the magnitude and timing of muscle actions. This study provides insight into the likely role of prophylactic knee bracing and muscle function in knee protection

Susan Haas v. 3M Co

USDC for the District of New Jerse

Shoe-Insole Technology for Injury Prevention in Walking

Impaired walking increases injury risk during locomotion, including falls-related acute injuries and overuse damage to lower limb joints. Gait impairments seriously restrict voluntary, habitual engagement in injury prevention activities, such as recreational walking and exercise. There is, therefore, an urgent need for technology-based interventions for gait disorders that are cost effective, willingly taken-up, and provide immediate positive effects on walking. Gait control using shoe-insoles has potential as an effective population-based intervention, and new sensor technologies will enhance the effectiveness of these devices. Shoe-insole modifications include: (i) ankle joint support for falls prevention; (ii) shock absorption by utilising lower-resilience materials at the heel; (iii) improving reaction speed by stimulating cutaneous receptors; and (iv) preserving dynamic balance via foot centre of pressure control. Using sensor technology, such as in-shoe pressure measurement and motion capture systems, gait can be precisely monitored, allowing us to visualise how shoe-insoles change walking patterns. In addition, in-shoe systems, such as pressure monitoring and inertial sensors, can be incorporated into the insole to monitor gait in real-time. Inertial sensors coupled with in-shoe foot pressure sensors and global positioning systems (GPS) could be used to monitor spatiotemporal parameters in real-time. Real-time, online data management will enable ‘big-data’ applications to everyday gait control characteristics

Ageing-related gait adaptations to knee joint kinetics: Implications for the development of knee osteoarthritis

The prevalence of knee osteoarthritis (OA) increases with ageing and this research aimed to identify gait adaptations that could reduce OA by investigating ageing effects on knee joint biomechanics. Participants were 24 healthy young males (18–35 yrs) and 14 healthy older males (60–75 yrs). Three-dimensional motion capture (Optotrak) and walkway-embedded force plates (AMTI) recorded their natural preferred-speed walking and the following parameters were computed: knee adduction moment, knee joint vertical force, foot contact angle, toe-out angle, foot centre of pressure displacement, time to foot flat, step length, step width and double support time. A 2 × 2 (age × limb) repeated measures mixed model analysis of variance design determined main effects and interactions. Pearson’s correlations between knee kinetic parameters and stride phase variables were also calculated. Both knee adduction moment and vertical joint force were larger in the older group. Relative to the young controls, older individuals showed a longer time to foot flat, less toe-out angle and wider steps. Correlation analysis suggested that reduced toe-out angle and increased step width were associated with lower knee adduction moment; furthermore, knee joint vertical force reduced with greater step length. Future research could focus on intervention strategies for managing excessive knee joint stresses to prevent the ageing-related development of knee OA

A Comparison of Treadmill and Overground Walking Effects on Step Cycle Asymmetry in Young and Older Individuals

Although lower limb strength becomes asymmetrical with age, past studies of aging effects on gait biomechanics have usually analyzed only one limb. This experiment measured how aging and treadmill surface influenced both dominant and nondominant step parameters in older (mean 74.0 y) and young participants (mean 21.9 y). Step-cycle parameters were obtained from 3-dimensional position/time data during preferred-speed walking for 40 trials along a 10 m walkway and for 10 minutes of treadmill walking. Walking speed (young 1.23 m/s, older 1.24 m/s) and step velocity for the two age groups were similar in overground walking but older adults showed significantly slower walking speed (young 1.26 m/s, older 1.05 m/s) and step velocity on the treadmill due to reduced step length and prolonged step time. Older adults had shorter step length than young adults and both groups reduced step length on the treadmill. Step velocity and length of older adults’ dominant limb was asymmetrically larger. Older adults increased the proportion of double support in step time when treadmill walking. This adaptation combined with reduced step velocity and length may preserve balance. The results suggest that bilateral analyses should be employed to accurately describe asymmetric features of gait especially for older adults

Effects of walking-induced fatigue on gait function and tripping risks in older adults

BACKGROUND: Fatigue and ageing contribute to impaired control of walking and are linked to falls. In this project, fatigue was induced by maximum speed walking to examine fatigue effects on lower limb trajectory control and associated tripping risk and overall gait functions of older adults. METHODS: Eleven young (18–35 years) and eleven older adults (>65 years) conducted 5-minute preferred speed treadmill walking prior to and following 6-minute maximum fast walking. Spatio-temporal gait parameters and minimum foot clearance (MFC) were obtained. Maximal muscle strength (hamstrings and quadriceps) was measured on an isokinetic dynamometer. Heart rate (HR) and rating of perceived exertion (RPE) assessed physiological effort and subjective fatigue. Physiological Cost Index computed walking efficiency. RESULTS: Fatigue due to fast walking increased step length, double support time and variability of step width. Only older adults reduced MFC due to fatigue. A trend of longer double support with greater MFC was found in the non-dominant limb. Lower walking efficiency was characterised as the ageing effect. Older adults did not increase HR during fast walking but higher RPE scores were observed. CONCLUSIONS: Older adults can increase tripping risk by 6 minutes of fast walking possibly by both impaired walking efficiency based on cardiac capacity and higher perceived fatigue due to elevated caution level. Regardless of age, increased step width variability due to fatigue was observed, a sign of impaired balance. Longer double support and greater MFC observed in the older adults’ non-dominant limb could be an asymmetrical gait adaptation for safety. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1743-0003-11-155) contains supplementary material, which is available to authorized users

Identification of foot pathologies based on plantar pressure asymmetry

Foot pathologies can negatively influence foot function, consequently impairing gait during daily activity, and severely impacting an individual’s quality of life. These pathologies are often painful and correspond with high or abnormal plantar pressure, which can result in asymmetry in the pressure distribution between the two feet. There is currently no general consensus on the presence of asymmetry in able-bodied gait, and plantar pressure analysis during gait is in dire need of a standardized method to quantify asymmetry. This paper investigates the use of plantar pressure asymmetry for pathological gait diagnosis. The results of this study involving plantar pressure analysis in fifty one participants (31 healthy and 20 with foot pathologies) support the presence of plantar pressure asymmetry in normal gait. A higher level of asymmetry was detected at the majority of the regions in the feet of the pathological population, including statistically significant differences in the plantar pressure asymmetry in two regions of the foot, metatarsophalangeal joint 3 (MPJ3) and the lateral heel. Quantification of plantar pressure asymmetry may prove to be useful for the identification and diagnosis of various foot pathologies

Minimum toe clearance events in divided attention treadmill walking in older and young adults: A cross-sectional study

BACKGROUND: Falls in older adults during walking frequently occur while performing a concurrent task; that is, dividing attention to respond to other demands in the environment. A particularly hazardous fall-related event is tripping due to toe-ground contact during the swing phase of the gait cycle. The aim of this experiment was to determine the effects of divided attention on tripping risk by investigating the gait cycle event Minimum Toe Clearance (MTC). METHODS: Fifteen older adults (mean 73.1 years) and 15 young controls (mean 26.1 years) performed three walking tasks on motorized treadmill: (i) at preferred walking speed (preferred walking), (ii) while carrying a glass of water at a comfortable walking speed (dual task walking), and (iii) speed-matched control walking without the glass of water (control walking). Position-time coordinates of the toe were acquired using a 3 dimensional motion capture system (Optotrak NDI, Canada). When MTC was present, toe height at MTC (MTC_Height) and MTC timing (MTC_Time) were calculated. The proportion of non-MTC gait cycles was computed and for non-MTC gait cycles, toe-height was extracted at the mean MTC_Time. RESULTS: Both groups maintained mean MTC_Height across all three conditions. Despite greater MTC_Height SD in preferred gait, the older group reduced their variability to match the young group in dual task walking. Compared to preferred speed walking, both groups attained MTC earlier in dual task and control conditions. The older group’s MTC_Time SD was greater across all conditions; in dual task walking, however, they approximated the young group’s SD. Non-MTC gait cycles were more frequent in the older group across walking conditions (for example, in preferred walking: young – 2.9 %; older - 18.7 %). CONCLUSIONS: In response to increased attention demands older adults preserve MTC_Height but exercise greater control of the critical MTC event by reducing variability in both MTC_Height and MTC_Time. A further adaptive locomotor control strategy to reduce the likelihood of toe-ground contacts is to attain higher mid-swing clearance by eliminating the MTC event, i.e. demonstrating non-MTC gaits cycles