Carpeted Surface Research Articles

Off the shelf: Investigating transfer of learning using commercially available virtual reality equipment.

The evolution of virtual reality (VR) has created the opportunity for a relatively low-cost and accessible method to practice motor skills. Previous studies have demonstrated how motor skill practice in non-immersive virtual environments transfers to physical environments. Though minimal research has investigated motor learning and transfer within immersive VR, multiple experiments provide empirical evidence of positive transfer effects. Most studies have used software engines and modified hardware to enhance the similarities between virtual and physical environments. However, many learners and practitioners currently use commercially available VR intending to enhance real-world performance, though there is very little evidence to support the notion of positive transfer for these systems. Therefore, this experiment aimed to investigate how motor skill practice using a commercially available VR system improved real-world performance and how that compared to physical practice. Participants (n = 68) were randomly selected into one of two groups: virtual reality (VR) practice (n = 33) or real-world (RW) practice (n = 35). The experiment occurred over two consecutive days, with a pretest, posttest, and practice phase occurring each day. The pre- and post-testing phases were identical for both groups and consisted of putting a golf ball 10 times on a carpeted surface towards the center of a target. The practice phases consisted of 60 total putts per day in the respective environment (VR or RW). Participants continuously alternated golf putting holes from three different distances until they accrued 60 total putts. Participants in the RW group performed golf putts to three targets. Participants in the VR group also performed golf putts on three different miniature golf putting holes, using the commercially available Oculus Rift and the Cloudlands VR Minigolf game. The VR putting targets were designed to replicate the putting holes in the physical environment. Separate 2 (group) x 4 (test) repeated measures ANOVAs were used to assess accuracy and club head kinematics. The results revealed a significant main effect for test, but not for group. Post hoc analyses revealed that both groups significantly improved their putting accuracy and club head kinematics at similar rates. The results from this study indicate that the transfer of learning that occurred as a result of practicing in a commercially available VR environment was similarly effective when compared to RW practice.

Propulsion Cost Changes of Ultra-Lightweight Manual Wheelchairs After One Year of Simulated Use.

Manual wheelchairs are available with folding or rigid frames to meet the preferences and needs of individual users. Folding styles are commonly regarded as more portable and storable, whereas rigid frames are commonly regarded as more efficient for frequently daily use. To date, there are no studies directly comparing the performances of the frame types. Furthermore, while differences have been reported in the longevity of the frame types, no efforts have been made to relate this durability back to the real-world performance of the frames. This study investigated the propulsion efficiencies of four folding and two rigid ultra-lightweight frames equipped with identical drive tires and casters. A robotic wheelchair tester was used to measure the propulsion costs of each chair over two surfaces: concrete and carpet. A motorized carousel was used to drive the chairs 511 km around a circular track to simulate one year of use for each wheelchair. After simulated use, five of the six wheelchairs showed no decrease in propulsion effort, indicating that the frames were able to withstand the stresses of simulated use without a detrimental impact on performance. In the unused "new" condition, rigid chairs were found to have superior (>5%) performance over folding frames on concrete and carpet, and in the "worn" condition rigid chairs had superior performance over folding chairs on concrete but were comparable on the carpeted surface.

Agreement between force and deceleration measures during backward somersault landings

ABSTRACT This study examined the agreement between force platform and inertial measurement unit (IMU) measures of backward somersault landings. Seven female gymnasts performed three trials, taking off from a 90 cm vaulting box and using competition landing technique. Two force platforms (1000 Hz) covered with a 6.4 cm thick carpeted landing surface measured the ground reaction forces. One inertial measurement unit (500 Hz) fixed on the second thoracic vertebra measured peak resultant deceleration of the gymnast. Measurement agreement between vertical and resultant peak force measures, and resultant peak force and peak deceleration was assessed using mean differences, Pearson’s correlation, and Cohen’s effect size (ES) statistics. There was perfect measurement agreement between vertical and resultant peak forces (R = 1.0, p < 0.001; ES = 0.005), but only moderate measurement agreement between resultant peak force and peak resultant deceleration (Mean Difference = −2.16%, R = 0.4, p = ns; ES = 0.121). Backward somersault landings can be assessed using either uni-axial or tri-axial force platforms to measure ground impact load/force, as the landing movements are almost purely vertical. However, force measures are not the same as peak resultant decelerations from IMUs which give an indication of impact shock. Landing load/shock measures are potentially important for injury prevention.

Phenomenological Modeling of Carpeted Surface for Drop Simulation of Portable Electronics

Using finite element (FE) analysis to simulate drop impact is widely adopted by the consumer electronics industry in the design process of portable devices. Most of such simulations model impact surface as a rigid or simple elastic surface. While this approach is valid for many common hard surfaces such as wood, tile, or concrete, it often does not provide a realistic risk assessment if the impact surface is a soft surface such as carpet. This paper describes a methodology to create a material model for carpeted impact surface that is suited for FE drop simulation. A multilayer hyperelastic–viscoelastic material model is used to model the mechanical response of the carpet under mechanical impact. Quasi-static and impact testing on the industrial carpet were performed to calibrate the model parameters with the help of optimization. Validation of the model was done by comparing the simulation predictions with measurements from the impact tests performed at different heights. Much better correlation between experimental measurements and simulation predictions were observed when using the multilayer hyper-viscoelastic model for carpet than using a single layer homogenous model. This approach can provide a better estimate and a more accurate representation for device drop risk on carpeted surfaces for design and development of portable products. The methodology can also be used to derive material models for other similar impact surfaces.

Resuspension of house dust and allergens during walking and vacuum cleaning

ABSTRACTConventional wisdom has been that hard, resilient surfaces resuspend fewer particles than carpeted surfaces, however, exceptions to this have been demonstrated and uncertainty remains about the factors that lead to this resuspension, notably, the effect of vacuum cleaning on either increasing or reducing resuspension from flooring. The purpose of this study was to determine how resuspension of house dust by aerodynamic size or particle type, including cat allergen and bacterial endotoxin, is affected by flooring, dust loading, embedding dust, and walking/cleaning activities. House dust was blown in and allowed to settle in a walk-in chamber after overnight deposition followed by walking or a vacuum cleaning procedure. Using an aerosol particle sizer and large-volume air samplers at different heights in the chamber, concentrations of airborne particles, resuspension rates, and fractions were computed for four types of flooring conditions during six walking activities. Carpeting resulted in significantly more airborne cat allergen and airborne endotoxin than a laminate floor. Height does have an effect on measured allergen over carpet and this is apparent with concentrations at the infant and adult air samplers. Walking on laminate flooring resuspends less house dust than walking on an equally dusty carpeted floor, where dust is entirely on the surface of the carpet. However, vacuum cleaning a laminate floor resuspended more dust than vacuum cleaning carpets, at large particle sizes of 5 µm and 10 µm. Activities following a deep cleaning of hard resilient or a carpeted surface is likely to leave no differences in resuspended particles between them.

The Role of Interface on the Impact Characteristics and Cranial Fracture Patterns Using the Immature Porcine Head Model

The role of impact interface characteristics on the biomechanics and patterns of cranial fracture has not been investigated in detail, and especially for the pediatric head. In this study, infant porcine skulls aged 2-19days were dropped with an energy to cause fracturing onto four surfaces varying in stiffness from a rigid plate to one covered with plush carpeting. Results showed that heads dropped onto the rigid surface produced more extensive cranial fracturing than onto carpeted surfaces. Contact forces generated at fracture initiation and the overall maximum contact forces were generally lower for the rigid than carpeted impacts. While the degree of cranial fracturing from impacts onto the heavy carpeted surface was comparable to that of lower-energy rigid surface impacts, there were fewer diastatic fractures. This suggests that characteristics of the cranial fracture patterns may be used to differentiate energy level from impact interface in pediatric forensic cases.

Pedometer Accuracy in Persons Using Lower-Limb Prostheses

It is important that all individuals obtain sufficient physical activity to increase health and fitness for the reduction of risk factors associated with cardiovascular disease. Pedometers are a means by which one can monitor and assess physical activity levels. The objective of this study was to assess the accuracy of three commercially available pedometers in persons with lower-limb amputations. Thirty-nine participants were fitted with an Omron HJ-112, a New Lifestyles 800, and a Digiwalker SW-701 on the right side of the hip, then walked at a self-selected pace on a carpeted level surface for 200 m. Repeated-measures (RM) analysis of variance (ANOVA) indicated a significant difference between the pedometers and the actual counts (ACs). Whereas the HJ-112 (mean [SD], 312.5 [38.3] steps) and the NL-800 (307.2 [35.1] steps) were not significantly different from AC (314.7 [73.9] steps), the SW-701 (255.57 [8.5] steps) significantly underestimated step counts, p < 0.05. Bland-Altman plots indicated the HJ-112 had the best agreement with AC, followed by the NL-800. Percentage error was lowest in the HJ-112 (0.69%), followed by NL-800 (2.4%), with the SW-701 eliciting the greatest error (18.8%). The HJ-12 and the NL-800 are viable options for persons with lower-limb amputations seeking to assess and/or monitor their physical activity levels.

Plantar pressure distribution in ice skates while gliding and standing compared to barefoot and trainer conditions

Background: The aim of this study was to identify whether there are differences between plantar pressure distributions experienced whilst wearing ice skates during ice-gliding, compared to standing whilst barefoot, wearing trainers and wearing ice skates. The results of this study aim to provide a greater understanding of the distribution of the pressure through the ice skate to the human musculoskeletal system. Material/Methods: Nine female participants were recruited for this study (age 36.6 years ± 15.3, mass 63.7kg ± 7.4 height 1.63m ± 4.1). Pressure applied to the plantar surface of the feet was recorded at 50Hz using an F-Scan sensor. Data was collected for 5 seconds while participants performed an ice glide in their own ice skates. Standing data was collected over the same period of time while participants stood still on a carpeted surface wearing their own ice skates, their own trainers and cotton socks without shoes. For each condition 10 trials of data were collected. Results: The results reported similar peak pressure distributions under the plantar region of the foot for standing and ice gliding while wearing ice skates. Furthermore, the results identified a shift of peak pressure values to the forefoot and midfoot regions whilst wearing ice skates compared to trainers. Conclusions: This research suggests information on plantar pressures during ice gliding may be obtained from standing data in future research and that ice skates may expose the wearer to an increased risk of plantar pressure related injuries in the forefoot/midfoot regions of the feet.

Evaluation of common angling-induced sources of epithelial damage for popular freshwater sport fish using fluorescein

Angling is a popular recreational activity across the globe and a large proportion of fish captured by anglers are released due to voluntary or mandatory catch-and-release practices. The handling associated with hook removal and return of the fish to their environment can cause physical damage to the epidermal layer of the fish which may affect the condition and survival of released fish. This study investigated possible sources of epithelial damage associated with several different handling methods (i.e., landing net types, interactions with different boat floor surfaces, tournament procedures) commonly used in recreational angling for two popular freshwater sport fish species, largemouth bass ( Micropterus salmoides) and northern pike ( Esox lucius). Epithelial damage was examined using fluorescein, a non-toxic dye, which has been shown to detect latent epithelial damage. Northern pike exhibited extensive epithelial damage after exposure to several of the induced treatments (i.e., interaction with a carpeted surface, knotted nylon net, and line rolling) but relatively little epithelial damage when exposed to others (i.e., knotless rubber nets, smooth boat surfaces, or lip gripping devices). Largemouth bass did not show significant epithelial damage for any of the treatments, with the exception of fish caught in a semi-professional live release tournament. The detection of latent injuries using fluorescein can be an important management tool as it provides visual examples of potential damage that can be caused by different handling methods. Such visualizations can be used to encourage fish-friendly angler behaviour and enhance the survival and welfare of released fish. It can also be used to test new products that are intended to or claim to reduce injury to fish that are to be released. Future research should evaluate the relationship between different levels of epithelial damage and mortality across a range of environmental conditions.

High resolution relative localisation using two cameras

Wheel odometry is a common method for high resolution relative localisation. However, wheel odometry relies on the integrity and accuracy of a kinematic model. In this paper, a new method for relative localisation, ‘visiodometry’, which does not rely on a kinematic model, is proposed. The system consists of two ground-facing cameras mounted on either side of the robot. From the sequence of images acquired, the relative change in pose of the robot is estimated using a phase correlation based method. Results on a plain coloured carpeted surface, show that the method provides a truly odometric type sensor data input similar in modality and resolution to wheel odometry. A method to calibrate the visiodometry system using a 1D object is also presented.

Evaluation of the TriTrac-R3D Triaxial Accelerometer in Measuring Energy Expenditure During Walking in Neurological Impairment

2091 The energy cost of independent ambulation is often magnified in persons with congenital and acquired lower extremity impairment (e.g., cerebral palsy, spina bifida, multiple sclerosis-MS, stroke-CVA, and parkinson's disease syndrome- PDS). Qualitative analysis and clinical rating of gait in these populations may not sufficiently reflect the capacity for independent ambulation as it relates to energy cost. PURPOSE: The purpose of this study was to determine whether the TriTrac-R3D accelerometer would accurately estimate energy expenditure (EE) in persons with impaired gait compared to EE measured using indirect calorimetry. SUBJECTS: Thirty neurologically-impaired subjects participated: CVA (n = 8), PDS (n = 9), and MS (n = 14). Preliminary assessment included a standard neurological exam, disease-specific, motor assessment, timed up-and-go, and qualitative video gait analysis. METHODS: Each subject performed a 5-minute walking protocol over a carpeted surface at a self-selected pace. Subjects wore a portable metabolic analyzer (Aerosport VO2000), the TriTrac R3D accelerometer and Polar® heart rate monitor. RESULTS: A 3 × 2 Repeated Measures AVOVA revealed the TriTrac R3D significantly underestimated EE in the PDS group by 25% (p<.01); while underestimating EE for the CVA subjects by 10%. The error between measurement devices was 1% for the MS group. Linear regression analysis using several disease-specific indices of impairment and motor function did not produce a viable model for improving the prediction of EE in either the PDS or CVA group (R2 = .36, SEE = 1.01, p <.01). CONCLUSION: Use of the TriTrac R3D to assess independent ambulation based on EE appears valid for ambulatory MS patients. In PDS and CVA patients its use should be made with caution and a clear understanding of the inherent error in the estimate.

The influence of commercial-grade carpet on postural sway and balance strategy among older adults.

The purpose of this research study was to examine the effect of a selected commercial-grade carpet on the static balance of healthy, older adults who had not fallen more than twice in the last 6 months. We tested a total of 45 participants. Each participant stood on a computerized balance machine and was subjected to a carpeted versus a noncarpeted condition while exposed to various sensory limitations. We measured both postural sway and balance strategy. The selected commercial-grade carpet did not affect postural sway. The participants were able to adapt to the sensory limitations regardless of whether they were standing on the carpet. Although balance strategy scores were significantly lower during the carpeted conditions, the clinical significance was questionable as the difference between the means was small for practical purposes. Healthy, older adults did not have difficulty maintaining static balance on the carpeted surface; however, the results could be different if participants who had a history of falling had been included. The results from this study are important and provide a basis of comparison for those individuals who have experienced more than two falls in the last 6 months or who have a history of falling.

Predicting slips and falls considering required and available friction

This study investigated the relationship among measurements of friction, the biomechanics of gait, and actual slip and fall events. The goal was to develop a method for estimating the probability of slips and falls based on measurements of available friction and required friction. Five subjects wearing safety harnesses walked down a ramp at various angles with either a tile or carpeted surface under dry, wet or soapy conditions. Ramp angles of 0°, 10° and 20° were used to vary the shear and normal foot force requirements. The dynamic coefficient of friction (DCOF) of shoe, floor surface and contaminant interfaces was measured. Required friction was assessed by examining the foot forces during walking trials when no slips occurred. Slips with recoveries and slips resulting in falls were recorded and categorized using a force plate and high-speed video camera. These data were then incorporated into a logistic regression to model the probability of a slip or fall event occurring based on the difference between the COF required by the foot forces generated and the measured DCOF. The results showed that the number of slip and fall events increased as the difference between the required COF and the measured DCOF increased. The logistic regression model fit the data well, resulting in an estimate of the probability of a slip or fall event based on the difference between the measured and required friction. This type of model could be used in the future to evaluate slip resistance measurement devices under various environments and assist in the design of safer work environments.

Energy expenditure during gait using the walkabout and isocentric reciprocal gait orthoses in persons with paraplegia

Objective: To compare the energy expenditure during walking using the Walkabout Orthosis (WO) and the Isocentric Reciprocal Gait Orthosis (IRGO) in persons with paraplegia. Design: A randomized cross-over design. Patients: Ten individuals with complete T9–12 paraplegia. Interventions: Subjects were trained to walk using the WO and the IRGO0 with elbow crutches. Main Outcome Measures: Subjects' energy expenditures during walking using each orthosis over three different terrains—flat tile, flat carpet, and 4° uphill ramp—were compared. Data collected included expired ventilation (L/min), heart rate (beats/ min), speed of walking (m/min), oxygen uptake (VO 2; L/min and mL/kg/min), oxygen cost (O 2 cost; mL/kg/m), and Physical Cost Index (PCI; beats/m). Subjects walked at a self-selected pace. Results: Subjects walked significantly slower with the WO than with the IRGO, regardless of the surface ( p < .05). The average speed of walking ranged from 5.2 ± 1.3 for the WO on the tiled surface to 11.5 ± 2.3m/min for the IRGO on the carpeted surface. Despite marked differences in self-selected walking speeds between the two orthoses, there were no differences in either heart rate or VO 2 among orthoses or surfaces. However, the O 2 cost of gait was significantly greater for the WO (range, 3.95 to 4.91mL/kg/m) compared with the IRGO (range, 1.6 to 1.8mL/kg/m). Likewise, the PCI was significantly greater using the WO (range, 8.4 to 10.3beats/m) than the IRGO (range, 4.3 to 7.Obeats/m). Conclusions: This study shows that the metabolic demands of walking with the WO are greater than walking with the IRGO in individuals with T9–12 paraplegia.

Evaluation of electromyographic biofeedback as an adjunct to therapeutic exercise in treating the lower extremities of hemiplegic patients.

The following controlled, preliminary investigation was designed to determine whether electromyographic biofeedback, in conjunction with therapeutic exercise, could influence the reacquisition of functional lower extremity movements in chronic hemiplegic patients. Both the control (standardized therapeutic exercise regimen) and experimental (therapeutic exercise regimen combined with electromyographic biofeedback) groups improved in ankle active range of motion; only the experimental group significantly shortened its timed ambulation over a carpeted surface. One patient in the experimental group who was given 12 additional training sessions showed further gains in knee and ankle joint angle measurements during walking. The apparent potential for rehabilitation of chronic hemiplegic patients and the benefits afforded to physical therapists from a standardized therapeutic exercise protocol are discussed.