Effect of Data and Gap Characteristics on the Nonlinear Calculation of Motion During Locomotor Activities.

This study investigated how data series length and gaps in human kinematic data impact the accuracy of Lyapunov exponents (LyE) calculations with and without cubic spline interpolation. Kinematic time series were manipulated to create various data series lengths (28% and 100% of original) and gap durations (0.05-0.20 s). Longer gaps generally resulted in significantly higher LyE% error values in each plane in noninterpolated data. During cubic spline interpolation, only the 0.20-second gap in frontal plane data resulted in a significantly higher LyE% error. Data series length did not significantly affect LyE% error in noninterpolated data. During cubic spline interpolation, sagittal plane LyE% errors were significantly higher at shorter versus longer data series lengths. These findings suggest that not interpolating gaps in data could lead to erroneously high LyE values and mischaracterization of movement variability. When applying cubic spline, a long gap length (0.20 s) in the frontal plane or a short sagittal plane data series length (1000 data points) could also lead to erroneously high LyE values and mischaracterization of movement variability. These insights emphasize the necessity of detailed reporting on gap durations, data series lengths, and interpolation techniques when characterizing human movement variability using LyE values.

Virtual reality augments effectiveness of treadmill walking training in patients with walking and balance impairments: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To systematically summarize and examine current evidence regarding the combination of virtual reality and treadmill training in patients with walking and balance impairments. DATA SOURCES: English language randomized controlled trials, participants with walking and balance impairments, intervention group used virtual reality and treadmill, control group only used treadmill with the same training frequency and number of sessions. Six bioscience and engineering databases were searched. METHODS: Two independent reviewers conducted study selection, data extraction, and quality assessment. Methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) scale. RESULTS: Sixteen randomized controlled trials including 829 participants were identified. Compared to treadmill-only training, virtual reality augmented treadmill training induced significantly faster walking (p < 0.001; standardized mean difference (SMD) = 0.55, 95%CI: 0.30 to 0.81), longer step length (p < 0.001; SMD = 0.74, 95%CI: 0.42 to 1.06), narrower step width (p = 0.03; SMD = -0.52, 95%CI: -0.97 to -0.06), longer single leg stance period (p = 0.003; SMD = 0.77, 95%CI: 0.27 to 1.27), better functional mobility (p = 0.003; SMD = -0.44, 95%CI: - 0.74 to -0.15), improved balance function (p = 0.04; SMD = 0.24, 95%CI: 0.01 to 0.47), and enhanced balance confidence (p = 0.03; SMD = 0.73, 95%CI: 0.08 to 1.37). Walking endurance did not differ significantly between groups (p = 0.21; SMD = 0.13, 95%CI: -0.07 to 0.34). CONCLUSIONS: Virtual reality augmented treadmill walking training enhances outcomes compared to treadmill-only training in patients with walking and balance impairments. The results of this review support the clinical significance of combining virtual reality with treadmill training with level 1A empirical evidence.

Walking and Fitness Improvements in a Child With Diplegic Cerebral Palsy Following Motor-Assisted Elliptical Intervention.

PURPOSE: To quantify effects of motor-assisted elliptical (Intelligently Controlled Assistive Rehabilitation Elliptical [ICARE]) training on walking and fitness of a child with cerebral palsy (CP). KEY POINTS: A 12-year-old boy with walking limitations due to spastic diplegic CP (Gross Motor Function Classification System II) participated in 24 sessions of primarily moderate- to vigorous-intensity ICARE exercise. Fitness improvements were evidenced clinically across sessions by the child's capacity to train for longer periods, at faster speeds, and while overriding motor's assistance. Postintervention, the child walked faster with greater stability and endurance and more rapidly completed the modified Time Up and Go test. CONCLUSION: The child's fitness and gait improved following engagement in a moderate- to vigorous-intensity gait-like exercise intervention. RECOMMENDATIONS FOR CLINICAL PRACTICE: Integration of moderate- to vigorous-intensity motor-assisted elliptical training can promote simultaneous gains in fitness and function for children with CP.

Computerized dynamic posturography detects balance deficits in individuals with a history of chronic severe traumatic brain injury.

BACKGROUND: Mild balance deficits can be challenging to detect in individuals with long-standing traumatic brain injuries. This study compared Computerized Dynamic Posturography (CDP) scores from individuals with traumatic brain injuries (TBI) to controls to determine if CDP could differentiate between the two groups and determine if there was a learning effect associated with testing that could be used to guide evaluation of baseline balance. METHODS: Ten ambulatory individuals with a history of severe TBI and 10 individuals without participated in three CDP sessions (24-72 hours apart). During each session, participants performed the Berg Balance Test, Dynamic Gait Index and three trials of a standardized balance assessment and Dynamic Movement Analysis (DMA) scores were recorded for each test. RESULTS: Individuals with TBI scored 93% higher (i.e. reflecting poorer balance) than the control group. The group with TBI exhibited 6.6-times more variability compared to the control group, with estimated variances of 0.3407 and 0.0517, respectively. A learning effect was detected in the group with TBI on the first day of testing (ßTBI F = -0.1241, p-value < 0.01). DISCUSSION: The CDP system detected balance differences between individuals with TBI and controls. Given the documented learning effect, the best of three trials should be used to accurately assess baseline scores.

Speech Recognition for Environmental Control: Effect of Microphone Type, Dysarthria, and Severity on Recognition Results.

This study examines the use of commercially available automatic speech recognition (ASR) across microphone options as access to environmental control for individuals with and without dysarthria. A study of two groups of speakers (typical speech and dysarthria), was conducted to understand their performance using ASR and various microphones for environmental control. Specifically, dependent variables examined included attempts per command, recognition accuracy, frequency of error type, and perceived workload. A further sub-analysis of the group of participants with dysarthria examined the impact of severity. Results indicated a significantly larger number of attempts were required (P = 0.007), and significantly lower recognition accuracies were achieved by the dysarthric participants (P = 0.010). A sub-analysis examining severity demonstrated no significant differences between the typical speakers and participants with mild dysarthria. However, significant differences were evident (P = 0.007, P = 0.008) between mild and moderate-severe dysarthric participants. No significant differences existed across microphones. A higher frequency of threshold errors occurred for typical participants and no response errors for moderate-severe dysarthrics. There were no significant differences on the NASA Task Load Index.

Virtual Rehabilitation and COVID-19: Varied Adoption and Satisfaction Among Patients and Providers Participating in a Multi-Site Survey Study.

The COVID-19 pandemic compelled rapid healthcare adaptations including increased use of telehealth (TH) and virtual care (VC) to provide rehabilitation services. This multi-site cross-sectional survey study examined rehabilitation patients' and providers' experiences with service delivery during the COVID-19 pandemic, including the use of TH/VC. Patients and providers who received or provided rehabilitation services were recruited from 1 of 3 large, post-acute rehabilitation systems located in the Southeastern and Midwestern United States during the COVID-19 pandemic. Participants rated personal satisfaction with rehabilitation services received or rendered during the pandemic and willingness to use TH/VC in the future. Questions also addressed accessibility, ease of use, and perceived barriers to TH/VC use. The adoption and personal satisfaction of TH/VC for rehabilitation care varied between patients and providers. Patients reported higher levels of satisfaction compared to providers (P < .001). Patients who did not use TH/VC had higher satisfaction than those who did (P < .05). Patients were less willing than providers to use TH/VC (P < .001). Those who used TH/VC prior to the pandemic were more willing to use post-pandemic (P < .001). Patients reported TH/VC was useful in increasing health services accessibility yet were neutral as to the ability of TH/VC to improve outcomes. Patients and providers agreed that TH/VC was easy to learn and use. Medical providers found TH/VC more useful than therapy providers. Participants who used TH/VC during the pandemic are more willing to use the service again in the future. Understanding patient and provider preferences and perspectives is key to the continued use of TH/VC in rehabilitation care.

Occupational injuries and patient lift usage among physical rehabilitation therapists.

BACKGROUND: Physical therapists (PTs) and physical therapist assistants (PTAs) are at high risk for work-related musculoskeletal pain and discomfort. OBJECTIVE: Determine the prevalence and exposure risk factors for work-related injuries (WRIs) among rehabilitation PTs and PTAs. METHODS: A cross-sectional research survey was conducted among 170 PTs and 67 PTAs at 51 free-standing rehabilitation hospitals and rehabilitation units embedded in general hospitals in the Midwestern states of Iowa, Kansas, Missouri and Nebraska. The prevalence of WRIs and significant risk factors for developing WRIs were determined for PTs and PTAs. RESULTS: The 1-year prevalence of WRIs among PTs and PTAs working in physical rehabilitation was 29.5%. Multifaceted causes were identified including frequently bending/twisting, over-exerting force during patient handling activities, inadequate lifting devices, and lack of ongoing training for mechanical lifting device usage. CONCLUSIONS: Equipment usage barriers point to a critical need for technology creation, research, and education to advance worker safety while simultaneously enhancing patient outcomes.

Muscle demand and kinematic similarities between pediatric-modified motor-assisted elliptical training at fast speed and fast overground walking: Real-world implications for pediatric gait rehabilitation.

The purpose of this research was to compare children's lower extremity muscle activity and kinematics while walking at fast pace and training at fast speeds with and without motor-assistance on a pediatric-modified motor-assisted elliptical. Twenty-one children without disabilities were recruited and fifteen completed all three training conditions at self-selected fast pace. Repeated-measures ANOVAs identified muscle demand (peak, mean, duration) differences across device conditions and fast walking. Root mean square error compared overall kinematic profiles and statistical parametric mapping identified kinematic differences between conditions. Motor-assisted training reduced lower extremity muscle demands compared to training without the motor's assistance (16 of 21 comparisons) and to fast walking (all but one comparison). Training without the motor's assistance required less muscle effort than fast walking (16 of 21 comparisons). Kinematic differences between device conditions and fast walking were greater distally (thigh, knee, ankle) than proximally (trunk, pelvis, hip). In summary, transitioning from training with to without the motor's assistance promoted progressively greater activity across the lower extremity muscles studied, with sagittal plane kinematic changes most apparent at the distal joints. Our findings highlight how motor-assistance can be manipulated to customize physiologic challenges to lower extremity muscles prior to fast overground walking.

Effect of gap-filling technique and gap location on linear and nonlinear calculations of motion during locomotor activities.

BACKGROUND: Marker occlusion during camera-based movement analysis is common. Different interpolation techniques are available for estimating location of missing marker trajectories. RESEARCH QUESTION: What is the effect of gap location and interpolation technique on linear and nonlinear measures for a given kinematic time series? METHODS: Kinematic data were recorded during motor-assisted elliptical training and treadmill walking. Gap-filling techniques (i.e., Cubic, Makima, Autoregressive, Nearest Neighbor, and No Interpolation) and gap locations experimentally applied to each cycle across initially complete time series (Gap 1: local minimum and maximum peaks; Gap 2: maximum peaks; Gap 3: maximum peaks at negative slope; Gap 4: random locations) were examined during linear (Maxima and Minima joint angles) and nonlinear [maximum Lyapunov exponent (LyE)] measures. RESULTS: Gap-filling technique and gap location influenced values calculated for linear and nonlinear measures of joint motions. When referenced to the gold standard (original data series without gaps), across all joints studied the average % error of Maxima and Minima joint angles and LyE % error were lower when applying Cubic, Makima, Autoregressive, and Nearest Neighbor techniques compared to No Interpolation (p < 0.0001). The % error of Maxima joint angles was lower for Gaps 1, 3, and 4 compared to Gap 2 (p = 0.0003), while % error of Minima joint angles was lower for Gaps 2 and 3, compared to Gaps 1 and 4 (p < 0.0001). An interaction between gap-filling technique and gap location was identified for LyE % error, in which Gap 4 % error was significantly greater during No Interpolation compared to other gap-filling techniques (p < 0.0001). SIGNIFICANCE: Findings can guide selection of appropriate techniques to manage missing kinematic data points in camera-based motion analysis time series. Gap-filling techniques significantly reduced error in calculating select linear and nonlinear measures of variability, with Cubic most consistently resulting in the greatest reduction in error.

Perceived importance of AAC messages to support communication in rehabilitation settings.

PURPOSE: Permanent or temporary speech loss can occur due to a variety of medical conditions and often requires individuals to use augmentative and alternative communication (AAC) strategies and technologies to support communication. The use of AAC in medical and rehabilitation settings is critical to ensure the health, safety and psychological well-being of communicatively vulnerable individuals. METHOD: This study surveyed the perceived importance of communication messages within five categories (Basic Needs, Patient-Provider Specific Communication, Social, Feelings, and Messages for Young Children) by individuals with disability who have undergone recent medical care as well as by rehabilitation care providers. RESULTS: Results indicated that, with only a few exceptions, participants with disability more frequently selected all of the messages listed under the Patient-Provider Specific, Social, and Feelings categories compared to rehabilitation care providers' responses. Additionally, the individuals with disabilities selected messages that were more personalised to their specific care needs under Basic Needs. Both participant groups were asked to also suggest other messages that they perceived as important under each category. The other suggested messages demonstrated the potential need to provide personalisation to AAC displays to best meet the communication needs of individuals with disability.Implications for RehabilitationThere is a critical need for individuals who find themselves in medical settings (ICU, acute care hospital, rehabilitation hospital, etc.) to be able to communicate. This study provides preliminary information on the breadth of communication content that is perceived as relevant by individuals with disability and rehabilitation care providers. The need to provide personalized as well as a wide range of communication content options was of particular importance to individuals with disability. This information may provide specific guidance on how to best develop augmentative and alternative communication options for individuals in medical settings.

Test-retest reliability and minimal detectable change of the computerized dynamic posturography PROPRIO for adults with chronic traumatic brain injury.

PURPOSE: Balance deficits after brain injury, including reactive recovery from unexpected perturbations, can persist well after rehabilitation is concluded. While traditional clinical assessments are practical, the anticipatory nature of the tasks may mask perceptible balance control. Computerized dynamic posturography can directly quantify capacity to respond to unexpected, external perturbations. This study examined the reliability of the computerized dynamic posturography assessment with the device PROPRIO® 4000 in adults with traumatic brain injury and created the minimal detectable change for its standardized test. METHODS: Ten adults (ages 21-55 years) with chronic (average 10 ± 6 years post-injury) severe (loss of consciousness 2-75 days) brain injury performed three trials of the Propriotest® on two separate days. The average of three trials and the best scores were used separately for analysis. Test-retest reliability was verified using Intraclass Correlation Coefficients with 95% confidence interval and standard error of measurement in relation to the Intraclass Correlation Coefficients at 95%. The minimal detectable change was calculated at 95% confidence level (minimal detectable change95) and Bland-Altman plots were created to express agreement between measurement days. RESULTS: The results exhibited excellent reliability for both average (Intraclass Correlation Coefficient of 0.969, standard error of measurement 50.9 points) and best (Intraclass Correlation Coefficient of 0.985, standard error of measurement 31.3 points) scores, with average and best minimal detectable change95 of 141.0 and 86.7 points, respectively. CONCLUSIONS: Clinicians and rehabilitation researchers can use these findings to determine if a Propriotest® change score represents a true post-treatment effect with adults with chronic brain injury.IMPLICATIONS FOR REHABILITATIONAfter brain injury, balance deficits are common and can persist well after completion of rehabilitation programs.Computerized dynamic posturography allows for objective quantification of one's capacity to respond to external perturbations.The device PROPRIO® 4000 provides reliable quantification of balance deficits of community dwelling individuals who have experienced a severe traumatic brain injury.The minimal detectable change scores created can assist clinicians and rehabilitation researchers detect whether a change in balance score represents a true effect of an intervention at post-treatment.

Feasibility of motor-assisted elliptical to improve walking, fitness and balance following pediatric acquired brain injury: A case series.

PURPOSE: Walking, fitness, and balance deficits are common following acquired brain injury (ABI). This study assessed feasibility, acceptability, and usefulness of a modified motor-assisted elliptical (ICARE) in addressing walking, fitness, and balance deficits in children with chronic ABIs. METHODS: Three children (> 5 years post-ABI) completed 24 ICARE exercise sessions (exercise time, speed, and time overriding motor-assistance gradually increased) to promote mass repetition of gait-like movements and challenge cardiorespiratory fitness. Parents' and children's perceptions of ICARE's safety, comfort, workout, and usability were assessed. Cardiovascular response, gait and balance outcomes were assessed. RESULTS: No adverse events occurred. Parent's Visual Analogue Scale (VAS) scores of perceived device safety (range 80-99), workout (range 99-100), and usability (range 75-100) were high, while comfort were 76-80 given commercial harness fit and arm support. Children's VAS scores all exceeded 89. Comfortable walking velocity, 2-Minute Walk Test, fitness, and Pediatric Balance Scale scores improved post-training, with many outcomes surpassing established minimal clinically important differences. CONCLUSION: Following engagement in moderate- to vigorous-intensity exercise promoting repetitive step-like movements on a specially adapted motor-assisted elliptical, three children with chronic ABI demonstrated improvements in walking, fitness and balance. Future research in community-based environments with a larger cohort of children with ABI is needed.

Variations in plantar pressure variables across elliptical trainers in older adults.

BACKGROUND: Ellipticals are used to address walking and cardiorespiratory training goals of older adults, some of whom are at risk for foot injuries. Variations in joint kinematics and muscle demands when using different ellipticals could lead to plantar pressure differences. This study explored plantar pressure variables during gait and use of four ellipticals. METHODS: Plantar pressures were recorded while 10 adults [68.1 (4.5) years] walked and used the True, Octane, Life Fitness, and SportsArt ellipticals. Repeated-measures ANOVAs (5 × 1) identified forefoot and heel differences across conditions. FINDINGS: Maximum forefoot forces and peak pressures were significantly lower than walking for each elliptical condition with one exception (Life Fitness peak pressure). However, sustained elliptical pedal contact time contributed to forefoot pressure-time integrals and dosages (i.e., cumulative pressure during one minute of activity) not varying significantly amongst elliptical and walking conditions. Heel maximum forces and peak pressures were significantly lower than walking during all elliptical conditions except SportsArt. Heel contact time on SportsArt and Octane exceeded walking, and SportsArt heel contact time exceeded Life Fitness. Heel pressure-time integral was greater on SportsArt compared to walking, Life Fitness, and True. Sports Art heel dosage exceeded Life Fitness and True. INTERPRETATION: While elliptical training's sustained double limb support diminished maximal forces and peak pressures under the forefoot and heel compared to walking, each ellipticals' pressure-time integral and dosage were not significantly lower than walking. These findings point to the importance of carefully initiating elliptical training programs to minimize tissue injury, particularly if sensory neuropathy is present.

Comparison of plantar pressure profile of young adults during training on elliptical devices and overground walking: A pilot study.

BACKGROUND: Elliptical training may offer advantages over other cardiorespiratory exercises for those requiring podiatric care, since its constant double-limb support diminishes recurring high-impact plantar forces while allowing exercise in a functional, upright posture. Unknown is the impact of distinct elliptical models, that can alter user's body mechanics, on potential variations in plantar pressure patterns. PURPOSE: To compare plantar pressure variables while exercising on four ellipticals and walking. METHODS: For this cross-sectional pilot study, plantar pressure data were recorded from ten young adults while exercising on four ellipticals (True, Octane, Life Fitness, SportsArt) and walking overground. One-way repeated measures ANOVA identified differences in heel, arch, and forefoot maximum force (MF), peak pressure (PP), and pressure-time integral (PTI). RESULTS: MF was lower under the heel when exercising on all ellipticals compared with walking, with further differences detected between models. PP was lower on all three foot regions when exercising on all ellipticals compared with walking, except Octane under the arch, with differences detected between ellipticals under the heel. PTI was lower under the heel and arch when exercising on some of the ellipticals compared with walking, with differences again detected under the heel between models. CONCLUSION: Plantar pressures were lower when exercising on the ellipticals compared with walking for most variables. Caution is recommended to which elliptical could be incorporated into therapeutic programs given that differences among models were detected under the heel.

Effect of motor-assisted elliptical training speed and body weight support on center of pressure movement variability.

BACKGROUND: A motor-assisted elliptical trainer is being used clinically to help individuals with physical disabilities regain and/or retain walking ability and cardiorespiratory fitness. Unknown is how the device's training parameters can be used to optimize movement variability and regularity. This study examined the effect of motor-assisted elliptical training speed as well as body weight support (BWS) on center of pressure (CoP) movement variability and regularity during training. METHODS: CoP was recorded using in-shoe pressure insoles as participants motor-assisted elliptical trained at three speeds (20, 40 and 60 cycles per minute) each performed at four BWS levels (0 %, 20 %, 40 %, and 60 %). Separate two-way repeated measures ANOVAs (3 × 4) evaluated impact of training speed and BWS on linear variability (standard deviation) and non-linear regularity (sample entropy) of CoP excursion (anterior-posterior, medial-lateral) for 10 dominant limb strides. FINDINGS: Training speed and BWS did not significantly affect the linear variability of CoP in the anterior-posterior or medial-lateral directions. However, sample entropy in both directions revealed the main effect of training speed (p < 0.0001), and a main effect of BWS was observed in the medial-lateral direction (p = 0.004). Faster training speeds and greater levels of BWS resulted in more irregular CoP patterns. INTERPRETATION: The finding that speed and BWS can be used to manipulate CoP movement variability when using a motor-assisted elliptical has significant clinical implications for promoting/restoring walking capacity. Further research is required to determine the impact of motor-assisted elliptical speed and BWS manipulations on functional recovery of walking in individuals who have experienced a neurologic injury or illness.

Psychological difficulties and parental well-being in children with musculoskeletal problems in the 2011/2012 National Survey of Children's Health.

OBJECTIVE: This study compared children with and without current musculoskeletal (MSK) problems on key indices of child psychological adjustment and parental well-being. RESEARCH METHOD: Prevalence estimates of psychological problems were compared for children ages 2-17 years with and without current MSK problems in the 2011/2012 National Survey of Children's Health. Multivariate logistic regression analyses examined the effects of MSK problem severity on the risk of psychological concerns. RESULTS: Population level differences in prevalence estimates were observed in psychological difficulties. Children with MSK problems were disproportionally affected by anxiety problems, depression, behavioral/conduct problems, and ADHD compared to children without MSK problems. Compared to children with mild MSK problems, children with severe MSK problems were 2.74 times more likely to have anxiety problems (95% CI [1.35, 2.86], p < .05). No other significant differences were found among children with mild, moderate, or severe MSK problems. Regarding parental well-being, compared to children without MSK problems, children with MSK problems were more likely to have mothers and fathers who often experience parenting stress/aggravation and have poor physical and mental health. CONCLUSIONS: Children with MSK problems are vulnerable to psychological difficulties that can affect their learning, development, and quality of life. Psychological screening and ensuring that these children receive effective mental health treatments should be a priority in pediatric health care settings. Consideration of parental physical and mental health is recommended in the assessment and treatment of children with MSK problems. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Therapeutic massage to enhance family caregivers' well-being in a rehabilitation hospital.

BACKGROUND AND PURPOSE: A massage therapy program was implemented to address the psychological well-being of family caregivers to patients in a rehabilitation hospital. The impact of massage "dosage" on caregiver stress and psychological well-being was examined in this study. Participants' perspectives on the program were also explored. MATERIALS AND METHODS: Thirty-eight family caregivers were randomized to receive either one massage per week or three massages per week for two weeks. Caregivers reported psychological symptoms and stress pre- and post-program. Program acceptability was assessed via responses on an exit survey. RESULTS: Overall, 79% of massages were received (89% among program completers). Post-program symptom scores were lower than baseline scores for both groups (F (1, 31) = 8.74 - 24.50, P < 0.01). Exit surveys indicated high program acceptability and perceived benefits. CONCLUSION: Findings suggest that massage services would be welcomed, utilized, and beneficial for improving the psychological well-being of family caregivers in a rehabilitation hospital.

Muscle compensatory mechanisms during able-bodied toe walking.

The purpose of this study was to use muscle-actuated forward dynamic simulations to quantify individual muscle contributions to body support (vertical ground reaction force) and propulsion (horizontal ground reaction force) and the mechanical energetics of the body segments during toe and heel-toe walking performed by able-bodied subjects to identify possible compensatory mechanisms necessary to toe walk. The simulations showed that an increased magnitude of plantar flexor power output in early stance, which was necessary to maintain the equinus posture during toe walking, contributed to body support and acted to brake (decelerate) the center-of-mass in the horizontal direction. This in turn required a reduction in the contributions to support from the vastii, gluteus maximus and biarticular hamstring muscles and decreased contributions to braking from the vastii and to a lesser extent the gluteus maximus. In late stance, the soleus contributed less to body support and forward propulsion during toe walking, which when combined with the increased braking by the plantar flexors in early stance, required a prolonged contribution to forward propulsion from the hamstrings from mid- to late stance. The multiple compensatory mechanisms necessary to toe walk have important implications for distinguishing between underlying pathology and necessary compensatory mechanisms, as well as for identifying the most appropriate treatment strategy for equinus gait.

Variations in plantar pressure variables across five cardiovascular exercises.

PURPOSE: To quantify variations in plantar pressure variables in healthy adults across five cardiovascular exercises. METHODS: Ten young (19-35 yr old) and 10 middle-aged (45-60 yr old) individuals participated. After equipment familiarization, plantar pressure data were recorded during walking, running, elliptical training, stair climbing, and recumbent biking. Separate one-way analyses of variance with repeated measures identified significant differences in pressure variables across exercises and between age groups under the forefoot, arch, and heel. RESULTS: Forefoot: Peak pressures were higher during walking (253 kPa), running (251 kPa), and elliptical training (213 kPa) than stair climbing (130 kPa) and recumbent biking (41 kPa; P < or = 0.001). Biking pressures were lower than all other conditions (P < 0.001). Arch: Pressures were higher during running (144 kPa) compared with all other conditions (P < or = 0.001). Intermediate-level pressures during walking (119 kPa) and elliptical training (102 kPa) exceeded those during stair climbing (80 kPa; P < or = 0.002). Pressures were lowest during recumbent biking (33 kPa; P < 0.001). Heel: Pressures were highest during walking (215 kPa) and running (188 kPa), exceeding those recorded during all other activities (P < 0.001). Moderate elliptical training pressures (94 kPa) surpassed stair climbing values (66 kPa; P = 0.014). Pressures were lowest during recumbent biking (25 kPa; P < 0.001). The only significant difference identified between age groups was a larger arch contact area in the young compared with middle-aged, when averaged across exercises (P = 0.011). CONCLUSIONS: When protection of the forefoot is important (e.g., diabetic foot neuropathies), biking and stair climbing offer optimal pressure reductions. If protecting the heel from high pressures and forces is warranted, recumbent biking, stair climbing, and elliptical training provide greater relief.

The neuromuscular demands of toe walking: a forward dynamics simulation analysis.

Toe walking is a gait deviation with multiple etiologies and often associated with premature and prolonged ankle plantar flexor electromyographic activity. The goal of this study was to use a detailed musculoskeletal model and forward dynamical simulations that emulate able-bodied toe and heel-toe walking to understand why, despite an increase in muscle activity in the ankle plantar flexors during toe walking, the internal ankle joint moment decreases relative to heel-toe walking. The simulations were analyzed to assess the force generating capacity of the plantar flexors by examining each muscle's contractile state (i.e., the muscle fiber length, velocity and activation). Consistent with experimental measurements, the simulation data showed that despite a 122% increase in soleus muscle activity and a 76% increase in gastrocnemius activity, the peak internal ankle moment in late stance decreased. The decrease was attributed to non-optimal contractile conditions for the plantar flexors (primarily the force-length relationship) that reduced their ability to generate force. As a result, greater muscle activity is needed during toe walking to produce a given muscle force level. In addition, toe walking requires greater sustained plantar flexor force and moment generation during stance. Thus, even though toe walking requires lower peak plantar flexor forces that might suggest a compensatory advantage for those with plantar flexor weakness, greater neuromuscular demand is placed on those muscles. Therefore, medical decisions concerning whether to reduce equinus should consider not only the impact on the ankle moment, but also the expected change to the plantar flexor's force generating capacity.