Determining Trendelenburg test validity and reliability using 3-dimensional motion analysis and muscle dynamometry.

BACKGROUND: The hip abductor muscle group stabilises the pelvis during gait to prevent excessive pelvic drop. Hip abductor weakness has been linked to musculoskeletal conditions such as chronic low-back pain. As such, it is important that practitioners can correctly diagnose hip abductor weakness in a clinical setting. Although the Trendelenburg test is commonly used by practitioners, the validity of this test to assess hip abductor weakness in the absence of musculoskeletal injury remains questionable. The aim of this study was to determine the validity of the Trendelenburg test, as observed by a practitioner, to assess frontal plane pelvic motion and hip abductor strength in a population without intra-articular hip disorders. METHODS: This study was performed between June 14th and October 16th 2019. Eighteen participants were recruited for this study. Peak normalised isometric and isokinetic hip abductor torque were measured bilaterally (n = 36) using the Biodex System 4 isokinetic dynamometer. Each participant performed the Trendelenburg test bilaterally (n = 36) while a graduate year chiropractic practitioner assessed for a "positive" or "negative" sign. The test was simultaneously recorded using Vicon 3-Dimensional motion capture to measure frontal plane pelvic motion and elevation. Correlation analyses were performed between the measures of peak hip abductor torque and pelvic motion to determine if any relationship existed. Agreement between the practitioner and 3-Dimensional analysis was calculated using the kappa (κ) statistic. RESULTS: Weak, non-significant correlations were found between hip abductor strength and pelvic motion before outlier removal. Significant (p < 0.05) yet weak correlations were found after outlier removal, except for isometric hip abductor strength. Weak agreement was found between the chiropractic practitioner and 3-Dimesnional analysis for the Trendelenburg test assessment (κ = 0.22-0.25). CONCLUSIONS: This study found no significant relationship between normalised peak isometric and isokinetic hip abductor torque and frontal plane pelvic motion during the Trendelenburg test in a healthy young adult population. There was also poor agreement between the practitioner and pelvic motion assessments. Caution should be used when using this test, in the absence of intra-articular hip pathology, to assesses hip abductor weakness. Before any definitive conclusion can be made, studies with a larger sample size should be performed.

Changing the Physical Activity Behavior of Adults With Fitness Trackers: A Systematic Review and Meta-Analysis.

OBJECTIVE: To examine whether a fitness tracker (FT) intervention changes physical activity (PA) behavior compared to a control condition or compared to an alternative intervention. DATA SOURCE: Searches between January 01, 2010, and January 01, 2019, were conducted in PubMed, CINAHL, Cochrane CENTRAL, EMBASE, and PsycINFO. INCLUSION/EXCLUSION CRITERIA: Randomized clinical trials of adults using an FT to change PA behavior were included. Nonclinical trials, studies that included the delivery of structured exercise, and/or studies that only used the FT to assess PA were excluded. DATA EXTRACTION: Extracted features included characteristics of the study population, intervention components, PA outcomes, and results. DATA SYNTHESIS: Papers were pooled in a statistical meta-analysis using a fixed effects model. Where statistical pooling was not possible, standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated. Findings were presented in a narrative form and tables. RESULTS: Of 2076 articles found, 21 were included in the review. A small yet significant positive effect (SMD = 0.25, 95% CI = 0.17-0.32; P < .01; I2 = 56.9%; P = .03) was found in step count for interventions compared to control. A small yet significant negative effect (SMD = -0.11, 95% CI = -0.20 to -0.02; P = .02; I2 = 58.2%; P = 0.03) was found in moderate-to-vigorous PA for interventions compared to an alternative intervention. CONCLUSION: Trackers may enhance PA interventions, as a general positive effect is found in step count compared to a control. However, there is no evidence of a positive effect when interventions are compared to an alternative intervention. It is unknown whether results are due to other intervention components and/or clinical heterogeneity.

An Investigation of Pressure Profiles and Wearer Comfort During Walking With a Transtibial Hydrocast Socket.

OBJECTIVE: The aims of the study were to conduct an investigation of the transtibial hydrocast socket interface pressures during walking and to explore potential relationships between pressures experienced and resultant wearer comfort. DESIGN: In this cross-sectional study, pressure data at the limb and hydrocast socket interface during walking were collected from 16 users of hydrocast sockets. The pressures at this interface were described by location, magnitude, and duration for all participants and were compared between the most and least comfortable participants. RESULTS: High pressures were found about the bony prominences of the residual limb, especially the tibial crest of the anterior distal region. Factors identified as potentially causing discomfort (P < 0.1, d > 0.80) were high peak pressures at the anterior proximal region and longer durations of submaximal loading at the lateral proximal region and the anterior and medial distal regions. High pressure variability at the anterior proximal region may also contribute to discomfort (P = 0.106, d = 0.88). CONCLUSIONS: The hydrocast socket interface pressures have been described for a cohort of users. A number of differences were found in the pressure profiles of the most and least comfortable participants. These differences suggest trends between the identified pressure parameters and resultant wearer comfort. Future studies should confirm these exploratory results.

The functional, spatio-temporal and satisfaction outcomes of transtibial amputees with a hydrocast socket following an extended usage period in an under-resourced environment.

BACKGROUND: Transtibial hydrocast sockets have been shown to be a potential alternative to hand-cast patella-tendon bearing sockets, the use of which would have particular benefits in under-resourced environments. However, data concerning wearer outcomes of hard hydrocast sockets (i.e. those without silicone liners), especially over long-term usage periods, is scarce in the literature. RESEARCH QUESTIONS: Are there any changes in wearer functional, spatio-temporal or satisfaction outcomes over a long usage period with a hydrocast socket? And how do the post-usage period outcomes compare with those from the wearers original prostheses? METHODS: In this pre-post interventional study, the clinical outcomes of twenty-one experienced transtibial prostheses users were evaluated using widely-accepted and employed methods to assess wearer functional capacity, mobility, gait and satisfaction. The participants were fit with a hard hydrocast socket and the outcomes after an extensive usage period of 5 months were compared to the pre-usage period data following initial fitting and the data collected from the participants' original prosthetic limb. RESULTS: Significant differences were found in the temporal parameters of gait, all indicating decreased reliance on the intact limb and an increased loading of the prosthetic limb with the post-usage period hydrocast socket compared to both the pre-usage period socket and the participants' original limbs. No differences in the functional capacity, mobility, spatial gait parameters or satisfaction were found between the socket conditions. SIGNIFICANCE: This is the largest study to date of functional, spatio-temporal and satisfaction outcomes of hydrocast sockets following an extended usage period in an under-resourced environment.

Exercise at an onsite facility with or without direct exercise supervision improves health-related physical fitness and exercise participation: An 8-week randomised controlled trial with 15-month follow-up.

ISSUE ADDRESSED: Physical activity and exercise participation is limited by a perceived lack of time, poor access to facilities and low motivation. The aim was to assess whether providing an exercise program to be completed at the workplace with or without direct supervision was effective for promoting health-related physical fitness and exercise participation. METHODS: Fifty university employees aged (Mean ± SD) 42.5 ± 11.1 years were prescribed a moderate- to vigorous-intensity aerobic and resistance exercise program to be completed at an onsite facility for 8 weeks. Participants were randomly allocated to receive direct exercise supervision or not. Cardiorespiratory fitness (V̇O2max ) and maximal muscular strength were assessed at baseline and 8 weeks. Self-report physical activity was assessed at baseline, 8 weeks and 15 months post-intervention. RESULTS: Attendance or exercise session volume were not different between groups. Cardiorespiratory fitness (Mean ± 95% CI); +1.9 ± 0.7 mL·kg·min-1 ; P < .001), relative knee flexion (+7.4 ± 3.5 Nm·kg-1 %; P < .001) and extension (+7.4 ± 4.6 Nm·kg-1 %; P < .01) strength increased, irrespective of intervention group. Self-reported vigorous-intensity physical activity increased over the intervention (mean ± 95% CI; +450 ± 222 MET·minutes per week; P < .001), but did not remain elevated at 15 months (+192 ± 276 MET·minutes per week). CONCLUSION: Providing a workplace exercise facility to complete an individually-prescribed 8-week exercise program is sufficient to improve health-related physical fitness in the short-term independent to the level of supervision provided, but does not influence long-term participation. SO WHAT?: Lower cost onsite exercise facility supervision is as effective at improving physical health and fitness as directly supervised exercise, however ongoing support may be required for sustained physical activity behaviour change.

Transtibial Prosthetic Socket Shape in a Developing Country: A study to compare initial outcomes in Pressure Cast hydrostatic and Patella Tendon Bearing designs.

This study compared the physical function and comfort level of patients with unilateral transtibial amputation after being fitted with a hand-cast Patella Tendon Bearing (PTB) socket and a pressure-cast (PCAST) hydrocast socket. The latter technique aims to reduce the skill dependency currently required for socket manufacture and fit. The study was conducted at the Vietnamese Training Centre for Orthopaedic Technologies and involved seventeen Vietnamese participants with unilateral transtibial amputation, all of whom were long term users of prosthetics. All participants were fitted with two sockets manufactured using both hand-cast and PCAST techniques with International Committee of the Red Cross components. Walking tests (timed up and go test and six-minute-walk-test), spatio-temporal gait analyses and subjective comfort assessments were completed after a short acclimatisation period with each socket. The participant-preferred socket was also noted. No significant differences were found for the measures of mobility, functional capacity, spatio-temporal gait parameters, gait symmetry, perceived comfort or participant socket preference. The results show the initial patient outcomes are similar when participants are fitted with a hand-cast PTB socket and a PCAST hydrocast sockets. Future work should confirm these findings in a longer trial.

Validation of the Fitbit One, Garmin Vivofit and Jawbone UP activity tracker in estimation of energy expenditure during treadmill walking and running.

OBJECTIVES: To determine the validity of energy expenditure estimation made by the Fitbit One, Garmin Vivofit and Jawbone UP activity trackers during treadmill walking and running. Determining validity of such trackers will inform the interpretation of the data they generate. DESIGN: Cross-sectional study. METHOD: Fourteen adults walked at 0.70, 1.25, 1.80 ms-1 and ran at 2.22, 2.78, 3.33 ms-1 on a treadmill wearing a Fitbit One, Garmin Vivofit and Jawbone UP. Estimation of energy expenditure from each tracker was compared to measurement from indirect calorimetry (criterion). Paired t-tests, correlation coefficients and Bland-Altman plots assessed agreement and proportional bias. Mean percentage difference assessed magnitude of difference between estimated and criterion energy expenditure for each speed. RESULTS: Energy expenditure estimates from the Fitbit One and Garmin Vivofit correlated significantly (p< 0.01; r= 0.702; 0.854) with criterion across all gait speeds (0.70-3.33 ms-1). Fitbit One, Garmin Vivofit and Jawbone UP correlated significantly (p < 0.05; r = 0.729; 0.711; 0.591) with criterion across all walking speeds (0.70-1.80 ms-1). However, only the Garmin Vivofit correlated significantly (p< 0.05; r = 0.346) with energy expenditure estimations from criterion across running speeds (2.22-3.33 ms-1). Bland-Altman plots showed proportional bias for the Fitbit One and Garmin Vivofit. Energy expenditure estimations of single speeds were overestimated by the Fitbit One and underestimated by the Garmin Vivofit. CONCLUSIONS: Energy expenditure reported by the devices distinguished between walking and running, with a general increase as exercise intensity increased. However, the reported energy expenditure from these devices should be interpreted with caution, given their potential bias and error. Practical implications Although devices report the same outcome of EE estimation, they are not equivalent to each other and differ from criterion measurements during walking and running. These devices are not suitable as research measurement tools for recording precise and accurate EE estimates but may be suitable for use in interventions of behaviour change as they provide feedback to user on trends in energy expenditure. If intending to use these devices in studies where precise measurements of energy expenditure are required, researchers need to undertake specific validation and reliability studies prior to interventions and the collection of cross-sectional data.

A Multiple Regression Approach to Normalization of Spatiotemporal Gait Features.

Normalization of gait data is performed to reduce the effects of intersubject variations due to physical characteristics. This study reports a multiple regression normalization approach for spatiotemporal gait data that takes into account intersubject variations in self-selected walking speed and physical properties including age, height, body mass, and sex. Spatiotemporal gait data including stride length, cadence, stance time, double support time, and stride time were obtained from healthy subjects including 782 children, 71 adults, 29 elderly subjects, and 28 elderly Parkinson's disease (PD) patients. Data were normalized using standard dimensionless equations, a detrending method, and a multiple regression approach. After normalization using dimensionless equations and the detrending method, weak to moderate correlations between walking speed, physical properties, and spatiotemporal gait features were observed (0.01 < |r| < 0.88), whereas normalization using the multiple regression method reduced these correlations to weak values (|r| <0.29). Data normalization using dimensionless equations and detrending resulted in significant differences in stride length and double support time of PD patients; however the multiple regression approach revealed significant differences in these features as well as in cadence, stance time, and stride time. The proposed multiple regression normalization may be useful in machine learning, gait classification, and clinical evaluation of pathological gait patterns.

Pressure casting technique for transtibial prosthetic socket fit in developing countries.

This study investigated a low-cost and low-skill dependent pressure casting technique (PCAST) to fabricate and fit transtibial (TT) prosthetic sockets in a developing country. Thirteen adult volunteers (average age 47 yr) with unilateral TT amputation participated. After fitting, five participants were lost to follow-up (four rejected the prosthesis and one died). The eight remaining participants used the prosthesis for an average of 167 +/- 1 d and indicated regular use throughout this period. Success was evaluated by measures of satisfaction (Satisfaction with Prosthesis Questionnaire [SATPRO]), physical function, and gait recorded after fitting and following the usage period. SATPRO results showed high levels of satisfaction on both occasions. After the usage period, the timed up-and-go and six-minute walk performances increased by 1.7 +/- 2.0 s and 60 +/- 29 m (p = 0.001), respectively, whereas gait speed, cadence, step and stride length, support base, and percent gait cycle times remained unchanged. The results show that a TT PCAST socket (with some minor modifications) was successfully fitted to eight of the participants (success rate of 62%). It is reasonable to conclude that this technique may assist people with TT amputation in a developing country where there is a lack of trained personnel. Importantly, this technique may reduce TT prosthetic costs and increase fitting opportunity in a developing country.

Obstacle crossing following stroke improves over one month when the unaffected limb leads, but not when the affected limb leads.

While it is well established that obstacle crossing is impaired following stroke, it is not known whether obstacle crossing improves as gait improves following stroke. The purpose of this study was to determine whether obstacle crossing changed over a one month time period in people with a recent stroke. Twenty participants receiving rehabilitation following a recent stroke were tested on two occasions one month apart. Participants received usual care rehabilitation, including physiotherapy, between the tests. The main outcome measure was obstacle crossing speed as participants stepped over a 4-cm high obstacle. Secondary measures were spatiotemporal variables. Data were collected via a three dimensional motion analysis system. When leading with the affected limb no changes in obstacle crossing speed or spatiotemporal variables were observed over the one month period. When leading with the unaffected limb, crossing speed significantly increased (p=.002), and affected trail limb swing time (p=.03) and crossing step double support time reduced (p=.016). While not significant, the lead and trail limb pre-obstacle distance increased (p=.08), and lead swing time (p=.052) reduced. Change in obstacle crossing speed did not correlate with change in level gait speed. Obstacle crossing does not necessarily improve over a one month time period in people receiving rehabilitation following stroke. These findings suggest that there may be a need for more targeted training of obstacle crossing, particularly when leading with the affected limb.

People with stroke who fail an obstacle crossing task have a higher incidence of falls and utilize different gait patterns compared with people who pass the task.

BACKGROUND: Obstacle crossing is impaired in people following stroke. It is not known whether people with stroke who fail an obstacle crossing task have more falls or whether the gait adjustments used to cross an obstacle differ from those used by people who pass the task. OBJECTIVE: The purposes of this study were (1) to identify whether a group of people with stroke who failed an obstacle crossing task had a greater incidence of falling and (2) to determine whether people who fail an obstacle crossing task utilize different gait adjustments. DESIGN: This was a prospective, observational study. METHODS: Thirty-two participants with a recent stroke were recruited. Participants walked at self-selected speed and stepped over a 4-cm-high obstacle. Performance was rated as pass or fail, and spatiotemporal, center of mass (COM), and center of pressure (COP) data were collected. Prospective falls data were recorded for 20 participants over a 6-month period. RESULTS: The incidence of fallers was significantly higher (incidence rate=0.833) in the group that failed the obstacle crossing task than in the group that passed the task (incidence rate=0.143). The group that failed the task had a slower walking speed and greater normalized separation between the trail heel (unaffected support limb) and COM as the affected lead toe cleared the obstacle. This group exhibited greater normalized times from affected lead toe clearance to landing, unaffected trail toe clearance to landing, and affected trail toe-off to toe clearance. LIMITATIONS: The sample size was small, and falls data were available for only 20 participants. CONCLUSIONS: Obstacle crossing is an important task to consider in people following stroke and may be useful in identifying those at risk of falls.

Over-ground walking on level and sloped surfaces in people with stroke compared to healthy matched adults.

PURPOSE: To investigate the basic spatio-temporal gait characteristics of people with stroke whilst walking on sloped and level terrain, and to compare this performance to healthy matched adults. METHOD: Fifteen community dwelling people with stroke who walked with a hemiplegic gait and a reference group of 15 adults without impairments matched for sex, age and height participated in this descriptive, observational study. Basic gait spatio-temporal measures were recorded at self-selected speed across a GAITRite mat placed on level, uphill and downhill (ramp gradient 1:14 or 4.1°) surfaces. Measures recorded were gait speed, cadence, step length, support base, single and double limb support duration and step length symmetry. Group and walking condition effects were assessed by two separate 2-way (group × slope) repeated measures multivariate analysis of variance. RESULTS: The stroke group walked slower (p < 0.001) than the reference group for all conditions. Within-group analyses found the stroke group decreased their speed and step length when walking downhill compared to level and uphill walking (p < 0.001). In contrast, the reference group maintained speed across all walking conditions. CONCLUSIONS: The findings suggest that walking on slopes affects gait speed in people with stroke and this may have implications when walking in the community. IMPLICATIONS FOR REHABILITATION: • Although a high percentage of people achieve walking independence following a stroke, few achieve independent community mobility. • Walking on slopes is an important aspect of community mobility. • When walking down a standard gradient ramp, people with stroke reduced their speed and step length, relative to level over-ground and uphill walking. • It is recommended that attention be directed to assessment and treatment of walking on slopes as part of stroke rehabilitation, as this may have implications when walking in the community.

Can an accelerometer-based monitor be used to accurately assess physical activity in a population of survivors of critical illness?

PURPOSE: To investigate the validity and reliability of the Activity Monitoring Pod (AMP331) to record gait parameters in  healthy young adults (YA) and intensive care unit inpatients (ICU). METHODS: Fifteen YA completed a series of over-ground walks. Another 15 YA completed a series of treadmill walks. The ICU group (N=20) completed a series of over-ground walks with repeat trials. Gait parameters were recorded simultaneously for each walk. RESULTS: For the YA over-ground condition, no significant differences were found between the measures recorded by the systems. For the YA treadmill condition, 43% of the measures differed (P < .05). For the ICU group, the AMP331 underestimated distance and speed by 3m and 25cm/s respectively. Reliability measures for distance (ICC 0.99, 95%CI 0.98 - 0.99) and step count (ICC 0.99, 95%CI 0.99 - 1.00) were excellent. CONCLUSIONS: The AMP 331 is a valid instrument for recording basic gait parameters for over-ground walking in healthy YA and ICU survivors.

Aging modifies joint power and work when gait speeds are matched.

It is well known that ankle joint power generation (A2) is reduced in healthy older adults (OG) during gait. No general consensus exists, however, as to what fundamental compensatory actions are made at the knee and hip joints by the OG to compensate for this loss of power. The failure to control gait speed may account for this lack of agreement. This study investigated the effect of aging on lower limb joint power and work during gait. The gait patterns of eight old (OG: 66.8±5.4 yr) and 12 young adults (YG: 26.6±2.9 yr) were recorded for a range of matched speeds (1.0 m s(-1), 1.3 m s(-1), 1.6 m s(-1)). Speed did not differ between the groups. Combining speeds, the OG generated 17% less A2 power and 21% less A2 work (p<0.05). Compared to the YG, the OG generated 46% more H1 work, 30% more H2 peak power, 16% more H3 peak power, 30% more K3 peak power and 19% more K4 peak power (p<0.05). These actions by the OG were associated with less ankle plantar-flexion, more hip flexion and anterior pelvic tilt (p<0.05). The OG adopted a different gait pattern at the faster speeds by generating more H3 work than A2 work. This shows the OG rely on hip flexors to propel the leg into swing when ankle plantar-flexor function is reduced. This may partly explain how gait changes emerge with aging.

Basic gait and symmetry measures for primary school-aged children and young adults. II: walking at slow, free and fast speed.

This study recorded basic gait data from 656 healthy primary school-aged children (5-13 years) and 81 young adults (18-27 years) whilst walking over-ground across a level walkway at varying speed. It investigated the effect of gait speed and re-examined the issue of gait maturation. Participants completed 6-8 walks at self-selected slow, free and fast speed along a GAITRite walkway whilst wearing athletic shoes. Outcome measures (non-normalized and normalized) were gait speed, cadence, step and stride length, step and stride time, support base, single and double support (%), stance duration (%), foot angle and associated symmetry measures. Compared to free speed, participants walked 24% slower for the slow speed and 30% faster for the fast speed (p<0.0001). Both normalized and non-normalized measures of cadence, step and stride length increased with speed (p<0.001) whereas step and stride time reduced (p<0.001). As a percentage of the gait cycle, single support and stance duration increased with speed (p<0.001) whereas double support reduced (p<0.001). Foot angle was significantly less (less toe-out) for the fast speed than the free and slow speeds (p<0.001) whereas support base was unaffected by speed. Symmetry measures were unaffected by age or speed. Step and stride symmetry differentials (combining conditions) fell around 0.8 cm, whereas symmetry differentials for step and stance time, single and double support fell around 0.7%. This information can be used by clinicians and researchers to assess the gait of children.

Stride dynamics, gait variability and prospective falls risk in active community dwelling older women.

BACKGROUND: Measures of walking instability such as stride dynamics and gait variability have been shown to identify future fallers in older adult populations with gait limitations or mobility disorders. This study investigated whether measures of walking instability can predict future fallers (over a prospective 12 month period) in a group of healthy and active older women. METHODS: Ninety-seven healthy active women aged between 55 and 90 years walked for 7 min around a continuous walking circuit. Gait data recorded by a GAITRite(®) walkway and foot-mounted accelerometers were used to calculate measures of stride dynamics and gait variability. The participant's physical function and balance were assessed. Fall incidence was monitored over the following 12 months. RESULTS: Inter-limb differences (p≤0.04) in stride dynamics were found for fallers (one or more falls) aged over 70 years, and multiple fallers (two or more falls) aged over 55 years, but not in non-fallers or a combined group of single and non-fallers. No group differences were found in the measures of physical function, balance or gait, including variability. Additionally, no gait variable predicted falls. CONCLUSIONS: Reduced coordination of inter-limb dynamics was found in active healthy older fallers and multiple fallers despite no difference in other measures of intrinsic falls risk. Evaluating inter-limb dynamics may be a clinically sensitive technique to detect early gait instability and falls risk in high functioning older adults, prior to change in other measures of physical function, balance and gait.

Physical function, gait, and dynamic balance of transfemoral amputees using two mechanical passive prosthetic knee devices.

OBJECTIVE: To investigate the effect of the 3R90 and 3R92 (Otto Bock Healthcare) mechanical passive prosthetic knee devices on the physical function, gait, and dynamic balance (sudden stop and turn) of transfemoral amputees. DESIGN: Intervention study with crossover design. SETTING: University research center. PARTICIPANTS: Men (N=5; mean age ± SD, 58.8±11.9y) with unilateral transfemoral amputation. INTERVENTION: Prosthetic knee joints (N=2; 3R90 and 3R92). Acclimatization ranged from 14 to 47 days (25.5±9.3d). MAIN OUTCOME MEASURES: Physical function, gait, dynamic balance. RESULTS: The Timed Up and Go Test, 6-Minute Walk Test, and Four Square Step Test measures improved with the 3R92. Total scores on the Prosthesis Evaluation Questionnaire were similar for the 3R92 (82.0±6.3) and the participant's own or original device (83.9±4.8). These devices were rated higher than the 3R90 (65.5±16.8). Compared with the original device, gait velocity was significantly slower (5cm/s; P=.017) with the 3R92, but was unchanged for the 3R90. This difference was not considered clinically significant because the effect size was small (0.2). No other significant gait differences were found. Large temporal gait asymmetries observed with the original device remained with the 3R90 and 3R92 (step, ≈20%; single support, ≈30%; stance, ≈19%). Although no significant differences were found for the sudden-turn or sudden-stop tasks, the sudden-turn group success rates were highest with the original devices. CONCLUSIONS: Gait and symmetry measures were unchanged. Gait speed was slower with the 3R92, but this was not considered to be clinically significant. Sudden-turn success rates generally were higher with the original devices. A crossover stepping movement was more difficult to implement than a side-stepping movement during sudden turns.

Voluntary activation of the ankle plantar flexors following whole-body vibration.

This study investigated the effect of whole-body vibration (WBV) on the voluntary activation of the ankle plantar flexors. Twelve healthy young adults were randomly exposed to two treatments on separate occasions. The first (non-WBV) involved stretching of the plantar flexors at end range of dorsiflexion for five 1-min bouts. The second involved the same stretch with WBV (26 Hz) for five 1-min bouts. Attempted maximal voluntary contractions (AMVCs) of the plantar flexors were performed on an isokinetic dynamometer (30 degrees s(-1)) before and after each treatment. A twitch interpolation technique was used to investigate voluntary activation. Post-treatment data were normalised against pre-treatment data. Subjects were classified as maximally (n = 6) or sub-maximally (n = 6) activated using the pre-treatment twitch interpolation data. The effects of WBV were assessed by repeated measure (RM) MANOVA. After WBV, the group of subjects classified as sub-maximally activated increased peak voluntary torque and rate of voluntary torque production (P < 0.05), whereas angular displacement to peak torque reduced (P < 0.05); i.e. peak torque was produced at a longer muscle length. No significant non-WBV treatment effects were found for this group. No significant WBV effects were found for the group of subjects classified as maximally activated. This study found that the response to WBV was dependent on the level of voluntary activation of the ankle plantar flexors during a set of AMVCs.

Obstacle crossing performance does not differ between the first and subsequent attempts in people with stroke.

This study investigated whether obstacle crossing performance differs between the first and subsequent attempts in people recovering from stroke. Thirty two people with stroke performed eight trials stepping over a 4 cm high obstacle. Spatiotemporal measures of gait were captured by a Vicon 3D motion analysis system. Data collected only from those subjects who completed three trials leading with the affected limb or three trials leading with the unaffected limb were analysed. These criteria resulted in data from only 22 subjects being used in the analysis. Repeated measures MANOVA analyses showed no differences in the spatiotemporal data between the first, second or third trials when leading with either the affected (p=.317) or unaffected limb (p=.801). In general, intraclass correlations showed there were moderate to strong correlations for the spatiotemporal data across the trials (.612-.952), with the exception of trail step time (.480). These results show there are no differences between the spatiotemporal data collected in the first, second and third obstacle crossing trials. This suggests data from a single trial can be considered representative of performance in people with stroke.