Objective:This study explored the link between hip abductor function, assessed through the Trendelenburg test (TT), and pelvic drop during walking and running across various terrains and speeds. Methods:A sample of 19 healthy adults (11 females, 8 males; average age 24.4 years, height 1.74 meters, weight 72.5 kilograms) participated. The TT was conducted on both sides of each participant's body, followed by walking at three speeds (self-selected, slow, fast) on 3 slopes (-10%, level, 10%) and running at 2 speeds (8 and 10 km/h) on the same slopes, using a motorized treadmill. Pelvic motion was captured with a 3D system to analyze maximum and minimum pelvic motion (P MAX, P MIN) and range of angular motion (P ROM). Participants were divided into "positive" and "negative" groups based on TT results. Independent and paired t tests (with Bonferroni corrections), along with Pearson's correlations, were used to analyze data. Results:Significant differences in P MAX and P MIN were observed between the groups, with the "positive" group showing 5.3° and 5.9° less movement, respectively, than the "negative" group. However, no significant differences were found in P ROM data between the groups across all gait tasks, and no correlation was identified between TT P ROM data and P ROM gait data in different walking conditions. Conclusion:This study showed no association between the effects of hip abductor weakness (as identified by the TT) and pelvic mobility during walking and running gait in a healthy, young population. While the TT may serve as a valuable tool for identifying hip abductor weakness in a clinical setting, its direct applicability to predicting dynamic pelvic motion during walking and running remains limited.

BACKGROUND:Muscle stiffness is commonly associated with a sensation of tightness, pain and movement difficulty. It is unclear, however, whether changes in muscle stiffness can be objectively identified by myotonometry across time. This study investigated whether a myotonometer (MyotonPRO) can detect changes in muscle stiffness by delayed-onset muscle soreness (DOMS). METHODS:Twenty-three healthy adults participated in this study. DOMS was achieved in the gastrocnemii by downhill-backwards walking on a motorised treadmill. Subjective ratings of gastrocnemii pain and stiffness were recorded using the numerical rating scale. The MyotonPRO was used to record and extract objective muscle stiffness data. Recordings were taken at baseline and over a three-week recovery period. Spearman's rho correlation analyses were conducted between objective measures and subjective ratings of pain and stiffness. Repeated measure ANOVA tests were conducted to investigate the effect of DOMS over time. FINDINGS:No significant correlations were found between the objective measures and subjective ratings of pain (p = 0.22) or stiffness (p = 0.51). Myotonometry identified significant effects of DOMS on muscle stiffness (p < 0.001) over time. Significant effects of DOMS on subjective pain and stiffness rating data were found over time (p < 0.001). INTERPRETATIONS:Although DOMS was found to affect objective measures of muscle stiffness, these changes were not associated with subjective ratings. Future studies could replicate this study using other myotonometry methods to further investigate muscle stiffness and involve a larger cohort. Other work should investigate muscle stiffness in clinical musculoskeletal conditions resulting from injury or chronic pain.

This paper discusses the derivation of a set of dynamic load factors for calculation of walking response on the basis of measurements made during a biomechanics research carried out with young adults. Firstly, a quite large number of experimental data on single footstep force were collected. The single footstep forces were then superimposed to generate the force time history for a continuous walk. This was followed by the transformation of the resultant force to the frequency domain from which the dynamic load factors for the first ten harmonics of a pacing rate can be extracted. A statistical analysis was employed on the dynamic load factors to acquire their design values in terms of the 90-th or 95-th percentile. The waking force function recommended by various design guides and that developed in the paper were then used in a comprehensive finite element model to predict the vibration level of a building floor. Current design guides on floor vibration normally suggest using four harmonics in the walking force whereas load factors for ten harmonics were developed in this paper. The acceleration response of the floor was found to increase by 5-33% when walking harmonics beyond the fourth harmonic were considered. The inclusion of higher harmonics would therefore lead to a more conservative estimation of the floor response.

Introduction: Increasing physical activity among posttreatment breast cancer survivors is essential, as greater physical activity reduces the relative risk of cancer-specific mortality. This trial examines how a fitness tracker-based intervention changes the physical activity behaviour of inactive posttreatment breast cancer survivors. Methods: Seventeen physically inactive posttreatment breast cancer survivors participated in a randomised cross-over controlled trial. Participants underwent a 12-week intervention of a fitness tracker combined with a behavioural counselling and goal-setting session and 12 weeks of normal activity (control). The primary outcome was the change in physical activity assessed by accelerometry over seven days. Results: The intervention achieved a mean increase of 4.5 min/day of moderate-vigorous physical activity, representative of a small-moderate effect (d = 0.34). Changes in time spent as a proportion of the day in light physical activity (-8.3%) and in sedentary behaviour (7.9%), were both significantly different to baseline (t (16) = 3.522, p < 0.01; t (16) = -3.162, p < 0.01). Conclusion: Interindividual differences in the change of patterns of physical activity behaviour suggest that only for some, fitness trackers can achieve a change in the level of moderate-vigorous physical activity.

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.

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.

The paper explores the risk of work-related musculoskeletal injury in tying steel reinforcement bars. Three tools are compared to determine the extent to which ergonomic tools can reduce the risk of injury to the back and wrist in steel-tying. A whole body system of wearable sensors was used to measure biomechanical risk in tying. Three tools were assessed to determine their impact on the risk of work-related musculoskeletal injury when used at different heights. These were: a conventional pincer-cutting tool; a power-driven tying tool, and a long handled stapler tool. No tool was found to work best in all situations. The long handled stapler tool significantly reduced trunk inclination when used from ground to shoulder height, but produced higher trunk extension (backward bending) when used above shoulder height. The power tying tool did not reduce the need to bend when working at lower work heights. The power-tying tool produced significantly lower peak wrist flexion values compared to the conventional pincer-cutter tool at all work heights except overhead. The power tying tool involved significantly lower levels of wrist rotation than the conventional pincer-cutter tool at all work heights above knee level. Many assessments of ergonomic risk factors in construction rely on observational methods. The use of small, lightweight wearable sensors permits the objective measurement of biomechanical risk factors for work-related musculoskeletal injury, as well as providing objective performance data that can be used in the design and selection of task-specific tools. Our analysis of work by height also provides insight into the way in which risk factors and reduction opportunities afforded by different tools vary depending on the height at which work is to be performed.

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.

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.

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 four square step test (FSST) is commonly used to assess dynamic standing balance in elderly adult populations. To date, only the time (recorded by a stop-watch) to complete the test has been used. Other important dynamic balance information such as step velocity and step displacement can be extracted. This study re-examined the validity of recording the FSST time with a stop-watch by comparing it to a “gold standard” method (Vicon) and investigated the relationship between FSST stop-watch time and measures of step velocity, step displacement, and age. After familiarization, fourty-one healthy adults (42 ± 12 yrs.) completed three FSST trials. The FSST time was recorded by a stop-watch and the participants’ foot movements were simultaneously recorded by a Vicon motion system (120 Hz). Measures extracted from the Vicon system were FSST time, step velocity (four directions) and step displacement (four directions). A paired t-test was used to compare FSST time recorded by each system. Pearson’s correlation analyses were conducted to identify relationships between measures. No significant difference was found between the FSST time recorded by the methods (mean difference = 0.02 ± 0.11 s). Moreover, a strong positive linear relationship (r = 0.99, p < 0.0001) was found between the FSST time recorded by the methods. A moderate linear relationship was found between the FSST time (Vicon) and step velocity (r = 0.67, p < 0.0001). Poor linear relationships were found between (1) step velocity and step displacement, (2) FSST time (Vicon) and step displacement, (3) FSST time (both methods) and age, (4) age and step velocity, and (5) age and step displacement. In conclusion, the FSST stop-watch method is valid. Moreover, it may be used to predict step velocity but not step displacement. No relationship was found between age and the FSST time, step velocity or step displacement.

Wearing high heeled footwear during gait increases risks of trips and falls, and suffering from lower-limb injuries. High heel footwear increases knee extension moment and hence knee joint load. Consequently, prolonged wearing of high heel footwear may increase risks of knee osteoarthritis. Although, many studies have investigated the effect of heel height on knee joint moments, most studies do not account for the confounding effect of walking speed. Three-dimensional gait analysis and inverse dynamics were used to investigate the effect of heel height and walking speed on the peak knee joint moment during stance. This found heel height affects the peak knee extension moment more significantly than walking speed. More importantly, this study shows that wearers of higher heel heights are likely to be exposed to greater knee compression forces than when walking faster.

Many challenges are faced by large numbers of people with lower limb amputation in developing countries. Foremost are cost and access to skilled prosthetic services. Attempts have been made to develop socket fabrication techniques that require little or no prosthetic skill. This study investigated a water pressure casting technique (PCAST) to fabricate and fit transtibial (TT) prosthetic sockets. Ethics approval and informed consent were obtained. Fifty-three adults with unilateral TT amputation were recruited from VIETCOT (Hanoi). VIETCOT staff with ISPO category II qualifications fabricated and fitted the prostheses. Firstly, a cotton sock was placed over the residual limb followed by a plaster wrap. The participant stood with the intact limb on a weight-scale and placed the residual limb into a plastic bag-type diaphragm housed in a cylindrical tank filled with water until they stood normally with half body weight supported. Upon hardening a positive plaster model was made and a socket fabricated with a distal pelite cap. A polypropylene socket was then moulded and attached to ICRC prosthetic components and a rubber foot. The same person fabricated, fitted and aligned the prosthesis. Once a participant indicated satisfaction, the following tasks were completed: timed up-and-go (TUG), six-minute walk (6MWT), walking (GAITRite mat) and satisfaction questionnaire (SATPRO). These tasks were also completed after an extended usage period (146 ± 28 days). Thirty-one of the participants were successfully fitted: fourteen fits failed, eight failed to return, withdrew or became deceased. SATPRO (n = 31) showed high levels of satisfaction (81

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.

Abstract 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.

This study investigated the efficacy of vibration exercise (VbX) as a warm-up modality for maximal overground sprinting. Ten national level sprinters participated in a randomized crossover design (14.0 x 7.4 days washout period). A VbX warm-up was compared to a warm-up involving sprint-specific exercises (control condition). The VbX warm-up involved 10 x 1 minute bouts delivered by a Galileo 900 side-alternating plate (frequency = 26 Hz, peak-to-peak displacement = 9 mm) with 30 s rest between bouts (total time = 15 minutes). The sprint-specific warm-up involved jogging, dynamic exercises and sprinting drills followed by 3 x 40 m sub-maximal sprints not exceeding 95% of maximal speed over a 15 minute period. After each warm-up (within 2 minutes), 6 x 40 m maximum sprints were completed from a crouch start position with starting blocks. Outcome measures were recorded by timing gates (Swift Performance, Australia) and a Vicon Motion Measurement System (Oxford, UK). Measures recorded were sprint time over the 0-4 m, 5-10 m, 10-20 m, 20-40 m and 5-40 m intervals. The stride length, stride velocity and stride time of both legs were recorded over the 0-4 m interval by the Vicon system. All measures remained unchanged across warm-up modalities. It is reasonable to conclude that VbX may be used as an alternative warm-up for sprinting over 40 m. Given its time efficiency and suggested relatively low metabolic cost, VbX may be a suitable warm-up for activities requiring multiple sprints over a competition day or game period.

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.