Dose-Response Effect of an Inertia Flywheel Postactivation Performance Enhancement Protocol on Countermovement Jump Performance.

The purpose of this study was to investigate the dose-response effect of a high-load, 6-repetition, maximum effort inertial flywheel (IFw) squat postactivation performance enhancement (PAPE) protocol on countermovement jump (CMJ) performance metrics. Thirteen subjects completed 5 squat testing sessions: 1 session to determine back-squat 6-repetition maximum, 1 session to determine 6-repetition maximum IFw load, and 3 sessions to investigate the dose-response effect of an IFw PAPE protocol set at the load determined in the second session. In the IFw PAPE sessions, subjects completed either 1, 2, or 3 sets of IFw squats, then performed 5 CMJs over 12 minutes (1, 3, 6, 9, and 12 min post-IFw). All CMJ tests were conducted on a force platform where CMJ performance outcomes and impulse variables were calculated. There was no main time or volume effect for jump height, contact time, reactive strength index, peak force, or any of the impulse variables. A main time effect was identified for flight time (P = .006, effect size = 0.24) and peak power (P = .001, effect size = 0.28). The lack of change in jump height may indicate that too much fatigue was generated following this near-maximal IFw squat protocol, thereby reducing the PAPE effect.

The application of the Lyapunov Exponent to analyse human performance: A systematic review.

Variability is a normal component of human movement, allowing one to adapt to environmental perturbations. It can be analysed from linear or non-linear perspectives. The Lyapunov Exponent (LyE) is a commonly used non-linear technique, which quantifies local dynamic stability. It has been applied primarily to walking gait and appears to be limited application in other movements. Therefore, this systematic review aims to summarise research methodologies applying the LyE to movements, excluding walking gait. Four databases were searched using keywords related to movement variability, dynamic stability, LyE and divergence exponent. Articles written in English, using the LyE to analyse movements, excluding walking gait were included for analysis. 31 papers were included for data extraction. Quality appraisal was conducted and information related to the movement, data capture method, data type, apparatus, sampling rate, body segment/joint, number of strides/steps, state space reconstruction, algorithm, filtering, surrogation and time normalisation were extracted. LyE values were reported in supplementary materials (Appendix 2). Running was the most prevalent non-walking gait movement assessed. Methodologies to calculate the LyE differed in various aspects resulting in different LyE values being generated. Additionally, test-retest reliability, was only conducted in one study, which should be addressed in future.

Plantar pressures are higher in cases with diabetic foot ulcers compared to controls despite a longer stance phase duration.

BACKGROUND: Current international guidelines advocate achieving at least a 30 % reduction in maximum plantar pressure to reduce the risk of foot ulcers in people with diabetes. However, whether plantar pressures differ in cases with foot ulcers to controls without ulcers is not clear. The aim of this study was to assess if plantar pressures were higher in patients with active plantar diabetic foot ulcers (cases) compared to patients with diabetes without a foot ulcer history (diabetes controls) and people without diabetes or a foot ulcer history (healthy controls). METHODS: Twenty-one cases with diabetic foot ulcers, 69 diabetes controls and 56 healthy controls were recruited for this case-control study. Plantar pressures at ten sites on both feet and stance phase duration were measured using a pre-established protocol. Primary outcomes were mean peak plantar pressure, pressure-time integral and stance phase duration. Non-parametric analyses were used with Holm's correction to correct for multiple testing. Binary logistic regression models were used to adjust outcomes for age, sex and body mass index. Median differences with 95 % confidence intervals and Cohen's d values (standardised mean difference) were reported for all significant outcomes. RESULTS: The majority of ulcers were located on the plantar surface of the hallux and toes. When adjusted for age, sex and body mass index, the mean peak plantar pressure and pressure-time integral of toes and the mid-foot were significantly higher in cases compared to diabetes and healthy controls (p < 0.05). The stance phase duration was also significantly higher in cases compared to both control groups (p < 0.05). The main limitations of the study were the small number of cases studied and the inability to adjust analyses for multiple factors. CONCLUSIONS: This study shows that plantar pressures are higher in cases with active diabetic foot ulcers despite having a longer stance phase duration which would be expected to lower plantar pressure. Whether plantar pressure changes can predict ulcer healing should be the focus of future research. These results highlight the importance of offloading feet during active ulceration in addition to before ulceration.

Reliability of lower limb strength assessment in female team sport athletes.

BACKGROUND: Lower limb injury rates have increased dramatically in line with increased female sport participation levels. Muscle strength is a modifiable lower limb injury risk factor, guiding performance monitoring and rehabilitation. OBJECTIVES: The aim of this study was to investigate the test-retest reliability of isokinetic and isometric lower limb peak torque to body mass of muscles acting on the hip, knee, and ankle in female team sport athletes. It was hypothesised the test-retest reliability would be good (intraclass correlation coefficients (ICC) ≥ 0.75). METHODS: Thirty-eight female athletes (Australian Rules Football = 18, netball = 12, soccer = 8) aged 16-35 years participated in this study. Participants performed isokinetic (60°/s and 120°/s) and isometric testing on a Biodex Isokinetic Dynamometer on three separate days. RESULTS: Poor to good reliability was demonstrated for all joint movements (ICC = 0.38-0.88) with small to moderate effect sizes (0.00-0.43) and typical errors (5.65-24.49). CONCLUSION: Differences in peak torque to body mass were observed between sessions one and two and/or one and three, demonstrating a learning effect. Therefore, three testing sessions, and/or the inclusion of a familiarisation session, is recommended for future assessments in populations unfamiliar with dynamometry.

Time to stabilisation of the cervical spine when supported by a pillow in side lying.

Currently, there is little information to guide consumers, retailers and health professionals about the length of time it takes for the cervical spine to stabilise when resting on a pillow. The aim of this study was to determine the time required to achieve stabilisation of the cervical spine when supported by a polyester pillow and innerspring mattress in side lying. Twenty-four asymptomatic females rested in a standardised side lying position during the capture of 3D data from markers placed over cervical landmarks. Time to stabilisation was assessed for each axis, each landmark and globally for each participant. A large variation in global stabilisation times was identified between participants; however, 70.8% of participants had stabilised by 15 min or earlier. Fifteen minutes is the best estimate of the time to stabilisation of the cervical spine for young females in a side lying position when resting on a polyester pillow. PRACTITIONER SUMMARY: This study aimed to determine the time required to achieve stabilisation of the cervical spine when supported by a polyester pillow and innerspring mattress in side lying. Through a laboratory study using 3D VICON® motion analysis technology, we identified that 70.8% of participants had stabilised by 15 min.

Reliability of the running vertical jump test in female team sport athletes.

Injury rates to the lower limb have increased over the past 40 years, coinciding with increases in female sport participation rates. Sport specific tests such as the running vertical jump (RVJ) are utilised for injury risk profiling, however the test-retest reliability is unknown. OBJECTIVES: The aim of this study was to investigate the test-retest reliability of the thorax, pelvis and lower limb joint angular kinematics and kinetics for the RVJ test in female team sport athletes. DESIGN: Three-dimensional motion capture with force plate integration was utilised as participants performed five trials on each limb on three separate days. SETTING: Testing occurred in a biomechanics laboratory. PARTICIPANTS: Thirty-four females (Australian Rules Football = 15, Netball = 12, Soccer = 7) participated in this study. MAIN OUTCOME MEASURES: Intraclass correlation coefficients (ICC), effect sizes and typical errors (TE) of segment and joint angular kinematics and kinetics were calculated. RESULTS: Poor to excellent reliability (ICC = -0.12 - 0.92), small to large effect sizes (0.00-0.90) and TE (0.02-289.24) were observed across segment and joint angular kinematics and kinetics. CONCLUSIONS: The RVJ test is recommended when analysing ground reaction forces and joint angular kinematics in female team sport athletes.

Evaluation of Athlete Monitoring Tools across 10 Weeks of Elite Youth Basketball Training: An Explorative Study.

The growth of sport science technology is enabling more sporting teams to implement athlete monitoring practices related to performance testing and load monitoring. Despite the increased emphasis on youth athlete development, the lack of longitudinal athlete monitoring literature in youth athletes is concerning, especially for indoor sports such as basketball. The aim of this study was to evaluate the effectiveness of six different athlete monitoring methods over 10 weeks of youth basketball training. Fourteen state-level youth basketball players (5 males and 9 females; 15.1 ± 1.0 years) completed this study during their pre-competition phase prior to their national basketball tournament. Daily wellness and activity surveys were completed using the OwnUrGoal mobile application, along with heart rate (HR) and inertial measurement unit (IMU) recordings at each state training session, and weekly performance testing (3x countermovement jumps [CMJs], and 3x isometric mid-thigh pulls [IMTPs]). All of the athlete monitoring methods demonstrated the coaching staff's training intent to maintain performance and avoid spikes in workload. Monitoring IMU data combined with PlayerLoad™ data analysis demonstrated more effectiveness for monitoring accumulated load (AL) compared to HR analysis. All six methods of athlete monitoring detected similar trends for all sessions despite small-trivial correlations between each method (Pearson's correlation: -0.24 < r < 0.28). The use of subjective monitoring questionnaire applications, such as OwnUrGoal, is recommended for youth sporting clubs, given its practicability and low-cost. Regular athlete education from coaches and support staff regarding the use of these questionnaires is required to gain the best data.

Neurological scoring and gait kinematics to assess functional outcome in an ovine model of ischaemic stroke.

Background: Assessment of functional impairment following ischaemic stroke is essential to determine outcome and efficacy of intervention in both clinical patients and pre-clinical models. Although paradigms are well described for rodents, comparable methods for large animals, such as sheep, remain limited. This study aimed to develop methods to assess function in an ovine model of ischaemic stroke using composite neurological scoring and gait kinematics from motion capture. Methods: Merino sheep (n = 26) were anaesthetised and subjected to 2 hours middle cerebral artery occlusion. Animals underwent functional assessment at baseline (8-, 5-, and 1-day pre-stroke), and 3 days post-stroke. Neurological scoring was carried out to determine changes in neurological status. Ten infrared cameras measured the trajectories of 42 retro-reflective markers for calculation of gait kinematics. Magnetic resonance imaging (MRI) was performed at 3 days post-stroke to determine infarct volume. Intraclass Correlation Coefficients (ICC's) were used to assess the repeatability of neurological scoring and gait kinematics across baseline trials. The average of all baselines was used to compare changes in neurological scoring and kinematics at 3 days post-stroke. A principal component analysis (PCA) was performed to determine the relationship between neurological score, gait kinematics, and infarct volume post-stroke. Results: Neurological scoring was moderately repeatable across baseline trials (ICC > 0.50) and detected marked impairment post-stroke (p < 0.05). Baseline gait measures showed moderate to good repeatability for the majority of assessed variables (ICC > 0.50). Following stroke, kinematic measures indicative of stroke deficit were detected including an increase in stance and stride duration (p < 0.05). MRI demonstrated infarction involving the cortex and/or thalamus (median 2.7 cm3, IQR 1.4 to 11.9). PCA produced two components, although association between variables was inconclusive. Conclusion: This study developed repeatable methods to assess function in sheep using composite scoring and gait kinematics, allowing for the evaluation of deficit 3 days post-stroke. Despite utility of each method independently, there was poor association observed between gait kinematics, composite scoring, and infarct volume on PCA. This suggests that each of these measures has discreet utility for the assessment of stroke deficit, and that multimodal approaches are necessary to comprehensively characterise functional impairment.

Influence of peripheral arterial disease and supervised walking on heart rate variability.

OBJECTIVE: To examine the influence of peripheral arterial disease (PAD) on heart rate variability (HRV) in patients, and to examine the influence of an intense long-term (12 months) exercise program on HRV in PAD patients. METHODS: This study involved ambulatory patients attending a local hospital and university center. Participants were twenty-five patients with diagnosed PAD and intermittent claudication and 24 healthy, age-matched adults. Interventions involved random allocation of PAD patients to 12 months of conservative medical treatment (Conservative) or medical treatment with supervised treadmill walking (Exercise). The main outcome measures were time- and frequency-domain, nonlinear HRV measures during supine rest, and maximal walking capacity prior to and following the intervention. RESULTS: Despite significantly worse walking capacity (285 ± 190 m vs 941 ± 336 m; P < .05), PAD patients exhibited similar resting HRV to healthy adults. At the 12-month follow-up, Exercise patients exhibited a significantly greater improvement in walking capacity (183% ± 185% vs 57% ± 135%; P = .03) with similar small nonsignificant changes in HRV compared with Conservative patients. CONCLUSIONS: The current study demonstrated that PAD patients exhibited similar resting HRV to healthy adults with 12 months of intense supervised walking producing similar HRV changes to that of conservative medical treatment. The greater walking capacity of healthy adults and PAD patients following supervised exercise does not appear to be associated with enhanced HRV.

Acute nonhypothermic exposure to cold impedes motor skill performance in video gaming compared to thermo-neutral and hot conditions.

The study examined whether or not acute exposure to unfamiliar hot or cold conditions impairs performance of highly skilled coordinative activities and whether prior physical self-efficacy beliefs were associated with task completion. Nineteen volunteers completed both Guitar Hero and Archery activities as a test battery using the Nintendo Wii console in cold (2 degrees C), neutral (20 degrees C), and hot (38 degrees C) conditions. Participants all completed physical self-efficacy questionnaires following experimental familiarization. Performances of both Guitar Hero and Archery significantly decreased in the cold compared with the neutral condition. The cold trial was also perceived as the condition requiring both greater concentration and effort. There was no association between performance and physical self-efficacy. Performance of these coordinative tasks was compromised by acute (nonhypothermic) exposure to cold; the most likely explanation is that the cold condition presented a greater challenge to attentional processes as a form of environmental distraction.

Influence of non-level walking on pedometer accuracy.

The YAMAX Digiwalker pedometer has been previously confirmed as a valid and reliable monitor during level walking, however, little is known about its accuracy during non-level walking activities or between genders. Subsequently, this study examined the influence of non-level walking and gender on pedometer accuracy. Forty-six healthy adults completed 3-min bouts of treadmill walking at their normal walking pace during 11 inclines (0-10%) while another 123 healthy adults completed walking up and down 47 stairs. During walking, participants wore a YAMAX Digiwalker SW-700 pedometer with the number of steps taken and registered by the pedometer recorded. Pedometer difference (steps registered-steps taken), net error (% of steps taken), absolute error (absolute % of steps taken) and gender were examined by repeated measures two-way ANOVA and Tukey's post hoc tests. During incline walking, pedometer accuracy indices were similar between inclines and gender except for a significantly greater step difference (-7+/-5 steps vs. 1+/-4 steps) and net error (-2.4+/-1.8% for 9% vs. 0.4+/-1.2% for 2%). Step difference and net error were significantly greater during stair descent compared to stair ascent while absolute error was significantly greater during stair ascent compared to stair descent. The current study demonstrated that the YAMAX Digiwalker SW-700 pedometer exhibited good accuracy during incline walking up to 10% while it overestimated steps taken during stair ascent/descent with greater overestimation during stair descent. Stair walking activity should be documented in field studies as the YAMAX Digiwalker SW-700 pedometer overestimates this activity type.

Within- and Between-Body-Site Agreement of Skin Autofluorescence Measurements in People With and Without Diabetes-Related Foot Disease.

BACKGROUND: Skin autofluorescence has been used to assess longer term glycemic control and risk of complications. There is however no agreed site at which autofluorescence should be measured. This study evaluated the within- and between-site agreement in measurement of skin autofluorescence using a noninvasive advanced glycation end product (AGE) reader. METHODS: Overall, 132 participants were included: 16 with diabetes-related foot ulcers (DFU), 63 with diabetes but without foot ulcers (DMC), 53 without diabetes or foot ulcers (HC). Skin autofluorescence was measured using the AGE Reader (DiagnOptics technologies BV, the Netherlands). Three consecutive skin autofluorescence measurements were each performed at six different body sites: the volar surfaces of both forearms (arms), dorsal surfaces of both calves (legs), and plantar surfaces of both feet (feet). Within- and between-site agreements were analyzed with concordance correlation coefficients (CCC) and 95% confidence intervals (95% CI), absolute mean differences (±standard deviation), and Bland-Altman limits of agreement. RESULTS: The agreement between repeat assessments at the same site was almost perfect (CCC [95% CI] ranging from 0.94 [0.91-0.96] for assessments in the right foot to 0.99 [0.99-0.99] for assessments in the left arm). The limits of agreement were narrow within ±0.5 arbitrary units for all sites. The between-site agreement in measurements was poor (CCC < 0.65) with large maximum absolute mean differences (±SD) in arbitrary units (DFU = 3.40 [±2.04]; DMC = 3.15 [±2.45]; HC = 2.72 [±1.83]) and wide limits of agreement. CONCLUSIONS: Skin autofluorescence measurements can be repeated at the same site with adequate repeatability but measurements at different sites in the same patient have marked differences. The reason for this variation across sites and whether this has any role in diabetes-related complications needs further investigation.

Gait in People With Nonhealing Diabetes-Related Plantar Ulcers.

BACKGROUND: Abnormalities in gait have been associated with high plantar pressures and diabetes-related plantar foot ulcers. Whether these are a transient response to the ulcer or are representative of long-term lower limb biomechanical abnormalities is currently unknown. OBJECTIVE: The aim of this study was to examine whether 12 gait parameters identified as being associated with nonhealing diabetes-related plantar foot ulcers at baseline remained associated during a 6-month follow-up period. DESIGN: This was a longitudinal observational case-control study. METHODS: Gait assessments were performed at entry and twice during follow-up over a 6-month period in 12 participants with nonhealing diabetes-related plantar foot ulcers (case participants) and 62 people with diabetes and no history of foot ulcers (control participants) using a standardized protocol. Linear mixed-effects random-intercept models were used to identify gait parameters that consistently differed between case participants and control participants at all assessments after adjustment for age, sex, body mass index, presence of peripheral neuropathy, and follow-up time. Standardized mean differences (SMD) were used to measure effect sizes. RESULTS: Five of the 12 gait parameters were significantly different between case participants and control participants at all 3 time points. Case participants had a more abducted foot progression angle (SMD = 0.37), a higher pelvic obliquity at toe-off (SMD = -0.46), a greater minimum pelvic obliquity (SMD = -0.52), a lower walking speed (SMD = -0.46), and a smaller step length (SMD = -0.46) than control participants. LIMITATIONS: The limitations included a small sample size, the observational nature of the study, and the inability to evaluate the impact of gait on wound healing. CONCLUSIONS: This study identified abnormal gait parameters consistently associated with nonhealing diabetes-related plantar foot ulcers. Further research is needed to test the clinical importance of these gait characteristics.

Intralimb coordination variability in peripheral arterial disease.

BACKGROUND: Increased variability has been traditionally associated with decreased movement performance due to disease and aging. However, recent research indicates that variability may be of functional importance in motor control. Thus the purpose of this study was to determine whether individuals with peripheral arterial disease and suffering from intermittent claudication have reduced intralimb joint coordination variability compared to individuals without peripheral arterial disease. A further aim was to examine the efficacy of various techniques used to describe intralimb joint coordination variability. METHODS: Participants with peripheral arterial disease and suffering from intermittent claudication (n=28) were selected based on an appropriate history of peripheral arterial disease and intermittent claudication, ankle brachial pressure index <0.9 in at least 1 leg and a positive Edinburgh claudication questionnaire response. A further group of participants (n=25) free of peripheral arterial disease (ankle brachial pressure index >0.9) and who were non-regular exercisers were recruited from the community to act as age and mass matched controls. All participants underwent 2D angular kinematics analysis during normal walking. Intralimb coordination variability was measured using parameterization, vector coding and normalized root mean square techniques applied to relative motion plots of various joint couplings. Differences between groups were examined by one-way ANOVA. FINDINGS: Participants with peripheral arterial disease and suffering from intermittent claudication displayed significantly greater intralimb joint coordination variability than age and mass matched controls participants for all joint couplings using all intralimb joint coordination variability techniques. INTERPRETATION: These findings suggest that higher levels of intralimb joint coordination variability of the lower limbs in participants with peripheral arterial disease and suffering from intermittent claudication may be an adaptation of the motor control system to deal with perturbations associated with the gradual onset of claudication pain.

Lower limb movement variability in patients with peripheral arterial disease.

BACKGROUND: Peripheral arterial disease is a chronic obstructive disease of the arteries of the lower limb caused by atherosclerosis. The resultant decrease in blood flow can result in symptoms of pain in the lower limb on exercise known as intermittent claudication. Exercise induced pain is experienced in the calves, thigh or buttocks restricting activities of daily living and thus reducing quality of life. METHODS: This study investigated lower limb movement variability in individuals with peripheral arterial disease-intermittent claudication (n=28) compared to individuals without peripheral arterial disease-intermittent claudication (control, n=25). A further aim was to examine the efficacy of various techniques used to describe single joint movement variability. All participants underwent two-dimensional angular kinematics analysis of the lower limb during normal walking. Single joint movement variability was measured using linear (spanning set and coefficient of variation) techniques. Between group differences were examined by one-way ANOVA. FINDINGS: The peripheral arterial disease-intermittent claudication participants displayed significantly higher levels of lower limb movement variability in all joints when assessed using the coefficient of variation technique. There were no significant between group differences using the spanning set technique. INTERPRETATION: Individuals with peripheral arterial disease-intermittent claudication have higher levels of lower limb movement variability and reduced walking speed compared to healthy age and mass matched controls. This variability may be an adaptation to the gradual onset of ischaemic pain in this population.

Effect of Different Evasion Maneuvers on Anticipation and Visual Behavior in Elite Rugby League Players.

This study examined the anticipation and visual behavior of elite rugby league players during two different evasion maneuvers (side- and split-steps). Participants (N = 48) included elite rugby league players (n = 38) and controls (n = 10). Each participant watched videos consisting of side- and split-steps, and anticipation of movement and eye behavior were measured. No significant differences between the groups or evasion maneuvers were found. The split-step was significantly harder to predict. Elite players appeared to spend more time viewing the torso and mid-region of the body compared with the controls.

Pedometer accuracy during walking over different surfaces.

PURPOSE: This study examined the effect of surface (concrete, grass, dry beach sand, wet beach sand) and gender on pedometer accuracy during walking. METHODS: Fifty-two healthy university students volunteered for this study and completed six 150-m walking trials for each of the four different surfaces while wearing a YAMAX SW-700 Digiwalker pedometer. For each trial, time, number of steps taken and number of steps registered by the pedometer were recorded. These variables and pedometer accuracy for each walking surface and gender were analyzed by two-way repeated-measures ANOVA and Tukey's post hoc tests. RESULTS: Walking over dry beach sand significantly reduced walking speed (concrete, 5.6 +/- 0.5 km.h(-1); grass, 5.6 +/- 0.5 km.h(-1); dry beach sand, 5.0 +/- 0.5 km.h(-1): wet beach sand, 5.4 +/- 0.4 km.h(-1)) and increased the number of steps taken (concrete, 190 +/- 13; grass, 186 +/- 12; dry beach sand, 207 +/- 12; wet beach sand, 194 +/- 11) and registered (concrete, 195 +/- 14; grass, 191 +/- 14; dry beach sand, 213 +/- 15; wet beach sand, 201 +/- 16) by the pedometer compared with concrete and grass. Compared with males, females registered a greater number of pedometer steps (204 +/- 18 vs 197 +/- 15) and a greater absolute (9 +/- 12 vs 3 +/- 7 steps) and relative (4.46 +/- 5.72 vs 1.63 +/- 3.57%) pedometer error during walking over dry beach sand. CONCLUSIONS: Walking on a soft surface such as dry beach sand significantly reduced walking speed and increased pedometer error for females compared with males, possibly by exacerbating hip and walking movements. Identification of gender and softer surfaces should be considered when documenting physical activity levels in field studies.

Influence of Rest on Players' Performance and Physiological Responses during Basketball Play.

Pre-match warm-ups are standard in many sports but the focus has excluded the substitute players. The aim of this research was to investigate the result of inactivity on physiological and performance responses in substitute basketball players during competition. Two basketball players from the second tier of the State League of Queensland, Australia volunteered for this study and were assessed for performance (countermovement jump-CMJ) and physiological (core temperature via ingestible pill; skin temperature at the arm, chest, calf and thigh; heart rate-HR) responses prior to and following a 20-min warm-up, and during the first half of a competitive basketball match (2 × 20-min real time quarters). Warm up resulted in increases in CMJ (~7%), HR (~100 bpm) and core (~0.8 °C) and skin (~1.0 °C) temperatures. Following the warm up and during inactivity, substitute players exhibited a decrease in all responses including CMJ (~13%), HR (~100 bpm), and core (~0.5 °C) and skin (~2.0 °C) temperatures. Rest resulted in reductions in key performance and physiological responses during a competitive match that poses a risk for match strategies. Coaches should consider implementing a warm up to enhance core/skin temperature for substitute players immediately before they engage with competition to optimise player performance.

Plantar pressures are elevated in people with longstanding diabetes-related foot ulcers during follow-up.

OBJECTIVE: High plantar pressures are implicated in the development of diabetes-related foot ulcers. Whether plantar pressures remain high in patients with chronic diabetes-related foot ulcers over time is uncertain. The primary aim of this study was to compare plantar pressures at baseline and three and six months later in participants with chronic diabetes-related foot ulcers (cases) to participants without foot ulcers (controls). METHODS: Standardised protocols were used to measure mean peak plantar pressure and pressure-time integral at 10 plantar foot sites (the hallux, toes, metatarsals 1 to 5, mid-foot, medial heel and lateral heel) during barefoot walking. Measurements were performed at three study visits: baseline, three and six months. Linear mixed effects random-intercept models were utilised to assess whether plantar pressures differed between cases and controls after adjusting for age, sex, body mass index, neuropathy status and follow-up time. Standardised mean differences (Cohen's d) were used to measure effect size. RESULTS: Twenty-one cases and 69 controls started the study and 16 cases and 63 controls completed the study. Cases had a higher mean peak plantar pressure at several foot sites including the toes (p = 0.005, Cohen's d = 0.36) and mid-foot (p = 0.01, d = 0.36) and a higher pressure-time integral at the hallux (p<0.001, d = 0.42), metatarsal 1 (p = 0.02, d = 0.33) and mid-foot (p = 0.04, d = 0.64) compared to controls throughout follow-up. A reduction in pressure-time integral at multiple plantar sites over time was detected in all participants (p<0.05, respectively). CONCLUSIONS: Plantar pressures assessed during gait are higher in diabetes patients with chronic foot ulcers than controls at several plantar sites throughout prolonged follow-up. Long term offloading is needed in diabetes patients with diabetes-related foot ulcers to facilitate ulcer healing.

The reproducibility of acquiring three dimensional gait and plantar pressure data using established protocols in participants with and without type 2 diabetes and foot ulcers.

BACKGROUND: Several prospective studies have suggested that gait and plantar pressure abnormalities secondary to diabetic peripheral neuropathy contributes to foot ulceration. There are many different methods by which gait and plantar pressures are assessed and currently there is no agreed standardised approach. This study aimed to describe the methods and reproducibility of three-dimensional gait and plantar pressure assessments in a small subset of participants using pre-existing protocols. METHODS: Fourteen participants were conveniently sampled prior to a planned longitudinal study; four patients with diabetes and plantar foot ulcers, five patients with diabetes but no foot ulcers and five healthy controls. The repeatability of measuring key biomechanical data was assessed including the identification of 16 key anatomical landmarks, the measurement of seven leg dimensions, the processing of 22 three-dimensional gait parameters and the analysis of four different plantar pressures measures at 20 foot regions. RESULTS: The mean inter-observer differences were within the pre-defined acceptable level (<7 mm) for 100 % (16 of 16) of key anatomical landmarks measured for gait analysis. The intra-observer assessment concordance correlation coefficients were > 0.9 for 100 % (7 of 7) of leg dimensions. The coefficients of variations (CVs) were within the pre-defined acceptable level (<10 %) for 100 % (22 of 22) of gait parameters. The CVs were within the pre-defined acceptable level (<30 %) for 95 % (19 of 20) of the contact area measures, 85 % (17 of 20) of mean plantar pressures, 70 % (14 of 20) of pressure time integrals and 55 % (11 of 20) of maximum sensor plantar pressure measures. CONCLUSION: Overall, the findings of this study suggest that important gait and plantar pressure measurements can be reliably acquired. Nearly all measures contributing to three-dimensional gait parameter assessments were within predefined acceptable limits. Most plantar pressure measurements were also within predefined acceptable limits; however, reproducibility was not as good for assessment of the maximum sensor pressure. To our knowledge, this is the first study to investigate the reproducibility of several biomechanical methods in a heterogeneous cohort.