Lower Cadence Research Articles

A scoping review of the motor impairments in autism spectrum disorder.

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder mainly defined by impairments in communication and socialization. Although motor symptoms are not typically considered central to the disease, their high frequency and early onset have been recurrently reported in the literature. Therefore, this scoping review provides a broad description of these motor impairments across all ages, as well as a discussion of their relevance and relation to other clinical aspects of ASD. The scientific search was carried out in Scopus, Pubmed, Embase, and Web of Science databases. Nineteen studies were selected after applying the eligibility criteria. The studies analyzed 784 participants diagnosed with ASD compared to 540 controls. Motor function was assessed by means of varied kinds of scales and questionnaires. The main motor domains evaluated included features of fine and gross motor skills, manual dexterity, coordination/motor control/praxis, balance, running speed/agility, strength, gait, whole-body movements, aiming and catching (ball skills), and repetitive movements. Motor impairments are consistently observed in ASD from the first years of life, persisting into adulthood. It includes a significant deficit in performance of manual, posture, strength, and gait behavior/skills. The deficits described in ASD comprised impairments in fine and gross motor skills, lower balance, lower cadence, and greater variation of gait control, as well as weakness among other features that leads this population to move in an adaptive way affecting their interactions in real life.

Noradrenergic cardiac denervation is associated with gait velocity in Parkinson disease: a dual ligand PET study.

Preliminary data suggest that gait abnormalities in Parkinson disease (PD) may be associated with sympathetic cardiac denervation. No kinematic gait studies were performed to confirm this observation. We aimed to correlate spatiotemporal kinematic gait parameters with cardiac sympathetic denervation as determined by cardiac [11C]HED PET in PD. Retrospective database analysis of 27 PD patients with cardiac sympathetic denervation. All patients underwent spatiotemporal kinematic gait assessment (medication 'off' state), cardiac [11C]HED and dopaminergic brain [11C]DTBZ PET scans. We employed a hierarchical regression approach to examine associations between the extent of cardiac denervation, dopaminergic nigrostriatal neurodegeneration, and three gait parameters - velocity, step length and cadence. More extensive cardiac denervation was associated with slower velocity (estimate: -1.034, 95% CI [-1.65, -0.42], p = 0.002), shorter step length (estimate: -0.818, 95% CI [-1.43, -0.21], p = 0.011) and lower cadence (estimate: -0.752, 95% CI [-1.28, -0.23], p = 0.007) explaining alone 30% (Adjusted-R²: 0.297), 20% (Adjusted-R²: 0.202) and 23% (Adjusted-R²: 0.227) of the variability, respecivetly. These associations remained independent of striatal dopaminergic impairment and confounding factors such as age, Hoehn and Yahr (HY) stages, peripheral neuropathy, cognition, and autonomic symptoms. In contrast, striatal dopaminergic denervation was significantly associated with step length (estimate: 0.883, 95% CI [0.29, 1.48], p = 0.005), explaining about 24% of the variability but was dependent of HY stage. More severe cardiac noradrenergic denervation was associated with lower gait velocity, independent of striatal dopaminergic denervation and HY stage, impacting both step length and cadence. These results suggest independent contributions of the peripheral autonomic system degeneration on gait dynsfunction in PD.

The Use of Novel Instrumented Socks to Detect Changes in Daily Life Mobility During an Exercise Intervention in Prostate Cancer Survivors Treated with Androgen Deprivation Therapy

ObjectivesTo describe changes in daily life mobility in prostate cancer survivors treated with androgen deprivation therapy (ADT) after a 6-month exercise intervention using novel instrumented socks and to identify characteristics of participants who exhibited changes in daily life mobility. MethodsA subset of participants in a fall prevention exercise trial completed objective tests and patient-reported surveys of physical functioning, and wore instrumented socks for up to 7 days to measure daily life mobility. Changes in cadence, double support proportion, and pitch angle of the foot at toe-off were selected as measures of daily life mobility previously found to be different in men exposed to ADT for prostate cancer versus controls. Daily life mobility was compared from baseline to 6 months using paired t-tests. Characteristics of responders who improved their daily life mobility were compared to nonresponders using two-sample t-tests, Chi-squared proportion tests, or Fisher's Exact Tests. ResultsOur sample included 35 prostate cancer survivors (mean age 71.6 ± 7.8 years). Mean cadence, double support proportion, and pitch angle at toe-off did not change significantly over 6 months of exercise, but 14 participants (40%) improved in at least two of three daily life mobility measures (“responders”). Responders were characterized by lower physical functioning, lower cadence in daily life, fewer comorbidities, and better social and mental/emotional functioning. ConclusionsCertain daily life mobility measures potentially impacted by ADT could be measured with instrumented socks and improved by exercise. Men who start with lower physical functioning and better social and mental/emotional functioning appear most likely to benefit, possibly because they have more to gain from exercise and are able to engage in a 6-month intervention. Implications for Nursing PracticeTechnology-based approaches could provide nurses with an objective measure of daily life mobility for patients with chronic illness and detect who is responding to rehabilitation.

Gait signatures of endurance runners with low back pain: A case controlled cross sectional study

BackgroundLow back pain (LBP) is an understudied condition among runners, and it is unclear what biomechanical features could be targeted for gait retraining to mitigate pain. Research questionHow do running biomechanics differ between healthy individuals and those with running-related LBP? MethodsThis was a case-controlled, comparative study design of community runners: running-related LBP (n=52) and healthy controls (n=52). All runners completed running history forms and performed a 3-dimensional gait analysis. Kinematic data were collected using a motion capture system and normalized to a gait cycle, while participants ran on a level grade at self-selected speed on an instrumented treadmill. Current running volume, temporal-spatial, kinetic and kinematic features were compared between groups. ResultsThe LBP group had 39.5 % lower weekly distance and 15.4 % fewer were currently training for a race (all p<.05). Runners with LBP demonstrated lower cadence (166±10 step/min vs. 171±9 step/min; p=.05), greater center of gravity lateral displacement (1.4±0.5 cm vs. 1.2 ±.3 cm; p=.044) and greater stride width variability (1.3±0.4 cm versus 1.0 ± 0.04 cm; p=.008). Runners with LBP had a greater Vertical Average Loading Rate ([VALR] 67.7±22.2 bodyweights [BW]/s vs. 62.2±21.5 BW/s; p=.022), and higher joint moments (N*m/(kg*m)) at the knee in the sagittal plane (2.13±0.50 vs. 1.87±0.56; p <.001), frontal plane (1.44±0.39 vs. 1.29±0.29; p=.013), and at the hip in the frontal plane (2.04±0.51 vs. 1.84±0.41; p=.024). No differences were found between groups in the pelvis, hip, knee, and ankle joint excursions in any plane of motion during a typical gait cycle. SignificanceThese collective motion signature may reflect challenges with control of motion and VALR in the presence of back pain. Cadence training to increase step rate, coupled with core/hip muscle activation, may be an important strategy to reduce motion variability, impact loading rate and pain symptoms while running.

Detailed cool star flare morphology with CHEOPS and TESS

Context. White-light stellar flares are proxies for some of the most energetic types of flares, but their triggering mechanism is still poorly understood. As they are associated with strong X and ultraviolet emission, their study is particularly relevant to estimate the amount of high-energy irradiation onto the atmospheres of exoplanets, especially those in their stars’ habitable zone. Aims. We used the high-cadence, high-photometric capabilities of the CHEOPS and TESS space telescopes to study the detailed morphology of white-light flares occurring in a sample of 130 late-K and M stars, and compared our findings with results obtained at a lower cadence. Methods. We employed dedicated software for the reduction of 3 s cadence CHEOPS data, and adopted the 20 s cadence TESS data reduced by their official processing pipeline. We developed an algorithm to separate multi-peak flare profiles into their components, in order to contrast them to those of single-peak, classical flares. We also exploited this tool to estimate amplitudes and periodicities in a small sample of quasi-periodic pulsation (QPP) candidates. Results. Complex flares represent a significant percentage (≳30%) of the detected outburst events. Our findings suggest that high-impulse flares are more frequent than suspected from lower-cadence data, so that the most impactful flux levels that hit close-in exoplanets might be more time-limited than expected. We found significant differences in the duration distributions of single and complex flare components, but not in their peak luminosity. A statistical analysis of the flare parameter distributions provides marginal support for their description with a log-normal instead of a power-law function, leaving the door open to several flare formation scenarios. We tentatively confirmed previous results about QPPs in high-cadence photometry, report the possible detection of a pre-flare dip, and did not find hints of photometric variability due to an undetected flare background. Conclusions. The high-cadence study of stellar hosts might be crucial to evaluate the impact of their flares on close-in exoplanets, as their impulsive phase emission might otherwise be incorrectly estimated. Future telescopes such as PLATO and Ariel, thanks to their high-cadence capability, will help in this respect. As the details of flare profiles and of the shape of their parameter distributions are made more accessible by continuing to increase the instrument precision and time resolution, the models used to interpret them and their role in star-planet interactions might need to be updated constantly.

Gait Alterations and Association With Worsening Knee Pain and Physical Function: A Machine Learning Approach With Wearable Sensors in the Multicenter Osteoarthritis Study.

The objective of this study was to identify gait alterations related to worsening knee pain and worsening physical function, using machine learning approaches applied to wearable sensor-derived data from a large observational cohort. Participants in the Multicenter Osteoarthritis Study (MOST) completed a 20-m walk test wearing inertial sensors on their lower back and ankles. Parameters describing spatiotemporal features of gait were extracted from these data. We used an ensemble machine learning technique ("super learning") to optimally discriminate between those with and without worsening physical function and, separately, those with and without worsening pain over two years. We then used log-binomial regression to evaluate associations of the top 10 influential variables selected with super learning with each outcome. We also assessed whether the relation of altered gait with worsening function was mediated by changes in pain. Of 2,324 participants, 29% and 24% had worsening knee pain and function over two years, respectively. From the super learner, several gait parameters were found to be influential for worsening pain and for worsening function. After adjusting for confounders, greater gait asymmetry, longer average step length, and lower dominant frequency were associated with worsening pain, and lower cadence was associated with worsening function. Worsening pain partially mediated the association of cadence with function. We identified gait alterations associated with worsening knee pain and those associated with worsening physical function. These alterations could be assessed with wearable sensors in clinical settings. Further research should determine whether they might be therapeutic targets to prevent worsening pain and worsening function.

Accretion Disk Size and Updated Time-delay Measurements in the Gravitationally Lensed Quasar SDSS J165043.44+425149.3

We analyze variability in 15-season optical lightcurves from the doubly imaged lensed quasar SDSS J165043.44+425149.3 (SDSS1650), comprising five seasons of monitoring data from the Maidanak Observatory (277 nights in total, including the two seasons of data previously presented in Vuissoz et al.), five seasons of overlapping data from the Mercator telescope (269 nights), and 12 seasons of monitoring data from the US Naval Observatory, Flagstaff Station at lower cadence (80 nights). We update the 2007 time-delay measurement for SDSS1650 with these new data, finding a time delay of ΔtAB=−55.1−3.7+4.0 days, with image A leading image B. We analyze the microlensing variability in these lightcurves using a Bayesian Monte Carlo technique to yield measurements of the size of the accretion disk at λ rest = 2420 Å, finding a half-light radius of log(r 1/2/cm) = 16.19−0.58+0.38 assuming a 60° inclination angle. This result is unchanged if we model 30% flux contamination from the broad-line region. We use the width of the Mg ii line in the existing Sloan Digital Sky Survey spectra to estimate the mass of this system’s supermassive black hole, finding M BH = 2.47 × 109 M ⊙. We confirm that the accretion disk size in this system, whose black hole mass is on the very high end of the M BH scale, is fully consistent with the existing quasar accretion disk size–black hole mass relation.

The Effect of Postural Restoration Institute Training on Selected Kinematic Variables of Lower Limbs and Pelvis During Walking in Middle-Aged Men With Nonspecific Chronic Low Back Pain: A Prospective Observational Study

Background and Aims Concerning the effectiveness of training on people with chronic low back pain, the present study aimed to evaluate the effect of postural restoration institute (PRI) training on lower limb kinematics during walking in middle-aged subjects with discogenic low back pain. Methods In this prospective observational quasi-experimental study, 42 people participated in three groups: people without low back pain (healthy group, n=14) and people with low back pain in two groups (intervention group, n=14; and control group, n=14). Kinematic data were recorded by 7 Qualisys cameras with a frequency of 100 Hz in the pretest and post-test. Analysis of variance with repeated measures was used in SPSS software version 23 at a significance level 0.05. Results The results showed that people with low back pain in the intervention and control groups walk with a slower velocity, lower cadence, and shorter step length than healthy individuals for both right and left limbs. However, after the PRI training, the intervention group showed a significant increase in those three variables. Furthermore, there were significant differences between the healthy group and the two groups of intervention and control in the range of motion (ROM) for the pelvis in the sagittal and frontal planes, the right hip joint in the horizontal plane, the right ankle in the frontal plane, the left hip joint in the sagittal and horizontal planes as well as the left ankle in the sagittal plane. After applying PRI, the differences between the healthy and the intervention groups regarding the pelvis ROM on the sagittal plane, the right ankle ROM on the sagittal plane, the left hip joint ROM on the frontal plane, and the left knee ROM on the sagittal plane were minimized and became insignificant. Conclusion The present study’s findings confirmed the effectiveness of using PRI training in improving biomechanical indicators, such as the range of joint movements and increasing the velocity and step length of walking, to treat and manage the performance of people with discogenic chronic low back pain.

Optimising spectroscopic observations of transiting exoplanets

Context.When observing the atmospheres of transiting exoplanets using high-resolution spectroscopy, the aim is to detect well-resolved spectral features with high signal-to-noise ratios (S/Ns), as is possible today with modern spectrographs. However, obtaining such high-quality observations comes with a trade-off: a lower cadence of fewer, longer exposures across the transit collects more photons thanks to reduced overheads, enhancing the S/N of each observation, while a higher cadence of several shorter exposures minimises spectral feature smearing due to the continuously changing radial velocity of the planet.Aims.Considering that maximising S/N and minimising smearing are both beneficial to analysis, there is a need to identify the optimal compromise between the two for a given target. In this work, we aim to establish where this compromise lies for a typical exoplanet transit observation in order to benefit future data collection and subsequent interpretation.Methods.We modelled real transit events based on targets as they would be observed with VLT/CRIRES+ at Paranal Observatory, Chile. Creating four hypothetical scenarios, we simulated each set of transmission spectra across 100 realisations of the same transit event in order to vary the time resolution only. We removed telluric and stellar lines from these data sets using the SYSREM algorithm and analysed them through cross-correlation with model templates, measuring how successfully each time resolution and case detected the planetary signal and exploring how the results vary.Results.We demonstrate that there is a continuous change in the significance of the cross-correlation detection based on the trade-off between high and low time resolutions, and that, averaged over a large number of realisations, the function of this significance has clear maxima. The strength and location of these maxima vary depending on, for example, planet system parameters, instrumentation, and the number of removal iterations. We discuss why observers should therefore take several factors into account using a strategy akin to the ‘exposure triangle’ employed in traditional photography where a balance must be struck by considering the full context of the observation. Our method is robust and may be employed by observers to estimate the best observational strategies for other targets.

Effect of applied cadence in repeated sprint cycling on muscle characteristics

PurposeThis study aimed to investigate physiological responses, muscle–tendon unit properties of the quadriceps muscle, and mechanical performance after repeated sprint cycling at optimal and 70% of optimal cadence.MethodsTwenty recreational cyclists performed as first sprint performance cycling test and during subsequent sessions two repeated sprint cycling protocols at optimal and 70% of optimal cadence, in random order. The muscle–tendon unit outcome measures on the dominant leg included muscle thickness, fascicle length (Lf), pennation angle (θp), and stiffness for the rectus femoris (RF), vastus lateralis (VL), and vastus medialis muscle (VM) at baseline, immediately after repeated sprint cycling, and 1-h post-exercise.ResultsThe results showed an increase in muscle thickness and θp in RF, VL, and VM for both cadences from baseline to immediately after exercise. The Lf decreased in RF (both cadences), while stiffness decreased in RF, VL, and VM at optimal cadence, and in VL at 70% of optimal cadence from baseline to immediately after exercise.ConclusionThe present study revealed that the alterations in muscle characteristics were more marked after repeated sprint cycling at optimal cadence compared with a lower cadence most likely as a result of higher load on the muscle–tendon unit at optimal cadence.

Motor‐cognitive dual tasking in the clinical setting: a sensitive measure of functional impairment in early Alzheimer’s disease

AbstractBackgroundGait is a complex everyday activity that depends upon supraspinal activity and a host of cognitive functions such as attention and executive functions. As cognition declines in neurodegenerative diseases, the interaction and competition for neuronal resources during motor‐cognitive dual‐tasking (e.g., walking while talking) might be a sensitive measure of subtle functional impairments in early Alzheimer’s disease (AD). Here, we aim to identify gait deficits due to neuronal competition across the AD spectrum.MethodThis investigation is part of the ongoing Remote Assessment of Disease and Relapse – Alzheimer’s Disease (RADAR‐AD) study. We attached three inertial measurement units (accelerometer and gyroscope) to both feet and one hip to assess dual task effects (DTE) assessing gait performance with/without concurrent serial subtraction‐by‐1 task in four groups: 1) amyloid negative healthy controls (HC, N = 59); and 2) amyloid positive preclinical AD (PreAD, N = 30); 3) prodromal AD (ProAD, N = 51); and 4) mild‐to‐moderate AD dementia (MildAD, N = 44) (Table 1). We furthermore investigated associations of DTE with observer‐reported cognition.ResultGroup comparisons showed that dual‐tasking induced lower cadence and increased stance, which were significantly different between HC and ProAD. Several DTE measures of variability differed significantly between PreAD and MildAD, with variability in the path length separating best between PreAD and ProAD (Table 2, Figure 1). DTE measures were associated with observer‐rated divided attention only in the MildAD group.ConclusionNeuronal competition as assessed with motor‐cognitive dual‐tasking, specifically the DTE variability, might reflect functional deficits already in early AD, and could be a valuable additional measure to detect early impairments not captured by cognitive or motor tests alone. Future studies should implement an adaptive cognitive load to improve sensitivity/specificity in early AD stages and investigate the use of sensor technologies in predicting and monitoring changes in gait and fall prevention in later stages of the disease. This work has received support from the EU/EFPIA Innovative Medicines Initiative Joint Undertaking (grant No 806999). www.imi.europa.eu. This communication reflects the views of the RADAR‐AD consortium and neither IMI nor the European Union and EFPIA are liable for any use that may be made of the information contained herein.

Sex-related differences in gait characteristics and their associations with symptoms in individuals with patellofemoral osteoarthritis

BackgroundPatellofemoral osteoarthritis (OA) is an important subgroup of knee OA. However, the influence of sex on gait characteristics in patients with patellofemoral OA is unknown. Research questionCompare gait characteristics in females and males with patellofemoral OA and investigate their associations with patellofemoral joint-related symptoms and limitations. MethodsMixed effects polynomial regression models compared knee flexion-extension and adduction moments, knee flexion angles, and vertical ground reaction forces over 100% of stance between 26 females and 22 males with patellofemoral OA, with and without adjustment for walking speed and body mass. Multivariable linear regression models were then used to investigate the associations of gait characteristics with symptoms and limitations measured with the Knee injury and Osteoarthritis Outcome Score Patellofemoral Pain and Osteoarthritis (KOOS-PF) Subscale. Models included a sex-by-gait interaction term, and if significant, separate models were built for females and males. ResultsWhile controlling for walking speed and body mass, females had lower knee flexion moment (6–19% and 97–100% of stance), knee extension moment (45–86% of stance), knee adduction moment (3–37% and 69–99% of stance), vertical ground reaction force (1–97% of stance) and knee flexion angle (90–100% of stance) compared with males, when fitted over 100% of stance. Lower cadence, lower knee flexion angular impulse, and higher peak knee flexion angle were associated with worse KOOS-PF scores. Associations were not modified by sex. SignificanceThere are distinct sex-based differences in gait characteristics throughout stance with patellofemoral OA when adjusting for body mass and walking speed. Lower cadence and knee flexion angular impulse, and higher peak knee flexion angle were associated with more extreme patellofemoral joint-related symptoms and limitations.

O.4.2-8 Gait differences between adults with COPD and healthy controls: systematic review and metaanalyses

Abstract Purpose Fall risk is increased in adults with COPD. Although gait is an important risk factor for falls, hospitalisations, and mortality, the available literature shows inconsistencies on whether gait differs between adults with COPD and healthy controls. The aim of this study was to identify differences in digitally-measured gait characteristics during laboratory tests between adults with COPD and healthy controls. Methods As part of the Mobilise-D project (https://www.mobilise-d.eu), we conducted a systematic review built upon a previous scoping review (Polhemus, A. et al. npj Digit. Med. 2021). The search was updated in July 2021. Teams of two reviewers independently screened articles and extracted data. Meta-analyses were performed in studies not considered at a high risk of bias. Results Twenty-five studies were included. Gait speed was studied in 17 studies (68%), step length in 9 (36%), step time in 7 (28%), cadence in 6 (24%) and step width in 5 (20%). Meta-analyses revealed that adults with COPD walked with a lower self-selected speed and top speed than healthy controls. There was a trend towards a lower step length, lower cadence and higher step time at a self-selected walking speed in adults with COPD compared to healthy controls. Step width was similar for both groups. Conclusion Adults with COPD exhibit slower gait than healthy controls. This could contribute to the increased fall risk in adults with COPD. Support/Funding Source This work was supported by the Mobilise-D project that has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement No. 820820.

Laboratory and free-living gait performance in adults with COPD and healthy controls.

Gait characteristics are important risk factors for falls, hospitalisations and mortality in older adults, but the impact of COPD on gait performance remains unclear. We aimed to identify differences in gait characteristics between adults with COPD and healthy age-matched controls during 1) laboratory tests that included complex movements and obstacles, 2) simulated daily-life activities (supervised) and 3) free-living daily-life activities (unsupervised). This case-control study used a multi-sensor wearable system (INDIP) to obtain seven gait characteristics for each walking bout performed by adults with mild-to-severe COPD (n=17; forced expiratory volume in 1 s 57±19% predicted) and controls (n=20) during laboratory tests, and during simulated and free-living daily-life activities. Gait characteristics were compared between adults with COPD and healthy controls for all walking bouts combined, and for shorter (≤30 s) and longer (>30 s) walking bouts separately. Slower walking speed (-11 cm·s-1, 95% CI: -20 to -3) and lower cadence (-6.6 steps·min-1, 95% CI: -12.3 to -0.9) were recorded in adults with COPD compared to healthy controls during longer (>30 s) free-living walking bouts, but not during shorter (≤30 s) walking bouts in either laboratory or free-living settings. Double support duration and gait variability measures were generally comparable between the two groups. Gait impairment of adults with mild-to-severe COPD mainly manifests during relatively long walking bouts (>30 s) in free-living conditions. Future research should determine the underlying mechanism(s) of this impairment to facilitate the development of interventions that can improve free-living gait performance in adults with COPD.

Temporary Partial Weight-Bearing Restriction in Elderly Patients Treated With a Plate Fixation After a Distal Femur Fracture had a Negative Long-Term Impact on Gait Recovery.

Restricted weight-bearing is still used after lower extremity fracture surgery in elderly patients. The long-term effect on gait recovery in elderly patients with distal femur fractures (DFF) and their ability to comply with the restrictive weight-bearing regime is unknown. This study aimed to investigate the effect of restricted postoperative weight-bearing on gait recovery (actual weight-bearing and cadence) during a 1-year follow-up. This study evaluated secondary outcomes from a randomized controlled trial (32 patients ≥65years, with a traumatic DFF). Internal fixation was achieved using an anatomical lateral plate. Patients were allocated to either immediate full weight-bearing (FWB) or partial weight-bearing (PWB) (30% of body weight) for 8weeks. Pressure-sensitive sensors (F-scan™ system, Tekscan, Massachusetts, USA) were used to measure weight-bearing and cadence postoperatively and at 8-, 16-, and 52-week follow-ups. Twenty-six patients with at least 1 measurement were included. There was a statistically significant difference in actual weight-bearing between the PWB and FWB groups postoperatively of 32.3% (95% confidence interval CI, -50.0; -13.0, P < .001) and at the 8-week follow-up of 36.8% (95% CI -61.0; -18.0, P = .01), but not at later follow-ups. The PWB group presented a consistently lower cadence compared to the FWB group, which was statistically significant at the 16-week follow-up with 9.0 steps/min (95% CI -16.2; -1.1, P = .047) and 52-week follow-up with 9.3 steps/min (95% CI -18.0; -3.9, P = .009). Restricting postoperative weight-bearing in elderly patients with a DFF had a significant effect on postoperative weight-bearing. The effect lingered with a delayed return to FWB and persistent significantly lower cadence in the PWB group. These findings suggest that even temporary weight-bearing restrictions most likely have negative long-term effects on gait function at 1year and, therefore, cannot be recommended.

Change in activity patterns in the prefrontal cortex in different phases during the dual-task walking in older adults

BackgroundStudies using functional near-infrared spectroscopy (fNIRS) have shown that dual-task walking leads to greater prefrontal cortex (PFC) activation compared to the single-task walking task. However, evidence on age-related changes in PFC activity patterns is inconsistent. Therefore, this study aimed to explore the changes in the activation patterns of PFC subregions in different activation phases (early and late phases) during both single-task and dual-task walking in both older and younger adults.MethodsOverall, 20 older and 15 younger adults performed a walking task with and without a cognitive task. The activity of the PFC subregions in different phases (early and late phases) and task performance (gait and cognitive task) were evaluated using fNIRS and a gait analyzer. ResultsThe gait (slower speed and lower cadence) and cognitive performance (lower total response, correct response and accuracy rate, and higher error rate) of older adults was poorer during the dual task than that of younger adults. Right dorsolateral PFC activity in the early period in older adults was higher than that in younger adults, which declined precipitously during the late period. Conversely, the activity level of the right orbitofrontal cortex in the dual-task for older adults was lower than for younger adults.ConclusionsThese altered PFC subregion-specific activation patterns in older adults would indicate a decline in dual-task performance with aging.

Duration Effects on Wingate and Functional Power Threshold Test Outputs in Female Cyclists.

The response of female cyclists depending on the functional test duration has not been studied. This study aims to analyse the effect of modification of the duration of two different functional tests: Wingate (WAnT) and Functional Power Threshold (FTP) in female cyclists. Fourteen cyclists (27±8 years, 1,66±0,08 m, and 60,6±7,2 kg) performed 2 test days with a 24-hour break between days, varying the test duration (WAnT 20- or 30-sec, and FTP 8- or 10-min). Relative power output, cadence, heart rate, local oxygen saturation, lactate, and rating of perceived exertion were measured in each test. Time duration did not affect the power output outcomes in both tests (p>0,05). However, WAnT of 20 sec, compared with the test of 30 sec, resulted in a lower cadence decrease in the last 5 sec (p<0,01, ES=1,3), lower heart rate variables (peak, average and variation; p<0,01, ES>0,5), and higher execution inclination of local oxygen saturation (p<0,05 and ES=1,0). In conclusion, the time variations assessed do not alters power outcomes in female cyclists. However, higher acute fatigue can be observed in the WAnT of 30 sec, which suggests the use of the test of 20 sec to allow continue training afterwards.

Pathological gait in Rett syndrome: Quantitative evaluation using three-dimensional gait analysis

Ataxic-rigid gait is a characteristic gait pathology in patients with Rett syndrome (RTT). In the present study, we aimed to quantitatively evaluate gait pathology in patients with RTT using three-dimensional gait analysis (3DGA). We performed 3DGA in 11 patients with RTT ranging from 5 to 18 years (median age, 9 years) and in 33 age-matched healthy female controls. We compared the results of 3DGA, including spatiotemporal gait parameters and comprehensive indices of gait kinematics, such as the Gait Deviation Index (GDI) and Gait Profile Score (GPS), between the two groups. The GPS consists of nine sub-indices called Gait Variable Scores (GVSs). Decline in GDI or elevation of GPS and GVS indicated greater abnormal gait pathology. The patients demonstrated significantly slower walking speed, lower step length/length of the lower extremities, lower cadence, wider step width, and higher coefficient of variation of step length than the controls. Moreover, the patients had a lower GDI and higher GPS than the controls. The patients also exhibited higher GVSs for eight out of nine gait kinematics, particularly the sagittal plane in the pelvis, hip, knee, and ankle joint; coronal plane in the pelvis and hip joint; and horizontal plane in the pelvis than the controls. Quantitative evaluation of gait pathology in patients with RTT is possible using 3DGA. We found that in addition to ataxic-rigid gait, abnormalities in the coronal plane of the pelvis and hip joint and the horizontal plane of the pelvis were prominent.

Psychomotor slowing alters gait velocity, cadence, and stride length and indicates negative symptom severity in psychosis

Schizophrenia is a severe mental disorder, in which 50% of the patients present with motor abnormalities such as psychomotor slowing. Slow spontaneous gait has been reported in schizophrenia. However, comprehensive objective instrumental assessments of multiple gait conditions are missing. Finally, the specific gait patterns of subjects with psychomotor slowing are still unknown. Therefore, this study aimed to objectively assess multiple gait parameters at different walking conditions in patients with schizophrenia with and without psychomotor slowing. Also, we hypothesised gait impairments to correlate with expert ratings of hypokinetic movement disorders and negative symptoms. We collected gait data (GAITRite®) in 70 patients with psychomotor slowing (SRRS (Salpetriere retardation rating scale) ≥15), 22 non-psychomotor slowed patients (SRRS < 15), and 42 healthy controls. Participants performed four walking conditions (self-selected speed, maximum speed, head reclined, and eyes closed) and six gait parameters were extracted (velocity, cadence, stride length, functional ambulation profile (FAP), and variance of stride length and time). Patients with psychomotor slowing presented slower velocity, lower cadence, and shorter stride length in all walking conditions compared to healthy controls, with the non-slowed patients in an intermediate position (all F > 16.18, all p < 0.001). Secondly, slower velocity was associated with more severe hypokinetic movement disorders and negative symptoms. In conclusion, gait impairments exist in a spectrum with healthy controls on one end and patients with psychomotor slowing on the other end. Patients with psychomotor slowing are specifically impaired when an adaptation of gait patterns is required, contributing to the deleterious effects of sedentary behaviours.

The Effects of Cadence Manipulation on Joint Kinetic Patterns and Stride-to-Stride Kinetic Variability in Female Runners.

Altering running cadence is commonly done to reduce the risk of running-related injury/reinjury. This study examined how altering running cadence affects joint kinetic patterns and stride-to-stride kinetic variability in uninjured female runners. Twenty-four uninjured female recreational runners ran on an instrumented treadmill with their typical running cadence and with a running cadence that was 7.5% higher and 7.5% lower than typical. Ground reaction force and kinematic data were recorded during each condition, and principal component analysis was used to capture the primary sources of variability from the sagittal plane hip, knee, and ankle moment time series. Runners exhibited a reduction in the magnitude of their knee extension moments when they increased their cadence and an increase in their knee extension moments when they lowered their cadence compared with when they ran with their typical cadence. They also exhibited greater stride-to-stride variability in the magnitude of their hip flexion moments and knee extension moments when they deviated from their typical running cadence (ie,running with either a higher or lower cadence). These differences suggest that runners could alter their cadence throughout a run in an attempt to limit overly repetitive localized tissue stresses.