BACKGROUND:Weight acceptance during walking is essential for shock absorption, limb stability, and step-to-step transition, but its characterization with shank-mounted wearable sensors remains incomplete. Established early-stance events such as foot-flat, braking force peak, and opposite toe-off do not fully describe shank progression during loading response. RESEARCH QUESTION:Can the shank angular deceleration peak (SAD) serve as an inertial measurement unit (IMU)-compatible marker of early-stance shank progression, and does it provide distinct, complementary information alongside foot-flat, braking force, and opposite toe-off? METHODS:Two datasets were analyzed. In a healthy young dataset of 15 adults and 12594 steps, IMU, optical motion capture, and force-plate recordings were used to compare SAD timing between methods and across walking speeds, footwear, and heel-lift conditions. A separate total hip arthroplasty dataset of 80 healthy controls and 106 patients was used for asymmetry and discrimination analyses. RESULTS:SAD timing showed excellent agreement between IMUs and optical motion capture in the healthy young dataset, with ICC(2,1) values of 0.95 in barefoot and 0.92 in shod walking. Event timings changed systematically with speed, footwear, and heel-lift conditions, and SAD occurred after foot-flat during early stance. In the total hip arthroplasty dataset, asymmetry of all markers was higher before surgery and lower after surgery. Opposite toe-off and braking force peak showed the strongest discrimination between healthy controls and preoperative patients (AUC 0.81 and 0.80), whereas SAD showed moderate discrimination (AUC 0.72). SIGNIFICANCE:SAD complements established early-stance events and is promising for wearable assessment of shank progression during weight acceptance.
OBJECTIVE:To evaluate the agreement of spatiotemporal gait parameters obtained using OpenCap, a smartphone-based markerless motion capture system, with those measured using a marker-based optoelectronic motion capture system (VICON) as the reference standard. METHODS:Eleven healthy adults performed simultaneous 10-m walking trials recorded using VICON at 100 Hz and OpenCap with two iPhones at 4 K/60 fps. Gait speed, step length, stride length, stride time, cadence, and step width were calculated. Agreement was assessed using intraclass correlation coefficients (ICC), root mean square error (RMSE), mean absolute error (MAE), paired t-tests, and Bland-Altman analysis. RESULTS:OpenCap showed high agreement with VICON for spatial gait parameters, particularly gait speed, step length, and stride length, with ICC values of 0.98, 0.94, and 0.96, respectively. The RMSE/MAE values were 0.03/0.03 m/s for gait speed, 0.03/0.02 m for step length, and 0.05/0.05 m for stride length. The 95% limits of agreement for these parameters were generally within or comparable to previously reported minimal detectable change ranges. In contrast, cadence showed greater individual-level variability despite an ICC of 0.82, with RMSE and MAE values of 3.14 and 2.35 steps/min, respectively. Stride time and step width showed ICC values of 0.78 and 0.90, respectively, with RMSE/MAE values of 0.03/0.03 s and 0.01/0.01 m, respectively. CONCLUSION:OpenCap demonstrated acceptable measurement agreement for selected spatial gait parameters under the present experimental conditions, particularly gait speed and step length. However, cadence showed larger individual-level variability, and temporal and mediolateral parameters should be interpreted cautiously. Further studies in larger and more diverse populations are needed to confirm the clinical applicability of OpenCap-derived spatiotemporal gait parameters.
BACKGROUND:Fall prevention is a primary goal of rehabilitation for stroke survivors. However, previous studies have mainly relied on retrospective fall history, creating a temporal mismatch between gait assessment and instability events that may obscure gait characteristics associated with near-falls. RESEARCH QUESTION:Which gait-related factors are associated with near-falls in stroke survivors from the perspectives of trunk excursion, propulsion, and gait symmetry? METHODS:A total of 157 subacute stroke survivors were included, comprising 82 participants with near-falls during gait analysis and 75 without near-falls. Trunk angular excursion, propulsion-related variables including trailing limb angle (TLA) and late braking force (LBF), gait symmetry indices, and gait speed were obtained during normal walking trials. Univariable and multivariable logistic regression analyses were performed. A sensitivity analysis additionally adjusted for cane use, ankle-foot orthosis use, lower-extremity motor recovery, and time since stroke. Receiver operating characteristic (ROC) analysis was conducted to evaluate the discriminative ability of TLA. RESULTS:Reduced TLA and LBF, increased trunk angular excursion, greater gait asymmetry, and slower gait speed were associated with near-falls in univariable analyses. In the multivariable model, reduced TLA (odds ratio [OR]=0.18, 95% confidence interval [CI]=0.08-0.39, p < 0.001) and greater trunk rotational excursion (OR=2.12, 95% CI=1.17-3.87, p = 0.014) were independently associated with near-falls, whereas swing time symmetry index was not. These associations remained significant after adjustment for clinical confounders. TLA alone demonstrated good discriminative ability for identifying near-falls (AUC=0.884, 95% CI=0.826-0.934), with an optimal cutoff value of 3.26°. CONCLUSIONS:Reduced TLA and greater trunk rotational excursion were independently associated with near-falls during walking in stroke survivors. TLA showed good discriminative ability and may help identify individuals at increased risk of near-falls.
OBJECTIVE:The use of wearable inertial measurement units (IMUs) to measure kinematic parameters of high-risk movements, such as landing and cutting, for injury prevention is becoming more common. However, the validity and reliability of IMUs in assessing lower limb joint angles still lack comprehensive validation. This systematic review and meta-analysis assessed the validity and reliability of lower limb kinematic data captured by IMUs during landing and cutting tasks. METHODS:Comprehensive searches were conducted in the Web of Science, Scopus, PubMed, and EBSCO databases up to April 10, 2025, yielding 787 studies, with an update on August 14, 2025. The included articles were assessed for quality, and a meta-analysis was performed to calculate the pooled correlation coefficients for validity and reliability. RESULTS:Eleven studies were included in the systematic review, with seven in the meta-analysis, involving 268 participants. IMUs showed good to excellent validity in measuring the knee sagittal plane angle during landing and cutting (r = 0.91-0.92, ICC = 0.80-0.90), but poor validity for the knee frontal plane angle (r = 0.39-0.41, ICC = 0.20-0.22). For reliability, the IMU-measured hip sagittal plane angle showed excellent reliability during the landing task (ICC = 0.92), while the knee sagittal plane angle, hip frontal plane angle, and knee frontal plane angle exhibited good reliability (ICC = 0.77-0.89). In the cutting task, the knee frontal plane angle showed good reliability (ICC = 0.80), but reliability for other joints was generally moderate (ICC = 0.52-0.67), and reliability was poor for the knee transverse-plane angle and hip frontal-plane angle (ICC = 0.40-0.47). CONCLUSION:IMUs showed excellent validity and reliability for knee sagittal plane angles during landing and cutting tasks. However, the validity and reliability of other measures varied, and the limited number of studies warrants cautious interpretation.
Background Microprocessor-controlled prosthetic ankles have been developed to improve gait biomechanics in individuals with transtibial amputation; however, comparative biomechanical evidence across devices with different functional mechanisms remains limited. This study evaluated the biomechanical and metabolic effects of a newly developed motor-driven microprocessor-controlled ankle, RoFT® (MPA-2), compared with each participant’s everyday conventional prosthetic ankle (CPA) and a commercially available microprocessor-controlled ankle, Meridium® (MPA-1). Methods Eighteen individuals with unilateral transtibial amputation participated in this multicentre study. Each participant’s everyday CPA was assessed as the baseline condition, after which MPA-1 and MPA-2 were evaluated in a randomised crossover sequence. Each MPA was used for a two-week adaptation period, with a two-week washout period between MPA conditions. Three-dimensional gait analysis was performed to evaluate spatiotemporal, kinematic, kinetic, ground reaction force and symmetry index parameters. Cardiopulmonary exercise testing during treadmill walking assessed metabolic energy expenditure. Results MPA-2 produced greater amputated-limb ankle range of motion and peak positive ankle power, the primary outcome, than CPA and MPA-1. Propulsion-related anterior-posterior ground reaction force parameters were higher with MPA-2 than with MPA-1 but did not differ significantly from CPA. Intact-limb first peak vertical ground reaction force was lower with MPA-2 than with CPA. MPA-2 improved ankle power-generation symmetry, whereas propulsion impulse symmetry was poorer with MPA-1. Metabolic energy expenditure did not differ significantly among prosthetic conditions. Significance The RoFT® MPA showed favourable biomechanical effects on ankle power, propulsion-related mechanics, and selected measures of interlimb symmetry, although these biomechanical changes were not accompanied by reduced metabolic energy expenditure.
Background Running-related injuries have remained relatively stable over recent decades despite advances in athletic footwear design. This has led to a growing interest in minimalist footwear as a strategy for modifying running biomechanics. However, the effects of its use and the optimal characteristics of the transition period remain controversial, particularly regarding injury risk. Objective To analyze the injury prevalence associated with the transition to minimalist footwear and to identify the main biomechanical and musculoskeletal changes associated with injury risk reported in scientific literature. Method A systematic review and meta-analysis were conducted following the PRISMA 2020 guidelines. The literature search included international databases and covered the last 15 years, incorporating randomized controlled trials and prospective cohort studies. Eligibility criteria included a minimum transition period of four weeks in healthy runners with no previous experience with minimalist footwear. The effect size was estimated using a fixed effects model, and heterogeneity was assessed using Cochran's Q test and I2 statistic. Results A total of 12 studies were included in the qualitative synthesis and 7 in the meta-analysis, with a total of 313 participants. The transition to minimalist footwear was associated with a moderate increase in injury risk, with an overall effect size of 3.529 (95%CI: 2.41-4.646) and low heterogeneity. The most frequently reported injuries were bone marrow edema in the metatarsal region, Achilles tendinopathy and calf pain, related to the adoption of a forefoot strike pattern. Conclusions The transition to minimalist footwear is associated with a moderate increase in risk and significant increase in the prevalence of musculoskeletal injuries, related to changes in the foot strike pattern and to forefoot and Achilles tendon overload. Supervised retraining programs of at least 12 weeks may support progressive adaptation of the musculoskeletal system and reduce risk of injury.
PURPOSE:Perturbation-based balance training (PBT) targets reactive balance control through exposure to unexpected mechanical disturbances. Although growing evidence supports its potential role in fall prevention, methodological variability across studies limits synthesis and clinical translation. This review aimed to systematically map and characterize the methodological features of mechanically induced PBT interventions in healthy older adults. METHODS:This scoping review followed the Arksey and O'Malley framework with refinements by Levac et al. and the Joanna Briggs Institute. Reporting adhered to PRISMA-ScR guidelines. PubMed, EMBASE, Scopus, and Web of Science were searched from inception through April 2025. Eligible studies included peer-reviewed empirical investigations of mechanically induced PBT in adults ≥ 65 years reporting balance, gait, or fall-related outcomes. Data were extracted on perturbation modality, task context, training dosage, outcome domains, and follow-up assessment. RESULTS:Thirty-three studies met the inclusion criteria. Five primary perturbation categories were identified: treadmill-induced slips (n = 11), platform-based perturbations (n = 12), waist-pull systems (n = 4), overground trips (n = 4), and unspecified methods (n = 1). Single-session protocols were most common (n = 16), with fewer short-, moderate-, and long-duration programs. Balance outcomes were universally assessed, while gait and fall-related outcomes were reported in most studies. Follow-up beyond immediate post-testing was inconsistent, and alignment between training duration and retention assessment was limited. CONCLUSIONS:Mechanically induced perturbation-based balance training research in healthy older adults has been conducted predominantly in controlled laboratory environments and is characterized by substantial heterogeneity in intervention design. While reactive balance improvements were consistently reported, variability in intervention design, reporting practices, and follow-up timing limits direct comparison across studies and highlights the need for greater methodological standardization.
INTRODUCTION:Gait termination (GT), the transition from steady-state walking to stable standing, requires precise deceleration and postural control. Because multiple sclerosis (MS) is associated with heterogeneous motor, sensory and balance impairments, planned GT may reveal mobility alterations beyond those observed during steady-state walking. METHODS:This cross-sectional study included 25 ambulatory people with MS (pwMS; Expanded Disability Status Scale [EDSS] score ≤4.5) and 25 healthy controls (HC). Planned GT was assessed over six trials using the GAITRite® electronic walkway, with three trials terminating with each limb. Final termination-step width was designated as the primary outcome; other planned-GT outcomes were secondary, steady-state gait outcomes were supportive, and EDSS associations were exploratory. RESULTS:Final termination-step width was greater in pwMS than in HC (Hodges-Lehmann estimate, 5.65 cm; 95% confidence interval, 4.34-7.33; p < 0.001). pwMS also showed wider penultimate termination-step width, lower GT velocity, greater velocity reduction, shorter final step length, and longer double-support time (all Holm-adjusted p < 0.001). During steady-state walking, maximum step velocity was lower and step width was greater (both Holm-adjusted p = 0.015). In velocity-adjusted sensitivity analyses, differences in both termination-step widths, GT velocity, final step length, and double-support time remained significant (primary-outcome p < 0.001; secondary Holm-adjusted p ≤ 0.020). Higher EDSS scores were associated with wider penultimate (Kendall's tau-b=0.384, Holm-adjusted p = 0.010) and final (tau-b=0.488, Holm-adjusted p = 0.002) termination-step widths. CONCLUSION:Planned GT was characterised by greater velocity reduction, shorter final step length, wider terminal foot placement, and prolonged double-support time in pwMS. Planned GT may provide complementary information to steady-state gait assessment.
RESEARCH QUESTION:Upper-limb exoskeletons are known to reduce local muscle strain, but their impact on global postural regulation remains unclear. This study investigated whether upper-limb exoskeleton usage induces a compensatory trade-off in postural stability or a fundamental reorganisation of motor control strategies during sustained static loading. METHODS:Nineteen healthy participants performed a static holding task (10 kg) to exhaustion under two conditions: with and without a passive upper-limb exoskeleton. Neuromuscular fatigue was assessed via surface electromyography (sEMG) spectral analysis and pre-post maximal voluntary contractions (MVC). Postural dynamics were quantified using center-of-pressure (CoP) velocity, Detrended Fluctuation Analysis (DFA), and Multiscale Entropy (MSE) to assess system complexity and adaptability. RESULTS:Exoskeleton use significantly delayed task failure, nearly tripling time-to-exhaustion (896 s vs 307 s; P < 0.001), while attenuating the decline in EMG median frequency and preserving biceps MVC. Crucially, this endurance gain was accompanied by a strategic shift in postural control: exoskeleton use reduced CoP signal complexity (lower MSE) and increased short-term persistence (higher DFA α1), particularly in the medio-lateral axis. Importantly, this reduced complexity occurred without a concomitant increase in sway velocity. SIGNIFICANCE:These findings suggest that exoskeletons do not merely mechanically offload muscles but are associated with a shift toward a "low-complexity" control regime. This reorganisation accompanied the extended endurance and occurred without an increase in sway velocity, consistent with the device assuming part of short-term stability regulation rather than the system compensating through detrimental sway.
PURPOSE:The purpose of our study was to compare the influence of standing on a rigid surface or a foam pad on lower-leg intermuscular coherence in young and older adults. METHODS:Bipolar surface electromyography from the soleus, gastrocnemius medialis, and tibialis anterior was recorded in 18 young adults [mean ± standard deviation, 26 ± 4 yrs] and 18 older adults [71 ± 5 yrs] while they stood on a rigid surface or on a foam mat. Intermuscular coherence was calculated as the mean coherence between pairs of agonist (soleus, gastrocnemius medialis) and antagonist (soleus, tibialis anterior) muscles in the alpha (8-13 Hz) and beta (13-35 Hz) bands. RESULTS:Mean CoP velocity was greater when standing on foam than on a rigid surface in both groups (p < 0.001). When standing on foam compared with the rigid surface, mean alpha-band coherence increased in young (p < 0.001) but decreased in older adults (p = 0.036), regardless of the muscle pair. Agonist and antagonist beta-band coherence was greater when standing on foam compared with the rigid surface in both groups (p < 0.001). SIGNIFICANCE:Our findings provide novel evidence that support-surface compliance modulates intermuscular coherence between lower-leg muscle pairs during quiet standing. The difference in alpha-band coherence between young and older adults suggests an age-related reorganization of shared neural drive to postural muscles.
BACKGROUND:Altered lower extremity biomechanics and elevated patellofemoral joint stress are proposed mechanisms underlying patellofemoral pain (PFP). Although clinicians often associate muscle weakness with kinematic alterations in females with PFP, the relationship between muscle volume and movement strategies remains unclear. RESEARCH QUESTION:Is hip and knee muscle volume associated with lower extremity kinematics and energetics during a single-leg squat (SLS) in females with PFP? METHODS:This preliminary exploratory study included thirteen participants (age=25.8 ± 6.0 years; body mass index=26.0 ± 6.4 kg/m2) who underwent assessments of magnetic resonance imaging-derived lower extremity muscle volume (hip abductors, hip extensors, hip external rotators, and knee extensors) and three-dimensional SLS kinematics (sagittal and frontal hip, knee, and ankle joint angles) and energetics (sagittal and frontal hip, knee, and ankle joint work). Bivariate correlation analysis assessed associations between hip and knee muscle volume and SLS biomechanics. Variables demonstrating significant bivariate correlations were entered into multiple linear regression models, adjusting for pain and disability. RESULTS:Hip and knee muscle volume were not significantly associated with kinematics (p > 0.05). However, smaller muscle volume across all hip and knee muscle groups studied was (1) strongly associated with greater sagittal plane ankle joint work (r = -0.86 to -0.73; p ≤ 0.004) and (2) moderately associated with greater frontal plane hip joint work (r = -0.67 to -0.56; p ≤ 0.049). In exploratory adjusted regression analyses, these associations were observed after accounting for pain and disability (β=-0.81 to -0.45; p ≤ 0.05). SIGNIFICANCE:Hip and knee muscle volume were associated with lower extremity energetics during the SLS in females with PFP.
BACKGROUND:Early differentiation of progressive supranuclear palsy from Parkinson's disease is challenging due to overlapping motor features, particularly in early disease stages where clinical misclassification is common. Wearable inertial sensors provide high-resolution gait data that may reveal disease-specific and clinically relevant signatures. OBJECTIVE:To evaluate whether sensor-derived gait measures can distinguish progressive supranuclear palsy from Parkinson's disease using machine learning, and to compare performance between raw time-series signals and aggregate spatiotemporal variables, with emphasis on clinically interpretable gait biomarkers. METHODS:In this retrospective study, 34 participants with progressive supranuclear palsy and 410 with Parkinson's disease completed an instrumented Timed-Up-and-Go while wearing six synchronized sensors. Two input modalities were analyzed: raw accelerometer, gyroscope, and magnetometer signals sampled at 128 Hz; and 48 curated spatiotemporal features. Eight classifiers, including logistic regression, support vector machine, k-nearest neighbors, neural network, decision tree, random forest, extreme gradient boosting, and a baseline, were trained to classify progressive supranuclear palsy versus Parkinson's disease at the participant level using cross-validation procedures designed to prevent data leakage. The primary performance metric was macro-averaged F1-score. Shapley Additive Explanations were applied to aggregate-feature models to identify key discriminative gait features. RESULTS:Raw time-series models performed strongly, with gradient boosting achieving the highest macro-F1 (0.87), followed by random forest (0.86) and support vector machine (0.83). Aggregate models performed comparably, with gradient boosting reaching 0.88, followed by random forest (0.87) and support vector machine (0.84). Shapley analyses identified increased double-support time and mediolateral sway, and reduced stride length, gait speed, and trunk range of motion as the most distinctive gait impairments characterizing PSP relative to PD. CONCLUSIONS:Ensemble models reliably differentiated progressive supranuclear palsy from Parkinson's disease. Aggregate spatiotemporal models achieved performance comparable to raw signals while yielding clinically interpretable and physiologically meaningful gait biomarkers. These findings support the use of wearable sensor-based gait analysis combined with machine learning as a practical tool for improving differential diagnosis in movement disorder clinics.
OBJECTIVE:Gait impairment emerges early in Parkinson's disease (PD), yet quantitative kinematic characterization at Hoehn-Yahr (H-Y) stage 1 remains limited. This study examined lateralized gait deficits to identify early motor control biomarkers. METHODS:This cross-sectional study enrolled 30H-Y stage 1 participants with PD and 20 age-/sex-/BMI-matched healthy controls (controls). Three-dimensional gait analysis during the medication OFF state assessed spatiotemporal parameters, joint kinematics (hip/knee/ankle angles), and Gait Deviation Index (GDI). Within-PD limb comparisons (affected vs. relatively unaffected) used paired t-tests; between-group comparisons (each PD limb vs. controls) used independent-samples t-tests. RESULTS:The affected limb demonstrated a distinctive plantarflexed ankle position at initial contact (-1.25 ± 5.61°) compared with the relatively unaffected limb (2.50 ± 4.20°; Δ=-3.75°, 95% CI -6.15 to -1.35°, p = 0.003, Cohen's d = 0.580) and controls (2.35 ± 4.24°; Δ = -3.61°, p = 0.003). The relatively unaffected limb did not differ from controls (p = 0.888), confirming deficit specificity to the affected limb. Both PD limbs showed shorter stride length and lower walking velocity than controls (all Bonferroni-adjusted p < 0.020), as well as reduced peak hip extension (all Bonferroni-adjusted p < 0.006). CONCLUSION:H-Y stage 1 PD exhibits a lateralized plantarflexed ankle position at initial contact in the affected limb, alongside bilateral gait abnormalities relative to controls. Quantitative initial-contact analysis may provide a complementary marker of early motor dysfunction.
Background Poststroke hemiparetic gait often involves stance-phase knee hyperextension (genu recurvatum). Knee hyperextension persisting into preswing (PSw) can influence push-off and the subsequent swing-phase kinematics. This study investigated whether PSw hyperextension was associated with reduced forward propulsion and altered swing-phase kinematics, including functional limb shortening and peak knee-flexion angle. Methods Thirty patients with chronic poststroke hemiparesis and knee hyperextension were evaluated. Three-dimensional motion capture and force plates were used to measure overground walking. The outcome measures were peak forward propulsive force and swing-phase kinematics, specifically peak knee-flexion angle and functional limb shortening (quantified by the minimum pelvistoe distance). Patients were classified according to the presence of PSw hyperextension. Group differences and relationships among variables were examined using t-tests and correlation analyses. Path analysis assessed whether the relationship between PSw hyperextension and swing-phase kinematics was partly mediated by forward propulsion. Results Patients with PSw hyperextension showed significantly reduced forward propulsion and impaired functional limb shortening compared with those with knee hyperextension limited to earlier stance phases. Path analysis suggested that PSw hyperextension was associated with impaired functional limb shortening during swing, partly through reduced forward propulsion and partly through mechanisms independent of forward propulsion. Significance PSw hyperextension was associated with reduced forward propulsion and impaired functional limb shortening in patients with hemiparetic stroke. Addressing PSw hyperextension may help improve swing-phase mechanics during gait rehabilitation.
Background: The ability to characterise balance capacity through clinical assessment procedures is often limited by a focus on movement tasks substantially more predictable than those experienced in the real world. Consequently, assessment protocols may not sufficiently elicit and characterise the full range of sensory, cognitive and physical challenges present in daily life. Methods: A task-specific procedure for assessing balance control during gait via a treadmill-based augmented-reality environment called the ‘Benchmarking System for Assessing Balance’ (BeStABle) is proposed. The apparatus utilises unpredictable visual cues that prescribe discrete changes to foot placement patterns, requiring rapid stimulus perception, decision-making, and modification of body dynamics, followed by compensatory corrections to return to steady gait. This is representative of a wide variety of situations in community living and many reported circumstances of real-world falls. This assessment procedure is demonstrated with a case study comparing three high-functioning users of transtibial (below-knee) prostheses with a group of 19 able-bodied persons. Results: The BeStABle successfully discriminates the prosthesis users from the normative group in multiple outcomes, and most prominently when participants are cued to narrow their steps. The finding that certain gait adaptations are not realisable by the prosthesis users may help to refine future protocols for assessing gait and balance impairment with the BeStABle. Conclusion: The BeStABle treadmill-based augmented-reality environment enables the repeatable and objective assessment of gait adaptations through a process that is safe for subjects and efficient for clinicians.
Background The sit-to-stand transition is a key movement influenced by coordination, balance, and lower-limb strength. While laboratory-based studies show slower sit-to-stand angular velocity during pregnancy, free-living sit-to-stand angular velocity and its relationship to pregnancy-related discomforts remain unclear. Purpose This study examined differences between the second and third trimesters of pregnancy in free-living sit-to-stand angular velocity, movement behaviours, and discomfort frequency, and assessed whether changes in sit-to-stand angular velocity predicted discomfort changes. Methods Pregnant participants (n = 176) from the PRECISE Occupational Cohort in Denmark wore thigh-worn accelerometers for ∼one week during the second and third trimesters to measure sit-to-stand transitions, step counts, and movement behaviours. Weekly questionnaires reported the presence of lower back pain, pelvic pain, Braxton-Hicks contractions, fatigue, and lower-limb edema. Results Linear mixed models compared second and third trimesters, and regression models tested whether sit-to-stand angular velocity change predicted discomfort change, adjusting for age and pre-pregnancy body mass index. Median (d=-0.53) and 90th percentile sit-to-stand angular velocity (d=-0.47) were significantly lower in the third trimester, accompanied by fewer daily sit-to-stand angular transitions (d=-0.14) and reductions in step count (d=-0.29), standing time (d=-0.21), and moderate-to-vigorous physical activity (d=-0.43; all, p < 0.001). Pregnancy-related discomforts increased in frequency (p < 0.001), with pelvic pain (odds ratio (OR)= 5.02), Braxton-Hicks contractions (OR=17.9), and lower-limb edema (OR=9.23) showing the largest rises. Changes in median and 90th percentile sit-to-stand angular velocity were not associated with changes in the composite weekly discomforts (both, p > 0.235). Conclusion Free-living sit-to-stand angular velocity declines and discomfort prevalence rises between the second and third trimesters.
BACKGROUND:Internal hemipelvectomy is a limb-salvage procedure used to treat aggressive pelvic bone tumors. Depending on the extent of pelvic resection, the procedure can substantially alter pelvic stability, muscle attachment sites, and lower-extremity loading during gait. These structural changes are associated with altered movement patterns during walking, which may influence the ability to maintain functional ambulation. Although gait deviations following hemipelvectomy have been reported, the role of trunk motion within these altered gait patterns remains poorly understood. RESEARCH QUESTION:What trunk and lower-extremity gait patterns are observed during walking in an adolescent following type I, II, and III internal hemipelvectomy with limb salvage? METHODS:A 15-year-old adolescent post I-III internal hemipelvectomy without reconstruction at age 11 underwent three-dimensional motion analysis during walking. Gait was evaluated under two conditions: barefoot and with a solid ankle-foot orthosis (AFO) with shoe lift to address leg-length discrepancy. Trunk, pelvic, lower-extremity kinematics, joint moments and ground reaction forces were analyzed. RESULTS:The participant demonstrated exaggerated posterior trunk pitch and increased lateral trunk displacement during stance, accompanied by reduced hip, knee, and ankle excursion on the surgical limb. Despite diminished lower-extremity motion, altered sagittal-plane joint moments, and reduced propulsive impulses on the surgical limb, independent ambulation was maintained. SIGNIFICANCE:These findings suggest an association between exaggerated and asymmetrical trunk motion with preserved ambulation despite reduced lower-extremity mechanics; however, the specific relationship between trunk motion and center-of-mass control was not directly quantified.
OBJECTIVE:To investigate whether adding visuo-vestibular exercises to standard manual therapy and exercise produces superior improvements in sensorimotor function, pain, balance, and functional disability in adults with chronic neck pain. METHODS:This prospective, randomized controlled trial enrolled 58 adults with chronic neck pain (≥3 months) allocated to a manual therapy and exercise group (MtE; n = 29) or MtE plus visuo-vestibular exercises (MtE-VVE; n = 29). Both groups completed 12 supervised sessions over six weeks with a daily home exercise programme. Outcomes were assessed at baseline, 6 weeks, and 12 weeks, and included pain intensity (Visual Analog Scale [VAS]), upper extremity reaction time, computerized posturography, the Neck Disability Index (NDI), and cervical muscle endurance. RESULTS:Fifty-four participants (27 per group) completed the study. Both groups improved significantly across all outcomes (p < 0.001). At 12-week follow-up, the MtE-VVE group demonstrated superior outcomes: activity-related pain was reduced by an additional 2.00 cm (95% CI: 0.75-3.25; p = 0.005), bilateral reaction time improved by 1.70 s (p = 0.001), eyes-open mediolateral sway decreased by 0.50 mm (p < 0.001), NDI score was 6.30 points lower (95% CI: 3.42-9.18; p < 0.001), and cervical flexion and extension endurance improved by 12.00 s and 27.70 s, respectively (p ≤ 0.020). CONCLUSION:Adding visuo-vestibular exercises to standard manual therapy and exercise produces clinically meaningful and sustained improvements in activity-related pain, sensorimotor function, postural control, and functional disability in adults with chronic neck pain, and may be recommended as an effective adjunctive intervention.
Background Responses to gait perturbations are critical for maintaining dynamic stability and preventing falls, yet muscle-level mechanisms underlying these responses remain insufficiently understood, particularly during the initial contact (IC) phase. Research question How do individual lower-limb muscle forces adapt during perturbations at IC and in the subsequent recovery step? Methods Twenty-one healthy young women walked on a dual-belt treadmill while perturbations were induced via sudden belt deceleration at IC. Motion capture and ground reaction force data were processed in OpenSim to estimate muscle forces using static optimization. Peak muscle forces (PMF) during perturbed and recovery steps were compared with normal gait using Wilcoxon tests and subsequent FDR correction. Results During the perturbed step, PMFs increased significantly in 8 of 30 muscles. Following FDR correction, significant differences remained for five muscles, primarily involving proximal and biarticular muscles (e.g., biceps femoris, gastrocnemius, gluteus medius, piriformis, and adductor magnus), indicating a multi-joint stabilization strategy. During the recovery step, several muscles demonstrated increased PMFs, however none remained significant after FDR correction. Significance Gait perturbations at IC elicit increased involvement of a limited set of key stabilizing muscles, particularly across the hip, knee, and ankle joints. While recovery-step adaptations were observed, they should be considered exploratory due to the lack of statistical significance following correction for multiple comparisons. These findings provide novel insight into muscle-level mechanisms of balance recovery and may inform rehabilitation strategies targeting fall prevention.
INTRODUCTION:Postural sway is subtle adjusting movements when standing that maintain the center of mass within the base of support. Assessing postural sway enables detection of subtle balance impairments, thereby enhancing the sensitivity of balance assessments. Normative data on postural stability for interpretating clinical findings remains insufficient. This study aims to provide a normative dataset and identify predictors of postural sway to serve as a benchmark in clinical settings and research. METHODS:One hundred thirty-nine healthy adults (54% women) aged 20-69 years performed static and dynamic balance tests on the Biodex Biosway balance platform (Biosway Portable Balance System 950-460, Biodex Medical Systems, NY). The static balance tests were the Postural Stability Test and the modified Clinical Test of Sensory Integration and Balance (mCTSIB). The dynamic balance tests were the Limits of Stability tests (LOS). RESULTS:This study provides the first normative dataset for healthy adults aged 20-69 years, stratified by age and sex for static and dynamic balance tests for the Biodex Biosway balance platform. For the mCTSIB, each unit increase in BMI predicted an increase of 0.016 in score (p = 0.015), and each additional year of age predicted an increase of 0.055 in score (p = 0.0007), meaning poorer balance. For the LOS easy level, each unit increase in BMI predicted a reduction of 0.777 in the LOS overall score (p = 0.0297), and each additional year of age predicted a reduction of 0.274 in the LOS overall score (p = 0.0004), meaning poorer balance. DISCUSSION:These findings offer clinicians valuable reference values for interpreting individuals' objective balance performance using the Biodex Biosway balance platform. Increased BMI and age were consistent predictors of poorer balance.
