Search Results (404)

Background: The management of diabetic foot disease and knee osteoarthritis (OA) with smart orthotics holds significant importance during the early stages of these conditions, given their potential consequences, including functional impairment, chronic pain, and economic burden. Real-time monitoring of plantar foot pressure enables early detection of abnormal force distribution and gait biomechanics, allowing for the redirection of forces away from affected ulcers or arthritic joints. This is the first systematic review to synthesise clinical evidence for smart orthotics technology with real-time plantar pressure sensor biofeedback across both diabetic foot ulcer prevention and knee osteoarthritis management simultaneously. A search of the PROSPERO register confirmed no existing registration covers this specific combination. Objectives: To examine the clinical evidence for the use of standard and smart orthotics in the prevention and management of diabetic foot ulcers (DFUs) and knee OA, and to evaluate their impact on plantar pressure redistribution, ulcer recurrence, pain, biomechanics, and economic burden. Eligibility criteria: Studies published in English involving human adult participants (≥18 years) with a clinical diagnosis of diabetes mellitus (at risk of DFU or with peripheral neuropathy) or knee OA, where the intervention involved any orthotic device or smart/intelligent insole with clinical outcomes reported, were included. Studies on healthy individuals only, those not reporting participant age, and non-weight-bearing protocols not differentiated from weight-bearing were excluded. Information sources: Five databases were searched: CINAHL (EBSCO Information Services, Ipswich, MA, USA), PubMed Advanced (National Library of Medicine, Bethesda, MD, USA), Wiley Online Library (John Wiley & Sons, Hoboken, NJ, USA), Cochrane Library (Cochrane Collaboration, London, UK), and Google Scholar (Google LLC, Mountain View, CA, USA). Searches were completed in May 2026. Methods: We conducted a comprehensive literature review. This review was structured and reported with reference to the PRISMA 2020 statement (Preferred Reporting Items for Systematic Reviews and Meta-Analysis; University of Ottawa, Ottawa, ON, Canada) to guide transparency of reporting. It does not constitute a full Cochrane-style systematic review; risk of bias assessment was applied to key included studies and GRADE (Grading of Recommendations Assessment, Development and Evaluation; McMaster University, Hamilton, ON, Canada) certainty ratings were applied informally and narratively rather than as formal per-outcome evidence profiles. Five databases were searched yielding 92,637 records. After removal of 398 duplicates by Rayyan, 92,239 records remained. A subsequent automated keyword-based relevance filter applied within Rayyan (Rayyan AI, Doha, Qatar), prior to human screening, excluded 84,572 records that did not contain any terms related to orthotics, diabetic foot, or knee osteoarthritis, yielding 7667 records for human title/abstract screening. A narrative synthesis approach was adopted owing to the heterogeneity of study designs and outcome measures across included studies, which precluded meta-analysis. This review was not prospectively registered. A complete list of all 78 included studies, including those not individually discussed in the results and discussion. Results: The available clinical studies report promising findings for orthotics and smart orthotics in pain reduction, ulcer prevention, and potential reduction in economic burden, though conclusions are limited by small sample sizes, heterogeneity, and predominantly open-label designs. Recent research found that orthotics can be used to alter the gait pattern that influences knee OA by reducing excessive force on the affected joint. A randomised controlled trial demonstrated an 80% relative risk reduction in DFU recurrence (RR = 0.20; 95% CI: 0.06–0.79; p = 0.022), with absolute event rates of 6.3% in the intervention group versus 30.8% in controls (ARR = 24.5%); a second trial reported a 71% reduction in ulcer incidence over 18 months; and a third randomised controlled trial demonstrated statistically significant plantar pressure reduction (p < 0.01) in patients with diabetic neuropathy. Conclusions: The available evidence suggests that orthotics may be associated with improved pressure redistribution, reduced ulcer incidence, and benefit in the management of knee OA. Although the number of studies directly comparing smart orthotics with standard orthotics remains limited, the limited comparative studies suggested that smart orthotics showed promising results in reducing ulcer incidence, providing the patient with real-time feedback to offload via their electronic devices. These findings, while preliminary, highlight the potential of smart orthotic technology as an adjunct to standard orthotic care in reducing the overall burden of diabetic foot disease and knee osteoarthritis. Limitations: The primary methodological limitation of this review is the open-label design of all included smart orthotic trials, which precludes participant blinding and introduces performance bias. However, this limitation is structural and inherent to the wearable technology field—analogous to surgical trials—and is substantially mitigated by the use of objective primary outcome measures (plantar pressure and ulcer recurrence) across the three included RCTs, the consistency of effect direction across independent RCTs conducted in different countries, and a narrative sensitivity analysis confirming robustness of findings (Risk of Bias Across Studies Section). Formal per-outcome GRADE evidence profiles were not produced; overall certainty of evidence was assessed narratively with reference to GRADE domains and is judged to be low to moderate for smart orthotics in DFU prevention and low for knee OA management, consistent with the Level 2–3 evidence base and open-label study designs. Future adequately powered, multi-site RCTs with standardised outcome reporting, minimum 24-month follow-up, and integrated health economic modelling are the highest priority to extend these preliminary findings. Registration: This review was not prospectively registered. Full article

Background: Isokinetic strength of the knee joint represents a significant determinant of athletic performance and injury prevention; however, its relationship with explosive performance in young female athletes remains insufficiently explored. The aim of the study was to analyze the relationships between isokinetic strength of the knee joint at different angular velocities and explosive jumping performance in young female athletes. Methods: The research sample consisted of 13 young female athletes enrolled in sport-oriented educational programs specializing in athletics. Explosive lower-limb power was assessed using performance tests for countermovement jump (CMJ), countermovement jump free arms (CMJ FAs) and squat jump (SJ) administered with the Chronojump system. Isokinetic strength of the knee flexors and extensors was assessed using the Humac Norm dynamometer in the concentric mode at angular velocities of 60°/s, 180°/s, and 300°/s. Peak torque, the ipsilateral H:Q ratio, and bilateral asymmetries were evaluated. Pearson’s correlation coefficient was used to analyze the relationships between the investigated parameters. Results: The strongest relationships with explosive performance were observed for hamstring strength at an angular velocity of 180°/s, where significant high correlations were identified with performance in the CMJ (r = 0.693), CMJ FA (r = 0.754), and SJ (r = 0.713). In contrast, quadriceps strength demonstrated predominantly low to moderate associations with jumping performance, while no significant correlations were confirmed at an angular velocity of 300°/s. Bilateral asymmetries of the knee extensors and flexors were generally low, ranging approximately between 7 and 10%, whereas the values of the ipsilateral H:Q ratio were within the physiological range of approximately 50–55%. Conclusions: The results suggest that the ability to generate force at higher contraction velocities, particularly in the hamstrings, is significantly associated with explosive performance in young female athletes. At the same time, isokinetic strength assessment appears to be an appropriate tool for evaluating muscular strength, muscle balance, and potential asymmetries in youth sports. However, explosive performance cannot be explained solely by the level of maximal muscular strength, but rather by a complex interaction of neuromuscular and biomechanical factors. Full article

Many older residential toilet designs may pose substantial biomechanical demands for older adults with reduced lower-extremity strength, as standard seat heights often require increased joint range of motion (ROM) and compensatory upper-limb support during sit-to-stand (STS) transfer. This exploratory, repeated-measures biomechanical study evaluated the effects of a biomimetic Stand-assist Toilet Seat (BSTS) designed to facilitate STS movement through a forward-and-upward curvilinear lifting trajectory. Thirty community-dwelling older adults were stratified into high-, moderate-, and low-functioning groups according to normative 30 s Chair Stand Test performance. Participants completed repeated STS trials under conventional and BSTS-assisted seating conditions in randomized order. A synchronized multimodal assessment integrating MediaPipe Pose-based motion tracking for sagittal-plane kinematic analysis was used to quantify lower-limb kinematics and upper-limb kinetics. Mixed-design ANOVA revealed significant main effects of seating condition on hip and knee ROM (all p < 0.001, η²p > 0.70), indicating reduced lower-limb joint motion requirements under the BSTS condition. Significant reductions were also observed in peak arm-support force (F (1,27) = 14.57, p = 0.001, η²p = 0.35) and arm-support impulse (F (1,27) = 20.21, p < 0.001, η²p = 0.42), demonstrating decreased upper-limb loading during STS transfer. No significant interaction effects between seating condition and functional group were identified. These findings suggest that the BSTS modified STS movement patterns and reduced upper-limb loading demands in community-dwelling older adults. The combined kinematic and kinetic assessment approach may provide a practical method for biomechanical evaluation of assistive seating technologies in rehabilitation and aging-related applications. Full article

Background: Walking a dog on-leash is a common activity for a large portion of our society. Many dogs consistently pull on the leash, which transmits potentially dangerous forces to the human body. The purpose of this in silico study was to determine the effects of dog-leash tension and human posture on lumbar compression, and how comparable the effects of dog walking on lumbar compression are to lifting, an activity known to contribute to low back pain. Methods: Dog-leash simulations were performed with 50–300 N directed along the arm segment of a static three-dimensional musculoskeletal model across a range of trunk segment and shoulder joint angles. Lifting simulations were performed across a range of test postures with the model holding a 50–300 N weight close to the ground. Lumbar compression was computed for each simulation using McGill’s polynomial equation and compared with the 3400 N cutoff used to develop occupational safety guidelines. Results: Lumbar compression increased as trunk segment flexion increased for all simulation conditions. With 200 N of leash tension, lumbar compression exceeded 3400 N for all postures with 25° or more of trunk segment flexion. When lifting 150 N, lumbar compression exceeded 3400 N for all postures with shank segment angle of 80° or greater and knee flexion angle of 100° or less. Conclusions: Our in silico results suggest that dog owners should seek intervention if their dog routinely pulls on the leash with a force of 200 N or greater and should attempt to lean backward when resisting leash pulling to reduce lumbar compression and injury risk. Full article

Background/Objectives: The purpose of this study was to compare differences in positive lower limb joint work contributions during the concentric phase of the countermovement jump (CMJ) at various levels of perceived effort (PE). Methods: Twenty-four recreationally active individuals (12 males: age = 23 ± 5.0 y, weight = 83.8 ± 14.5 kg, height = 1.8 ± 0.1 m; 12 females: age = 23 ± 2.0 y, weight = 62.6 ± 12.0 kg, height = 1.6 ± 0.1 m) completed fifteen CMJs while kinematic and ground reaction force data were obtained. Jump height (JH), lower limb total work (W_total), and individual ankle (%_ankle), knee (%_knee), and hip (%_hip) joint work contributions were calculated for 100% (PE₁₀₀), 75% (PE₇₅), 50% (PE₅₀), and 25% (PE₂₅) perceived effort jumps. Results: One-way repeated measures ANOVA tests (α = 0.05) indicated JH and W_total were significantly different across all perceived effort levels. The %_ankle increased significantly as PE decreased, and %_hip decreased significantly as PE decreased. The %_ankle and %_hip were not significantly different between PE₅₀ and PE₇₅ conditions, and %_knee did not differ across PE levels. Conclusions: Reducing PE altered lower limb joint work contributions during the concentric phase of the CMJ by increasing %_ankle and decreasing %_hip. In addition, decreases in PE did not correspond proportionally to reductions in JH or W_total, suggesting that effort does not map linearly onto mechanical output during the CMJ. Full article

Preliminary estimation of lower-limb motor function is important in rehabilitation research, especially for biomechanical assessment of post-stroke hemiplegic gait. However, subject-specific musculoskeletal modeling in this population is challenging because standard maximum voluntary contraction (MVC) testing is often unsafe or unreliable for normalizing surface electromyography (sEMG) signals. To address this limitation, a normalized correction coefficient was introduced for pathological sEMG preprocessing, and an improved Hill-type muscle model (iHMM) was established to account for submaximal activation conditions. By combining inverse dynamics, static optimization, and a subject-specific lower-limb dynamic model, the proposed framework was used to estimate musculotendon force, knee joint torque, knee joint kinematics, and shank center-of-mass trajectory. In a preliminary validation involving six hemiplegic subjects, the predicted knee joint torques showed moderate to good agreement with the reference results, with correlation coefficients ranging from 0.724 to 0.807 and RMSE values ranging from 3.872 to 7.814 Nm. These preliminary results support the feasibility of the proposed framework for subject-specific biomechanical analysis of the hemiplegic lower extremity and suggest its potential utility in individualized rehabilitation assessment. Full article

Emergency responders face a high risk of musculoskeletal disorders (MSDs), particularly lower back injuries, due to frequent patient-handling tasks performed in awkward and dynamic postures. This aim of study is to utilize dual motion capture systems integrated with a digital human modeling (DHM) ergonomics tool to evaluate the biomechanical effects of two common two-person carrying techniques: facing forward and facing each other. Twenty-two participants lifted a 25 kg mannequin while wearing Xsens motion sensors, and lumbar forces and joint angles were analyzed using Siemens Jack software (v9.0). Peak compressive and anterior–posterior (AP) shear forces, along with trunk, hip, and knee joint angles, were examined. Compressive forces ranged from approximately 948.6 to 2955.6 N, and AP shear forces ranged from 286.0 to 827.0 N. Mean compressive and AP shear forces were higher during the facing-each-other task (1977.3 N and 595.0 N) than during the facing-forward task (1596.0 N and 462.0 N). Males experienced higher spinal loads than females across both tasks. The facing-each-other technique was associated with greater hip flexion, lower knee flexion, and reduced trunk flexion, whereas the facing-forward technique resulted in less hip flexion, greater knee flexion, and greater trunk flexion. Overall, under the conditions of the present study, the facing-forward technique was associated with lower lumbar loading indicators. Integrating motion capture with DHM offers a valuable approach for evaluating realistic rescue tasks and can inform ergonomic training strategies for emergency responders. Full article

This study aimed to estimate vertical ground reaction force (vGRF) and lower-limb joint moments during football cutting movements using a trunk-mounted inertial measurement unit (IMU) combined with a Random Forest model, and to validate the feasibility of this approach. IMU data collected during 45° cutting tasks were corrected using an Extended Kalman Filter (EKF). The model demonstrated good and consistent performance for vGRF (coefficient of determination, R² = 0.766; correlation coefficient, r = 0.796) and sagittal plane moments of the ankle and knee (R² = 0.661–0.689, r = 0.807–0.842). While Bland–Altman analysis indicated low bias and generally good agreement, precision at the individual-trial level and accuracy for non-sagittal plane moments somewhat reflected the inherent within-player trial-to-trial variability in movement execution, particularly in non-sagittal loading patterns. It should be noted that performance estimates under the current trial-based validation design may differ from those obtained using a subject-independent framework such as leave-one-subject-out cross-validation. This study demonstrates that a single trunk-mounted IMU can reliably estimate key lower-limb loading patterns, providing a practical foundation for wearable-based kinetic monitoring in applied football settings. Full article

Anterior cruciate ligament (ACL) injury risk is elevated in female youth football, yet knee joint loading has mainly been studied under controlled laboratory conditions. This limits understanding of how injury risk emerges during realistic match situations. This study provided a field-based kinetic characterization of football-specific movements by estimating knee abduction moments (KAMs) using wearable sensors and machine learning. Fifty-two highly talented female youth players performed agility tasks during training, including structured exercises (F-EX) and game-based play (F-GAME). Full-body kinematics were collected with inertial measurement units, and a validated support vector machine model, trained on synchronized motion capture and force plate data, classified trials as high or low KAM. Across 662 change-in-direction trials, 9–12% were classified as high KAM in both conditions, indicating that potentially high-risk loading regularly occurs during routine actions. High KAM trials showed reduced knee and pelvis flexion, increased hip flexion, and greater pelvis rotation toward the cutting direction, reflecting upright, stiff movement strategies. Performance analyses revealed smaller cut angles in exercises and greater approach acceleration in game play, without differences in peak velocity. These findings demonstrate the feasibility of field-based kinetic screening and support a complex-systems perspective on ACL injury risk. Full article

The purpose of this study was to compare knee joint biomechanical characteristics and movement strategies according to the direction of the forward lunge in badminton and to provide practical insights for training and injury prevention. Eighteen female recreational badminton players performed forward lunges in three directions: center (CFL), left (LFL), and right (RFL). Knee joint angles and moments, center of mass (COM) velocity, ground reaction forces (GRF), and knee extensor and flexor muscle forces were analyzed. In addition, continuous biomechanical variables were examined using statistical non-parametric mapping (SnPM). The results showed that LFL demonstrated the fastest approach COM velocity and greater knee flexion moments at initial contact, along with the greatest knee flexor muscle force, which may be indicative of enhanced joint stabilization demand. RFL exhibited a smaller knee flexion angle and lower vertical ground reaction force but showed the greatest posterior braking force and the fastest recovery COM velocity, which may be indicative of greater movement efficiency. CFL showed significantly greater knee adduction angles and internal rotation moments, suggesting elevated rotational loading at the knee that may be associated with increased injury risk. These findings highlight direction-specific knee joint biomechanical characteristics during badminton forward lunges and may provide useful information for developing targeted training and injury prevention approaches. Full article

Background: Work-related musculoskeletal disorders (WMSDs) are prevalent among orthopaedic surgeons as a result of prolonged exposure to non-neutral postures and forceful manual tasks during surgery. Although working height is a key determinant of trunk and upper-limb posture, the systematic evaluation of ergonomic working-height recommendations in orthopaedic surgery remains limited. Methods: A simulated left total knee arthroplasty (TKA) was divided into twelve critical surgical steps and analysed across four commonly used surgeon positions (A–D). Two conditions were compared: uncorrected working height (N) and working height corrected according to Canadian Centre for Occupational Health and Safety (CCOHS) recommendations (C). Joint angles were measured from standardized photographs using Kinovea software, and postural load was quantified with the Rapid Entire Body Assessment (REBA) method. Two trained evaluators conducted three independent assessments, yielding 288 REBA scores. Results: Mean REBA scores decreased across all surgeon positions following ergonomic correction, with statistically significant reductions observed in positions A, B, and D. When pooled across all position–step combinations (n = 48), the mean reduction was 0.92 REBA points (95% CI 0.50–1.33; p < 0.001). Notably, 27 of the 48 position–step comparisons exceeded the minimal detectable change threshold. The largest reductions occurred during force-intensive surgical steps, including bone cutting, drilling, and implant impaction. Conclusions: Adjusting working height in accordance with CCOHS ergonomic recommendations reduces surgeons’ postural load during TKA. These findings support the integration of evidence-based ergonomic adjustments into routine orthopaedic surgical practice. Full article

Background: Supported standing is widely used in children and adolescents with severe cerebral palsy (CP) as part of rehabilitation programs aimed at maintaining musculoskeletal health and enabling participation. Despite its frequent clinical use, quantitative biomechanical evidence describing knee joint loading under different positioning conditions remains limited, particularly in individuals classified as GMFCS IV–V. The primary objective of this study was to quantify knee joint loading during supported standing across predefined combinations of verticalization angle and hip/knee flexion. The secondary objective was to investigate interaction effects between these variables and to assess whether increasing hip/knee flexion is associated with a linear reduction in knee joint loading. Methods: Twenty-six children and adolescents with CP (GMFCS IV–V; age 6–17 years) participated in the study. Measurements were performed using a standardized back-supported standing device. Knee joint loading was measured using integrated pressure sensors across six verticalization angles (0°, 30°, 45°, 60°, 75°, 90°) combined with four hip/knee flexion angles (0°, 15°, 30°, 45°). Forces were normalized to body weight (%BW). Statistical analysis was performed using repeated-measures analysis of variance. Results: Knee joint loading increased consistently with greater verticalization across all tested hip/knee flexion conditions (p < 0.001). A non-linear pattern was observed across flexion angles. Interaction effects between verticalization and hip/knee flexion were observed. Knee joint loading did not decrease linearly with increasing flexion; instead, the lowest loading was observed at approximately 15° hip/knee flexion, whereas both full extension and 45° flexion resulted in higher loads. Conclusions: Verticalization angle represents a key factor influencing knee joint loading during supported standing in children and adolescents with severe CP. Knee joint loading increases with greater verticalization, while hip/knee position shows a non-linear influence. The absence of a linear reduction in loading with increasing flexion highlights the presence of interaction effects between positioning variables and supports individualized positioning strategies in supported standing programs. Full article

To investigate how knee joint protector design affects the biomechanical characteristics of knee motion under various activities, this pilot study (n = 5) examined how knee joint protector design modulates knee biomechanics across walking, jogging, squatting, and sit-to-stand tasks using optical motion capture and AnyBody musculoskeletal modeling (FullBody_GRFPrediction). We quantified knee flexion kinematics, model-estimated joint reaction forces and moments, and model-estimated muscle activity of eight lower-limb muscles under four conditions with different levels of structural constraint: no protector (Pro.off), a conventional sleeve-type protector (Pro.a), a segmented support protector (Pro.b), and a wrapping fixation protector (Pro.c). The biomechanical protective performance of the knee joint protector was task- and phase-dependent. The results showed that Pro.a optimized muscle activation. Pro.b increased sagittal-plane design but increased joint loading and muscle activity. Pro.c induced noticeable distal compensation along the kinetic chain. The findings revealed that protector effects were task-dependent. Dynamic tasks mainly affected coronal-plane stability parameters, whereas quasi-static tasks more clearly altered sagittal load distribution. In this study, biomechanical protective performance is defined as reduced knee joint loading without disproportionate increases in model-estimated muscle activity or excessive loss of functional knee flexion range. Under this definition, greater structural constraint did not consistently produce a more favorable biomechanical profile. These results provide a feasibility baseline for task-specific protector evaluation and motivate confirmatory studies with larger cohorts and experimental validation. This study provides theoretical and methodological insights to guide future design and optimization of knee joint protectors. Full article

This paper studies a MuJoCo-based locomotion framework that couples an adaptive-frequency central pattern generator (AFCO-CPG) with single rigid-body dynamics model predictive control (MPC) for the RENS Q1 quadruped with elastic parallel knee joints. AFCO-CPG combines multi-scale phase coordination, saturated phase correction, and load-gated feedback, while MPC supplies feasible ground-reaction forces and returns load cues to the timing layer. In MuJoCo, the controller achieves stable diagonal-trot speed tracking from 0.4 to 1.2 m/s and recovers from short external pushes. A matched elastic-versus-rigid timing sweep shows a favorable flat-ground parameter band around $\omega =1.8$ Hz, with a best-case cost-of-transport reduction of 12.83% for the elastic model under identical controller gains. A flat-to-slope ascent case further verifies that AFCO timing is modulated when load conditions change. Ablation across nine controller variants shows that multi-scale coordination is the dominant component, causing a 135% increase in phase error and a 536% increase in recovery time when removed. A reduced-order early/late-contact benchmark further confirms faster re-locking than diagonal-only and minimal variants. The results support the value of combining neural timing, predictive force optimization, and compliant-leg feedback in high-fidelity simulation, while hardware validation remains future work. Full article

(1) Achilles tendon rupture is one of the most severe lower-limb injuries, frequently occurring during movements involving maximal dorsiflexion with the knee at near-full extension. Preventive strategies are crucial, particularly for athletes engaged in high-risk sports such as basketball. (2) In this work, we examined the effect of a novel Achilles brace on Achilles tendon loading during concentric and eccentric mechanisms associated with tendon rupture. (3) Twenty-eight young basketball players performed tests under two conditions: with the adaptive brace and without it (control). Participants were divided into two groups (n = 14 in both). The first group assessed concentric Achilles loading by performing three plantar-flexor strength tests in three different joint configurations: maximal dorsiflexion with the knee flexed (FKF); injury mechanism position—full plantar flexion with the knee extended (FKE); and neutral ankle position with the knee extended (NKE). The number of maximal heel-raise repetitions performed before onset of fatigue was recorded. The second group assessed eccentric tendon loading by performing single-leg forced maximal-velocity dorsiflexion with the knee extended. In all tests, the time between maximal plantar flexion and maximal dorsiflexion, as well as the ankle range of motion, was analyzed using 2D video. Paired t-tests were used to compare braced and control conditions. In all tests, the ankle range of motion (ROM) did not differ significantly between brace and control conditions. Wearing the brace significantly improved plantar-flexor muscle strength only in the FKE test (31 ± 1.3 repetitions with brace vs. 21 ± 1.3 in control, p < 0.05). No significant differences were found for the FKF (27 ± 1.3 vs. 25 ± 1.3) or NKE (25 ± 1.3 vs. 24 ± 1.3) positions. During drop eccentric loading, wearing the brace resulted in a significantly slower transition time from plantar flexion to dorsiflexion (460 ± 60 ms with brace vs. 320 ± 30 ms in control, p < 0.001). (4) In brief, the novel Achilles brace was found to significantly reduces Achilles tendon load during both concentric and eccentric activities, but only in high-risk joint positions. These findings suggest that the brace provides mechanical protection, and may reduce the risk of Achilles tendon rupture, in athletes exposed to high tendon stress. Full article