Curvilinear walking elevates fall risk and modulates slip and compensatory step attributes after unconstrained human slips.

While much attention has been paid to understanding slip-related falls in humans, little has been focused on curvilinear paths despite their prevalence, distinct biomechanical demands and increased slipping threat. We determined the mechanics, compensatory stepping reactions and fall risk associated with slips during fixed-speed walking across ranges of path curvature, slipped foot and slip onset phase contexts possible in the community, which builds upon previous work by examining speed-independent effects of curvilinear walking. Twenty-one participants experienced 15 unconstrained slips induced by a wearable friction-reducing device as motion capture and harness load cell data were recorded. Falls were most likely after early stance slips to the inside foot and increased at tighter curvatures. Slip distance and peak velocity decreased as slips began later in stance phase, did not differ between feet, and accelerated on tighter paths. Slipping foot directions relative to heading transitioned from anterior (forward) to posterior (backward) as slips began later in stance, were ipsilateral (toward the slipping foot side) and contralateral (toward the opposite side) for the outside and inside foot, respectively, and became increasingly ipsilateral/contralateral on tighter curvatures. Compensatory steps were placed anteriorly and ipsilaterally after outside and inside foot slips, respectively, and lengthened at later onset phases for outside foot slips only. Our findings illustrate slip magnitude and fall risk relationships that suggest slip direction may influence the balance threat posed by a slip, imply that walking speed may modify slip likelihood, and indicate the most destabilizing curved walking contexts to target in future perturbation-based balance training approaches.

Assessing the Acceptability and Effectiveness of a Novel Therapeutic Footwear in Reducing Foot Pain and Improving Function among Older Adults: A Crossover Randomized Controlled Trial.

INTRODUCTION: Nearly, a quarter of older adults suffer from frequent foot pain, impacting their quality of life. While proper footwear can alleviate this, design issues often hinder regular use. This study evaluated novel therapeutic footwear, designed for aesthetics and custom fit, to reduce foot pain. We hypothesized that older adults would experience less foot pain and favor the new footwear over their own. METHODS: This 12-week crossover randomized controlled trial evaluated the effectiveness of OrthoFeet therapeutic footwear on reducing foot pain in older adults (n = 50, age = 65 ± 5, 18% male) with moderate to severe pain. Participants were assigned to either the AB or BA sequence. In AB, they wore OrthoFeet shoes for 6 weeks and then their own shoes for another 6 weeks; BA followed the reverse order. Pain and function were measured using the Foot Function Index. Acceptability was assessed through a technology acceptance model (TAM) questionnaire. Data collected at baseline, six, and 12 weeks were analyzed using t tests, χ2 tests, and generalized linear model. RESULTS: Compared to participants' own shoes, OrthoFeet shoes significantly reduced foot pain and disability. Notable improvements were observed in "foot pain at its worst," "foot pain at the end of the day," "overall pain score," and "overall Foot Function Index score," all showing statistically significant reductions (p < 0.050). Participants reported high adherence to wearing the OrthoFeet shoes, averaging 8 h per day and 5.8 days per week. TAM scores favored OrthoFeet shoes over participants' own shoes in terms of ease of use, perceived benefit, and intention to recommend. Significant differences were noted in components representing perceived joint pain relief (p < 0.001, χ2 = 21.228) and the intention of use as determined by the likelihood of recommending the shoes to a friend with a similar condition (p < 0.001, χ2 = 29.465). Additionally, a majority of participants valued the appearance of the shoes, with 66% prioritizing shoe appearance and 96% finding the study shoes more stylish than their previous ones. CONCLUSION: This study underscores the significance of design and custom fit in promoting continuous wear for effective foot pain reduction in older adults. More research is needed on the intervention's long-term impacts.

Objective assessment of postural ergonomics in neurosurgery: integrating wearable technology in the operating room.

OBJECTIVE: Physical stress associated with the static posture of neurosurgeons over prolonged periods can result in fatigue and musculoskeletal disorders. Objective assessment of surgical ergonomics may contribute to postural awareness and prevent further complications. This pilot study examined the feasibility of using wearable technology as a biofeedback tool to address this gap. METHODS: Ten neurosurgeons, including 5 attendings (all faculty) and 5 trainees (1 fellow, 4 residents), were recruited and equipped with two wearable sensors attached to the back of their head and their upper back. The sensors collected the average time spent in extended (≤ -10°), neutral (> -10° and < 10°), and flexed (≥ 10°) static postures (undetected activity for more than 10 seconds) during spine and cranial procedures. Feasibility outcomes aimed for more than 70% of accurate data collection. Exploratory outcomes included the comparison of postural variability within and between participants adjusted to their demographics excluding nonrelated surgical activities, and postoperative self-assessment surveys. RESULTS: Sixteen (80%) of 20 possible recordings were successfully collected and analyzed from 11 procedures (8 spine, 3 cranial). Surgeons maintained a static posture during 52.7% of the active surgical time (mean 1.58 hrs). During spine procedures, all surgeons used an exoscope while standing, leading to a significantly longer time spent in a neutral static posture (p < 0.001, partial η2 = 0.14): attendings remained longer in a neutral static posture (36.4% ± 15.3%) than in the extended (9% ± 6.3%) and flexed (5.7% ± 3.4%) static postures; trainees also remained longer in a neutral static posture (30.2% ± 13.8%) than in the extended (11.1% ± 6.3%) and flexed (11.9% ± 6.6%) static postures. During cranial procedures, surgeons intermittently transitioned between standing/exoscope use and sitting/microscope use, with trainees spending a shorter time in a neutral static posture (16.3% vs 48.5%, p < 0.001) and a longer time in a flexed static posture (18.5% vs 2.7%, p < 0.001) compared with attendings. Additionally, longer cranial procedures correlated with surgeons spending a longer time (r = 0.94) in any static posture (extended, flexed, and neutral), with taller surgeons exhibiting longer periods in flexed and extended static postures (r = 0.86). Postoperative self-assessment revealed that attendings perceived spine procedures as more difficult than trainees (p = 0.029), while trainees found cranial procedures to be of greater difficulty than spine procedures (p = 0.012). Attendings felt more stressed (p = 0.048), less calmed (p = 0.024), less relaxed (p = 0.048), and experienced greater stiffness in their upper body (p = 0.048) and more shoulder pain (p = 0.024) during cranial versus spine procedures. CONCLUSIONS: Wearable technology is feasible to assess postural ergonomics and provide objective biofeedback to neurosurgeons during spine and cranial procedures. This study showed reproducibility for future comparative protocols focused on correcting posture and surgical ergonomic education.

Severity of Unconstrained Simultaneous Bilateral Slips: The Impact of Frontal Plane Feet Velocities Relative to the Center of Mass to Classify Slip-Related Falls and Recoveries.

Targeted interventions to prevent slip-related falls may be informed by specific kinematic factors measured during the reactive response that accurately discriminate recoveries from falls. But reactive responses to diverse slipping conditions during unconstrained simultaneous bilateral slips, which are closely related to real-world slips, are currently unknown. It is challenging to identify these critical kinematic factors due to the wide variety of upper and lower body postural deviations that occur following the slip, which affect stability in both the sagittal and frontal planes. To explore the utility of kinematic measurements from each vertical plane to discriminate slip-related falls from recoveries, we compared the accuracy of four Linear Discriminant Analysis models informed by predetermined sagittal or frontal plane measurements from the lower body (feet velocities relative to the center of mass) or upper body (angular momentum of trunk and arms) during reactive responses after slip initiation. Unconstrained bilateral slips during over-ground walking were repeatedly administered using a wearable device to 10 younger (24.7 ± 3.2 years) and 10 older (72.4 ± 3.9 years) adults while whole-body kinematics were measured using motion capture. Falls (n = 20) and recoveries (n = 40) were classified by thresholding the dynamic tension forces measured in an overhead harness support system and verified through video observation. Frontal plane measurements of the peak feet velocities relative to the center of mass provided the best classification (classification accuracy = 73.3%), followed by sagittal plane measurements (classification accuracy = 68.3%). Measurements from the lower body resulted in higher accuracy models than those from the upper body, but the accuracy of all models was generally low compared to the null accuracy of 66.7% (i.e., predicting all trials as recoveries). Future work should investigate novel models that include potential interactions between kinematic factors. The performance of lower limb kinematics in the frontal plane in classifying slip-related falls demonstrates the importance of administering unconstrained slips and measuring kinematics outside the sagittal plane.

Comparing single and multi-joint methods to detect knee joint proprioception deficits post primary unilateral total knee arthroplasty.

BACKGROUND: The use of various single-joint proprioception measurements has resulted in contradictory findings after knee arthroplasty. The use of balance as a surrogate measure to assess knee proprioception post-operation has resulted in further confusion. The aim of this study was to measure single joint knee proprioception in participants after unilateral knee arthroplasty, and compares it to multi-joint balance. METHODS: Eleven participants at 1 year after unilateral total knee arthroplasty and twelve age-matched controls were enrolled. The threshold to detect passive motion and the sensory organization test were used to measure single joint knee proprioception and multi-joint balance respectively. Two-way ANOVA and independent t-tests were used to measure differences between and within groups. Regression analysis was used to measure the association between proprioception and balance measurements. FINDINGS: Surgical knees demonstrated significantly more deficient proprioception compared to the non-surgical knees and both knees of the control groups during flexion (P < 0.01) and extension (P < 0.05). Non-surgical knees showed similar proprioception to both knees of the control group during flexion and extension. Within the knee arthroplasty group, only deficiencies during flexion showed significant correlation with Sensory Organization Test visual ratio. No additional differences between both groups during balance measurements, nor any correlations between local joint proprioception and balance were seen. INTERPRETATION: These findings indicate deficient surgical knee proprioception in participants one year after unilateral total knee arthroplasty. Limited associations between measurements indicate that balance may be a poor measure of single-joint proprioception.