Commingling Effects of Anterior Load and Walking Surface on Dynamic Gait Stability in Young Adults.

Treadmill walking has been used as a surrogate for overground walking to examine how load carriage affects gait. The validity of using treadmill walking to investigate load carriage's effects on stability has not been established. Thirty young adults were randomized into 3 front-loaded groups (group 1: 0%, 2: 10%, or 3: 20% of bodyweight). Participants carried their load during overground and treadmill walking. Dynamic gait stability (primary outcome) was determined for 2 gait events (touchdown and liftoff). Secondary variables included step length, gait speed, and trunk angle. Groups 1 and 2 demonstrated similar stability between walking surfaces. Group 3 was less stable during treadmill walking than overground (P ≤ .005). Besides trunk angle, all secondary outcomes were similar between groups (P > .272) but different between surfaces (P ≤ .001). The trunk angle at both events showed significant group- and surface-related differences (P ≤ .046). Results suggested that walking with an anterior load of up to 10% bodyweight causes comparable stability between surfaces. A 20% bodyweight front load could render participants less stable on the treadmill than overground. This indicates that anteriorly loaded treadmill walking may not be interchangeable with overground walking concerning stability for anterior loads of 20% bodyweight.

Walk with Me Hybrid Virtual/In-Person Walking for Older Adults with Neurodegenerative Disease.

This study presents a protocol for virtual and in-person walking groups for older adults with neurodegenerative diseases and addresses the decline in physical activity and social connectivity during the pandemic. Physical activity, specifically moderate-intensity walking, has been shown to have multiple health benefits for older adults. This methodology was created during the COVID-19 pandemic, contributing to lower physical activity levels and social isolation in older adults. Both the in-person and virtual classes utilize technology such as fitness tracking apps and video platforms. Data are presented from two groups of older adults with neurodegenerative disease: people with prodromal Alzheimer's disease and people with Parkinson's disease. Participants in the virtual classes were screened for balance impairments before the walk, and any person deemed at risk for falls was not eligible to participate virtually. As COVID vaccines became available and restrictions were lifted, in-person walking groups became feasible. Staff and caregivers were trained in balance management, roles/responsibilities, and delivering walking cues. Both walks, virtual and in-person, consisted of a warm up, a walk, and a cool down, and posture, gait, and safety cues were given throughout. Measures of the rate of perceived exertion (RPE) and heart rate (HR) were taken pre-warm up, post-warm up, and at 15 min, 30 min, and 45 min time points. Participants also used a walking application (app) on their phones to record the distance walked and the number of steps taken. The study showed a positive correlation between HR and RPE in both groups. The participants in the virtual group rated the walking group favorably in terms of improving their quality of life during a period of social isolation and contributing to physical, mental, and emotional well-being. The methodology shows a safe and feasible way to implement virtual and in-person walking groups for older adults with neurological diseases.

The Triple Step in Recreational Swing Dancers: A Kinematic Analysis.

Swing dancing is gaining popularity, yet our biomechanical understanding of swing dance remains poor, creating barriers to the development of training protocols and evaluation of performances. This study aimed to determine whether dancing with or without a partner affects the lower extremity kinematics of the triple step, and if the kinematics differ among the three steps of the dance element. Eight recreational swing dancers completed three sets of rightward triple steps with and without a partner. The angles in the sagittal, frontal and transverse planes were determined for bilateral lower limb joints and pelvis based on the kinematics collected by a motion capture system. Results illustrated that dancing with a partner has a significant effect on the angular kinematics of the lower extremity and pelvis. Dancers showed more restricted motion at the knee and hip in the sagittal and frontal planes when dancing with a partner. Additionally, differences were observed among the steps with most differences occurring between steps one and two and steps two and three in all three planes. These findings expand our knowledge of swing dancing biomechanics, possibly informing the design of future studies that will further expand our understanding of swing dancing.

A kinetic analysis of the triple step in recreational swing dancers.

Despite its increasing popularity, swing dancing has not been fully studied biomechanically, imposing challenges in understanding the movement patterns associated with swing dancing. The purpose of this study was to examine the biomechanics of the triple step, one of the most common swing dance elements. We intended to determine whether dancing with a partner affects kinetic measurements and if these measurements are different among the three steps. Eight recreational swing dancers completed three triple steps to the right and the left with and without a partner. The loading rate of the vertical ground reaction force was calculated for each step, and bilateral lower limb joints moments and powers were determined. Results illustrated that dancing with or without a partner has limited effect on the kinetic measurements. However, the outcome measurements differed among the steps: a higher peak vertical ground reaction force during the first and second steps, a greater loading rate during the second step, and the greatest joint power absorption at the ankle and knee during the second step were observed. The findings extend our understanding of the biomechanics of swing dancing, and could provide preliminary guidance for understanding swing dance-related injuries and improving performance of swing dancing.

Deep Brain Stimulation Impedance Decreases Over Time Even When Stimulation Settings Are Held Constant.

Objectives: To study whether and to what extent the therapeutic impedance and current change under long-term deep brain stimulation (DBS) with constant stimulation settings, which could inform the role of constant current stimulation. Methods: Therapy impedance and current measurements were retrospectively collected from patients with Parkinson's disease (PD) undergoing DBS of the subthalamic nucleus (STN) or essential tremor (ET) undergoing ventral intermediate nucleus (VIM). Baseline and follow-up measurements were obtained for intervals of at least 6 months without changes in stimulation settings. The single longest interval of constant stimulation for each electrode was included. Temporal trends in impedance and current were analyzed as absolute and relative differences and as the rate of change. Results: Impedance and current data from 79 electrodes (60 in STN, 19 in VIM) in 44 patients (32 with PD, 12 with ET) met inclusion criteria. The duration between baseline and follow-up measurements with constant stimulation settings was 17 months (median, with an interquartile range of 12-26 months) in the mixed group. Therapy impedance decreased by 27 ± 12 Ω/year (mean ± 2 standard errors; p < 0.0001), and therapy current increased at a rate of 0.142 ± 0.063 mA/year (p < 0.0001). Similar results were observed in the STN and VIM subgroups. Conclusions: Impedance decreases gradually over time, even when stimulation settings are kept constant. The rate of decrease is smaller than previously reported, suggesting that changes in stimulation settings contribute to impedance drift. Stimulation-independent impedance drift is gradual but relevant to constant-current programming.

Effect of downhill running grade on lower extremity loading in female distance runners.

Hill running is often used as a foundational training mechanism to build strength and speed. Distance runners in particular are at an increased likelihood of encountering steep hills during training runs. There is limited research regarding downhill running, and there is no research available on the biomechanics of females specifically during downhill running. The purpose of this study was to quantify the differences in loading when running downhill at different grades compared to a level surface in female distance runners to determine the potential risk for injury. Fifteen female distance runners (age: 23.5 ± 4.9 y), who ran 56.3 ± 20.9 km a week participated in this study. Participants ran on a force-instrumented treadmill at 4.0 m/s for 2 min at 0%, -5%, -10%, -15%, and -20% grades, with 5 min of rest between conditions. Study findings showed increased impact forces (p < 0.001), and increased loading rates (p < 0.001) with increasing downhill grades compared to level. These results indicate a significantly greater risk of overuse injury to the lower extremity with steeper downhill grades. Individuals need to be aware of these risks to plan and implement training programmes that will increase performance while minimising injury risk.