As age increases, a decline in lower extremity strength leads to reduced mobility and increased fall risks. This decline outpaces the age-related reduction in muscle mass, resulting in mobility limitations. Older adults with varying degrees of mobility-disability use different stepping strategies. However, the link between functional lower extremity strength and stepping strategy is unknown. Therefore, understanding how age-related reductions in functional lower extremity strength influence stepping strategy is vital to unraveling mobility limitations. Participants were recruited and tested at a local community event, where they were outfitted with IMUs and walked across a pressurized walkway. Our study reveals that older adults with normal strength prefer adjusting their step time during walking tasks, while those with reduced strength do not exhibit a preferred stepping strategy. This study provides valuable insights into the influence of functional lower extremity strength on stepping strategy in community-dwelling older adults during simple and complex walking tasks. These findings could aid in diagnosing gait deviations and developing appropriate treatment or management plans for mobility disability in older adults.
Conventional Parkinson's disease (PD) deep brain stimulation (DBS) utilizes a pulse with an active phase and a passive charge-balancing phase. A pulse-shaping strategy that eliminates the passive phase may be a promising approach to addressing movement disorders. The current study assessed the safety and tolerability of square biphasic pulse shaping (sqBIP) DBS for use in PD. This small pilot safety and tolerability study compared sqBiP versus conventional DBS. Nine were enrolled. The safety and tolerability were assessed over a 3-h period on sqBiP. Friedman's test compared blinded assessments at baseline, washout, and 30 min, 1 h, 2 h, and 3 h post sqBIP. Biphasic pulses were safe and well tolerated by all participants. SqBiP performed as well as conventional DBS without significant differences in motor scores nor accelerometer or gait measures. Biphasic pulses were well-tolerated and provided similar benefit to conventional DBS. Further studies should address effectiveness of sqBIP in select PD patients.
Individuals with an anterior cruciate ligament reconstruction (ACLR) commonly exhibit altered gait patterns, potentially contributing to an increased risk of osteoarthritis (OA). Joint moment contributions (JMCs) and support moments during incline and decline running are unknown in healthy young adults and individuals with an ACLR. Understanding these conditional joint-level changes could explain the increased incidence of OA that develops in the long term. Therefore, this knowledge may provide insight into the rehabilitation and prevention of OA development. We aimed to identify the interlimb and between-group differences in peak support moments and subsequent peak ankle, knee, and hip JMCs between individuals with an ACLR and matched controls during different sloped running conditions. A total of 17 individuals with unilateral ACLR and 17 healthy individuals who were matched based on sex, height, and mass participated in this study. The participants ran on an instrumented treadmill at an incline of 4°, decline of 4°, incline of 10°, and decline of 10°. The last 10 strides of each condition were used to compare the whole-stance phase support moments and JMCs between limbs, ACLR, and control groups and across conditions. No differences in JMCs were identified between limbs or between the ACLR and healthy control groups across all conditions. Support moments did not change among the different sloped conditions, but JMCs significantly changed. Specifically, ankle and knee JMCs decreased and increased by 30% and 33% from an incline of 10° to a decline of 10° running. Here, the lower extremities can redistribute mechanics across the ankle, knee, and hip while maintaining consistent support moments during incline and decline running. Our data provide evidence that those with an ACLR do not exhibit significant alterations in joint contributions while running on sloped conditions compared to the matched controls. Our findings inform future research interested in understanding the relationship between sloped running mechanics and the incidence of deleterious acute or chronic problems in people with an ACLR.
Background: Essential tremor (ET) is a common movement disorder characterized by kinetic and postural tremor in the upper extremities and frequently in the midline. Persons with ET often also exhibit gait ataxia. Previous studies have observed associations between midline tremor severity and gait ataxia in persons with ET, suggesting a common pathophysiology distinct from that of upper extremity tremor. However, a causal link between midline tremor and gait impairment has not been established. Methods: We investigated tremor and gait in 24 persons with ET before and after implantation of unilateral deep brain stimulation into the ventralis intermedius nucleus of the thalamus. Results: Stimulation significantly improved tremor in the targeted upper extremity and midline. However, gait was unaffected at the cohort level. Furthermore, improvement in midline tremor was not significantly associated with gait improvement. Discussion: These findings revealed that midline tremor and gait impairment may be dissociable in persons with ET.
PURPOSE: To compare joint moment contributions at the knee, ankle, and hip during flat, incline, and decline walking between limbs in individuals with ACL reconstructed (ACLR). METHODS: We analyzed 8 participants with ACLR. Each participant walked flat, uphill, and downhill at 0, 10, and -10 degrees with pre-determined speeds (1.3 m/s, 1.0 m/s, 1.0 m/s). Kinematic and kinetic data were collected during the final 30 seconds of each condition using 17 cameras (Vicon) and an instrumented split-belt treadmill (Bertec). Joint moment contributions at the hip, knee, and ankle were determined by dividing the peak sagittal joint moments by the sum of all three peak moments during stance. A 2x3 (limbxcondition) ANOVA was implemented to evaluate interlimb differences across conditions, with post-hoc bonferroni adjustments. RESULTS: No significant main effect of limb or limbxcondition interaction was found. Hip contributions were 13% greater during incline walking (28% contribution) compared to decline (15% contribution). During decline walking (57% contribution) knee contributions were 42% greater compared to incline (15% contribution) and 41% greater compared to flat walking (16% contribution. During flat walking (54% contributions) ankle contributions were 27% greater compared to decline (27% contributions) and 30% greater during incline walking (57% contributions) compared to decline. CONCLUSIONS: These results suggest that individuals with ACLR are capable of maintaining lower extremity joint symmetry with respect to walking at an incline and decline. Future studies will investigate differences in lower extremity joint contributions between individuals with ACLR and a healthy, age-matched control group.
The primary purpose of this study was to examine how the type and magnitude of changes in running behavior, as a consequence of COVID-19 pandemic restrictions, influence running-related injuries. Secondarily, we aimed to examine how lifestyle and psychosocial well-being measures may influence running behavior change. An online survey was advertised to individuals over the age of 18 that currently run or have previously participated in running for exercise. The survey questions examined injury history and new injuries sustained during COVID-19 restrictions, as well as changes related to training behavior changes, training environment changes, social behaviors, and psychosocial well-being. Changes reflected differences in running behaviors prior to COVID-19 restrictions (1 month prior to COVID-19 restrictions being imposed) and during COVID-19 restrictions (May 5 to June 10, 2020). A total of 1,035 runners were included in the analysis. Current injuries sustained during COVID-19 occurred in 9.5% of the runners. Injured runners made a greater number of total changes (
Despite the strong implications for rehabilitation design, the capability of individuals with anterior cruciate ligament reconstruction (ACLR) to adapt and store novel gait patterns have not been well studied.To investigate how reconstructive surgery may affect the ability to adapt and store novel gait patterns in persons with ACLR while walking on a split-belt treadmill.Controlled laboratory study.Gait adaptation was compared between 20 participants with ACLR and 20 healthy controls during split-belt treadmill walking. Gait adaptation was assessed in slow- and fast-adapting parameters by (1) the magnitude of symmetry during late adaptation and (2) the amount of the asymmetry during de-adaptation.Healthy individuals adapted a new walking pattern and stored the new walking pattern equally in both the dominant and nondominant limbs. Conversely, individuals with ACLR displayed impairments in both slow-adapting and fast-adapting derived gait adaptation and significant differences in behavior between the reconstructed and uninjured limb.While surgical reconstruction and physical therapy are aimed at improving mechanical stability to the knee, the study data suggest that fundamental features of motor control remain altered. After ACLR, participants display an altered ability to learn and store functional gait patterns.
Split-belt treadmill walking allows researchers to understand how new gait patterns are acquired. Initially, the belts move at two different speeds, inducing asymmetric step lengths. As people adapt their gait on a split-belt treadmill, left and right step lengths become more symmetric over time. Upon returning to normal walking, step lengths become asymmetric in the opposite direction, indicating deadaptation. Then, upon re-exposure to the split belts, step length asymmetry is less than the asymmetry at the start of the initial exposure, indicating readaptation. Changes in step length symmetry are driven by changes in step timing and step position asymmetry. It is critical to understand what factors can promote step timing and position adaptation and therefore influence step length asymmetry. There is limited research regarding the role of visual feedback to improve gait adaptation. Using visual feedback to promote the adaptation of step timing or position may be useful of understanding temporal or spatial gait impairments. We measured gait adaptation, deadaptation, and readaptation in twenty-nine healthy young adults while they walked on a split-belt treadmill. One group received no feedback while adapting; one group received asymmetric real-time feedback about step timing while adapting; and the last group received asymmetric real-time feedback about step position while adapting. We measured step length difference (non-normalized asymmetry), step timing asymmetry, and step position asymmetry during adaptation, deadaptation, and readaptation on a split-belt treadmill. Regardless of feedback, participants adapted step length difference, indicating that walking with temporal or spatial visual feedback does not interfere with gait adaptation. Compared to the group that received no feedback, the group that received temporal feedback exhibited smaller early deadaptation step position asymmetry ( p = 0.005). There was no effect of temporal or spatial feedback on step timing. The feedback groups adapted step timing and position similarly to walking without feedback. Future work should investigate whether asymmetric visual feedback also results in typical gait adaptation in populations with altered step timing or position control.
