Returning to work after dysvascular lower limb amputation-A novel multivariate approach to examine relative contributions of biopsychosocial predictors.

BACKGROUND: Returning to work is a key outcome of rehabilitation and social re-integration after lower limb amputation. It is important to understand what biopsychosocial factors contribute to returning to work after dysvascular amputation. OBJECTIVE: Examining relative contributions of functional and contextual predictors of returning to work in participants with lower limb amputation due to diabetes and other dysvascular diseases. STUDY DESIGN: Cross-sectional. METHODS: Return-to-work outcome, biopsychosocial characteristics including physical functioning, self-efficacy & perceived ability, and socioeconomical support data were collected from a purposive sample (n = 57) in a multi-state collaborative research network. Grouped Weighted Quantile Sum model analysis was conducted to evaluate relative contributions of biopsychosocial predictors. RESULTS: Less than 30% of the participants returned to work after their amputation. Physical functioning (odds ratio = 10.19; 95% CI 2.46-72.74) was the most important predictor group. Working before amputation, prosthetic mobility, and access to rehabilitation care were also identified as key factors associated with returning to work. CONCLUSIONS: Fewer than 1 in 3 participants with dysvascular amputation returned to work, despite an average age of only 54 years at the time of amputation. Physical functioning was shown to be the most important predictor, while socioeconomic factors such as a lack of access to care also contribute to not returning to work after dysvascular amputation.

Description, reliability and utility of a ground-reaction-force triggered protocol for precise delivery of unilateral trip-like perturbations during gait.

Tripping is a common cause of falls and a focus of many biomechanical investigations. Concerns regarding the precision of delivery of simulated-fall protocols reside in the current biomechanical methodology literature. This study aimed to develop a treadmill-based protocol that generated unanticipated trip-like perturbations during walking with high timing precision. The protocol utilized a side-by-side split-belt instrumented treadmill. Programmed treadmill belt acceleration profiles (two levels of perturbation magnitude) were triggered unilaterally at the instant the tripped leg bore 20% of the body weight. Test-retest reliability of fall responses was examined in 10 participants. Utility was examined as to whether the protocol could differentiate the fall recovery responses and likelihood of falls, estimated using peak trunk flexion angle after perturbation, between young and middle-aged adults (n = 10 per group). Results showed that the perturbations could be precisely and consistently delivered during early stance phases (10-45 milliseconds after initial contact). The protocol elicited excellent reliability of responses in both perturbation magnitudes (ICC = 0.944 and 0.911). Middle-aged adults exhibited significantly greater peak trunk flexion than young adults (p = 0.035), indicating that the current protocol can be utilized in differentiating individuals with different levels of fall risks. The main limitation of the protocol is that perturbations are delivered in stance rather swing phase. This protocol addressed some issues discussed in previous "simulated fall" protocols and may be useful for future fall research and subsequent clinical interventions.

A distal external focus of attention facilitates compensatory coordination of body parts.

Many studies have shown that focusing on an intended movement effect that is farther away from the body (distal external focus) results in performance benefits relative to focusing on an effect that is closer to the body (proximal external focus) or focusing on the body itself (internal focus) (see, Chua, Jimenez-Diaz, Lewthwaite, Kim & Wulf, 2021). Furthermore, the advantages of a distal external focus seem to be particularly pronounced in skilled performers (Singh & Wulf, 2020). The present study examined whether such benefits of more distal attentional focus may be associated with enhanced functional variability. Volleyball players (n = 20) performed 60 overhand volleyball serves to a target. Using a within-participants design, the effects of a distal external focus (bullseye), proximal external focus (ball) and an internal focus (hand) were compared. The distal focus condition resulted in significantly higher accuracy scores than did the proximal and internal focus conditions. In addition, uncontrolled manifold analysis showed that functional variability (as measured by the index of synergy) was greatest in the distal focus condition. These findings suggest that a distal external focus on the task goal may enhance movement outcomes by optimising compensatory coordination of body parts.

Patient Experience and Perceived Benefits of Physical Therapy after Lower Limb Amputation in Middle-Aged and Older Adults.

The current study aimed to investigate the long-term effects of receiving post-amputation physical therapy (PT) on individuals' self-reported functional outcomes and quality of life in middle-aged to older adults with lower limb amputation (LLA). Further, we qualitatively explored the patients' perception and experience of PT post-amputation. We assessed participants' functional outcomes using Short-Form Health Survey, Prosthetic Evaluation Questionnaire-Physical Mobility portion, and Fear of Falling Avoidance Behavior Questionnaire. Furthermore, participants' experience and perception to PT were assessed through in-person interviews guided by the custom Amputation Patient Perception Survey. Functional outcome scores were compared between participants who have (Yes-PT) and have not (No-PT) received PT following their amputations, controlling for age. Perception to PT was qualitatively analyzed. Out of the 70 participants, 56 had received PT (80%) following amputation. Functional outcome scores were not significantly different between Yes-PT and No-PT groups. Among participants in the Yes-PT group, 84% expressed overall positive perception toward their post-amputation PT care. Main positive and negative perceptions were related to outcome/benefits and unfulfilled needs/lack of benefits, respectively. Participants with LLA generally expressed a positive perception of PT. However, no significant long-term benefits were found. We recommend goal-directed intervention with patient engagement to improve care experience.

More bang for the buck: autonomy support increases muscular efficiency.

The purpose of this study was to examine whether conditions that provide performers with a sense of autonomy, by giving them choices, would increase movement efficiency. We evaluated neuromuscular activation as a function of choice, using surface electromyography (EMG), during isometric force production. Participants (N = 16) were asked to perform plantar flexions at each of three target torques (80%, 50%, 20% of maximum voluntary contractions) under both choice and control conditions. In the choice condition, they were able to choose the order of target torques, whereas the order was pre-determined in the control condition. Results demonstrated that while similar torques were produced under both conditions, EMG activity was lower in the choice relative to the control condition. Thus, providing performers with a choice led to reduced neuromuscular activity, or an increase in movement efficiency. This finding is in line with the notion that autonomy support readies the motor system for task execution by contributing to the coupling of goals and actions (Wulf and Lewthwaite, Psychon Bull Rev 23:1382-1414, 2016).

Four weeks of training with simple postural instructions changes trunk posture and foot strike pattern in recreational runners.

OBJECTIVES: Previous studies showed that adopting forward trunk lean and forefoot strike patterns may reduce risk of running-related knee injuries. However, the process of learning such forms is unclear. The purpose of the study was to investigate the effects of a 4-week training using simple postural instructions to elicit these changes. DESIGN: Longitudinal intervention study. SETTING: A training included postural instructions: 1) lean your trunk forward, and 2) land on the front part of your feet. PARTICIPANTS: Eighteen recreational runners. MAIN OUTCOME MEASURES: Participants were assessed prior to training (PRE), immediately after the instructions (iPST), during training at 2 weeks (2WK) and 4 weeks (4WK), and 7-10 days after the conclusion of training (RET). Assessment consisted of running trials performed at self-selected and controlled speeds, during which the trunk and foot strike angles were assessed. RESULTS: Comparing to PRE, forward trunk angle significantly increased by approximately 3.5° and foot strike angle by approximately 7° at 2WK, 4WK and RET. CONCLUSIONS: A 4-week training with simple postural instructions induced significant changes in trunk and foot strike patterns in recreational runners. Future study is needed to develop clinical therapeutic protocols for runners with and at risk of running-related knee injuries.

Preparation of Multifunctional Fe@Au Core-Shell Nanoparticles with Surface Grafting as a Potential Treatment for Magnetic Hyperthermia.

Iron core gold shell nanoparticles grafted with Methotrexate (MTX) and indocyanine green (ICG) were synthesized for the first time in this study, and preliminarily evaluated for their potential in magnetic hyperthermia treatment. The core-shell Fe@Au nanoparticles were prepared via the microemulsion process and then grafted with MTX and ICG using hydrolyzed poly(styrene-alt-maleic acid) (PSMA) to obtain core-shell Fe@Au-PSMA-ICG/MTX nanoparticles. MTX is an anti-cancer therapeutic, and ICG is a fluorescent dye. XRD, TEM, FTIR and UV-Vis spectrometry were performed to characterize the nanoparticles. The data indicated that the average size of the nanoparticles was 6.4 ± 09 nm and that the Au coating protected the Fe core from oxidation. MTX and ICG were successfully grafted onto the surface of the nanoparticles. Under exposure to high frequency induction waves, the superparamagnetic nanoparticles elevated the temperature of a solution in a few minutes, which suggested the potential for an application in magnetic hyperthermia treatment. The in vitro studies verified that the nanoparticles were biocompatible; nonetheless, the Fe@Au-PSMA-ICG/MTX nanoparticles killed cancer cells (Hep-G2) via the magnetic hyperthermia mechanism and the release of MTX.