Applying elastic resistance bands for gait training: A simulation-based study to determine how band configuration affects gait biomechanics and muscle activation

BACKGROUND

Wearable robotic exoskeletons and leg braces are desirable for gait rehabilitation because they can apply loads directly to an affected joint. Yet, they are not widely used in clinics because they are costly and complex to set up. Conversely, tethered devices, such as elastic resistance bands, are widely available in clinics, are low-cost, and are quick to set up. However, resistance bands will affect walking differently based on how they are configured to pull on the leg (e.g., pulling forward or backward).

RESEARCH QUESTION

How can a resistance band be configured to alter muscle activation and gait biomechanics based on the segment it is attached to and the angle with which it attaches?

METHODS

We used an open-source musculoskeletal modeling platform to emulate several configurations of an elastic band pulling on the ankle, calf, and thigh at various angles during non-pathological walking. We evaluated gait biomechanics and simulated muscle activation using computed muscle control (CMC) and identified a subset of four configurations with potential applications for gait training. Eight non-pathological participants then walked on a treadmill under these configurations to verify how these configurations altered muscle activation.

RESULTS

We found that muscle activity greatly varied based on the location where the elastic band is attached and the angle with which the elastic band pulls on the leg. Notably, specific angles can be used to pull on the legs to elicit an increase or decrease in muscle activation.

SIGNIFICANCE

This study provides insight into how tethered devices can be configured to provide assistance or resistance during gait training. This information can be applied when developing low-cost gait training solutions for addressing individuals' impairments.

The effects of anterior bite plane on temporomandibular joint and mandibular morphology

Objectives

An anterior bite plane (ABP) is an orthodontic appliance that prevents posterior teeth from making contact. This appliance's functional concept is to reduce muscle activity, overcome deep overbite, and temporomandibular joint (TMJ) disorders (TMD). However, ABP treatment for malocclusion frequently results in unfavorable reversible and irreversible long-term effects. This problem presents difficulties for dentists in developing an appropriate treatment modification plan in order to achieve the best results. As a result, the goal of this study is to observe the effects of different ABP types on the TMJ and mandible.

Materials and Methods

Thirty-six three-month-old male Wistar strain rats were divided into three groups: control, upper flat, and upper-lower inclined ABP. The overbite and body weight were measured. TMJ was examined histologically using hematoxylin and eosin (HE). To observe the entire mandibular bone in response to ABP, mandibular planes and angulations were measured.

Results

After 7 days, the upper-lower inclined ABP group has significantly lower body weight than the control group. On days 7 and 14, overbite was significantly reduced in both the upper flat and upper-lower inclined ABP groups. The superficial layer of the condyle was depleted in both ABP groups, according to HE analysis. Mandibular angle analysis revealed that the upper-lower inclined ABP group had a greater incisal and ramus angle. Furthermore, lower incisor (Li)-condyle (Co) mandibular points increased significantly more in the upper-lower inclined ABP group than in the control group.

Conclusion

According to this study, various forms of ABP may have an impact on the TMJ and mandibular morphology, specifically on the length, angulation, and superficial surface of the condyle.

Contributions of implicit and explicit memories to sensorimotor adaptation of movement extent during goal-directed reaching

We examined how implicit and explicit memories contribute to sensorimotor adaptation of movement extent during goal-directed reaching. Twenty subjects grasped the handle of a horizontal planar robot that rendered spring-like resistance to movement. Subjects made rapid “out-and-back” reaches to capture a remembered visual target at the point of maximal reach extent. The robot’s resistance changed unpredictably between reaches, inducing target capture errors that subjects attempted to correct from one trial to the next. Each subject performed over 400 goal-directed reaching trials. Some trials were performed without concurrent visual cursor feedback of hand motion. Some trials required self-assessment of performance between trials, whereby subjects reported peak reach extent on the most recent trial. This was done by either moving a cursor on a horizontal display (visual self-assessment), or by moving the robot’s handle back to the recalled location (proprioceptive self-assessment). Control condition trials performed either without or with concurrent visual cursor feedback of hand motion did not require self-assessments. We used step-wise linear regression analyses to quantify the extent to which prior reach errors and explicit memories of reach extent contribute to subsequent reach performance. Consistent with prior reports, providing concurrent visual feedback of hand motion increased reach accuracy and reduced the impact of past performance errors on future performance, relative to the corresponding no-vision control condition. By contrast, we found no impact of interposed self-assessment on subsequent reach performance or on how prior target capture errors influence subsequent reach performance. Self-assessments were biased toward the remembered target location and they spanned a compressed range of values relative to actual reach extents, demonstrating that declarative memories of reach performance systematically differed from actual performances. We found that multilinear regression could best account for observed data variability when the regression model included only implicit memories of prior reach performance; including explicit memories (self-assessments) in the model did not improve its predictive accuracy. We conclude therefore that explicit memories of prior reach performance do not contribute to implicit sensorimotor adaptation of movement extent during goal-directed reaching under conditions of environmental uncertainty.