Comprehensive quantitative investigation of arm swing during walking at various speed and surface slope conditions

A Wearable Upper Extremity Rehabilitation Device for Inducing Arm Swing in Gait Training

This paper presents the design and validation of a proof-of-concept prototype for a wearable rehabilitation device to incorporate arm swing during gait rehabilitation. Unlike current stationary exoskeletons used for rehabilitation of upper limbs' function, assisting arm swing during gait requires inducing faster arm flexion/extension movements while maintaining the users' arms unconstrained in other directions. We developed a portable and underactuated system with features such as a large workspace and backdrivability to induce arm swing. Its wide workspace allowed the wearers to easily move their arms in different directions without any constraints. A modified double parallelogram linkage (mDPL) is proposed to allow the device to mimic the natural workspace of an arm. Additionally, a pulley drive and weight compensation system were created to place the motor on the users' back reducing the hindering weight of the actuators on their arms. Our experiments demonstrated this arm-swing rehabilitator could successfully induce arm movements at different arm configurations with low (0.67 Hz) and high (1.1 Hz) frequencies corresponding to slow and fast walking.

Joint behaviour during arm swing changes with gait speed and predicts spatiotemporal variability and dynamic stability in healthy young adults

BACKGROUND

Arm swing is linked to gait stability. How this is accomplished is unclear as most investigations artificially manipulate arm swing amplitude and examine average patterns. Biomechanical evaluation of stride-to-stride upper limb behaviour across a range of gait speeds, where the arm swings as preferred, could clarify this link.

RESEARCH QUESTION

How do stride-to-stride arm swing behaviours change with gait speed and relate to stride-to-stride gait fluctuations?

METHODS

Young adults (n = 45, 25 females) completed treadmill gait at preferred, slow (70% of preferred), and fast speed (130% of preferred) while full-body kinematics were acquired with optoelectronic motion capture. Arm swing behaviour was quantified by shoulder, elbow, and wrist joint angle amplitude (range of motion [ROM]) and motor variability (e.g. mean standard deviation [meanSD], local divergence exponent [λ_max]). Stride-to-stride gait fluctuation was quantified by spatiotemporal variability (e.g. stride time CV) and dynamic stability (i.e. trunk local dynamic stability [trunk λ_max], centre-of-mass smoothness [COM HR]). Repeated measures ANOVAs tested for speed effects and step-wise linear regressions identified arm swing-based predictors of stride-to-stride gait fluctuation.

RESULTS

Speed decreased spatiotemporal variability and increased trunk λ_max and COM HR in the anteroposterior and vertical axes. Adjustments in gait fluctuations occurred with increased upper limb ROM, particularly for elbow flexion, and increased meanSD and λ_max of shoulder, elbow, and wrist angles. Models of upper limb measures predicted 49.9-55.5% of spatiotemporal variability and 17.7-46.4% of dynamic stability. For dynamic stability, wrist angle features were the best and most common independent predictors.

SIGNIFICANCE

Findings highlight that all upper limb joints, and not solely the shoulder, underlie changes in arm swing amplitude, and that arm swing strategies pair with the trunk and contrast with centre-of-mass and stride strategies. Findings suggest that young adults search for flexible arm swing motor strategies to help optimize stride consistency and gait smoothness.

The effects of forearm movements on human gait during walking with various self-selected speeds

The forearms significantly contribute to the upper extremity movements and, consequently, whole-body responses during locomotion. The purpose of this study is to provide a more in-depth understanding of the mechanism controlling forearm movements during walking by comprehensively investigating the effects of the forearms on the lower and upper limb movements. Such an understanding can provide critical information for the design and control of robotic upper-limb prostheses. Twelve healthy young participants were recruited to compare their gait during (1) natural walking, (2) walking while wearing a pair of artificial passive forearms and having their actual forearms restrained by orthopedic braces, and (3) walking with only having their forearms restrained by the braces (i.e., no artificial forearms). While the passive forearms in condition 2 were to determine if the forearm movements were passively or actively controlled, condition 3 was to account for the effects of restraining the forearms in condition 2. The participants' lower-limb joint angles and spatiotemporal parameters remained unchanged across the three conditions while walking at their normal and fast self-selected gait speeds. However, significant decreases were observed in the shoulder and trunk angles, the interlimb coordination, and the shoulder-trunk correlations when walking with the artificial forearms. These observations were in tandem with the increased muscle activity of the biceps, trapeziuses, and posterior deltoids, which controlled the shoulder motion and trunk rotation during walking with the artificial forearms across both normal and fast self-selected speeds. Although not significant, the metabolic energy analysis of five participants revealed an increase during walking with artificial forearms. The results support the idea that the body actively controls the forearm movements through the shoulder and trunk rotations to mitigate the undesired disturbances induced by the passive forearm movements during locomotion.

Influence of non-immersive avatar-based gamification on the Hawthorne Effect in pediatric gait

BACKGROUND

The Hawthorne Effect occurs when participants alter their behavior when they are aware that they are being examined. The effect has been reported in many experiments, including gait analysis, and is considered an important source of bias that might impact both clinical and research results. Cognitive distraction is one potential solution to reducing the Hawthorne effect during gait analysis, but it is challenging in children, and can, in itself, alter gait. This study investigated the carryover effect of an alternative low-immersion avatar-based intervention on gait and subjective feelings in typically developing children.

RESEARCH QUESTION

Will a low-immersion avatar-based intervention change feelings and indicators of temporospatial and kinematic outcomes in children in a laboratory setting, potentially reducing the Hawthorne Effect?

METHODS

Typically developing children aged 5-13 participated in a standard laboratory gait analysis before experiencing a game in which they viewed their motion on monitors around the lab as that of a cartoon avatar in a 3D virtual environment. Following this intervention, standard walking trials were repeated. In addition, participants completed a survey of their feelings about the study both before onset and after completion.

RESULTS

Thirty-one children participated in the study, 16 females and 15 males, mean aged 9.1 years. Arm swing, proposed as a measure of how relaxed and natural gait was, increased significantly following the intervention, while temporospatial parameters did not. The effect was more pronounced in females and younger children. Participants felt significantly happier, more excited, less scared, and less sad after the intervention. Changes in feelings were not closely associated with changes in gait.

SIGNIFICANCE

This study suggests that gamification may reduce the Hawthorne effect and potentially produce more natural gait in children. The game intervention had a carryover effect, producing changes in gait even after the intervention was removed.

Whole body kinematic sex differences persist across non-dimensional gait speeds

Sex differences in human locomotion are of interest in a broad variety of interdisciplinary applications. Although kinematic sex differences have been studied for many years, the underlying reasons behind several noted differences, such as pelvis and torso range of motion, are still not well understood. Walking speed and body size in particular represent confounding influences that hinder our ability to determine causal factors. The purpose of this study was to investigate sex differences in whole body gait kinematics across a range of controlled, non-dimensional walking and running speeds. We hypothesized that as task demand (i.e. gait speed) increased, the influences of modifiable factors would decrease, leading to a kinematic motion pattern convergence between sexes. Motion capture data from forty-eight healthy young adults (24 M, 24 F) wearing controlled footwear was captured at three walking and three running Froude speeds. Spatiotemporal metrics, center of mass displacement, and joint/segment ranges of motion were compared between sexes using 2x6 mixed-model ANOVAs. Three dimensional time-series waveforms were also used to describe the time-varying behavior of select joint angles. When controlling for size, sex differences in spatiotemporal metrics and center of mass displacement disappeared. However, contrary to our hypothesis, sagittal plane ankle, frontal plane pelvis, and transverse plane pelvis and torso range of motion all displayed sex differences that persisted or increased with gait speed. Overall, most spatiotemporal sex differences appear to be related to size and self-selection of gait speeds, while in contrast, sex differences in joint motion may be more inherent and ubiquitous than previously thought. Discussion on potential causal factors is presented.

Age-related changes in arm motion during typical gait

BACKGROUND

When toddlers learn to walk, they do so with a typical high guard position of the arms. As gait matures, children develop a reciprocal arm swing. So far, there have been no attempts to describe age-related changes of arm movements during walking after this first rapid development.

RESEARCH QUESTION

The purpose of this study was to investigate age-related changes in arm movement during typical gait.

METHODS

All participants (n = 102) received gait analysis using a full-body marker set (Plug-in Gait). Participants were divided into five age-groups: young children (G1: n = 20; 3.0-5.9y), children (G2: n = 24; 6.0-9.9y), pubertal children (G3: n = 26; 10.0-13.9y), adolescents (G4: n = 16; 14.0-18.9y) and adults (G5: n = 16; 19.0-35.2y). Age-related changes in arm movements were investigated by comparing continuous joint angular waveforms (spm1d) between all groups, as well as by comparing the mean joint angle and range of motion of the different joints between age-groups.

RESULTS

The overall shape of movement patterns was comparable across all age groups. Nevertheless, with advancing age, consistency increased. At the shoulder, G1&2 showed a larger mean extension angle compared to older children and adults. The range of shoulder axial rotation was significantly larger in adults compared to all other age groups. In the youngest groups (G1-G2), an increased mean elbow flexion and mean wrist extension angle was found.

SIGNIFICANCE

Determining an exact age of maturation of arm swing remains difficult as parameter specific adult-like values were not reached at the same age but should not be set before the age of ten to fourteen years for any parameter.

Imposed Faster and Slower Walking Speeds Influence Gait Stability Differently in Parkinson Fallers

OBJECTIVE

To evaluate the effect of imposed faster and slower walking speeds on postural stability in people with Parkinson disease (PD).

DESIGN

Cross-sectional cohort study.

SETTING

General community.

PARTICIPANTS

Patients with PD (n=84; 51 with a falls history; 33 without) and age-matched controls (n=82) were invited to participate via neurology clinics and preexisting databases. Of those contacted, 99 did not respond (PD=36; controls=63) and 27 were not interested (PD=18; controls=9). After screening, a further 10 patients were excluded; 5 had deep brain stimulation surgery and 5 could not accommodate to the treadmill. The remaining patients (N=30) completed all assessments and were subdivided into PD fallers (n=10), PD nonfallers (n=10), and age-matched controls (n=10) based on falls history.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Three-dimensional accelerometers assessed head and trunk accelerations and allowed calculation of harmonic ratios and root mean square (RMS) accelerations to assess segment control and movement amplitude.

RESULTS

Symptom severity, balance confidence, and medical history were established before participants walked on a treadmill at 70%, 100%, and 130% of their preferred speed. Head and trunk control was lower for PD fallers than PD nonfallers and older adults. Significant interactions indicated head and trunk control increased with speed for PD nonfallers and older adults, but did not improve at faster speeds for PD fallers. Vertical head and trunk accelerations increased with walking speed for PD nonfallers and older adults, while the PD fallers demonstrated greater anteroposterior RMS accelerations compared with both other groups.

CONCLUSIONS

The results suggest that improved gait dynamics do not necessarily represent improved walking stability, and this must be respected when rehabilitating gait in patients with PD.