Does an outdoor virtual environment projected in a head-mounted display affect balance in healthy young adults?

Background: Virtual reality head-mounted display (VR-HMD) is increasingly used for balance evaluation and rehabilitation. However, more studies must be conducted on virtual environments (VE) effects. This study aimed to assess the impact of an outdoor VE projected in a high-quality VR-HMD and of the VR-HMD mass on postural stability, postural control and leaning.

A two-stage disto-proximal braking modality to interrupt gait initiation in healthy adults.

The purpose of this investigation was to determine the effect of unexpected gait termination in able-bodied participants during gait initiation on spatiotemporal and stance limb biomechanical parameters. Twenty-one healthy adults took part in this study and were divided into two groups based on the natural anterior or posterior incline of their trunk. Each participant performed 15 random trials of gait initiation: 10 trials with a Go signal and 5 with Go-&-Stop signals.

Machine Learning Identifies Chronic Low Back Pain Patients from an Instrumented Trunk Bending and Return Test.

Nowadays, the better assessment of low back pain (LBP) is an important challenge, as it is the leading musculoskeletal condition worldwide in terms of years of disability. The objective of this study was to evaluate the relevance of various machine learning (ML) algorithms and Sample Entropy (SampEn), which assesses the complexity of motion variability in identifying the condition of low back pain. Twenty chronic low-back pain (CLBP) patients and 20 healthy non-LBP participants performed 1-min repetitive bending (flexion) and return (extension) trunk movements.

Sample Entropy as a Tool to Assess Lumbo-Pelvic Movements in a Clinical Test for Low-Back-Pain Patients.

Low back pain (LBP) obviously reduces the quality of life but is also the world's leading cause of years lived with disability. Alterations in motor response and changes in movement patterns are expected in LBP patients when compared to healthy people. Such changes in dynamics may be assessed by the nonlinear analysis of kinematical time series recorded from one patient's motion.

Is treadmill walking biomechanically comparable to overground walking? A systematic review.

Background: The equivalency of treadmill and overground walking has been investigated in a large number of studies. However, no systematic review has been performed on this topic.

Research Question: The aim of this study was to compare the biomechanical, electromyographical and energy consumption outcomes of motorized treadmill and overground walking.

Standing posture and balance modalities in unilateral transfemoral and transtibial amputees.

Introduction: Lower limb amputation impairs postural performance that could be characterized by biomechanical parameters. This study is to investigate postural performance of persons with transfemoral and transtibial amputation compared to controls without amputation.

Methods: Eight transtibial, nine transfemoral and twelve able-bodied males participated in this study.

Untreated adolescent idiopathic scoliotic girls display altered balance modalities during self-paced voluntary body sways compared to able-bodied girls.

Introduction: This study investigated self-paced voluntary oscillations of scoliotic and non-scoliotic girls. Temporal variables and frequency coherence were calculated for the overall, low and high frequency bandwidths of the center of pressure excursions and free-moment to identify which variables best describe sway balance modalities in both groups.

Methods: Twenty-three girls with adolescent idiopathic moderate scoliosis (spinal curves to the right) formed the scoliotic group and 19 matched able-bodied girls formed the non-scoliotic group.

Induction of Neural Plasticity Using a Low-Cost Open Source Brain-Computer Interface and a 3D-Printed Wrist Exoskeleton.

Brain-computer interfaces (BCIs) have been proven to be useful for stroke rehabilitation, but there are a number of factors that impede the use of this technology in rehabilitation clinics and in home-use, the major factors including the usability and costs of the BCI system. The aims of this study were to develop a cheap 3D-printed wrist exoskeleton that can be controlled by a cheap open source BCI (OpenViBE), and to determine if training with such a setup could induce neural plasticity. Eleven healthy volunteers imagined wrist extensions, which were detected from single-trial electroencephalography (EEG), and in response to this, the wrist exoskeleton replicated the intended movement.

Contribution of Achilles tendon mechanical properties to torque steadiness in persons with transfemoral amputation.

Background: How Achilles tendon mechanics and plantar flexion strength and torque steadiness are altered in the intact leg of persons with trauma-related amputation is unknown. Understanding Achilles tendon mechanics following amputation will further inform rehabilitation approaches to enhance posture, balance, and force control.

Objective: Conduct a pilot study to quantify plantar flexion maximal voluntary contraction torque, torque steadiness, and Achilles tendon mechanics in persons with unilateral trauma-related transfemoral amputation and controls without amputation.

Frequency coherence analysis of postural balance in able-bodied and in non-treated adolescent idiopathic scoliotic girls.

Background: This study test if the frequency coherence calculated for the overall, low and high frequency bandwidths of the center of pressure excursions and free-moment calculated during standing balance are similar between scoliotic and non-scoliotic girls and if the coherence values within each frequency band are comparable for a given group of girls.

Methods: Twenty-nine girls with adolescent idiopathic scoliosis formed the scoliotic group and 22 able-bodied girls formed the non-scoliotic group. Each girl maintained a quiet upright stance on a force plate.

Does Unilateral Lower Limb Amputation Influence Ankle Joint Torque in the Intact Leg?

Objective: To investigate ankle torque and steadiness in the intact leg of transtibial and transfemoral unilateral amputees.

Design: Comparative study.

Setting: Medical rehabilitation centers.

Effect of the phase of force production on corticomuscular coherence with agonist and antagonist muscles.

During isometric contractions, the net joint torque stability is modulated with the force production phases, i.e., increasing (IFP), holding (HFP), and decreasing force (DFP) phases.

Effect of natural sagittal trunk lean on standing balance in untreated scoliotic girls.

Background: Generally, scoliotic girls have a tendency to lean further back than a comparable group of non-scoliotic girls. To date, no study has addressed how standing balance in untreated scoliotic girls is affected by a natural backwardly or forwardly inclined trunk.

Methods: 27 able-bodied young girls and 27 young girls with a right thoracic curve were classified as leaning forward or backward according to the median of their trunk sagittal inclination.

Shoe drop reduction influences the lower limb biomechanics of children tennis players during an open stance forehand: A longitudinal study.

Compared to traditional tennis shoes, using 0-drop shoes was shown to induce an immediate switch from rear- to forefoot strike pattern to perform an open stance tennis forehand for 30% of children tennis players. The purpose of the study was to examine the long-term effects of a gradual reduction in the shoe drop on the biomechanics of children tennis players performing open stance forehands. Thirty children tennis players participated in 2 laboratory biomechanical test sessions (intermediate: +4 months and final: +8 months) after an inclusion visit where they were randomly assigned to control (CON) or experimental (EXP) group.

Ultrasonographic quantification of architectural response in tibialis anterior to neuromuscular electrical stimulation.

While muscle contraction in voluntary efforts has been widely investigated, little is known about contraction during neuromuscular electrical stimulation (NMES). The aim of this study was to quantify in vivo muscle architecture of agonist and antagonist muscles at the ankle joint during NMES. Muscle fascicle lengths and pennation angles of the tibialis anterior (TA) and lateral gastrocnemius muscles were assessed via ultrasonography in 8 healthy young males.

Determination of optimal shoe fitting for children tennis players: Effects of inner-shoe volume and upper stiffness.

The purpose of this study was to determine the optimal inner-shoe volume for children tennis players. Sixteen participants, aged from 8 to 12 years old assessed comfort of 6 shoes, which were a combination of 3 lasts (thin, medium and wide) and 2 upper constructions (flexible and stiff), while a sock equipped with textile sensors was measuring the pressure applied on their foot. The thin last was based on the proportion of an adult last.

The influence of shoe aging on children running biomechanics.

Athletic children are prone to overuse injuries, especially at the heel and knee. Since footwear is an extrinsic factor of lower limb injury risk, the aim of this study was to assess the influence of shoe aging on children running biomechanics. Fourteen children active in sports participated in a laboratory biomechanical evaluation.

A reliable measure of footwear upper comfort enabled by an innovative sock equipped with textile pressure sensors.

Footwear comfort is essential and pressure distribution on the foot was shown as a relevant objective measurement to assess it. However, asperities on the foot sides, especially the metatarsals and the instep, make its evaluation difficult with available equipment. Thus, a sock equipped with textile pressure sensors was designed.

The influence of shoe drop on the kinematics and kinetics of children tennis players.

This study investigated the immediate effects of reducing the shoe drop (i.e. the difference between the heel and the forefoot height) on the kinematics and kinetics of the lower extremities of children tennis players performing a tennis-specific movement.

Differential impact of visual feedback on plantar- and dorsi-flexion maximal torque output.

The effect of visual feedback on enhancing isometric maximal voluntary contractions (MVC) was evaluated. Twelve adults performed plantar-flexion and dorsi-flexion MVCs in 3 conditions (no visual feedback, visual feedback, and visual feedback with target). There was no significant effect of visual conditions on dorsi-flexion MVC but there was an effect on plantar-flexion.

A new approach of the Star Excursion Balance Test to assess dynamic postural control in people complaining from chronic ankle instability.

The purpose of this study was to quantitatively and qualitatively assess dynamic balance with accuracy in individuals with chronic ankle instability (CAI). To this aim, a motion capture system was used while participants performed the Star Excursion Balance Test (SEBT). Reached distances for the 8 points of the star were automatically computed, thereby excluding any dependence to the experimenter.

Bilateral Strength Deficit Is Not Neural in Origin; Rather Due to Dynamometer Mechanical Configuration.

During maximal contractions, the sum of forces exerted by homonymous muscles unilaterally is typically higher than the sum of forces exerted by the same muscles bilaterally. However, the underlying mechanism(s) of this phenomenon, which is known as the bilateral strength deficit, remain equivocal. One potential factor that has received minimal attention is the contribution of body adjustments to bilateral and unilateral force production.

Enhanced precision of ankle torque measure with an open-unit dynamometer mounted with a 3D force-torque sensor.

Purpose: Many studies have focused on maximum torque exerted by ankle joint muscles during plantar flexion. While strength parameters are typically measured with isokinetic or isolated ankle dynamometers, these devices often present substantial limitations for the measurement of torque because they account for force in only 1 dimension (1D), and the device often constrains the body in a position that augments torque through counter movements. The purposes of this study were to determine the contribution of body position to ankle plantar-flexion torque and to assess the use of 1D and 3D torque sensors.

Is co-contraction responsible for the decline in maximal knee joint torque in older males?

While it is often reported that muscular coactivation increases with age, the mechanical impact of antagonist muscles, i.e., the antagonist torque, remains to be assessed.