Changes in corticospinal excitability of shoulder muscles across functional glenohumeral joint positions.

The shoulder is a complex region of the body that can be prone to injury associated with awkward postures due to a broad range of motion and relatively low stability. A better understanding of how arm orientation influences neural drive (excitability) to muscles surrounding the glenohumeral joint can provide insight into recruitment strategies. The purpose of this study was to determine the influence of glenohumeral joint angle on excitability of the muscles surrounding the shoulder complex.

Impact of repetitive mouse aiming on muscle fatigue and fine motor performance of the distal upper limb.

Gaming is demanding, however, the impact of gaming on muscle fatigue and performance changes is unclear. The purpose of this study was to evaluate muscle fatigue and performance impairments during an extended mouse aiming fatigue protocol. Twenty participants were recruited (8F, 12 M), separated into gaming and non-gaming groups.

A comprehensive scoping review and meta-analysis of upper limb strength asymmetry.

The "10% rule" of handedness asserts the dominant hand is 10% stronger than the non-dominant hand. Primarily derived from handgrip data, it is unclear if a generalized asymmetry exists across the upper limb. Understanding how strength asymmetry may be affected by handedness, sex, and exertion type has important implications for ergonomics design, sports performance, and clinical rehabilitation.

Impact of repetitive mouse clicking on forearm muscle fatigue and mouse aiming performance.

Exercise induced performance fatigue has been shown to impair many aspects of fine motor function in the distal upper limb. However, most fatiguing protocols do not reflect the conditions experienced with computer use. The purpose of this study was to determine how a prolonged, low-force mouse clicking fatigue protocol impacts performance fatigue of the distal upper limb for gamers and non-gamers.

Sex Difference in Lower-limb Electromyography and Kinematics when Using Resistance Bands during a Barbell Back Squat.

The aim of this study was to compare the muscle activity of the gluteus medius (GMe), gluteus maximus (GMa), biceps femoris (BF), vastus lateralis (VL), vastus medialis (VM) and erector spinae (ES) as well as medial knee displacement (MKD) while using varying stiffness resistance bands (red: 1.68 kg; black: 3.31 kg; gold: 6.

The effects of isometric hand grip force on wrist kinematics and forearm muscle activity during radial and ulnar wrist joint perturbations.

The purpose of this work was to investigate forearm muscle activity and wrist angular displacement during radial and ulnar wrist perturbations across various isometric hand grip demands. Surface electromyography (EMG) was recorded from eight muscles of the upper extremity. A robotic device delivered perturbations to the hand in the radial and ulnar directions across four pre-perturbation grip magnitudes.

Influence of muscle fatigue on motor task performance of the hand and wrist: A systematic review.

Muscle fatigue is represented as a reduction in force production capability; however, fatigue does not necessarily result in performance impairments. As the distal upper limb serves as the end effector when interacting or manipulating objects, it is important to understand how muscle fatigue may impact motor functionality. The aim of this study was to systematically review the literature to identify how various aspects of motor performance of the distal upper limb are impaired following muscle fatigue.

Wrist extensor muscle activity is less task-dependent than wrist flexor muscle activity while simultaneously performing moderate-to-high handgrip and wrist forces.

The aim of this study was to characterise wrist extensor and flexor muscle activity during combinations of moderate-to-high handgrip and wrist forces that are similar to actions and intensities used in many workplace settings. Surface electromyography was recorded from three wrist flexors and three wrist extensors while participants performed simultaneous handgrip forces and wrist forces ranging in intensities from 15% to 60% of maximum. While the wrist flexors were highly task-dependent, in that their activity significantly changed between conditions, wrist extensor activity was consistently high throughout the experiment.

Dynamic Wrist Flexion and Extension Fatigue Induced via Submaximal Contractions Similarly Impairs Hand Tracking Accuracy in Young Adult Males and Females.

We evaluated the effects of muscle fatigue on hand-tracking performance in young adults. Differences were quantified between wrist flexion and extension fatigability, and between males and females. Participants were evaluated on their ability to trace a pattern using a 3-degrees-of-freedom robotic manipulandum before (baseline) and after (0, 1, 2, 4, 6, 8, and 10 mins) a submaximal-intensity fatigue protocol performed to exhaustion that isolated the wrist flexors or extensors on separate days.

Sustained Isometric Wrist Flexion and Extension Maximal Voluntary Contractions Similarly Impair Hand-Tracking Accuracy in Young Adults Using a Wrist Robot.

Due to their stabilizing role, the wrist extensor muscles demonstrate an earlier onset of performance fatigability and may impair movement accuracy more than the wrist flexors. However, minimal fatigue research has been conducted at the wrist. Thus, the purpose of this study was to examine how sustained isometric contractions of the wrist extensors/flexors influence hand-tracking accuracy.

Sustained Isometric Wrist Flexion and Extension Maximal Voluntary Contractions on Corticospinal Excitability to Forearm Muscles during Low-Intensity Hand-Gripping.

The wrist extensors demonstrate an earlier fatigue onset than the wrist flexors. However, it is currently unclear whether fatigue induces unique changes in muscle activity or corticospinal excitability between these muscle groups. The purpose of this study was to examine how sustained isometric wrist extension/flexion maximal voluntary contractions (MVCs) influence muscle activity and corticospinal excitability of the forearm.

Characterizing forearm muscle activity in young adults during dynamic wrist flexion-extension movement using a wrist robot.

Current research suggests that the wrist extensor muscles function as the primary stabilizers of the wrist-joint complex. However, most investigations have utilized isometric study designs, with little consideration for wrist dynamics or changes in posture. The purpose of the present study was to assess forearm muscle activity during the execution of dynamic wrist flexion/extension in multiple forearm orientations (pronation/supination).

Characterizing forearm muscle activity in university-aged males during dynamic radial-ulnar deviation of the wrist using a wrist robot.

Functioning as wrist stabilizers, the wrist extensor muscles exhibit higher levels of muscle activity than the flexors in most distal upper-limb tasks. However, this finding has been derived mostly from isometric or wrist flexion-extension protocols, with little consideration for wrist dynamics or radial-ulnar wrist deviations. The purpose of this study was to assess forearm muscle activity during the execution of dynamic wrist radial-ulnar deviation in various forearm orientations (pronation/supination).

Investigating the Muscular and Kinematic Responses to Sudden Wrist Perturbations During a Dynamic Tracking Task.

Sudden disturbances (perturbations) to the hand and wrist are commonplace in daily activities and workplaces when interacting with tools and the environment. It is important to understand how perturbations influence forearm musculature and task performance when identifying injury mechanisms. The purpose of this work was to evaluate changes in forearm muscle activity and co-contraction caused by wrist perturbations during a dynamic wrist tracking task.

The influence of simultaneous handgrip and wrist force on forearm muscle activity.

The purpose of this study was to examine forearm muscle activity during simultaneous execution of dual motor tasks; hand-gripping and wrist forces. Surface electromyography was recorded from eight muscles of the upper-limb: flexor carpi radialis, flexor carpi ulnaris, flexor digitorum superficialis, extensor carpi radialis, extensor carpi ulnaris, extensor digitorum, biceps brachii and triceps brachii. Participants were seated with their forearm supported in a neutral position with an adjustable force transducer placed on either the palmar or dorsal side of the hand (for palmar/dorsal forces).

THERABAND® CLX gold reduces knee-width index and range of motion during overhead, barbell squatting.

This study examined the influence of the Theraband CLX gold band on lower-limb muscle activity and kinematics during an overhead barbell squat. Participants performed two sets (band and no-band) of 12 repetitions of overhead barbell squats at 25% bodyweight. Three-dimensional kinematics were measured using motion capture with rigid bodies placed bilaterally on the foot, shank, thigh and thorax.

Upper extremity posture and muscle activity during IV pole interaction.

. The physical demands associated with patient handling activities have been well documented in healthcare. However, many activities contribute to the physical demands of caregivers.

Changes in Corticospinal and Spinal Excitability to the Biceps Brachii with a Neutral vs. Pronated Handgrip Position Differ between Arm Cycling and Tonic Elbow Flexion.

The purpose of this study was to examine the influence of neutral and pronated handgrip positions on corticospinal excitability to the biceps brachii during arm cycling. Corticospinal and spinal excitability were assessed using motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation (TMS) and cervicomedullary-evoked potentials (CMEPs) elicited via transmastoid electrical stimulation (TMES), respectively. Participants were seated upright in front on arm cycle ergometer.