Motor Control

PURPOSE: The purpose of this study was to examine the balance recovery strategy in children with hearing (HI) and visual impairments (VI) compared with those without these disorders. MATERIALS AND METHODS: This study featured a cross-sectional design with subjects (N = 45) placed within one of three equally stratified purposive groups (HI, VI, and comparison) within the age range of 9-13 years (mean = 11.43, SD = 1.5). Balance recovery strategy was measured in static and after-perturbation conditions by a four-camera Vicon system used to record three-dimensional lower body kinematic data...

The present study examined how humans use the target information provided immediately before the onset of motor output to prepare the initial motor command in the target force production task. Twenty healthy individuals participated in this study. A target cursor indicating the target force, and a force cursor indicating the force produced with index finger flexion were presented, and participants produced force in response to the appearance of the force cursor so that it moved toward the target cursor as fast as possible...

This study aimed to investigate the kinematic changes in obstacle avoidance and prehension tasks performed simultaneously by older adults with a history of falls at different levels of task difficulty. Twenty-six older adults were divided into faller and nonfaller groups. The experimental protocol was divided into two different tasks: walking with obstacle avoidance and walking with obstacle avoidance combined with a reach-to-grasp task. Two types of sensors (Kinect v2 and Leap Motion Controller, respectively) were used to analyze gait and grasp...

Several devices (e.g., linear transducers) have been used for predicting resistance training intensity. However, subjective scales, such as rating of perceived exertion (RPE), are proposed as reliable and easier-to-use tools for monitoring intensity during resistance training. Accordingly, different perceptive scales have been presented in previous research for monitoring intensity during resistance training with elastic bands. The aim was to assess the accuracy and reliability of RPE for quantifying the potential maximal repetitions that could be performed at a given RPE (from 2 to 8 of 10) obtained in the first repetition...

This cross-sectional study examined the immediate effects of four types of real-time feedback during overground gait performed using inertial measurement units on gait kinematics in healthy young participants. Twelve healthy young participants (mean age: 27.1 years) performed 60-s gait trials with each of the following real-time feedback: walking spontaneously (no feedback trial); increasing the ankle plantar-flexion angle during the late stance (ankle trial); increasing the leg extension angle, defined the location of the ankle joint relative to the hip joint in the sagittal plane, during late stance (leg trial); and increasing the knee flexion angle during the swing phase (knee trial)...

Humans experience unanticipated external postural perturbations and recover their posture faster via involuntary responses than voluntary responses. Previous cross-sectional comparisons between athletes and untrained populations have suggested that daily motor experiences can lead to adaptations in the reflex system, but the temporal aspect of this adaptation has been unclear. Here we show that judokas have an earlier muscle activation response to even non-judo-specific external perturbations compared with an untrained population...

BACKGROUND: Individuals with visual impairment have balance deficits; therefore, this systematic review aimed to provide comprehensive insights into the balance control of individuals with visual impairments when compared with individuals with full vision. METHODS: Primary sources were obtained from eight databases including PubMed, LILACS, Science Direct, SCOPUS, CINAHL, PEDro, CENTRAL, and Web of Science. The search period covered years from inception to January 10, 2022...

Deficits in movement patterns during cutting while running might place soccer players at risk of injury. The objective was to compare joint angles and intersegment coordination between sexes and ages during an unanticipated side-step cutting task in soccer players. This cross-sectional study recruited 11 male (four adolescents and seven adults) and 10 female (six adolescents and four adults) soccer players. Three-dimensional motion capture was used to measure lower-extremity joint and segment angles as participants performed an unanticipated cutting task...

The referent control theory (RCT) for action and perception is an advanced formulation of the equilibrium-point hypothesis. The RCT suggests that rather than directly specifying the desired motor outcome, the nervous system controls action and perception indirectly by setting the values of parameters of physical and physiological laws. This is done independently of values of kinematic and kinetic variables including electromyographic patterns describing the motor outcome. One such parameter-the threshold muscle length, λ, at which motoneurons of a given muscle begin to be recruited, has been identified experimentally...

Wearing loose footwear, such as slippers, poses a risk factor for tripping. Previous studies have examined obstacle crossing to find strategies to avoid tripping. However, the effect of wearing slippers on the likelihood of tripping remains unclear. Therefore, this study aimed to determine whether wearing slippers while level walking and obstacle crossing affects kinematic characteristics and muscle activity. Sixteen healthy, young adults performed two tasks (a) while wearing slippers and (b) while barefoot: (1) level walking and (2) crossing a 10-cm obstacle...

BACKGROUND: Transcranial direct current stimulation (tDCS) has been demonstrated to facilitate motor performance in healthy individuals; however, results are variable. The neuromodulatory effects of tDCS during visuomotor tasks may be influenced by extrinsic visual feedback. However, this interaction between tDCS and visual feedback has not been explored for the lower limb. Hence, our objective was to explore if tDCS over the primary lower limb motor cortex differentially facilitates motor performance based on the availability of visual feedback...

Manual Reaction Time measures have been widely used to study interactions between perceptual, cognitive, and motor functions. The Stimulus-Response Compatibility is a phenomenon characterized through faster Manual Reaction Times when stimuli and response locations coincide (correspondent condition) than when they are on different sides (noncorrespondent condition). The present study adapted a protocol to study if the Stimulus-Response Compatibility effect can be detected during a virtual combat simulation. Twenty-seven participants were instructed to defend themselves by clicking a key in order to block the presented punch...

The purpose of this study was to assess the efficacy of a combined training program (CTP) in reducing the effects of dual tasking on the temporal parameters and kinematics of gait, as compared with single-task gait. A controlled, randomized, intervention study was performed in an intervention group and a control group. The intervention group attended three weekly CTP sessions for 24 weeks. Gait pattern was evaluated prior to the baseline intervention, at 12 weeks, and at 24 weeks (Repost). The sample was composed of 22 subjects diagnosed with multiple sclerosis with an Expanded Disability Status Scale score of 0-5...

This narrative review seeks to compare the various ways in which motor creativity has been measured and to critically evaluate those methods within the context of our contemporary understanding of motor creativity. Eligible studies included those of any study design, experimental or observational, as long as motor creativity was measured. Three databases (i.e., PubMed, Scopus, and ScienceDirect) were searched from the earliest possible start dates to December 2021. No risk of bias assessment was performed as the study outcomes were not the focus of the review...

The aim of this study was to explore the effects of mental fatigue from smartphone use and Stroop task on bench press force-velocity (F-V) profile, one-repetition maximum (1RM), and countermovement jump (CMJ) performance. Twenty-five trained subjects (age = 25.8 ± 5.7 years) completed three sessions separated by 1 week following a randomized double-blinded crossover design. Each session consisted of F-V relationship, 1RM, and CMJ measurements after performing 30 min of control, social media, or Stroop task...

This study aims to analyze the effects of a training program based on practice variability on the speed and accuracy of the tennis forehand approach to the net shot. The study sample consisted of 35 players of both genders, 22 men and 13 women (age 44 ± 10.9 years, height 1.73 ± 0.8 cm, and weight 74.7 ± 8.4 kg). Players were randomly distributed into two groups (control group = 18 and experimental group = 17). Both training groups worked a total volume of 4 weeks, seven sessions, and 15 min per session of forehand approach shot...

This study aimed to explore the effects of mental fatigue (MF) induced by an incongruent Stroop task (ST) and by using social media (SM) compared to watching a documentary (control) on dynamic resistance training. Twenty-one resistance-trained males attended three identical experimental sessions with the only difference of the randomized cognitive task (ST, SM, or control). Each session consisted of (a) baseline MF and motivation visual analogue scale responses, (b) cognitive task, (c) postvisual analogue scale responses, (d) warm-up, and (e) resistance training based on three sets of bench press at 65% of one-repetition maximum till concentric failure...

The aim of this systematic review was to investigate the effect of specific sprint and vertical jump training interventions on transfer of speed-power parameters. The data search was carried out in three electronic databases (PubMed, SCOPUS, and SPORTDiscus), and 28 articles were selected (13 on vertical jump training and 15 on sprint training). We followed the PRISMA criteria for the construction of this systematic review and used the Physiotherapy Evidence Database (PEDro) scale to assess the quality of all studies...

The purpose of the present systematic review and meta-analysis was to explore the effects of mental fatigue on upper and lower body strength endurance. Searches for studies were performed in the PubMed/MEDLINE and Web of Science databases. We included studies that compared the effects of a demanding cognitive task (set to induce mental fatigue) with a control condition on strength endurance in dynamic resistance exercise (i.e., expressed as the number of performed repetitions at a given load). The data reported in the included studies were pooled in a random-effects meta-analysis of standardized mean differences...

Contemporary descriptions of motor control suggest that variability in movement can be indicative of skilled or unskilled performance. Here we used principal component analysis to study the kicking performance of elite and sub-elite soldiers who were highly familiar with the skill in order to compare the variability in the first and second principal components. The subjects kicked a force plate under a range of loaded conditions, and their movement was recorded using optical motion capture. The first principal component explained >92% of the variability across all kinematic variables when analyzed separately for each condition, and both groups and explained more of the variation in the movement of the elite group...