Hand preference, performance abilities, and hand selection in children

Retrospective MRI analysis of 418 adult shoulder joints to assess the physiological morphology of the glenoid in a low-grade osteoarthritic population

BACKGROUND

Due to the difference in size between the humeral head and the glenoid, the shoulder joint is prone to instability. Therefore, the reconstruction of the physiological joint morphology is of great importance in shoulder joint preservation and replacement surgery. The aim of this study was to describe physiological reference parameters for the morphology of the glenoid for the first time.

MATERIAL AND METHODS

MRI images of the shoulder joints of 418 patients (mean age: 50.6 years [± 16.3]) were retrospectively analysed in a low-grade osteoarthritic population. The glenoid distance in coronal (GDc) and axial view (GDa), glenoid inclination (GI) and version (GV) as well as scapula neck length (SNL) were measured. Parameters were studied in association for age, gender, side and degeneration grade.

RESULTS

Mean GDc was 33.4 mm (± 3.6), mean GDa 26.8 mm (± 3.2), mean GI 10.5° (± 6.4), mean GV -0.4 mm (± 5.4) and mean SNL was 33.4 mm (± 4.7). GDa was significant higher in right shoulders (p < 0.001). GDc and GDa showed significant higher mean values in older patients (p < 0.001) and in shoulders with more severe degenerative changes (p < 0.05). While GDc, GDa and SNL were significant larger in male patients (p < 0.001), GI had a higher mean value in female shoulders (p = 0.021).

CONCLUSION

Age, gender and shoulder joint degeneration influence changes in the morphological parameters of the glenoid. These findings have to be considered in shoulder diagnostics and surgery.

CLINICAL TRIAL NUMBER

Not applicable.

Age, Sex, and Anatomical Location Patterns in Cutaneous Pyogenic Granuloma Cases

Importance

Cutaneous pyogenic granulomas (PGs) are commonly encountered, benign, vascular tumors, in which epidemiologic factors have been variably reported, in part, due to sample size limitations and a focus on either adult or pediatric patients.

Objective

To assemble a large dataset of pathologically diagnosed PGs across the continuum of age and investigate patterns of PGs by demographic factors, including age, sex, and anatomical location.

Design, Setting, and Participants

This retrospective case series included case reports of patients with pathologically confirmed PGs of cutaneous origin reported between April 1, 2010, to March 31, 2020. The pathology database at a large tertiary academic center in the Midwestern US was queried for case reports that included the term pyogenic granuloma or lobular capillary hemangioma. Individuals were included in the analytic sample if they had a pathologically confirmed diagnosis of a PG. PG cases were excluded if they included PG only as a part of the pathological differential diagnoses; were recurrent; or were of noncutaneous origin. These data were analyzed between March 2022 and March 2023.

Main Outcomes and Measures

The main outcomes were sex biases in frequency overall, by anatomical region, and by left-right laterality using exact binomial tests. Additional outcomes included differences in age-by-sex distribution overall and by anatomical region using Kolmogorov-Smirnov tests.

Results

Of 1009 unique pathologically confirmed PG records from 987 individuals, 376 individuals (38.1%) were younger than 18 years, of whom 122 (32.4%) were female. A total of 611 individuals were 18 years and older, of whom 364 (59.6%) were female. Overall, PGs between male and female individuals were equally distributed for all anatomical locations except lower extremities, in which females were more frequently affected. The distribution of PGs by age was significantly different between male and female individuals, with this difference primarily associated with the head/neck and trunk but not with upper extremity or lower extremity anatomical locations. Neither left-right laterality bias among upper extremity PGs nor anterior-posterior bias among truncal PGs was observed.

Conclusions and Relevance

In this retrospective case series, an age-by-sex interaction was found in the incidence of PGs, with PGs on the head/neck and trunk being more common in males younger than 20 years and in females 20 to 50 years of age. These findings suggest that trauma may not be a major etiologic factor for PGs. Future studies are necessary to confirm this and to understand the causes of the age-by-sex interaction.

Quantifying Hand Motion Complexity in Simulated Sailing Using Inertial Sensors

The control of hand movement during sailing is important for performance. To quantify the amount of regularity and the unpredictability of hand fluctuations during the task, the mathematical algorithm Approximate Entropy (ApEn) of the hand acceleration can be used. Approximate Entropy is a mathematical algorithm that depends on the combination of two input parameters including (1) the length of the sequences to be compared (m), and (2) the tolerance threshold for accepting similar patterns between two segments (r). The aim of this study is to identify the proper combinations of 'm' and 'r' parameter values for ApEn measurement in the hand movement acceleration data during sailing. Inertial Measurement Units (IMUs) recorded acceleration data for both the mainsail (non-dominant) and tiller (dominant) hands across the X-, Y-, and Z-axes, as well as vector magnitude. ApEn values were computed for 24 parameter combinations, with 'm' ranging from 2 to 5 and 'r' from 0.10 to 0.50. The analysis revealed significant differences in acceleration ApEn regularity between the two hands, particularly along the Z-axis, where the mainsail hand exhibited higher entropy values (p = 0.000673), indicating greater acceleration complexity and unpredictability. In contrast, the tiller hand displayed more stable and predictable acceleration patterns, with lower ApEn values. ANOVA results confirmed that parameter 'm' had a significant effect on acceleration complexity for both hands, highlighting differing motor control demands between the mainsail and tiller hands. These findings demonstrate the utility of IMU sensors and ApEn in detecting nuanced variations in acceleration dynamics during sailing tasks. This research contributes to the understanding of hand-specific acceleration patterns in sailing and provides a foundation for further studies on adaptive sailing techniques and motor control strategies for both novice and expert sailors.

Handedness in Alzheimer's disease: A systematic review

Handedness has traditionally been employed as a proxy of brain lateralization in research. Alzheimer's disease (AD) manifests as a neurodegenerative disorder characterized by impairments across various neuropsychological functions, including visuospatial and language, many of which exhibit lateralization in the human brain. While previous studies have investigated the relationship between AD and handedness, findings have been inconsistent. This article aims to provide an up-to-date overview of studies investigating hand preference in AD and the subtypes, specifically early- and late-onset AD. Through a synthesis of these studies, we conclude that handedness currently lacks utility as a diagnostic biomarker for AD and its subtypes, and this is further supported by the meta-analytic results based on data from over 10,000 AD patients. We emphasize the necessity for future research endeavors, particularly those leveraging advanced neuroimaging techniques to explore the role of brain asymmetry in AD.

Prevalence and plasma exosome-derive microRNA diagnostic biomarker screening of adolescent idiopathic scoliosis in Yunnan Province, China

Background

Idiopathic scoliosis significantly affects the physical and mental health of children and adolescents, with varying prevalence rates in different regions. The occurrence of idiopathic scoliosis is associated with genetic regulation and biochemical factors, but the changes in exosome-derived miRNA profiles among idiopathic scoliosis patients remain unclear. This study aimed to determine the prevalence of idiopathic scoliosis in Yunnan Province, China, and identify key exosome-derived miRNAs in idiopathic scoliosis through a cohort study.

Methods

From January 2018 to December 2020, a cross-sectional study on idiopathic scoliosis in children and adolescents was conducted in Yunnan Province. A total of 84,460 students from 13 cities and counties in Yunnan Province participated in a scoliosis screening program, with ages ranging from 7 to 19 years. After confirmation through screening and imaging results, patients with severe idiopathic scoliosis and normal control individuals were selected using propensity matching. Subsequently, plasma exosome-derived miRNA sequencing and RT-qPCR validation were performed separately. Based on the validation results, diagnostic performance analysis and target gene prediction were conducted for differential plasma exosome-derived miRNAs.

Results

The overall prevalence of idiopathic scoliosis in children and adolescents in Yunnan Province was 1.10%, with a prevalence of 0.87% in males and 1.32% in females. The peak prevalence was observed at age 13. Among patients diagnosed with idiopathic scoliosis, approximately 12.8% had severe cases, and there were more cases of double curvature than of single curvature, with thoracolumbar curvature being the most common in the single-curvature group. Sequencing of plasma exosome-derived miRNAs associated with idiopathic scoliosis revealed 56 upregulated and 153 downregulated miRNAs. Further validation analysis confirmed that hsa-miR-27a-5p, hsa-miR-539-5p, and hsa-miR-1246 have potential diagnostic value.

Conclusions

We gained insights into the epidemiological characteristics of idiopathic scoliosis in Yunnan Province and conducted further analysis of plasma exosome-derived miRNA changes in patients with severe idiopathic scoliosis. This study has provided new insights for the prevention and diagnosis of idiopathic scoliosis, paving the way for exploring clinical biomarkers and molecular regulatory mechanisms. However, further validation and elucidation of the detailed biological mechanisms underlying these findings will be required in the future.

Is it possible to identify physical-motor profiles of preschool children on their association with selected biosocial factors?

Biosocial factors play a crucial role in the physical-motor development (PMD) of children during the preschool age. The present study aims to identify physical-motor profiles throughout preschool age (3-6 years) and explore associations between profiles and selected biosocial factors such as age, sex, prematurity, weight, height, BMI, and participation in extracurricular physical activities. Data from 412 typically developing children (46.6% girls and 53.4% boys), aged 35-71 months (M = 51.21, SD = 10.47) was collected using the Psychomotor Activities Checklist and specifically the scale of Psycho-Motor Aspects. Cluster analysis made it possible to define four different childhood PMD profiles. High PMD; High PMD except left laterality; medium-low PMD; and low PMD. High PMD profile includes older children, with anthropometric measurements closer to the WHO recommendations, fewer preterm children, and greater participation in extracurricular physical activities. Low PMD profile includes younger children, with weight slightly above and height slightly below the WHO recommendations and low participation in extracurricular physical activities. This study allows us to identify specific trends that may be decisive for the motor development of children throughout preschool age, highlighting selected biological variables and participation in extracurricular physical activities.

Laterality and otorhinolaryngology: a review

BACKGROUND

Laterality of paired organs involves the function of the eyes, ears, hands and feet. Whilst most people have a right-handed preference, about 10 per cent are left-handed. Similarly, the right eye is usually preferred to the left. Medicine is both taught and practised for those with right hand and eye preference, and left-handed medical students and doctors must negotiate the right-handed world.

OBJECTIVE

This brief review looks at society's attitudes, medical training and the practice of otolaryngology in the UK towards laterality and handedness.

METHOD

Literature review.

RESULTS

Studies suggest that left-handers are more versatile and so are more ambidextrous. Conversely, this may result in problems when a right-hander tries to undertake a procedure with the non-dominant hand.

CONCLUSION

Cultures and attitudes are changing towards those who are left-handed. Left-handed surgeons may encounter difficulties in the clinical environment throughout their training.

Handedness, Bilateral, and Interdigit Strength Asymmetries in Male Climbers

PURPOSE

To determine whether there are bilateral and interdigit differences in the maximal force production of experienced climbers and whether these differences are mediated by ability level or preferred style of climbing.

METHODS

Thirty-six male climbers (age 30 [9.4] y) took part in a single-session trial to test their maximal force production on both hands. The tests included a one-arm maximal isometric finger flexor strength test (MIFS) and a one-arm individual MIFS. Bilateral differences were analyzed by strongest hand (defined as the hand that produced the highest MIFS value) and dominance (defined as the writing hand).

RESULTS

A pairwise t test found that MIFS was significantly greater for the strongest hand (mean difference = 4.1%, 95% CI, -0.052 to 0.029, P < .001), with handedness explaining 89% of the variation. A 2-way mixed-model analysis of variance determined that there were no interactions between preferred style (bouldering or sport climbing) and MIFS or between ability level (advanced or elite) and MIFS.

CONCLUSIONS

Climbers have significant finger flexor strength bilateral asymmetries between their strongest and weakest hand. Moreover, when dominance is controlled, this difference in strength is present, with the dominant hand producing more force. Neither preferred style of climbing nor the ability level of the climbers could explain these asymmetries. As such, practitioners should consider regularly monitoring unilateral strength, aiming to minimize the likelihood of large bilateral asymmetry occurring.

Adding up fine motor skills: Developmental relations between manual dexterity and numerical abilities

The strength and development of the relationship between mathematical and motor skills is explored across three age groups of normally developing children. The presence of this relationship is postulated in classical accounts of human development. In contemporary research, the existence of a relationship between motor development and the development of abstract concepts may inform theories of embodied cognition. Existing work supports a link between fine motor skills and various numerical and mathematical tasks in young children; however, few attempts have been made to investigate this relationship across different ages. We use a cross-sectional design to investigate the link between fine motor and mathematical skills in samples of 81-96 Kindergarten, 2nd-grade, and 4th-grade children. Bayesian correlations were performed to explore the relationship between fine motor skills and mathematical skills at different time points. The results show that correlational patterns vary across the three ages: in Kindergarten, manual dexterity of the dominant hand is related to math skills, in 2nd grade, the manual dexterity of the nondominant hand is related to math skills; and finally in 4th grade no such correlations are observable. These findings contribute to understanding the developmental trajectory of the relationship between motor skills and mathematical abilities and the internalization of numerical embodiment. Further investigation is needed to determine if fine motor skills can serve as an early indicator of mathematical skill development risk. Future work could also explore whether incorporating spatial and motor elements into mathematical tasks through whole-body or finger movement training supports the development of mathematical skills.

Influence of target location, task complexity, and gender on children's use of their preferred foot

The goal of the present study was to compare the choice of foot of right-footed children with varying strengths of foot preference when performing two tasks of different levels of complexity at three spatial locations. 30 right-footed children were tested. The results showed that the general tendency to use one's preferred foot to interact with an object is more or less pronounced depending on the object's location and the complexity of the task. The children used their non-preferred left foot more often during the simple task and when the object was presented to the left. Our findings also revealed interactions between gender, age, and spatial location. At five, girls used globally less their left foot than boys. In addition, girls used their preferred right foot more frequently than boys when the object was presented to the left. Based on these results, it can be concluded that foot selection depends on foot preference, task demand, environmental context, and biological factors associated with motor dominance.

Developmental models of motor-evoked potential features by transcranial magnetic stimulation across age groups from childhood to adulthood

To derive the maturation of neurophysiological processes from childhood to adulthood reflected by the change of motor-evoked potential (MEP) features. 38 participants were recruited from four groups (age mean in years [SD in months], number (males)): children (7.3 [4.2], 7(4)), preadolescents (10.3 [6.9], 10(5)), adolescents (15.3 [9.8], 11(5)), and adults (26.9 [46.2], 10(5)). The navigated transcranial magnetic stimulation was performed on both hemispheres at seven stimulation intensity (SI) levels from sub- to supra-threshold and targeted to the representative cortical area of abductor pollicis brevis muscle. MEPs were measured from three hand- and two forearm-muscles. The input-output (I/O) curves of MEP features across age groups were constructed using linear mixed-effect models. Age and SI significantly affected MEP features, whereas the stimulated side had a minor impact. MEP size and duration increased from childhood to adulthood. MEP onset- and peak-latency dropped in adolescence, particularly in hand muscles. Children had the smallest MEPs with the highest polyphasia, whereas I/O curves were similar among preadolescents, adolescents, and adults. This study illustrates some of the changing patterns of MEP features across the ages, suggesting developing patterns of neurophysiological processes activated by TMS, and to motivate studies with larger sample size.

How we get a grip: Microstructural neural correlates of manual grip strength in children

Maximal grip strength is associated with a variety of health-related outcome measures and thus may be reflective of the efficiency of foundational brain-body communication. Non-human primate models of grip strength strongly implicate the cortical lateral grasping network, but little is known about the translatability of these models to human children. Further, it is unclear how supplementary networks that provide proprioceptive information and cerebellar-based motor command modification are associated with maximal grip strength. Therefore, this study employed high resolution, multi-shell diffusion and quantitative T1 imaging to examine how variations in lateral grasping, proprioception input, and cortico-cerebellar modification network white matter microstructure are associated with variations in grip strength across 70 children. Results indicated that stronger grip strength was associated with higher lateral grasping and proprioception input network fractional anisotropy and R1, indirect measures consistent with stronger microstructural coherence and increased myelination. No relationships were found in the cerebellar modification network. These results provide a neurobiological mechanism of grip behavior in children which suggests that increased myelination of cortical sensory and motor pathways is associated with stronger grip. This neurobiological mechanism may be a signature of pediatric neuro-motor behavior more broadly as evidenced by the previously demonstrated relationships between grip strength and behavioral outcome measures across a variety of clinical and non-clinical populations.

Stress exposure, hand preference, and hand skill: A deep phenotyping approach

ABSTRACTStress exposure and reactivity may show differential associations with handedness, but shallow phenotyping may influence the current knowledge. Importantly, different handedness measures do not necessarily show high correlations with each other and should not be used interchangeably as they may reflect different dimensions of laterality. Here, data on handedness from 599 participants in the population-based, longitudinal Dortmund Vital Study was used to determine various asymmetry indices. Hand preference was assessed with the Edinburgh Handedness Inventory (EHI) and the lateral preference inventory (LPI) measuring handedness, footedness, earedness, and eyedness. Hand performance was determined using the pegboard test. In addition, data on several dimensions of stress exposure and reactivity, including hair cortisol, and mental well-being was analysed to determine associations with handedness. All handedness measures correlated significantly with each other, with the strongest correlation between the EHI and the LPI handedness score. The EHI and LPI hand measures resulted in the highest effect sizes and most consistent correlations with stress or mental well-being. In contrast, the pegboard test only showed very little association with the stress and mental well-being measures. This highlights the importance of handedness phenotyping. Including preference measures is recommended to disentangle the link between handedness and mental health.

Age and Gender Differences in Anthropometric Characteristics and Motor Performance of 3 through 6 Young Kids Aged (Pilot Study)

BACKGROUND

It is crucial to evaluate children's motor coordination and strength to identify possible motor deficits on the right or left side of the body. However, whether a distinction exists in children aged 3-6 must be clarified. The goal of the current research was to investigate the differences in motor skills between preschool boys and girls, dominant and non-dominant hands or legs, in children of preschool age. (2) Methods: The present study was conducted on a sample of children (boys, n = 52; girls, n = 52; age range, 3-6 years). Three motor tests evaluated on both sides of the body served as the sample of factors used to measure athletic performance. Leg tapping (15 s), hand tapping (15 s), and a maximal hand grip strength (HGS) test kg. (3) Results: The study's findings show no statistically significant variations in preschool boys' and girls' motor skills. Preschool girls had better results in the right leg tapping than preschool boys t (98) = 2.08; p ≤ 0.04. We found a significant difference between genders aged 3-4, 4-5, and 5-6 years. No correlation was found between the girls' three variables and age. A small but significant positive correlation was found between dominant hand tapping and age r² (52) = 0.21; p ≤ 0.01, dominant leg tapping and age r² (52) = 0.20; p ≤ 0.01 and dominant HGS and age r² (52) = 0.17; p ≤ 0.01. No noticeable differences were identified when comparing the dominant side with the non-dominant side in each group. The results show that most children prefer to use their right hand and right leg as their dominant sides. (4) Conclusion: The authors of this study focus on the functional (frequency of movements) and dynamic (differences in muscle strength between body sides) elements of asymmetry. Future studies should examine the influence of morphology on performance with the dominant or non-dominant body side.

Kinesthetic Coordination Abilities in 6-Year-Old Children: School Quintile, Gender, and Hand Dominance Differences

Proprioceptive kinaesthetic control underpins motor movements of developing children and can be influenced by several factors. The main aim of this study was to establish proprioceptive kinaesthetic coordination differences in six-year-olds from different school quintiles, of different genders, and with different handedness. A total of 193 six-year-olds from 10 schools of different quintiles in the Motheo District, Mangaung, were included, of which 97 (50.3%) were boys and 96 (49.7%) were girls. A quantitative cross-sectional study design was followed to determine proprioceptive kinaesthetic coordination differences. Right-handed participants performed significantly better than left-handed participants in the Finger-to-Nose task (p = 0.0125) when moving and positioning their dominant arm and hand. When using their dominant arm, significant differences in the shoulder-level-arm-raise (p = 0.0288) favoured boys. Girls showed superior execution of the force perception task (p = 0.0322). In conclusion, significant proprioceptive kinaesthetic coordination differences in six-year-olds were mainly not evident. Future work should explore proprioceptive kinaesthetic coordination differences in children of other ages and determine the practical implications of identified differences.

Handedness in low-birthweight children: Insights in lateralization

Low-birthweight (LBW) children (n = 96) weighing less than 2.5 kg at birth and normal birthweight (NBW) children (n = 96) from Delhi, India, between the ages of 5 and 12 years were assessed for intelligence with Ravens Colored Progressive Matrices (RCPM), their handedness and hand proficiency for unimanual and bimanual performance. The objective was to know if there is a relation between birthweight and the development of handedness. Compared with NBW children, the LBW group had lower percentile scores for the RCPM. The LBW children were less lateralized than the NBW children in the hand preference test. The LBW children were faster than the NBW for sorting objects with each hand separately, but they were slower in the bimanual envelope task. This indicates a delay in interhemispheric transfer and the development of the corpus callosum that connects the cerebral hemispheres to enable bimanual coordination. In the absence of more direct evidence, hand skill was used as an index of the extent of lateralized control for performance. Findings indicate a relation between birthweight and lateralization in children tested for hand preference.

Does the Degree and/or Direction of Handedness in Children With Developmental Coordination Disorder Influence Motor and Cognitive Performance? A Pilot Study

Research has shown that nonright-handedness in children with developmental coordination disorder (DCD) is associated with poorer motor and cognitive performance. This study investigated the influence of degree and direction of handedness on performance using the Home Handedness Questionnaire, the Hit-the-Dot test, the Movement Assessment Battery for Children, and the digital Trail-Making Test. Eighteen children with DCD and 21 typically developing children aged 8–12 years participated in this study. The distribution of degree and direction of handedness in the group of DCD children were not different from that found in the typically developing group. In the Hit-the-Dot test, typically developing children significantly performed better than children with DCD, no matter which hand was dominant or to which degree. A significant inconsistent-handed advantage in the subdomain balance was found for children with DCD. Inconsistent handedness also seems to be an advantage for children with DCD on the digital Trail-Making Test performance. The relationship between the subcategories of the Movement Assessment Battery for Children and the digital Trail-Making Test part B is stronger for consistent than for inconsistent handedness. Our findings suggest that children with DCD and inconsistent handedness might benefit from greater crosstalk across hemispheres. In addition, these predispositions can be reinforced or discouraged throughout development and via occupational therapy.

Influence of long-term participation in amateur sports on physical posture of teenagers

Aim

The aim of this cross-sectional study was to explore the influence of long-term participating in amateur sports on body posture of school students.

Methods

A survey on sport participation was conducted on 1,658 volunteer students aged from 6 to 17 years in two primary schools and one meddle school in Tianjin city. The PA200LE body posture evaluation system and a SpineScanSH-115 electronic spine measuring instrument were used to assess the participants' body posture. According to the survey results and against the inclusion and exclusion criteria, 1,124 eligible participants were divided into seven sport participation groups and seven age-matched control groups for statistical comparisons.

Results

Compared with the age-matched controls, the natural standing thoracic kyphosis angle of the swimming group (35.0 ± 9.5 VS 31.2 ± 8.5; t =  - 2.560; p = 0.011) and the football group (34.6 ± 7.2 VS 31.9 ± 7.5; t =  - 2.754; p = 0.006) were found to be significantly larger; the natural standing lumbar lordosis angle (-23.0 ± 11.0 VS -27.0 ± 11.1; t = 0.344; p = 0.024) and the upright sitting lumbar lordosis angle (-11.7 ± 8.4 VS -15.2 ± 12.3; t = 5.738; p = 0.030) of the swimming group was significantly smaller; the upright sitting thoracic kyphosis angle of the running group (25.1 ± 9.3 VS 22.6 ± 9.9; t =  - 1.970; p = 0.050) was significantly larger; the upright sitting thoracic kyphosis angle (23.9 ± 8.9 VS 27.0 ± 7.6; t = 2.096; p = 0.038), the learning position thoracic kyphosis angle (31.0 ± 8.6 VS 37.1 ± 8.9; t = 3.076; p = 0.003), the shoulder level (-1.3 ± 2.1 VS 0.0 ± 2.5; t = 2.389; p = 0.019) and waist level (-1.2 ± 1.7 VS -0.3 ± 1.7; t = 2.511; p = 0.013) of the table tennis group were significantly smaller.

Conclusions

The results showed that long-term participation in recreational sports training had an impact on the physical posture of adolescents.

Could hand-eye laterality profiles affect sport performance? A systematic review

Background

Laterality effects on sports performance have been a field of interest for the sports sciences, especially in asymmetrical sports, which require the preferential use of one side of the body. Some sports in particular involve the visual system and ocular laterality, due to the need to clearly focus on a dynamic object (ball, opponent, projectile, etc.). The relationship between manual and ocular laterality results in two perceptual-motor profiles, one where the dominant hand and eye are ipsilateral (uncrossed hand-eye laterality profile, UC-HELP), and the other where they are contralateral (crossed hand-eye laterality profile, C-HELP).

Methodology

A systematic review of the literature was carried out to determine the prevalence of hand-eye laterality profiles in the different sports modalities and their relationship with psychological factors and sports performance. Searches of PsycInfo, Medline, Scopus and grey literature identified 14 studies (2,759 participants) regarding hand-eye laterality in sports that met the eligibility criteria.

Results

Previous studies have estimated that between 10-30% of the general population exhibit a C-HELP, and 70-90% have an UC-HELP. The results of the reviewed studies indicate that in some sports the percentage of C-HELP is higher in regular and high-level athletes than in the normal population: golf (52.55%), soccer (53%), tennis (42%) and team sports (50.7%). In target sports (archery and shooting) athletes with an UC-HELP seem to have an advantage given the significant concentration of this profile in the highest performing populations (82.3%). In basketball, cricket and golf, the literature reviewed also reported biomechanical differences in the execution of some techniques between the two profiles. We did not find any study in our review that related hand-eye laterality with cognitive, tactical, or psychological aspects of athletes.

Conclusions

These results should be taken with great caution due to the potential bias linked to the methodologies used in the investigations, the heterogeneity in the assessment of hand-eye laterality, the few studies available on the subject and the indirect nature of many of the observed relationships between performance and laterality. For further investigation, we propose a standardized terminology and protocol of hand-eye laterality assessment in sports. The advancement in knowledge about hand-eye laterality profiles, along with the study of the relationship with psychological or tactical-sports patterns, can contribute to more effective development plans for athletes and can be a complement to talent detection.

Handgrip strength and its correlation with anthropometric determinants and hand dimensions in children aged 6-12 years: A cross-sectional study

BACKGROUND

Handgrip strength is considered an important interpreter of general health, and hand functions in children. It is mainly influenced by anthropometric determinants and hand dimensions.

OBJECTIVE

To assess the handgrip strength and their association with anthropometric determinants, hand circumference, hand span, and hand length among school children in both the dominant and non-dominant hand.

METHODS

Anthropometric measurements, hand circumference, hand span, hand length, and grip strength measurements were obtained from 133 school children of both genders aged 6-12 years. A Jamar hand-held dynamometer was used to measure handgrip strength and the hand dimensions with a tape measure in cm.

RESULTS

Significant differences were found between the handgrip strength among boys and girls. The dominant hand was found to be sturdier than the non-dominant hand in both genders. We also found a significant correlation of anthropometric determinants and hand dimensions with handgrip strength. Age, BMI, hand circumference, hand span, and hand length had a strong correlation with grip strength (p < 0.01).

CONCLUSIONS

The study revealed the reference values and concluded its correlations with hand dimensions among school children aged 6-12 years and this information can serve as a manual for interpretation of handgrip strength measurements in children.

Age-dependent perturbation of the perceptual and postural vertical by visual roll vection and susceptibility to motion sickness in children

BACKGROUND

The visual contribution to the perceptual and postural vertical is mediated by a multisensory integration process and may relate to children's susceptibility to motion sickness that is hypothesized to arise from intersensory conflicts.

OBJECTIVE

To analyze the maturation of visual contribution to the perceptual and postural vertical in conjunction with the motion sickness susceptibility in childhood.

METHODS

In 81 healthy children (aged 2-17 years; 57 females), adjustments of the subjective visual vertical and posturographically tested mediolateral displacements of body sway were measured during free upright stance and large-field visual motion stimulation in the roll plane (roll vection). Motion sickness susceptibility was assessed by taking the history of parents and children.

RESULTS

Vection-induced tilts of the visual vertical showed a linear age-dependent decrease with largest tilts in the youngest (2-7 years; median of 20°) and smallest tilts in the oldest age group (13-17 years; median of 9-10°). Analogously, postural tilts as measured by mediolateral body sway were greatest in the youngest and smallest in the oldest age group. In contrast, motion sickness susceptibility was lowest in the youngest and highest in the oldest age group and exhibited an inverse correlation with vection-induced tilts of the visual vertical.

CONCLUSION

Roll vection-induced tilts of the visual and postural vertical exhibited a similar age-dependent course with the greatest effects in the youngest and the least effects in the oldest age group, the latter of which exhibited the highest susceptibility to motion sickness.

Physiological Offset Parameters of the Adult Shoulder Joint-A MRI Study of 800 Patients

Background: Humeral offset (HO) and glenoidal offset (GO) are important morphological parameters in diagnostics and therapy for shoulder pathologies. However, physiological reference values have not yet been sufficiently determined. The aim of the present study was to establish physiological reference values for shoulder offset parameters (SOPs). Methods: MRI images of the shoulder joints of 800 patients (mean age: 50.13 years [±16.01]) were analysed retrospectively. HO, GO, lateral glenoidal humeral offset (LGHO), humeral shaft axis offset (HAO) and cortical offset (CO) were measured. SOPs were examined for associations with age, gender, side and osteoarthritis. Results: The mean HO was 26.19 (±2.70), the mean GO was 61.79 (±5.67), the mean LGHO was 54.49 (±4.69), the mean HAO was 28.17 (±2.82) and the mean CO was 16.70 (±3.08). For all SOPs, significantly higher values were measured in male shoulders. There was a significantly (p < 0.001) higher mean value for HO, GO and LGHO in right shoulders. There was a significant correlation between age and LGHO, and HAO and CO, but not between age and HO or GO. Shoulders with osteoarthritis and non-osteoarthritis did not differ in the mean value of HO, GO, LGHO and HAO, except for CO (p = 0.049). Conclusion: Reference values for SOPs in the adult shoulder joint were determined for the first time. Significant gender-specific differences were found for all measured SOPs. In addition, it was seen that for some SOPs, the joint side and the patient’s age has to be taken into account in shoulder diagnostics and surgery.

Waterloo Handedness Questionnaire: Cross-Cultural Adaptation and Psychometric Properties of the Arabic Version

Handedness is one of the most studied behavioural predictors of cerebral lateralization. Assessing handedness is often essential in neuropsychology and motor behaviour research. Thus, it is important that self-reported assessment tools for determining handedness are available in multiple languages for different cultures. The purpose of the present study was to conduct a translation and cross-cultural adaptation of the Waterloo Handedness Questionnaire into the Arabic language and to assess its psychometric properties. Two independent forward translations were performed by two native Arabic speakers and then synthesized into one version. The synthesized version was backtranslated into English by two independent bilingual translators. An expert committee was formed to review the translation and adaptation process. A final Arabic version of the WHQ was obtained, the WHQ-Ar. Two hundred and ninety adult Arabic speakers were recruited to participate in the study and investigate the properties of the WHQ-Ar. Results showed that the WHQ-Ar had no floor or ceiling effect. For construct validity, results of factor analysis revealed that the WHQ-Ar had two dimensions. Further, the WHQ-Ar had excellent internal consistency with Cronbach′s alpha = 0.93. For test-retest reliability, intraclass correlation coefficient score was 0.94. The Bland-Altman plot showed acceptable agreement between test and retest scores. Therefore, the WHQ-Ar is a valid, reliable tool and ready for use among the Arabic-speaking population for determining handedness.

The influence of vestibular system and fetal presentation on handedness, cognitive and motor development: A comparison between cephalic and breech presentation

Genetics are undoubtedly implicated in the ontogenesis of laterality. Nonetheless, environmental factors, such as the intrauterine environment, may also play a role in the development of functional and behavioral lateralization. The aim of this study was to test the Left-Otolithic Dominance Theory (LODT; Previc, 1991) by investigating a hypothetical developmental pattern where it is assumed that a breech presentation, which is putatively associated with a dysfunctional and weakly lateralized vestibular system, can lead to weak handedness and atypical development associated with language and motor difficulties. We used the ALSPAC cohort of children from 7 to 10 years of age to conduct our investigation. Our results failed to show an association between the vestibular system and fetal presentation, nor any influence of the latter on hand preference, hand performance, or language and motor development. Bayesian statistical analyses supported these findings. Contrary to our LODT-derived hypotheses, this study offers evidence that fetal presentation does not influence the vestibular system's lateralization and seems to be a poor indicator for handedness. Nonetheless, we found that another non-genetic factor, prematurity, could lead to atypical development of handedness. This article is protected by copyright. All rights reserved.

U can't touch this! Face touching behaviour whilst driving: implications for health, hygiene and human factors

Analysis of thirty-one hours of video-data documenting 36 experienced drivers highlighted the prevalence of face-touching, with 819 contacts identified (mean frequency: 26.4 face touches/hour (FT/h); mean duration: 3.9-seconds). Fewer face-touches occurred in high primary workload conditions (where additional physical/cognitive demands were placed on drivers), compared to low workload (4.4 and 26.1 FT/h, respectively). In 42.5% of touches (or 11.2 FT/h), mucous membrane contact was made, with fingertips (33.1%) and thumbs (35.6%) most commonly employed. Individual behaviours differed (ranging from 5.1 to 90.7 FT/h), but there were no significant differences identified between genders, age-groups or hand used. Results are of relevance from an epidemiological/hygiene perspective within the context of the COVID-19 pandemic (and can therefore inform the design of practical solutions and encourage behavioural change to reduce the risk of self-inoculation while driving), but they also help to elucidate how habitual human behaviours are imbricated with the routine accomplishment of tasks.

Reliability of a novel technique to assess palmar contracture in young children with unilateral hand injuries

BACKGROUND

Palmar contracture in young children can have significant developmental consequences. Despite this, objective techniques to measure palmar range of movement and quantify contracture in young children are limited.

PURPOSE

The purpose of this study was to determine the reliability of hand span and hand length measures in young children and to establish whether there is any association with age, sex and presence of a palmar burn injury in the reliability of these measures. The study also sought to determine the normative difference and establish a cut off value for the between-hand difference to identify loss of movement in 1 hand.

STUDY DESIGN

Cross sectional METHODS: Forty-four children aged 0 to <5 years were recruited. Twenty-two children had a unilateral palmar burn injury and 22 did not have a palmar burn injury. Each child's hand span and hand length were measured 3 times. This was performed twice by the first assessor and once by the second assessor. Intraclass correlation coefficients were calculated to determine the intra-rater and inter-rater reliability. The largest of the 3 values for both hand span and hand length from the first assessor's first assessment were used to determine the normative between-hand difference. Outliers were removed prior to determining the normative difference. Children were considered outliers if their between-hand difference in hand span and/or hand length was in the top 5% of values.

RESULTS

Excellent reliability was established for hand span and hand length measures for the whole group (intra-rater ICC_2,1 ≥0.95, inter-rater ICC_2,1 ≥0.94). The mean normative between-hand difference for both measures was 2 mm. The cut-off for the normative difference in hand span was <9 mm and hand length was <6 mm.

CONCLUSION

This measurement technique has excellent reliability and could be a useful method to quantify palmar range of movement and identify contracture in young children with unilateral hand injuries.

Isokinetic Assessment of Shoulder Joint Strength Ratios in Male Recreational Weightlifters: A Cross-Sectional Study

Background

Isokinetic strength imbalance is a risk factor for movement dysfunctions and injuries related to shoulder complex. The effects of recreational weightlifting on developing the imbalances between the shoulder muscles are not yet known.

Objectives

To investigate the isokinetic concentric shoulder muscle strength values (peak torque normalized to body weight) in recreational weightlifters (RWL) and to compare the shoulder muscles agonist/antagonist ratios with nonweightlifters.

Methods

Thirty male RWL with mean age, weight, height, and body mass index (BMI) of 21.56 years, 84.25 kg, 175.34 cm, and 26.51 kg/m², respectively, matched with nonweightlifters served as a control group. The normalized concentric peak torque values of shoulder flexors, extensors, abductors, adductors, and internal and external rotators were measured at angular velocity 120°/sec by using Biodex isokinetic system. Moreover, the agonist/antagonist strength ratio for all muscle groups were calculated.

Results

The normalized peak torques of RWL group were significantly greater than the control group (p < 0.05). The abductor/adductor and external rotator/internal rotator ratios of the RWL were significantly lower than the control group (p = 0.008 and 0.009, respectively). Conversely, there was no significant difference between both groups in relation to the flexor/extensor ratio (p = 0.259).

Conclusion

These results suggested that the recreational weightlifting exercises place trainees at risk of muscle imbalances. Therefore, the restoration of a normal concentric abductor/adductor and external rotator/internal rotator strength ratios may decrease the risk of possible shoulder injury.

Associations between measures of physical fitness and cognitive performance in preschool children

BACKGROUND

Given that recent studies report negative secular declines in physical fitness, associations between fitness and cognition in childhood are strongly discussed. The preschool age is characterized by high neuroplasticity which effects motor skill learning, physical fitness, and cognitive development. The aim of this study was to assess the relation of physical fitness and attention (including its individual dimensions (quantitative, qualitative)) as one domain of cognitive performance in preschool children. We hypothesized that fitness components which need precise coordination compared to simple fitness components are stronger related to attention.

METHODS

Physical fitness components like static balance (i.e., single-leg stance), muscle strength (i.e., handgrip strength), muscle power (i.e., standing long jump), and coordination (i.e., hopping on one leg) were assessed in 61 healthy children (mean age 4.5 ± 0.6 years; girls n = 30). Attention was measured with the "Konzentrations-Handlungsverfahren für Vorschulkinder" [concentration-action procedure for preschoolers]). Analyses were adjusted for age, body height, and body mass.

RESULTS

Results from single linear regression analysis revealed a significant (p < 0.05) association between physical fitness (composite score) and attention (composite score) (standardized ß = 0.40), showing a small to medium effect (F² = 0.14). Further, coordination had a significant relation with the composite score and the quantitative dimension of attention (standardized ß = 0.35; p < 0.01; standardized ß =  - 0.33; p < 0.05). Coordination explained about 11% (composite score) and 9% (quantitative dimension) of the variance in the stepwise multiple regression model.

CONCLUSION

The results indicate that performance in physical fitness, particularly coordination, is related to attention in preschool children. Thus, high performance in complex fitness components (i.e., hopping on one leg) tends to predict attention in preschool children. Further longitudinal studies should focus on the effectiveness of physical activity programs implementing coordination and complex exercises at preschool age to examine cause-effect relationships between physical fitness and attention precisely.

Examining Variations Between Everyday Life Handedness and Lateral Preferences for Sport-Specific Skills in Children

Purpose: This study aimed to analyze both sport-specific lateral preferences and handedness for everyday life tasks among school-aged children. Method: A total of 533 children (254 males and 279 females) aged 6 to 15 years old were assessed. Children's handedness was determined according to the laterality score from Edinburgh Handedness Inventory (EHI), while lateral preferences were assessed for 16 different sport-specific tasks. Results: The percentage of children with a left hand preference was lower for unilateral (10.5-14.3%) than for bilateral (19.5-31.7%) tasks. An increased prevalence of left-sided preference was also obtained for foot tasks (13.3-26.8%) and rotation along the vertical axis (28.5%). Similarly, hand preference for unilateral sport-specific tasks and EHI scores were largely correlated (r = 0.551-0.630), while these correlations were lower for bilateral hand tasks (r = 0.148-0.418), foot tasks (r = 0.201-0.386) and rotation preference (r = 0.129). Moreover, left-handed children evidenced less lateralized behavior for sport-specific tasks than right-handed children. Conclusions: The current study has shown that sport-specific lateral preferences and their correlations with handedness vary considerably depending on the task and individual characteristics in developmental ages. These findings emphasize the relevance of task-specific assessments of lateral preferences when looking at sports skills during childhood.

Assessing Smoothness of Arm Movements With Jerk: A Comparison of Laterality, Contraction Mode and Plane of Elevation. A Pilot Study

Measuring the quality of movement is a need and a challenge for clinicians. Jerk, defined as the quantity of acceleration variation, is a kinematic parameter used to assess the smoothness of movement. We aimed to assess and compare jerk metrics in asymptomatic participants for 3 important movement characteristics that are considered by clinicians during shoulder examination: dominant and non-dominant side, concentric and eccentric contraction mode, and arm elevation plane. In this pilot study, we measured jerk metrics by using Xsens^® inertial measurement units strapped to the wrists for 11 different active arm movements (ascending and lowering phases): 3 bilateral maximal arm elevations in sagittal, scapular and frontal plane; 2 unilateral functional movements (hair combing and low back washing); and 2 unilateral maximal arm elevations in sagittal and scapular plane, performed with both arms alternately, right arm first. Each arm movement was repeated 3 times successively and the whole procedure was performed 3 times on different days. The recorded time series was segmented with semi-supervised algorithms. Comparisons involved the Wilcoxon signed rank test (p < 0.05) with Bonferroni correction. We included 30 right-handed asymptomatic individuals [17 men, mean (SD) age 31.9 (11.4) years]. Right jerk was significantly less than left jerk for bilateral arm elevations in all planes (all p < 0.05) and for functional movement (p < 0.05). Jerk was significantly reduced during the concentric (ascending) phase than eccentric (lowering) phase for bilateral and unilateral right and left arm elevations in all planes (all p < 0.05). Jerk during bilateral arm elevation was significantly reduced in the sagittal and scapular planes versus the frontal plane (both p < 0.01) and in the sagittal versus scapular plane (p < 0.05). Jerk during unilateral left arm elevation was significantly reduced in the sagittal versus scapular plane (p < 0.05). Jerk metrics did not differ between sagittal and scapular unilateral right arm elevation. Using inertial measurement units, jerk metrics can well describe differences between the dominant and non-dominant arm, concentric and eccentric modes and planes in arm elevation. Jerk metrics were reduced during arm movements performed with the dominant right arm during the concentric phase and in the sagittal plane. Using IMUs, jerk metrics are a promising method to assess the quality of basic shoulder movement.

The Handedness Index Practical Task (HI20): An economic behavioural measure for assessing manual preference

ABSTRACTBecause self-report hand preference measures are limited to investigating cognitive aspects of manual laterality, valid, easy-to-administer and economic behavioural methods are needed for capturing the motoric component of handedness. Therefore, this study introduces the Handedness Index Practical Task (HI₂₀) and tests it in a sample of 206 students (M_age = 23.79 years, SD_age = 3.01 years), half of whom were self-specified left-handers. After confirming good reliabilities at the subscale and total scale levels, k-means cluster analysis allowed an empirically based partitioning of test subjects into left- (n = 72), mixed- (n = 23) and right-handers (n = 111). To validate this categorization and the HI₂₀ index, data were compared with the Edinburgh Handedness Inventory (EHI), EHI-short, HI₂₂ and hand grip strength. The congruency between the HI₂₀ clusters and alternative categorizations ranged from 95.6% to 84.0%, while the clusters explained large portions of variance in grip strength differences. The HI₂₀ sub- and total scores showed strong correlations with other measures of lateral preference. Altogether, the freely available HI₂₀ emerges as a reliable and valid alternative for behavioural handedness assessment, whose power lies in explaining differential hand use patterns and enabling fine-grained examinations of handedness.

Hand preference for unimanual and bimanual tasks: Evidence from questionnaires and preferential reaching

The current research compared hand selection in a preferential reaching paradigm with unimanual (i.e., pick-up cup) and bimanual (pick-up cup and pour from pitcher) tasks. In addition, relationships between self-report, questionnaire-based hand preference (unimanual and bimanual) and patterns of hand selection were assessed. Data offer support for a division of labour between the hands in at the midline; however, bimanual selection otherwise reflects consideration of object proximity (i.e., location) and comfort (i.e., biomechanical constraints). When grasping cups in right space, the right-hand was used to stabilize the cup and left-hand to mobilize the pitcher, whereas the opposite pattern was observed in left-space. Unimanual hand selection was also driven by object location. Subsequent analyses revealed a relationship between unimanual measures, but not bimanual measures of hand preference. Overall, findings support the notion that questionnaire data are associated with hand preference for grasping to a certain extent; however, use of a comprehensive battery of assessments is recommended when assessing and/or predicting handedness.

Development of Laterality and Bimanual Interference of Fine Motor Movements in Childhood and Adolescence

Drawing and handwriting are fine motor skills acquired during childhood. We analyzed the development of laterality by comparing the performance of the dominant with the nondominant hand and the effect of bimanual interference in kinematic hand movement parameters (speed, automation, variability, and pressure). Healthy subjects (n = 187, 6-18 years) performed drawing tasks with both hands on a digitizing tablet followed by performance in the presence of an interfering task of the nondominant hand. Age correlated positively with speed, automation, and pressure, and negatively with variability for both hands. As task complexity increased, differences between both hands were less pronounced. Playing an instrument had a positive effect on the nondominant hand. Speed and automation showed a strong association with lateralization. Bimanual interference was associated with an increase of speed and variability. Maturation of hand laterality and the extent of bimanual interference in fine motor tasks are age-dependent processes.

Asymmetrical activation and asymmetrical weakness as two different mechanisms of adolescent idiopathic scoliosis

There have been many studies on adolescent idiopathic scoliosis related abnormal muscle contractions of the spine. However, previous studies using surface electromyography to investigate paraspinal muscle asymmetry are controversial, lacking in clarity of results, and hindered by methodological limitations. The purpose of this study was to investigate the relationship between imbalance factors including surface electromyography activity according to the scoliosis curve type and leg length discrepancy and adolescent idiopathic scoliosis curve types. Seventy-nine patients with scoliosis were prospectively enrolled and were divided into five types: single thoracic, thoracolumbar, lumbar, double thoracic, and double major. Cobb angle and structural variables were measured. Surface electromyography examinations were conducted at the 7th, 12th thoracic erector spinae, 3rd lumbar erector spinae, and multifidus muscles during the superman position keeping prone spinal extension to lift the arms and legs off the floor. Whole spine radiographs were obtained to measure the Cobb angle, coronal imbalance, pelvic height and angle, and femoral head height. In the double major, thoracolumbar, and lumbar types, the mean root mean squared (RMS) EMG amplitudes were significantly higher on the convex side than the concave side (P < 0.005). In the DM type, the mean RMS EMG amplitudes of ES_T7 and ES_L3 where the apex was located were significantly higher at the convex side than those of the concave side (P < 0.005, effect size (Cohen’s d) for ES_T7/ES_L3: 0.517/0.573). The TL and L types showed a similar pattern. The mean RMS EMG amplitudes of the ES_T12 concave side and Mu_L3 and ES_L3 concave sides were significantly lower than those of the convex side in the TL and L types, respectively (P < 0.008, effect size (Cohen’s d) for ES_T12/Mu_L3/ES_L3: 0.960/0.264/0.448). Conversely, there were no significant differences in the single thoracic and double thoracic types. All structural variables (coronal imbalance, pelvic height and angle, and femur head height) were higher in the lumbar type, but only coronal imbalance was significantly different (P < 0.05). Different patterns of asymmetry of paraspinal muscles and structural variables were described based on the curvature of the spine. L type showed that EMG activity was asymmetric in the paraspinalis muscles where the apex was located and that structural asymmetry, such as coronal imbalance was significantly greater than other types. DM type showed similar paraspinalis asymmetry pattern to the ST type but there was no structural asymmetry in DM and ST types. TL type has the features of both thoracic and lumbar origins. Understanding these could contribute to the management in correcting scoliosis.

Observational Analysis of Lateral Preference in Kumite Initiation: A Starting Point in the Longitudinal Programming of Formative Karate

We used observational methodology to analyze lateral conditioning in the technical-tactical performance of high level 8-9-year-old karatekas, specifically in relation to the guard action that supports the technical action and the body segment with which it is performed. We designed an ad hoc observation instrument to analyze lateral preference in the technical-tactical actions that take place during the kumite. We relied on LINCE software for data registration, and we found good inter-observer reliability, calculated with Cohen's Kappa coefficient. Generalizability Theory supported the homogeneity of the behavior deployed by these combatants. Our results represent a starting point in the longitudinal programming of karate. By relating our results and those of other studies that have addressed lateral performance in formative karate in the kumite modality, we are able to draw a roadmap of a karateka's path towards the equilaterality that is inherent in an elite competitor: (a) the 8-9 year old karateka must overcome a conditioned lateral prevalence by adopting a forward non-dominant leg guard so as to then attack with the dominant body segment; (b) the eqilateral use of the right or left fist must occur later, between the 12-13 year age group and the senior category; and (c) there will then be less decisive lateral conditioning in the execution of offensive leg techniques.

Handedness Development: A Model for Investigating the Development of Hemispheric Specialization and Interhemispheric Coordination

The author presents his perspective on the character of science, development, and handedness and relates these to his investigations of the early development of handedness. After presenting some ideas on what hemispheric specialization of function might mean for neural processing and how handedness should be assessed, the neuroscience of control of the arms/hands and interhemispheric communication and coordination are examined for how developmental processes can affect these mechanisms. The author’s work on the development of early handedness is reviewed and placed within a context of cascading events in which different forms of handedness emerge from earlier forms but not in a deterministic manner. This approach supports a continuous rather than categorical distribution of handedness and accounts for the predominance of right-handedness while maintaining a minority of left-handedness. Finally, the relation of the development of handedness to the development of several language and cognitive skills is examined.

The influence of body position on bioelectrical impedance spectroscopy measurements in young children

Bioelectrical impedance techniques are easy to use and portable tools for assessing body composition. While measurements vary according to standing vs supine position in adults, and fasting and bladder voiding have been proposed as additional important influences, these have not been assessed in young children. Therefore, the influence of position, fasting, and voiding on bioimpedance measurements was examined in children. Bioimpedance measurements (ImpediMed SFB7) were made in 50 children (3.38 years). Measurements were made when supine and twice when standing (immediately on standing and after four minutes). Impedance and body composition were compared between positions, and the effect of fasting and voiding was assessed. Impedance varied between positions, but body composition parameters other than fat mass (total body water, intra- and extra-cellular water, fat-free mass) differed by less than 5%. There were no differences according to time of last meal or void. Equations were developed to allow standing measurements of fat mass to be combined with supine measurements. In early childhood, it can be difficult to meet requirements for fasting, voiding, and lying supine prior to measurement. This study provides evidence to enable standing and supine bioimpedance measurements to be combined in cohorts of young children.

A Narrative Review of Limb Dominance: Task Specificity and the Importance of Fitness Testing

ABSTRACT

Virgile, A and Bishop, C. A narrative review of limb dominance: Task specificity and the importance of fitness testing. J Strength Cond Res 35(3): 846-858, 2021-Preferential limb function must be sustained through repetitious asymmetrical activities for continuous athletic development and, ultimately, optimal athletic performance. As such, the prevalence of limb dominance and between-limb differences is common in athletes. Severe between-limb differences have been associated with reductions in athletic performance and increased injury risk in athletes. However, in the current literature, the terms limb preference and limb dominance have been used interchangeably. Together, these terms include a limb that is subjectively preferred and one that is objectively dominant in 1 or more performance measures from a variety of athletic tasks. In this review, we (a) discuss reported correspondence between task-specific limb preference and limb dominance outcomes in athletes, (b) provide greater context and distinction between the terms limb preference and limb dominance, and (c) offer pragmatic strategies for practitioners to assess context-specific limb dominance. A limb that is subjectively preferred is not necessarily objectively dominant in 1 or more athletic qualities or sport-specific tasks. Further to this, a limb that is objectively superior in 1 task may not exhibit such superiority in a separate task. Thus, limb preference and limb dominance are both task-specific. As such, we propose that practitioners intentionally select tasks for limb dominance assessment which resemble the most relevant demands of sport. Because limb dominance profiles are inconsistent, we suggest that practitioners increase assessment frequency by integrating limb dominance testing into standard training activities. This will allow practitioners to better understand when changes reflect sport-specific adaptation vs. potential performance or injury ramifications.

Hand preference and Mathematical Learning Difficulties: New data from Greece, the United Kingdom, and Germany and two meta-analyses of the literature

Increased rates of atypical handedness are observed in neurotypical individuals who are low-performing in mathematical tasks as well as in individuals with special educational needs, such as dyslexia. This is the first investigation of handedness in individuals with Mathematical Learning Difficulties (MLD). We report three new studies (N = 134; N = 1,893; N = 153) and two sets of meta-analyses (22 studies; N = 3,667). No difference in atypical hand preference between MLD and Typically Achieving (TA) individuals was found when handedness was assessed with self-report questionnaires, but weak evidence of a difference was found when writing hand was the handedness criterion in Study 1 (p = .049). Similarly, when combining data meta-analytically, no hand preference differences were detected. We suggest that: (i) potential handedness effects require larger samples, (ii) direction of hand preference is not a sensitive enough measure of handedness in this context, or that (iii) increased rates of atypical hand preference are not associated with MLD. The latter scenario would suggest that handedness is specifically linked to language-related conditions rather than conditions related to cognitive abilities at large. Future studies need to consider hand skill and degree of hand preference in MLD.

The influence of object size on second-order planning in an overturned cup task

For children, second-order planning in object manipulation, as demonstrated by the end-state comfort (ESC) effect, is constrained by numerous factors. As a step towards delineating the influence of object size, children (ages 6-10, n = 113) and adults (ages 18-25, n = 17) performed an overturned cup task with 8 cup sizes (4.7-8.4 cm diameter). Contrary to the hypothesis, cup size did not predict the overall proportion of trials with ESC. An increase in age and hand length did result in more ESC. Subsequent analyses with children, which focused on each cup size, revealed an increase in the ratio of hand size to cup size resulted in an increase in ESC with the 4.7, 5.2, 6.2, and 6.7 cm cups, age was a significant predictor with 4.7, 5.2, and 6.2 cm cups, and the interaction was significant for the 6.2 cm cup. No other significant results emerged. Together, findings offer preliminary support for the notion that object size does constrain children's motor planning skills to a certain degree (i.e., with large cups); however, further inquiry is warranted to elucidate the link between object size and hand size in children's performance of tasks requiring second-order planning.

The effect of a natural disaster on handgrip strength in prepubertal Indian children exposed to a severe cyclone during the prenatal and early postnatal growth

Natural disasters (NDs) experienced by women and their children during prenatal and infant growth may have long-lasting effects on offspring’s development. Handgrip strength (HGS) is one of the measures of muscular strength and an indicator of health status. This study compared HGS in children exposed to cyclone Aila in India during their prenatal and infant growth compared to a control group from a non-affected, adjacent area. The total sample involved 444 boys and 423 girls aged 7–9 years, categorised into 3 groups: prenatally exposed to Aila, exposed to Aila in infancy, and the control group, non-exposed to Aila. Results revealed that prenatally exposed children of both sexes had significantly lower HGS than the controls (at least, p < 0.001 in boys; p < 0.05 in girls). On the other hand, the postnatally exposed boys, but not the girls, showed lower HGS than the controls. A significant effect of a group factor (ND exposure) on HGS was observed even after controlling for confounding variables (age, height, BMI, birth weight, gestational age; at least, p < 0.05). Our findings indicate that prenatal or early postnatal experience of a ND may have association with impaired HGS in prepubertal children.

Effects of a Strength-Dominated Exercise Program on Physical Fitness and Cognitive Performance in Preschool Children

ABSTRACT

Wick, K, Kriemler, S, and Granacher, U. Effects of a strength-dominated exercise program on physical fitness and cognitive performance in preschool children. J Strength Cond Res 35(4): 983-990, 2021-Childhood is characterized by high neuroplasticity that affords qualitative rather than quantitative components of physical activity to maximize the potential to sufficiently develop motor skills and foster long-term engagement in regular physical activity. This study examined the effects of an integrative strength-dominated exercise program on measures of physical fitness and cognitive performance in preschool children. Children aged 4-6 years from 3 kindergartens were randomized into an intervention (INT) group (n = 32) or a control group (n = 22). The 10-week intervention period was conducted 3 times per week (each session lasted 30 minutes) and included exercises for the promotion of muscle strength and power, coordination, and balance. Pre and post training, tests were conducted for the assessment of muscle strength (i.e., handgrip strength), muscle power (i.e., standing long jump), balance (i.e., timed single-leg stand), coordination (hopping on right/left leg), and attentional span (i.e., "Konzentrations-Handlungsverfahren für Vorschulkinder" [concentration-action procedure for preschoolers]). Results from 2 × 2 repeated-measures analysis of covariance revealed a significant (p ≤ 0.05) and near significant (p = 0.051) group × time interaction for the standing long jump test and the Konzentrations-Handlungsverfahren. Post hoc tests showed significant pre-post changes for the INT (p < 0.001; d = 1.53) but not the CON (p = 0.72; d = 0.83). Our results indicate that a 10-week strength-dominated exercise program increased jump performance with a concomitant trend toward improvements in attentional capacity of preschool children. Thus, we recommend implementing this type of exercise program for preschoolers.

A modality selective effect of functional laterality in pain detection sensitivity

The ability to detect environmental changes is essential to determine the appropriate reaction when facing potential threats. Both detection and reaction functions are critical to survival, and the superior performance of motor reaction for the dominant hand is well recognized in humans. However, it is not clear whether there exists laterality in sensitivity to detect external changes and whether the possible laterality is associated with sensory modality and stimulus intensity. Here, we tested whether the perceptual sensitivity and electrophysiological responses elicited by graded sensory stimuli (i.e., nociceptive somatosensory, non-nociceptive somatosensory, auditory, and visual) that were delivered on/near the left and right hands would be different for right-handed individuals. We observed that perceived intensities and most brain responses were significantly larger when nociceptive stimuli were delivered to the left side (i.e., the non-dominant hand) than to the right side (i.e., the dominant hand). No significant difference was observed between the two sides for other modalities. The higher sensitivity to detect nociceptive stimuli for the non-dominant hand would be important to provide a prompt reaction to noxious events, thus compensating for its worse motor performance. This laterality phenomenon should be considered when designing experiments for pain laboratory studies and evaluating regional sensory abnormalities for pain patients.