Activities of Daily Living, Physical Activity, Physical Fitness and Quality of Life in Children with Congenital Heart Disease: A Case-Control Study

BACKGROUND

Despite reports of reduced physical fitness in children with congenital heart disease (CHD), no specific performance evaluations for activities of daily living have been conducted.

OBJECTIVES

The aim was to compare the activities of daily living, quality of life, posture, physical fitness and physical activity levels of children with CHD with healthy controls (HC).

METHODS

The study included 30 children aged 6-14 diagnosed with moderate or severe CHD and 30 age-sex-matched HC. The sociodemographic and clinical data of the participants were recorded. All participants went through several tests, namely the TGlittre-P test for activities of daily living, the 6-minute walk test (6MWT) for functional capacity, the Fitnessgram test battery for physical fitness, the hand dynamometer for measuring grip strength, the pedometer for measuring physical activity, and both the child and parents reported the Pediatric Quality of Life Inventory (PedsQL) for evaluating the quality of life, in addition to posture analyses. Values of p < 0.05 were considered statistically significant.

RESULTS

Individuals with CHD had a longer TGlittre-P test completion time and a shorter 6MWT distance than HC (TGlittre-P: CHD 3.45 [3.24-4.02]min vs. HC 3.10 [2.57-3.23]min, 6MWT: CHD 514.00 [412.50-566.00]m vs. HC 591.50 [533.00-631.00]m). For the CHD group, sit-ups, push-ups, trunk lift, and sit-and-reach test scores within the Fitnessgram battery, grip strength, posture, and quality of life scores were lower than those for the HC group. Physical activity levels were similar in the groups.

CONCLUSIONS

The performance of activities of daily living, functional capacity, physical fitness, posture, and quality of life of children with moderate and severe CHD were affected compared to healthy peers.

Normative values for hand grip and pinch strength for 6 to 18 year-olds in Saudi Arabia

BACKGROUND

Normative values for hand grip and pinch strength among children in Saudi Arabia has not been well established. Therefore, the main aim of this study is to establish normative values for hand grip and pinch strength in children aged 6 to 18 years in Saudi Arabia.

METHODS

A cross-sectional study was conducted from different 5 regions in Saudi Arabia. Participants between the age of 6 years and 18 years old were recruited through different primary and secondary schools in Saudi Arabia. Data for age, gender, Body Mass Index, and preferred hand were collected. Hand grip strength was measured using digital hand dynamometer and the tip pinch, palmar pinch, and key pinch strength were measured using the hydraulic pinch gauge.

RESULTS

A total of 616 participants included in this study (318 boys and 298 girls). Participants were stratified into 5 chronological age groups of 6-7 years, 8-9, 10-11, 12-13, 14-15, 16-17, and 18 years. The results showed an overall trend of increasing hand grip strength and pinch strength with age regardless of hand preference. Boys had significantly higher grip strength than girls in all age groups (P < 0.05).

CONCLUSION

This study established normative values for hand grip and pinch strength in the healthy Saudi pediatric and adolescent population, using boys and girls aged 6 to 18. The outcomes of this study also demonstrated that gender, age, and hand preference can all have an impact on how strong a handgrip develops.

Narrative Review of Sex Differences in Muscle Strength, Endurance, Activation, Size, Fiber Type, and Strength Training Participation Rates, Preferences, Motivations, Injuries, and Neuromuscular Adaptations

ABSTRACT

Nuzzo, JL. Narrative review of sex differences in muscle strength, endurance, activation, size, fiber type, and strength training participation rates, preferences, motivations, injuries, and neuromuscular adaptations. J Strength Cond Res 37(2): 494-536, 2023-Biological sex and its relation with exercise participation and sports performance continue to be discussed. Here, the purpose was to inform such discussions by summarizing the literature on sex differences in numerous strength training-related variables and outcomes-muscle strength and endurance, muscle mass and size, muscle fiber type, muscle twitch forces, and voluntary activation; strength training participation rates, motivations, preferences, and practices; and injuries and changes in muscle size and strength with strength training. Male subjects become notably stronger than female subjects around age 15 years. In adults, sex differences in strength are more pronounced in upper-body than lower-body muscles and in concentric than eccentric contractions. Greater male than female strength is not because of higher voluntary activation but to greater muscle mass and type II fiber areas. Men participate in strength training more frequently than women. Men are motivated more by challenge, competition, social recognition, and a desire to increase muscle size and strength. Men also have greater preference for competitive, high-intensity, and upper-body exercise. Women are motivated more by improved attractiveness, muscle "toning," and body mass management. Women have greater preference for supervised and lower-body exercise. Intrasexual competition, mate selection, and the drive for muscularity are likely fundamental causes of exercise behaviors in men and women. Men and women increase muscle size and strength after weeks of strength training, but women experience greater relative strength improvements depending on age and muscle group. Men exhibit higher strength training injury rates. No sex difference exists in strength loss and muscle soreness after muscle-damaging exercise.

Motor organization of unilateral polymicrogyria associated with ipsilateral brainstem atrophy - a case report

Background

Polymicrogyria refers to the disruption of normal cerebral cortical development late in neuronal migration or in early cortical organization. Although patients with polymicrogyria feature relatively favorable motor outcomes, polymicrogyric lesions accompanied by extensive unilateral hemispheric atrophy and ipsilateral brainstem atrophy may induce poorer motor outcomes. This study is the first to employ transcranial magnetic stimulation (TMS) and diffusion tensor imaging (DTI) to characterize changes to motor organization and white matter tracts induced by polymicrogyria.

Case presentation

We document a case of a 16-year-old female with left hemiplegic unilateral polymicrogyria associated with ipsilateral brainstem atrophy. Magnetic resonance imaging (MRI) of the brain revealed unilateral polymicrogyria to have affected anterior cortical areas, including the perisylvian region on the right side. The right halves of the brain and brainstem were significantly smaller than the left halves. Although our patient was found to exhibit cortical dysplasia of the right frontoparietal and sylvian fissure areas and a decreased number of fibers in the corticospinal tract (CST) of the affected side on DTI, the connectivity of the CST was preserved up to the motor cortex. We also measured the cross-sectional area of the CST at the level of the pons. In TMS, contralateral motor evoked potentials (MEPs) were evoked from both hands, but the ipsilateral MEPs were evoked only from the left hand. The left hand featured a long duration, polyphasic pattern of contralateral MEPs.

Discussion and conclusion

TMS revealed that the concurrent bilateral projections to the paretic hand from the affected and unaffected hemispheres and contralateral MEPs in the paretic hand were polyphasic, indicating delayed electrophysiological maturation or a pathologic condition of the corticospinal motor pathways. In DTI, the cross-sectional area of the CST at the level of the pons on the affected side was smaller than that on the unaffected side. These DTI findings reveal an inadequate CST volume. Despite extensive brain malformation and ipsilateral brainstem atrophy, our patient had less severe motor dysfunction and presented with involuntary mirror movements. Mirror movements in the paretic hand are considered to indicate ipsilateral corticospinal projections from the unaffected hemisphere and may suggest favorable motor outcomes in early brain injury.

The Effect of Voluntary Physical Activity in an Enriched Environment and Combined Exercise Training on the Satellite Cell Pool in Developing Rats

Aim: Postnatal skeletal muscle growth is strongly associated with a satellite cell pool. Early adolescence might be a crucial period when different exercise training interventions have specific consequence on satellite cells. Pax7 and MyoD have been suggested as the leading indicators of satellite cell activation.

Methods: In this study, pre-adolescent male rats (n = 18) were either subjected to an enriched environment that facilitated physical activities or combined training or control for three weeks. The flexor hallucis longus muscle was removed for biochemical and histochemical analysis.

Results: Findings demonstrated that exercise trained rats displayed high levels of serum IGF-1 (p <0.05). There was an increase in Pax7 (p <0.05) and MyoD (p <0.001) mRNA expression. A significant increase in the mean fiber area (p <0.01), satellite cell (p <0.001), and myonuclear numbers (p <0.01) were also observed in both intervention groups. Importantly, enriched rats showed lower corticosterone levels (p <0.05) compared to training ones. Regarding performance, trained and enriched rats had significant improvement in forelimb grip strength (p <0.01) and load-carrying capacity (p <0.05).

Conclusion: Type of physical exercise is an essential part in changing satellite cells pool. Different and frequent physical activities in an enriched environment can be effective for muscle development.

A meta-analysis of the association between male dimorphism and fitness outcomes in humans

Humans are sexually dimorphic: men and women differ in body build and composition, craniofacial structure, and voice pitch, likely mediated in part by developmental testosterone. Sexual selection hypotheses posit that, ancestrally, more 'masculine' men may have acquired more mates and/or sired more viable offspring. Thus far, however, evidence for either association is unclear. Here, we meta-analyze the relationships between six masculine traits and mating/reproductive outcomes (96 studies, 474 effects, N = 177,044). Voice pitch, height, and testosterone all predicted mating; however, strength/muscularity was the strongest and only consistent predictor of both mating and reproduction. Facial masculinity and digit ratios did not significantly predict either. There was no clear evidence for any effects of masculinity on offspring viability. Our findings support arguments that strength/muscularity may be sexually selected in humans, but cast doubt regarding selection for other forms of masculinity and highlight the need to increase tests of evolutionary hypotheses outside of industrialized populations.

Pediatric Co-Norms for Finger Tapping, Grip Strength, and Grooved Pegboard in a Community Sample

OBJECTIVE

Motor tests, including Finger-Tapping Test, Grooved Pegboard Test, and Grip Strength Test, are frequently used by neuropsychologists when assessing pediatric populations. Many of the norms available for these measures are outdated, have not been co-normed, and have samples with limited diversity. This study aims to provide updated, co-norms for three commonly used motor tasks with a diverse population.

METHOD

Participants (n = 476; age range 6-14) were recruited from community settings to complete each of the three motor tests.

RESULTS

Results demonstrate generally improved performance across ages with no significant difference between performance of males and females on the Grooved Pegboard Test or the Finger Tapping Test. The only significant findings were on the Grip Strength Test where 12-14-year-old boys demonstrated stronger performance on the dominant hand.

CONCLUSION

This study provides updated and co-normed data on frequently used motor tasks with a diverse pediatric sample, which are useful for clinicians.

The role of pre-pubertal training history on hippocampal neurotrophic factors and glucocorticoid receptor protein levels in adult male rats

Neurotrophic factors play an integral role in hippocampal plasticity, and interaction with HPA axis components, especially glucocorticoid receptors (GR), can mediate the structural and functional changes. In the present work, we investigated the long-term effects of combined exercise training (CET) and voluntary physical activity in an enriched environment (EE) in the pre-pubertal period on hippocampal neurotrophic factors and GR. For this purpose, a longitudinal study was designed. After three weeks, all rats were kept in the standard cages without any interventions until adulthood. Western blot analysis revealed a significant increase in hippocampal BDNF and VEGF protein levels in both EE and CET groups (P < 0.001), along with an increase in GR protein levels. In addition, EE decreased serum corticosterone levels compared to CET (P < 0.05). Serum insulin-like growth factor-1 (IGF-1) levels did not demonstrate remarkable changes between groups. Training interventions during sensitive developmental periods may produce profound and long-lasting effects on the hippocampus, at least in part by interactive effects of neurotrophic factors cascades and GR.

Low birth weight and its relation to physical fitness parameters in children: Its negative effect on muscle strength and cardiorespiratory endurance

BACKGROUND

There is increasing evidence that low birth weight has a negative effect on physical fitness, muscle strength, and cardiorespiratory endurance, although the findings are inconsistent.

OBJECTIVES

This study aimed to evaluate whether birth weight acts as a prenatal determinant of physical fitness parameters and to determine the role of environmental or biological variables on this effect.

METHODS

One hundred and sixty-seven children aged 6-14 years were included in this study. The anthropometric data, physical activity index, standing long jump, flexibility, handgrip strength, and cardiorespiratory fitness were evaluated.

RESULTS

A positive correlation was found between birth weight and cardiorespiratory fitness (r = .349; p < .001), right handgrip strength (r = .337; p < .001), and left handgrip strength (r = .320; p < .001), suggesting that children with low birth weight had the worst performance in both cardiorespiratory endurance and grip strength tests. These findings remained significant after adjustment for prematurity, sex, age, physical activity index, and body mass index (BMI). Stepwise multiple regression analyses revealed a significant interaction of high birth weight, older age, and low BMI in predicting better cardiorespiratory endurance (R² = .308). When handgrip strength was tested as the dependent variable, we found that high birth weight, male sex, and older age emerged as important determinants for both sides.

CONCLUSION

Children aged 6-14 years born with a birth weight < 2.5 kg have low handgrip strength and cardiorespiratory fitness, which seems to be mediated partially by influences of both prenatal environment (e.g., birth weight) and biological variables (e.g., age, sex, BMI).

The Measurement of Strength in Children: Is the Peak Value Truly Maximal?

It is unclear whether the measurement of maximum muscle strength in younger children can be performed accurately due to factors such as motivation and maturity (i.e., the ability to receive instruction). If there is a large change in a ratio between muscular strength and size from the youngest to the oldest, then this might provide some indication that the youngest may not have been able to voluntarily activate their muscles for reasons mentioned previously. The purpose of this study was to observe the ratio between handgrip strength (HGS) and forearm muscle thickness (MT) across differing ages in younger children. A total of 1133 preschool children (559 boys and 574 girls) between the ages of 4.5 and 6.5 years had MT and HGS measurements and calculated the ratio of HGS/MT (kg/cm). Linear regression was used to assess the impact of age and sex on the dependent variables of MT, HGS, and the HGS/MT ratio. The HGS/MT ratio increases moderately from age 4.5 to 6.5 in both boys and girls. However, the difference in this ratio was small between the age ranges in this sample. Our results indicate children as young as 4.5 may be accurately measured with the handgrip strength test.

Muscle fitness and its association with body mass index in children and adolescents aged 7-18 years in China: a cross-sectional study

BACKGROUND

The present study was the first one aimed to investigate the current muscle fitness and its associated factors among children and adolescents in mainland China.

METHODS

From Nov 2013 to Jul 2014, 2283 children and adolescents aged 7-18 were recruited in Hainan and Shaanxi Provinces in China by cross-sectional design. Information on anthropometry and muscle fitness, measured by hand grip strength (GS), vertical jump (VJ) and sit-and-reach (SR), were collected. Analysis of covariance was performed by using general linear regression models to identify the association between BMI and muscle fitness.

RESULTS

The means of GS, VJ and SR in boys were 22.30 ± 11.55 kg, 22.93 ± 6.80 cm and 3.58 ± 7.31 cm, respectively, and in girls were 16.61 ± 6.87 kg, 18.11 ± 4.08 cm and 7.18 ± 5.72 cm, respectively. GS (from 8.26 kg in the 7-8-year-old group to 27.91 kg in the 17-18 group) and SR (from 1.75 cm in the-8-year-old group to 10.12 cm in the 17-18 group) increased with age (both p for trend < 0.001). Boys had higher GS and VJ, but significantly lower SR than girls in each age group (p < 0.001). After adjusting for age, sex, residential areas and study regions, GS increased with elevated BMI (compared with normal weight group, the regression coefficient for thinness and overweight/obesity were - 2.997(95%CI: -3.693 to - 2.301) and 1.220 (95%CI: 0.285 to 2.155), respectively. With the p values less than 0.001 and 0.011, respectively). For VJ, there was no difference found between normal weight group and overweight/obesity group (p = 0.550), but the thinness group had the lowest performance (regression coefficient = - 2.681, 95%CI from - 3.965 to - 1.397, p < 0.001). For SR, compared with normal weight group, the regression coefficients for thinness and overweight/obesity were - 1.313(95%CI: -2.228 to - 0.399) and - 1.623(95%CI: -3.216 to - 0.030) respectively, both p < 0.05.

CONCLUSIONS

Increased body weight may have a positive association with isometric muscle strength measured by grip strength, but a negative one with strength of lifting the body. Sex difference was also found in the performance of flexibility.

Kinematic characteristics of arm and trunk when drinking from a glass in children with and without cerebral palsy

BACKGROUND

Children with cerebral palsy (CP) often have difficulty with activities that require the upper extremities secondary to deficits in strength and range of motion, spasticity, and poor timing and coordination of movement. This study aimed to identify and compare timing and coordination of the trunk and upper extremity in children with and without CP during a functional task.

METHODS

Eighteen children, N = 9 with CP and N = 9 with typical development were enrolled. Participants were seated in a standard chair and instructed to drink from a glass placed at a distance of 75% of available arm length. The task was divided into 3 Phases: 1) reaching to the glass, 2) transporting the glass to the mouth, and 3) returning the glass to the table. The spatiotemporal and angular variables were analyzed with 3D kinematics of movement using a 4-camera Qualysis Motion System.

FINDINGS

Children with CP demonstrated poor upper extremity timing and coordination. Despite significant trunk displacement used as a compensation in Phase 1, children with CP demonstrated a significantly lower mean velocity and velocity peak during Phases 2 and 3; and demonstrated less straight motion which required more time and movement units in all phases.

INTERPRETATION

Children with CP demonstrated poor upper extremity timing and coordination when drinking (even when they successfully completed the task) measured by more trunk displacement, slower, less straight movements, and more movement units. Current rehabilitation strategies could consider training speed and use functional tasks that require different strategies across multiple phases.

Handgrip strength in 6-12-year-old children: The Health Oriented Pedagogical Project (HOPP)

AIMS

The aim of the study was to describe the natural course of handgrip strength development in primary school children and to establish a reference material to be used in future screening studies. In addition, the study aims to investigate a possible association between handgrip strength and cardiovascular risk factors.

METHODS

Anthropometric measures along with results for handgrip strength, endurance tests, blood pressure and cholesterol were measured on 2272 children of both sexes. An ROC analysis was used to estimate the suitability of handgrip strength as a predictor for known cardiometabolic risk factors.

RESULTS

A reference material for handgrip strength is presented for boys and girls aged 6-12 years. The results indicate that handgrip strength is unsuitable as a predictor for cardiometabolic risk factors in children.

CONCLUSIONS

The results may be used as reference values for handgrip strength in 6-12-year-old children of both sexes. Handgrip strength may not be used as a screening tool for cardiometabolic risk factors in pre-pubertal children.

Socio-demographic differences in Colombian children's muscular fitness: Does scaling for differences in body size present a challenge to conventional thinking?

OBJECTIVES

In low- to middle-income countries, children from less-deprived areas (from families of higher socio-economic status [SES]) have superior muscular fitness than those from low-SES groups. They are also taller and heavier, factors associated with muscular fitness. The purpose of this study was to identify any socio-demographic differences in Colombian children's muscular fitness and examine how these conclusions can be modified by scaling for differences in body size.

METHODS

A total of 38,098 youths (46% girls), ninth grade students (aged 14-15 years), participated in a study of cross-sectional design. We recorded SES and family incomes, stature, and mass. Standing broad jump and handgrip strength were used to assess muscular fitness. A multiplicative allometric model was adopted to adjust for body-size differences.

RESULTS

Children from the mid- to high-SES groups jumped significantly higher than children from the lowest SES group, although no SES group difference in grip strength was observed. After adjusting for body size, children from higher SES and with higher family incomes had significantly lower handgrip strength, and their superior jump height performances remained but were greatly reduced. Only children from the highest SES now jumped significantly higher that the lowest SES group.

CONCLUSIONS

The superior jump performance and no difference in handgrip strength of Colombian children from higher SES may simply reflect their superior physiques. When body size is accounted for, these differences are reduced or even reversed, suggesting that children from higher SES groups should not be complacent regarding their apparent superior muscular fitness.

Handgrip Strength and Malnutrition (Undernutrition) in Hospitalized Versus Nonhospitalized Children Aged 6-14 Years

BACKGROUND

Diagnosing undernutrition in hospitalized pediatric populations is crucial to provide timely nutrition interventions. Handgrip strength (HGS), a measurement of muscle function, is a reliable indicator of undernutrition. However, limited research exists on HGS in hospitalized pediatric patients. The primary aim of this study was to determine if HGS differed between hospitalized children within 48 hours of admission and nonhospitalized children. A secondary purpose was to describe the association of HGS with height, weight, body mass index (BMI), mid upper arm circumference (MUAC), activity level, disease severity, nutrition risk, and nutrition intervention.

METHODS

One hundred nine hospitalized and 110 nonhospitalized patients aged 6-14 years participated in this cross-sectional nonequivalent control group design study. Weight, height, MUAC, and HGS were measured within 48 hours of hospital admission for the hospitalized group or immediately following a well-child visit for the control group.

RESULTS

Based on analysis of covariance, the HGS was estimated to be 12.4 ± 0.37 kgF (mean ± SE) for hospitalized subjects and 13.1 ± 0.37 for nonhospitalized subjects ( P = .2053). HGS was associated with age ( P < .0001), height ( P < .0001), dominant hand ( P < .0001), and MUAC z scores ( P = .0462).

CONCLUSION

HGS was not significantly different between hospitalized and nonhospitalized participants, although anthropometric measurements were similar between groups. A strong relationship was demonstrated between HGS and BMI and MUAC z scores. Further research is needed that examines serial HGS measurements, feasibility in hospitalized patients, and the association of HGS measurements and nutrition risk.

Reliability of Sargent Jump Test in 4- to 5-Year-Old Children

We assessed the test-retest reliability of the Sargent jump (VJ) for vertical jumping performed by 4 and 5 years old pre-schoolers. The VJ was administered three times (familiarization, test, and retest) to 163 children (mean age: 4.48 ± 0.5 years; 55.8% girls). The results were compared with those obtained in the standing long jump (SLJ) and in the 25 -m dash test to identify how its performance correlated with other measures of leg power. Systematic change in the mean and retest correlations with these other measures were used to help analyze VJ test-retest reliability. Additionally, Pearson correlation coefficients were used to examine the degree of association between the test and retest trials of the VJ. The VJ showed a higher correlation and agreement in the 4-year-old, compared with the 5-year old, group (r_c = 0.956 vs. 0.796; α = 0.95 vs. 0.84; ICC: 0.828; 95% CI: 0.730-0.891 vs 0.739; 95% CI: 0.589-0.834). Effect sizes were small ( d ≤ 0.285) for all the VJ tests performed. Fair to poor significant relationships were established between the VJ (test), VJ (retest), and the SLJ. No significant association was observed between the VJ and the 25 -m dash tests. Our findings suggest that the Sargent jump test is reliable when executed by 4- and 5-year-olds. The lack of a strong association with other measures of leg power should be taken into account at the time of selecting the most appropriate test to assess this strength dimension.

The Influence of Hand Preference on Grip Strength in Children and Adolescents; A Cross-Sectional Study of 2284 Children and Adolescents

Introduction

In adults the preferred hand is often considered to be around 10% stronger than the non-preferred hand. Whether the same is true for children and adolescents remains unclear. The objective of this study is therefore to determine whether there is a difference in grip strength between the preferred and non-preferred hand in developing children, to establish whether this difference is similar for children of a different gender or hand preference, and whether there is a difference in grip strength of the preferred hand of left-preferent (LP) and right-preferent (RP) children.

Design

Cross-sectional study.

Participants

Participants were recruited from schools in the northern provinces of the Netherlands. The study included healthy children and adolescents in the age range of 4–17 years.

Outcome Measures

Each child was allowed a total of four attempts using the JAMAR hand dynamometer, two attempts with each hand. All individual attempts were scored. Hand preference was determined by asking which hand was used to write, or in the case of 4- and 5-year-olds, which hand was used to draw a shape.

Results

The study population comprised 2284 children and adolescents. RP boys and girls scored significantly higher with their preferred hand, the difference amounting to 9.5 and 10.1% respectively. LP girls scored significantly higher with their preferred hand, but this difference was only 3.0%. For LP boys no significant difference was found in favor of either hand. LP children score higher with the non-preferred hand and tie scores on both hands more often than RP children.

Conclusion

The 10% rule of hand preference is applicable to RP children ranging in age between 4 and 17 years, but not to LP children. In contrast to LP boys, LP girls are generally significantly stronger with their preferred hand.

Hand Strength, Handwriting, and Functional Skills in Children With Autism

OBJECTIVE. To establish hand strength development trends in children with autism and to investigate correlations between grip and pinch strength, components of handwriting, and functional activities in children with and without autism.

METHOD. Fifty-one children were divided into two groups: typically developing children and children on the autism spectrum. Each child completed testing for pinch and grip strength, handwriting legibility, pencil control, and independence in functional activities.

RESULTS. The children with autism followed the same strength development trends as the typically developing children. Grip strength correlated with pencil control in both groups and with handwriting legibility in the typically developing children but not in the children with autism. Grip and pinch strength correlated with independence with functional activities in both groups.

CONCLUSION. This study provides evidence that grip and pinch strength are important components in developing pencil control, handwriting legibility, and independence with functional fine motor tasks.

Normative Values for Grip and Pinch Strength for 6- to 19-Year-Olds

OBJECTIVES

To provide current normative data for grip and pinch strength in children and young adults aged 6 to 19 years as well as to examine the effect of age, sex, and hand dominance on grip and pinch strength.

DESIGN

Descriptive cross-sectional.

SETTING

Two grade schools, 2 high schools, and 1 university.

PARTICIPANTS

Participants (N=1508; 741 male students and 767 female students) aged 6 to 19 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Means and SDs were calculated for each strength measurement (grip, tip pinch, lateral pinch, palmar pinch) and stratified by age and sex. Analysis of covariance and 2-sample t tests were used to analyze the data.

RESULTS

The analyses demonstrated that age and sex had a significant effect on hand strength values, as evidenced by increasing hand strength with age as well as greater hand strength in males than in females. Hand dominance was not shown to have a significant effect on hand strength. The results of this study were statistically significantly different from previously published normative values, with most hand strength values being lower than those published 28 years ago.

CONCLUSIONS

Having updated normative data are paramount for rehabilitation practitioners to compare the grip and pinch strength of their clients with the average values to objectively assess impairment and tracking progress. The statistical significance observed for most data collected in this study as compared with those previously published supports the need for continually updating normative data.

Aggressive-antisocial boys develop into physically strong young men

Young men with superior upper-body strength typically show a greater proclivity for physical aggression than their weaker male counterparts. The traditional interpretation of this phenomenon is that young men calibrate their attitudes and behaviors to their physical formidability. Physical strength is thus viewed as a causal antecedent of aggressive behavior. The present study is the first to examine this phenomenon within a developmental framework. We capitalized on the fact that physical strength is a male secondary sex characteristic. In two longitudinal cohorts of children, we estimated adolescent change in upper-body strength using the slope parameter from a latent growth model. We found that males' antisocial tendencies temporally precede their physical formidability. Boys, but not girls, with greater antisocial tendencies in childhood attained larger increases in physical strength between the ages of 11 and 17. These results support sexual selection theory, indicating an adaptive congruence between male-typical behavioral dispositions and subsequent physical masculinization during puberty.

Genetic influences on the development of grip strength in adolescence

Enhanced physical strength is a secondary sex characteristic in males. Sexual dimorphism in physical strength far exceeds sex differences in stature or total body mass, suggesting a legacy of intense sexual selection. Upper-body strength is a particularly promising marker of intrasexual competitiveness in young men. Consequently, it is assumed that sex-influenced gene expression contributes to the development of physical strength. It is unclear, however, whether the underlying sources of individual differences in strength development are comparable across sex. We obtained three measurements of hand-grip strength (HGS) over a six-year period spanning adolescence in male and female same-sex twins (N = 2,513). Biometrical latent growth models were used to partition the HGS variance at age 11 (intercept) and its growth over time (slope) into genetic and environmental components. Results demonstrated that variance around the intercept was highly heritable in both males and females (88% and 79%, respectively). In males, variance around the slope exceeded that of the intercept, while the reverse held for females. Additive genetic effects accounted for most (80%) of the variance around the slope in males, but were of less importance in females (heritability = 28%). Absolute genetic variance around the slope was nearly nine-fold higher in males. This striking disparity suggests that the developmental processes shaping HGS growth are different between the sexes. We propose that this might account for the sex-specific pattern of associations between HGS and external measures (e.g., digit ratio and physical aggression) typically reported in the literature. Our results underscore the role of endogenous androgenic influences in the development of physical strength.

Age as a moderator of the secular trend for grip strength in Canada and the United States

PURPOSE

To determine whether grip strength changed on average over recent decades at each of two age levels (children and adolescents versus adults) in Canada and the US.

METHODS

For each sex, weighted least squares regression analyses were performed on mean grip strength values as reported in studies conducted from the 1960s onwards.

RESULTS

Grip strength did not change significantly as a function of year tested in children and adolescents, whereas it declined as a negatively accelerated function of year tested in adults.

CONCLUSION

The results are contrary to what might be expected given that body weight has increased in both countries in recent decades and given that grip strength has been found to be positively correlated with body weight. It is suggested that there was a concurrent change in a factor that operated to counteract the effect of increased body weight on grip strength, a prime candidate being a decrease in levels of serum vitamin D. It is also suggested that the secular decline in adult grip strength can be explained by a factor that affects muscular function but which has a long latency period, a prime candidate here being obesity history.

Grip strength is strongly associated with height, weight and gender in childhood: a cross sectional study of 2241 children and adolescents providing reference values

QUESTION

What are reference values for grip strength in children and adolescents based on a large and heterogeneous study population? What is the association of grip strength with age, gender, weight, and height in this population?

DESIGN

Cross-sectional study.

PARTICIPANTS

Participants were recruited from schools in the northern provinces of the Netherlands. The study included healthy children and adolescents ranging in age from 4 to 15 years.

OUTCOME MEASURES

All children had their height (cm) and weight (kg) measured and were allowed a total of four attempts using the Jamar hand dynamometer: twice with each hand. Grip strength scores (kg) were recorded for the dominant and non-dominant hands.

RESULTS

The study population comprised 2241 children and adolescents. Reference values for both genders are provided according to age and dominance. Grip strength shows a linear and parallel progression for both genders until the age of 11 or 12, after which grip strength development shows an acceleration that is more prominent in boys.

CONCLUSION

There is a significant difference in grip strength with each ascending year of age in favour of the older group, as well as a trend for boys to be stronger than girls in all age groups between 4 and 15 years. Weight and especially height have a strong association with grip strength in children.