The impact of gender, body dimension and body composition on hand-grip strength in healthy children

Sex Differences in Track and Field Elite Youth

PURPOSE

To understand athletic performance before and after puberty, this study determined 1) the age at which the sex difference increases among elite youth track and field athletes for running and jumping events, and 2) whether there is a sex difference in performance before ages associated with puberty among elite youth athletes.

METHODS

Track and field records of elite US male and female youth (7-18 yr) across 3 yr (2019, 2021, and 2022) were collected from an online database ( athletic.net ). The top 50 performances were recorded for 100-, 200-, 400-, and 800-m track running, long jump, and high jump.

RESULTS

Males ran faster than females at every age in the 100, 200, 400 and 800 m ( P < 0.001). When combining all running events, the sex difference (%) was 4.0% ± 1.7% between 7 and 12 yr and increased to 6.3% ± 1.1% at 13 yr and 12.6% ± 1.8% at 18 yr ( P < 0.001). Similarly, males jumped higher and farther than females at every age ( P < 0.001). For long jump, the sex difference was 6.8% ± 2.8% between 7 and 12 yr, increasing to 8.5% ± 1.7% at 13 yr and 22.7% ± 1.4% at 18 yr ( P < 0.001). For high jump, the sex difference was 5.3% ± 5.2% between 7 and 12 yr, increasing to 12.4% ± 2.9% at 15 yr and 18.4% ± 2.04% at 18 yr ( P < 0.001).

CONCLUSIONS

Before 12 yr of age in elite youth track and field athletes, there was a consistent and significant sex difference of ~5%, such that males ran faster and jumped higher and farther than females. The magnitude of the sex difference in performance increased markedly at 12-13 yr for running and long jump and 14 yr for high jump and thus was more pronounced after ages associated with puberty.

Hormonal Basis of Biological Sex Differences in Human Athletic Performance

Biological sex is a primary determinant of athletic human performance involving strength, power, speed, and aerobic endurance and is more predictive of athletic performance than gender. This perspective article highlights 3 key medical and physiological insights related to recent evolving research into the sex differences in human physical performance: (1) sex and gender are not the same; (2) males and females exhibit profound differences in physical performance with males outperforming females in events and sports involving strength, power, speed, and aerobic endurance; (3) endogenous testosterone underpins sex differences in human physical performance with questions remaining on the roles of minipuberty in the sex differences in performance in prepubescent youth and the presence of the Y chromosome (SRY gene expression) in males, on athletic performance across all ages. Last, females are underrepresented as participants in biomedical research, which has led to a historical dearth of information on the mechanisms for sex differences in human physical performance and the capabilities of the female body. Collectively, greater effort and resources are needed to address the hormonal mechanisms for biological sex differences in human athletic performance before and after puberty.

Adjusting for muscle strength and body size attenuates sex differences in the exercise pressor reflex in young adults

Females typically exhibit lower blood pressure (BP) during exercise than males. However, recent findings indicate that adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI; metaboreflex isolation). In addition, body size is associated with HG strength but its contribution to sex differences in exercising BP is less appreciated. Therefore, the purpose of this study was to determine whether adjusting for strength and body size would attenuate sex differences in BP during HG and PEI. We obtained beat-to-beat BP in 110 participants (36 females, 74 males) who completed 2 min of isometric HG exercise at 40% of their maximal voluntary contraction followed by 3 min of PEI. In a subset (11 females, 17 males), we collected muscle sympathetic nerve activity (MSNA). Statistical analyses included independent t tests and mixed models (sex × time) with covariate adjustment for 40% HG force, height2, and body surface area. Females exhibited a lower absolute 40% HG force than male participants (Ps < 0.001). Females exhibited lower Δsystolic, Δdiastolic, and Δmean BPs during HG and PEI than males (e.g., PEI, Δsystolic BP, 15 ± 11 vs. 23 ± 14 mmHg; P = 0.004). After covariate adjustment, sex differences in BP responses were attenuated. There were no sex differences in MSNA. In a smaller strength-matched cohort, there was no sex × time interactions for BP responses (e.g., PEI systolic BP, P = 0.539; diastolic BP, P = 0.758). Our data indicate that sex differences in exercising BP responses are attenuated after adjusting for muscle strength and body size.NEW & NOTEWORTHY When compared with young males, females typically exhibit lower blood pressure (BP) during exercise. Adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI), but the contribution of body size is unknown. Novel findings include adjustments for muscle strength and body size attenuate sex differences in BP reactivity during exercise and PEI, and sex differences in body size contribute to HG strength differences.

Associations between grip strength, cardiorespiratory fitness, cardiovascular risk and mental health in forcibly displaced people from a Greek refugee camp

Muscular strength represents a specific component of health-related fitness. Hand grip strength is used as a simple and dynamic marker of maximum voluntary force of the hand and to estimate overall strength. Today, little is known about the relationship between grip strength and health in forcibly displaced populations. In the present study, we examined whether grip strength is associated with various health outcomes in a sample of forcibly displaced people living in a Greek refugee camp. The present analyses are part of a larger pragmatic randomized controlled trial. In this paper, cross-sectional baseline data of 143 participants (71 men, 72 women) will be presented. In addition to grip strength, the following physical and mental health outcomes were assessed: body weight and body composition, blood pressure, total cholesterol, low- and high-density lipoprotein cholesterol, triglycerides, blood glucose levels (HbA1c), post-traumatic stress disorder (PTSD) symptoms, depressive and anxiety symptoms, pain, and quality of life. Linear regression analyses were carried out to examine how grip strength is associated with the health outcomes, separately for absolute and normalized grip strength scores. Grip strength was positively and strongly associated with percentage muscle mass (normalized grip strength: Stand. B = 0.58, p < .001), whereas a negative association existed for percentage body fat (normalized grip strength: Stand. B = - 0.58, p < .001). No statistically significant associations occurred between grip strength and the other cardiovascular risk markers. In contrast, we found that participants with higher normalized grip strength reported higher levels of PTSD (normalized grip strength: Stand. B = 0.36, p < .05) and depressive symptoms (normalized grip strength: Stand. B = 0.29, p < .05). No significant association occurred between grip strength, anxiety, pain and quality of life. Measuring grip strength in forcibly displaced people can be a useful way to assess their overall muscle strength. Grip strength tests are easy to implement, and results can be used to assess the effects of specific intervention measures. Nevertheless, our results question the usefulness of grip strength as a marker of cardiovascular health and mental wellbeing in a refugee camp setting.

Handgrip strength associates with effort-dependent lung function measures among adolescents with and without asthma

Studies have shown association between handgrip strength (HGS) and FEV1, but the importance of this in relation to asthma pathophysiology and diagnostics remains unclear. We investigated the relationship between HGS and lung function metrics and its role in diagnosing asthma. We included 330 participants (mean age: 17.7 years, males: 48.7%) from the COPSAC2000 cohort and analyzed associations between HGS, asthma status, spirometry measures (FEV1, FVC, MMEF, FEV1/FVC), airway resistance (sRaw), methacholine reactivity (PD20) and airway inflammation (FeNO). Finally, we investigated whether HGS improved FEV1 prediction and classification of asthma status. HGS was only associated with forced flows, i.e., positive association with FEV1 and FVC for both sexes in models adjusted for age, height, and weight (P < 0.023). HGS improved adjusted R2-values for FEV1 prediction models by 2-5% (P < 0.009) but did not improve classification of asthma status (P > 0.703). In conclusion, HGS was associated with the effort-dependent measures FEV1 and FVC, but not with airway resistance, reactivity, inflammation or asthma status in our cohort of particularly healthy adolescents, which suggests that the observed associations are not asthma specific. However, HGS improved the accuracy of FEV1 estimation, which warrants further investigation to reveal the potential of HGS in asthma diagnostics.

Relationship between age and handgrip strength: Proposal of reference values from infancy to senescence

Introduction

Measurement of hand grip strength (HGS) has been proposed as a key component of frailty and has also been suggested as a central biomarker of healthy aging and a powerful predictor of future morbidity and mortality.

Objectives

(a) To determine whether a nonlinear relationship model could improve the prediction of handgrip strength (HGS) compared to the linear model and (b) to propose percentiles to evaluate HGS according to age and sex for a regional population of Chile from infancy to senescence.

Methods

A cross-sectional descriptive study was developed in a representative sample of the Maule region (Chile). The volunteers amounted to 5,376 participants (2,840 men and 2,536 women), with an age range from 6 to 80 years old. Weight, height, HGS (right and left hand) according to age and sex were evaluated. Percentiles were calculated using the LMS method [(L (Lambda; asymmetry), M (Mu; median), and S (Sigma; coefficient of variation)].

Results and discussion

There were no differences in HGS from 6 to 11 years of age in both sexes; however, from 12 years of age onwards, males presented higher HGS values in both hands (p < 0.05). The linear regression between age with HGS showed values of R ² = 0.07 in males and R ² = 0.02 in females. While in the non-linear model (cubic), the values were: R ² = 0.50 to 0.51 in men and R ² = 0.26 in women. The percentiles constructed by age and sex were: P5, P15, P50, P85, and P95 by age range and sex. This study demonstrated that there is a nonlinear relationship between chronological age with HGS from infancy to senescence. Furthermore, the proposed percentiles can serve as a guide to assess and monitor upper extremity muscle strength levels at all stages of life.

Handgrip Strength Is Associated with Metabolic Syndrome and Insulin Resistance in Children and Adolescents: Analysis of Korea National Health and Nutrition Examination Survey 2014-2018

Background

Reduced handgrip strength (HGS) is associated with adverse cardiometabolic health outcomes. We examined HGS, metabolic syndrome (MetS), and insulin resistance (IR) in children and adolescents.

Methods

The following population-based data from 2,797 participants (aged 10-18 years) of the Korea National Health and Nutrition Examination Survey 2014-2018 were analyzed: complete anthropometric measures, HGS, MetS, and IR (subgroup with fasting insulin, n=555). HGS was analyzed as the combined HGS (CHGS) and the normalized CHGS (nCHGS=CHGS divided by body weight).

Results

At a mean age of 14.4 years, 276 participants (9.9%) had abdominal obesity, 56 (2.0%) had MetS, and 118 (20.9%) had IR. Individual components of MetS and IR were inversely associated with the nCHGS. The odds ratios (ORs) for MetS and IR decreased significantly with higher nCHGS after adjustment for sex, age, physical activity, and sedentary times. The optimal cut-off values that predicted MetS were 0.80 kg/kg (males) and 0.71 kg/kg (females), with significant associations with MetS (OR: 7.4 in males; 5.7 in females) and IR (OR: 3.3 in males; 3.2 in females) observed when nCHGS values were lower than those cut-offs.

Conclusion

HGS is associated with MetS and IR and might be a useful indicator of cardiometabolic risk factors in children and adolescents.

Differential Relationship of Grip Strength with Body Composition and Lifestyle Factors Between Indian Urban and Rural Boys and Girls

OBJECTIVES

To assess grip strength and gender differences in grip strength in 9-18-y-old urban and rural Indian children, to study association of grip strength with body composition, and assess determinants of grip strength.

METHODS

This was part of a multicenter, cross-sectional, school-based study (n = 1978, mean age 13.3 ± 2.2 y) from three urban and rural states. Anthropometry, body composition, dietary intake, physical activity, sunlight exposure, and grip strength (in kg) were measured.

RESULTS

Mean grip strength increased with age but plateaued in girls after 12 y and was higher in boys (19.6 ± 9.2) than girls (14.3 ± 5.3) (p < 0.05). Mean grip strength was higher in urban (21.05 ± 9.7) than in rural boys (17.8 ± 8.2) (p < 0.05), and comparable in urban (14.9 ± 5.2) and rural girls (13.8 ± 5.5). Grip strength in girls remained lower than boys after adjusting for muscle mass. Difference between boys and girls reduced after body size [body mass index (BMI)] correction, but remained low in girls, plateauing after 15 y. Muscle mass and age were significant determinants of grip strength in all children. On addition of lifestyle factors to the model, grip strength was explained to varied degrees in the children.

CONCLUSION

In boys, nutrition through body size and composition was largely responsible for the differences in grip strength, and in girls, additionally, sociocultural factors also possibly impacted grip strength.

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.

Association of the Mediterranean Dietary Quality Index with handgrip strength and muscle endurance: A cross-sectional study

Mediterranean diet is a healthy eating pattern associated with various health advantages. Different scoring methods of adherence to this diet have been used to investigate the association between the Mediterranean diet and muscle outcomes. The present study aimed to investigate the association of the Mediterranean Dietary Quality Index (Med-DQI) with handgrip strength (HS) and muscle endurance (ME). The current cross-sectional study involved 268 Iranian adults aged 18-70 years. Anthropometric measures were evaluated. We used the 168-item food frequency questionnaire (FFQ) to develop the Med-DQI score. The Med-DQI score ranges from 0 to 14 (lower score suggests higher adherence to Mediterranean diet). HS was measured by a digital handgrip dynamometer, and ME was the amount of time to reach a maximum of 50% of grip strength. Multiple regression analysis was used to determine the association of Med-DQI and its components with HS and ME. Med-DQI score was not associated with mean handgrip strength (MHS) (p = .34) and mean muscle endurance (MME) (p = .69) in the crude model. The associations remained insignificant after the adjustment of covariates (p = .16, .31, respectively). Among the components of Med-DQI, cholesterol, meats, fish, and cereals were positively correlated with MHS (p < .001 for all). Meats (p = .02), olive oil (p < .001), cereals (p = .04), fruits and vegetables (p < .001 for all) were also positively correlated with MME. According to our findings, Med-DQI score is not associated with MHS and MME in a population of Iranian adults. Further longitudinal studies are required to confirm these findings.

Effects of a Mixed Exercise Program on Overweight and Obese Children and Adolescents: A Pilot, Uncontrolled Study

Pediatric excess weight has reached severity worldwide, affecting physical health. Decreasing weight and body mass index (BMI) after exercise intervention reduces the cardiometabolic consequences; the role of age and gender on the effectiveness of exercise in overweight youth was debated in this study. A total of 138 overweight/obese young (75 girls, 63 boys) were recruited at Perugia (Italy) University to follow an exercise program. Participants were allocated into two groups (children, n = 88 and adolescents, n = 50). The study aimed to verify the efficacy of a mixed resistance–endurance exercise program in anthropometric and physical performance measures, evaluating the influence of gender and age on two groups of young overweight/obese participants. In children, we observed a statistically significant improvement in fat mass percentage, fat-free mass, waist circumference (WC), fat mass, as well as in strength, endurance, speed, and flexibility measures. We also observed reduced WC and waist-to-height ratio (WHtR) values in girls. In the adolescents’ subgroup, results showed a statistically significant variation in fat mass percentage, BMI, WC, and WHtR, and strength of the upper and lower limbs; we also observed a weight reduction in girls. A clinical approach, with the combination of strength and dynamometric tests plus the body composition study using air plethysmography methodology, is health-effective and allows for the monitoring of the efficacy of an exercise program in overweight/obese young people.

Maternal Testosterone Concentrations in Third Trimester and Offspring Handgrip Strength at 5 Years: Odense Child Cohort

BACKGROUND

Maternal testosterone in pregnancy may have conditioning effects on offspring muscle strength.

PURPOSE

To investigate possible associations between maternal testosterone concentrations in third trimester and offspring handgrip strength (HGS) at 5 years.

METHODS

In the prospective, population-based Odense Child Cohort, total testosterone (TT) at gestational week 27-28 and 5-year HGS were measured in 1017 mother-child pairs. TT was measured by liquid chromatography-tandem mass spectrometry and free testosterone (FT) was calculated from TT and sex hormone-binding globulin (SHBG). Multivariable regression analyses were performed with HGS < 10th percentile as cutoff for low HGS.

RESULTS

Third-trimester FT concentration was 0.004 (0.002-0.007) nmol/L, geometric mean (mean - SD; mean + SD). The mean (SD) 5-year HGS was 8.7 (1.8) kg in boys and 8.1 (1.7) kg in girls (P < 0.001). Higher FT concentrations were associated with lower HGS (β = -0.186, P = 0.048), after adjustment for maternal age, parity, offspring sex, and 5-year height and weight. FT > 0.004 nmol/L was associated with higher risk of 5-year HGS < 10th percentile with odds ratios (95% CI) of 1.58 (1.01, 2.47; P = 0.047; n = 1,017) and 1.69 (1.05, 2.74; P = 0.032) after further adjustment for children's organized sports in subgroup analysis (n = 848). Lower HGS in relation to higher FT concentrations was found in all linear models but was not always statistically significant. HGS was not associated with maternal TT and SHBG levels.

CONCLUSION

Third trimester FT was inversely associated with offspring muscle strength assessed by HGS at 5 years of age, which may suggest a negative effect of maternal FT on offspring muscle strength.

The effect of body composition on strength and power in male and female students

PURPOSE

The aim of this study is to determine and to compare the effect of sex differences in percentage of body fat on the strength and power performances of the legs and arms during short maximal exercise.

METHODS

72 male and 64 female students aged 20 to 23 years were enrolled in this study. After assessing their morphological characteristics (body mass, height and percentage of fat mass), a squat jump test (SJ), a 5 successive jump test (5JT), a hand gripping (HG) and back strength (BS) tests have been conducted for each subject. Male students were re-tested after being weighed down with a weight equivalent to the mean differences in body fat recorded between the two sexes in the form of a loaded worn vest.

RESULTS

Male are 15.7% heavier and 7.4% taller and presented a percentage of fat mass (17.2 ± 1.8%) significantly (p < 0.001) lower than that of women subject (25.0 ± 2.5%) (difference male vs female for fat mass: -45.5%). HG, BS, 5JT and SJ performances were significantly higher in males (44 ± 5 kg, 141 ± 2 kg, 11 ± 1 m and 32.4 ± 2,7 cm, respectively) than in females (31.0 ± 4 kg, 81.6 ± 13 kg, 8.7 ± 0.7 m and 21.1 ± 1.9 cm, respectively). In the control (unloaded) condition, the relative difference between males and females represented 23.5% and 34.7% of the male performances for 5JT and SJ, respectively. In the weighted condition, the relative difference between weighted males and females still represented 11.7% and 23.8% of the weighted male performances for 5JT and SJ, respectively. Cancelling the sex difference in fat mass by adding weight in males reduced by 50.1% the sex difference during 5JT and 31.4% and 71.7% for hight and power results, respectively during SJ test.

CONCLUSION

During short and maximal exercise, male performed better with their hands, back and legs than female students. Excess fat for female students has a disadvantageous effect on vertical and horizontal jumps performances. The persistence of sex differences after weighting of male students indicates that body fat is responsible for 30 to 70% of the observed differences between sexes performances and power outcomes during jump tests.

Normative data for handgrip strength in Iranian healthy children and adolescents aged 7-18 years: comparison with international norms

BACKGROUND

Grip strength is an essential component of physical fitness. The objective of this study was to develop normative handgrip strength data for Iranian healthy boys and girls comparing their handgrip strength with international reference values.

METHODS

Handgrip strength was measured in 2637 healthy children/adolescents (1391 boys and 1246 girls), aged 7-18 years, using a standard adjustable Jamar hand dynamometer (Model 5030 J1, Sammons Preston Rolyan, Bolingbrook, IL, USA). Body mass (kg) and stature (cm) were measured and body mass index was computed in kg/m2. The sample was stratified by gender, age, and hand preference.

RESULTS

Handgrip strength increased with age and was considerably higher in boys than in girls for all age groups (p < 0.001). Grip strength had a parallel and linear growth for both genders until the age of about 11 years and showed a steeper upward slope in boys than in girls thereafter. The findings of the current investigation were significantly different from those of the previously published normative data, especially for boys over the age of 12 years and girls in the age range of 7-18 years (p < 0.001). This difference was mainly in such a way that the Iranians had lower handgrip strength.

CONCLUSIONS

The differences between present results and those of similar available in the literature in this field emphasize the significant role of using normative data specific to a particular population in research or clinical settings.

Physical Activity, Fitness, and Cognitive Performance of Estonian First-Grade Schoolchildren According Their MVPA Level in Kindergarten: A Longitudinal Study

Little is known about the longitudinal trajectories and associations regarding physical activity (PA), physical fitness (PF), and cognitive skills in childhood. Accelerometer-based PA, sedentary behavior (SB), PF, and cognitive skills were measured in Estonian children (n = 147) in kindergarten (6.6 years) and again at school (7.6 years). Children were subgrouped into lower and upper quartiles by their moderate-to-vigorous PA (MVPA) at 6.6 years. Children in the upper quartile had lower SB, higher PA, and greater muscular strength. Attending school, MVPA in the lower quartile improved. In both subgroups, most strength values and cognitive skills improved, while balance deteriorated in first grade. In the upper quartile, a greater MPA at 6.6 years predicted lower perceptual skills at 7.6 years. A greater SB at 6.6 years predicted higher verbal skills, light and moderate PA and MVPA, and lower verbal skills at 7.6 years after taking into account confounding factors such as the child's sex, age, awake wear time (AWT), maternal education, and/or child's sports participation. A vigorous PA at 6.6 years predicted perceptual (in upper quartile) or verbal (in lower quartile) skills at 7.6 years after controlling for similar confounders. No correlation for PF at 6.6 years and cognitive skills at 7.6 years existed; after adjusting for the above-mentioned confounders relative to upper/lower-limb strength, the 4 × 10 m shuttle run results predicted higher perceptual or verbal skills; static balance and cardiorespiratory fitness predicted lower verbal skills. Cardiorespiratory fitness predicted higher perceptual skills after controlling for sex, age, and AWT. Overall, PA and strength were constantly better and SB lower in the upper quartile, yet the lower quartile demonstrated improved MVPA in first grade, and both subgroups increased most components of their strength and cognitive skills in first grade. Higher levels of VPA at kindergarten predicted either better perceptual or verbal skills in first grade after controlling for confounders; the opposite associations were found for other PA levels and cognitive skills in the higher quartile. PF components at kindergarten predicted either superior or inferior cognitive skills in first grade after adjusting for confounders.

Preschool physical activity and fitness predicts conceptual, verbal and perceptual skills at school

This study investigated longitudinal relationships between physical activity (PA), fitness and cognitive performance at early years. In total, 147 children at the age of 6.6 and 7.6 years participated in the study. PA and sedentary behaviour (SB) were registered with accelerometer. Skinfold thickness measurements were used to assess body composition. Children's cardiorespiratory fitness (CRF), muscular strength and speed-agility fitness was assessed using PREFIT fitness test battery and static balance by EUROFIT test battery. Cognitive skills were measured with modified Boehm-3 test. Linear regression analyses showed that PA at the age of 6.6 years was positively, while SB was negatively associated with the conceptual skills at the age of 7.6 years after adjusting for confounders. Positive associations were observed between CRF, lower-limbs strength relative to fat-free mass, static balance at the age of 6.6 years with perceptual skills at 7.6 years in unadjusted analysis. PA and fitness were not associated with verbal abilities. Physically active lifestyle and CRF, relative explosive strength of the lower limbs, balance at 6.6 years in kindergarten predict conceptual and perceptual skills, but does not predict verbal abilities 1 year later at first grade in school. SB affects negatively conceptual skills.

Characteristics of Selected Somatic and Motor Abilities of Youth Soccer Players with Diabetes Type 1 Treated with Insulin Pump Therapy

Long-term insulin treatment can slow the growth process and decrease physical fitness level in children. In diabetic children, these two developments should be constantly monitored. The aim of the present study was to examine differences in somatic and physical fitness characteristics between soccer-training boys with type 1 diabetes and healthy boys of the same age (reference values based on Polish population norms for somatic and motor parameters). The participants were 94 boys (8–17 years), diagnosed with diabetes, who participated in soccer training on a regular basis and received routine medical care. The study involved (a) anthropometric and body composition measurements, (b) general motor ability assessments, and (c) comparison of those characteristics with the healthy Polish population. The diabetic boys were found to have lower levels of almost all somatic traits and motor abilities as compared with the healthy boys (p ≤ 0.05). Handgrip strength was a variable with the smallest difference between the two groups. The observed differences indicate the necessity to design an appropriate control and assessment system based on simple medical and fitness field tests for diabetic children and adolescents. It will allow optimizing advanced training as well as minimize health risks before, during, or after exercise.

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).

Analysis of hand-forearm anthropometric components in assessing handgrip and pinch strengths of school-aged children and adolescents: a partial least squares (PLS) approach

Background

The purpose of this study was to examine the influence of hand-forearm anthropometric dimensions on handgrip and pinch strengths among 7–18 years children and adolescents and to investigate the extent to which these variables can be used to predict hand strength.

Methods

Four types of hand strengths including handgrip, tip to tip, key, and three-jaw chuck pinches were measured in 2637 healthy children and adolescents (1391 boys and 1246 girls) aged 7–18 years using standard adjustable Jamar hydraulic hand dynamometer and pinch gauge. A set of 17 hand-forearm anthropometric dimensions were also measured with an accurate digital caliper and tape measure.

Results

No significant differences were found between the hand strengths of boys and girls up to the age of 10 years. Gender related differences in handgrip and pinches were observed from the age of 11 years onwards, with boys always being stronger. The dominant hand was stronger than the non-dominant hand (8% for handgrip and by about 10% for all three types of pinches). The strongest correlations were found between the hand length and hand strengths (r > 0.83 for handgrip and three all pinches; p < 0.001, 2-tailed). Based on the partial least squares (PLS) analysis, 8 out of 17 anthropometric indices including hand length, hand circumference, thumb length, index finger length, middle finger length, and forearm length had considerable loadings in the PLS analysis, which together accounted for 46% of the total variance.

Conclusions

These results may be used by health professionals in clinical settings as well as by designers to create ergonomic hand tools.

Physical fitness in preschool children in relation to later body composition at first grade in school

BACKGROUND

This study aimed to investigate whether better physical fitness in kindergarten predicts later healthier body composition in first grade at school.

METHODS

Body composition was assessed by skinfold thickness measurements. Physical fitness tests included 20 m shuttle run test, handgrip strength test, standing long jump test, 4x10 m shuttle run test as part of PREFIT fitness test battery, and one-leg stance test from EUROFIT test battery. The participants of this study were 147 Estonian children (51% boys) aged 6-8 years, who were measured in the transition from kindergarten to school.

RESULTS

After adjusting for maternal body mass index, educational attainment, child's sex, age at the measurements, greater cardiovascular and motor fitness, relative lower body strength, static balance at 6.6 yr were associated with lower fat mass index, fat mass percentage at 12-month follow-up. The relative lower body strength above the median at 6.6 yr were related to lower fat mass index and fat mass percentage at 12-month follow-up, while the static balance test results demonstrated the opposite associations. Improvements in the 4x10 m shuttle run test results during the 12-month follow-up period were associated with the most beneficial changes in body composition status, such as increases in fat-free mass index and decreases in fat mass index, fat mass percentage, waist-to-height ratio after adjusting for maternal body mass index, educational attainment, child's sex, age, at the measurements and baseline values of exposures.

CONCLUSION

Better physical fitness tests results at 6.6 yr in kindergarten generally predicted lower body fat parameters in children at 7.6 yr in first grade at school.

Physical Performance Regarding Handgrip Strength in Women with Polycystic Ovary Syndrome

OBJECTIVE

 The present study aimed to investigate the physical performance of handgrip strength (HGS) in women with polycystic ovary syndrome (PCOS).

METHODS

 A case-control study that included 70 women with PCOS and 93 age-matched healthy women aged between 18 and 47 years with body mass index (BMI) between 18 Kg/m²-39.9 Kg/m². The serum levels of total testosterone, androstenedione, insulin, estradiol, thyroid-stimulating hormone (TSH), prolactin, sex hormone-binding globulin (SHBG), and 17-hydroxyprogesterone (17-OHP) were measured. The free androgen index (FAI) and the homeostatic model assessment of insulin resistance (HOMA-IR) were calculated. The body composition regions of interest (ROIs) were assessed by dual-energy X-ray absorptiometry (DXA), and the handgrip strength (HGS) was evaluated for both the dominant and the non-dominant hands with a manual Sammons Preston (Bolingbrook, IL, US) bulb dynamometer.

RESULTS

 Women with PCOS had high serum levels of total testosterone (p < 0.01), androstenedione (p = 0.03), and insulin (p < 0.01), as well as high FAI (p < 0.01) and HOMA-IR (p = 0.01) scores. Compared with the non-PCOS group, the PCOS group had greater total lean mass in the dominant hand (p < 0.03) and greater HGS in both the dominant and the non-dominant hands (p < 0.01). The HGS was correlated with lean mass (p < 0.01).

CONCLUSION

 Women with PCOS have greater HGS. This may be associated with age and BMI, and it may be related to lean mass. In addition, the dominance effect on muscle mass may influence the physical performance regarding HGS in women with PCOS.

Test-Retest Reliability of Handgrip Strength Measurement in Children and Preadolescents

The reliability of handgrip strength (HGS) measurement has been confirmed in adults but has been sparsely addressed in pediatric populations. The aims of this study are twofold: to determine whether sex, age and/or hand-dominance influence the test–retest differences and to establish the reliability level of the HGS measurement in typical developing pediatric participants. A total of 338 participants aged 7–13 years were tested using a digital handgrip strength (HGS) dynamometer (Jamar Plus+ Dynamometer) by the same rater on two testing trials separated by a one-day interval between sessions. The HGS testing was conducted according to the American Society of Hand Therapists recommendations. Relative and absolute reliability statistics were calculated. Age influenced the test–retest difference of the HGS measurement as children compared to preadolescents had lower intraclass correlation coefficients (0.95 vs. 0.98), standard error of measurement (SEM) (0.74 vs. 0.78 kg), smallest detectable difference (SDD) (2.05 vs. 2.16 kg) and higher values of the percentage value of SEM (5.48 vs. 3.44%), normalized SDD (15.52 vs. 9.61%) and a mean difference between the test and retest values (0.50 vs. 0.02 kg) for the dominant hand. The results indicate that the protocol using the Jamar digital handgrip dynamometer is a reliable instrument to measure HGS in participants aged 7–13 years with typical development. Clinicians and researchers therefore can have confidence in determining the minimally clinical effect for HGS.

Exploring associations between neuromuscular performance, hypermobility, and children's motor competence

OBJECTIVES

To evaluate if neuromuscular performance and hypermobility are factors associated with children's motor competence.

DESIGN

Cross-sectional observation study.

METHODS

Data was collected on 60 children aged 6-12 years; motor competence was determined using the Movement Assessment Battery for Children-2 test, with children classified into 3 groups (Typically Developing n=30; 'At Risk' of low motor competence (LMC) n=9; LMC n=21). Neuromuscular performance was determined utilising the Resistance Training Skills Battery for Children (RTSBc), 5-repetition maximum (5RM) leg press and Biodex dynamometry to assess isometric and isokinetic peak torque of the knee flexors and extensors. Hypermobility was measured using the Beighton and Lower Limb Assessment Score.

RESULTS

Between-groups MANCOVA revealed typically developing children scored significantly higher on the RTSBc than those 'at risk' of LMC (p=0.021) and those in the LMC group (p<0.001). 5RM scores also differed between groups, with typically developing children achieving significantly higher scores than the LMC group. No differences were found between groups for isometric or isokinetic measures of strength. Sequential regression analysis revealed neuromuscular performance variables explained 44.7% of the variance in motor competence, with RTSBc (p<0.001) and 5RM (p=0.019) emerging as positive significant predictors. Hypermobility failed to explain significant variance in motor competence beyond that explained by neuromuscular performance.

CONCLUSIONS

Neuromuscular performance of children varies according to levels of motor competence, with those with LMC performing poorly on tasks requiring multi-joint movement. Furthermore, neuromuscular performance predicted almost half the variance observed in motor competence and highlights a novel intervention strategy.

FACTORS ASSOCIATED TO QUALITY OF LIFE IN CHILDREN AND ADOLESCENTS WITH CYSTIC FIBROSIS

Objective:

To verify the association between quality of life, functional capacity and clinical and nutritional status in children and adolescents with cystic fibrosis (CF).

Methods:

Cross-sectional study, including patients from eight to 18 years old with CF. Quality of life, functional capacity, nutritional status and clinical status were evaluated with the Cystic Fibrosis Questionnaire; the 6-minute walk test (6MWT) and manual gripping force (MGF); the height percentiles for age and body mass index for age and respiratory function test, respectively. Pearson and Spearman correlation tests and logistic regression were used to analyze the data.

Results:

A total of 45 patients, 13.4±0.5 years old, 60% female, 60% colonized by Pseudomonas aeruginosa and 57.8% with at least one F508del mutation participated in the study. When assessing the perception of quality of life, the weight domain reached the lowest values, and the digestive domain, the highest. In the pulmonary function test, the forced expiratory volume of the first second was 77.3±3.3% and the 6MWT and MGF presented values within the normal range. There was an association between quality of life and functional capacity, nutritional status and clinical status of CF patients.

Conclusions:

The study participants had good clinical conditions and satisfactory values of functional capacity and quality of life. The findings reinforce that the assessment of quality of life may be important for clinical practice in the management of treatment.

First steps to establishing an equestrian morphology: can Vitruvian ratios help?

Within equestrianism there is increasing focus on rider position and posture, not only in terms of aesthetics and the overall harmonious picture it may portray of the horse-rider combination, but more importantly on the rider’s physical ability to deliver clear, well-timed signals to the horse during training and competitive performance. Anthropometry has been successfully used in a wide range of non-equestrian sports to identify morphologies that are more likely to be successful than others in completing the tasks required by the particular sport or discipline. As physical data have become more readily accessible questions have arisen regarding the rider’s physical ability to achieve and maintain ‘ideal’ and symmetrical riding positions allowing them to transfer their weight and manage their limbs and consequently deliver distinguishable signals to the horse. Clearly identified ideal morphologies exist for a wide range of sports, but there is nothing for equestrianism. Da Vinci’s Vitruvian ‘man’ possesses ideal geometric proportions that depict perfect symmetry and proportion. Within equestrian it is common belief that riders (and horses) should be symmetrical. This study explored how the dimensions of a population of 51 female riders (24.8±8.29 years) aligned with Vitruvian ideals. Ten relative body proportions, selected as potentially the most relevant to horse riding, were obtained for each subject and ratios with total height derived. Only arm span, shoulder width and upper chest to the top of the head in relation to total height aligned with Vitruvian ratios (all P>0.05). Two primary principal components were identified – total height and arm span that could be of potential use for development of an equestrian morphology. Although horse riders’ physical dimensions failed to align well with Vitruvian measures, total height and arm length may have the potential to explain differences in riders’ ability to physically interact with horses and consequently impact their welfare.

Normative reference values on handgrip strength among healthy adults of Dhulikhel, Nepal: A cross-sectional study

Context

Handgrip strength (HGS) is the amount of static force that the hand can generate around the dynamometer and can be defined as the ability of the hand to hold the objects between the thumb and fingers. Handgrip measurement is simple but also a valid measure of overall muscle strength and also provides an objective index of functional integrity of upper extremity.

Aims

To provide population-based HGS reference values for Nepalese adults from 19 to 70 years of age.

Settings and Design

A cross-sectional study was conducted in Dhulikhel community among 526 participants.

Methods and Materials

Jamar Dynamometer was used for measuring HGS based on the recommendation provided by the American Society of Hand Therapists.

Statistical Analysis Used

Data were analyzed using STATA version 14.

Results

Men exhibited higher HGS compared to women with maximum grip strength observed in age group of 19-29 which were 47.24 kg and 32.51 kg for men and women, respectively. HGS decreases with increasing age in both dominant and nondominant hands.

Conclusions

The normative reference values provided in this study may serve as a guide for interpreting grip-strength measurements obtained from tested individuals.

Obesity Affects Postural Control in Middle Childhood and Adolescence but not in Early Childhood

Introduction: Overweight/obese children have postural control differences compared with normal-weight children. Nevertheless, there are not studies that analyze the effect of obesity during the entire period comprised between childhood and adolescence. The objective of this study was to determine the differences in postural control between normal-weight and overweight/obese participants during early and middle childhood and adolescence. Methods: 359 children were divided into six groups according to age and weight status. Each participant carried out one 30-s trial with eyes open (EO) and one 30-s trial with eyes closed (EC). Center of pressure signals were acquired using a Wii Balance Board. Mean velocity in antero-posterior (MVAP) and medio-lateral (MVML) directions and the 95% confidence interval ellipse area were calculated. Results: A Mann Whitney U-test showed significant differences between normal-weight and obese 8- to 12-year-old children in MVAP and MVML in both EO and EC. In 13- to 17-year-old adolescents, there were differences between normal-weight and overweight/obese in ellipse area and MVML, both in EO and EC condition. There were no differences in postural stability between normal-weight and overweight/obese 4- to 7-year-old children. Conclusions: Obesity reduces postural stability only in middle childhood and adolescence but not in early childhood.

Grip strength among Indigenous and non-Indigenous Australian adults: a longitudinal study of the effects of birth size and current size

OBJECTIVES

Indigenous Australians are born smaller than non-Indigenous Australians and are at an increased risk of early onset of frailty. This study aimed to identify the relationship between birth size, current size and grip strength, as an early marker of frailty, in Indigenous and non-Indigenous young adults.

DESIGN

Cross sectional data from two longitudinal studies: Aboriginal birth cohort (Indigenous) and top end cohort (non-Indigenous).

SETTING

Participants reside in over 40 urban and remote communities across the Northern Territory, Australia.

PARTICIPANTS

Young adults with median age 25 years (IQR 24-26); 427 participants (55% women), 267 (63%) were remote Indigenous, 55 (13%) urban Indigenous and 105 (25%) urban non-Indigenous.

OUTCOME MEASURES

Reliable birth data were available. Anthropometric data (height, weight, lean mass) and grip strength were directly collected using standardised methods. Current residence was classified as urban or remote.

RESULTS

The rate of low birthweight (LBW) in the non-Indigenous cohort (9%) was significantly lower than the Indigenous cohort (16%) (-7%, 95% CI -14 to 0, p=0.03). Indigenous participants had lower grip strength than non-Indigenous (women, -2.08, 95% CI -3.61 to -0.55, p=0.008 and men, -6.2, 95% CI -9.84 to -2.46, p=0.001). Birth weight (BW) was associated with grip strength after adjusting for demographic factors for both women (β=1.29, 95% CI 0.41 to 2.16, p=0.004) and men (β=3.95, 95% CI 2.38 to 5.51, p<0.001). When current size (lean mass and body mass index [BMI]) was introduced to the model BW was no longer a significant factor. Lean mass was a positive indicator for grip strength, and BMI a negative indicator.

CONCLUSIONS

As expected women had significantly lower grip strength than men. Current size, in particular lean mass, was the strongest predictor of adult grip strength in this cohort. BW may have an indirect effect on later grip strength via moderation of lean mass development, especially through adolescence and young adulthood.

Local cryostimulation acutely preserves maximum isometric handgrip strength following fatigue in young women

Several types of cryostimulation have been recently proposed to rapidly lower skin temperature therefore gaining a possible neuro/muscular recovery after strenuous exercise or, more generally, in sports. Local cryostimulation may be a viable and relatively portable tool to obtain physiological benefits in previously-efforted muscular districts. However, cohesive and standardized cryo-exposure protocols are lacking as well as the righteous procedure to efficaciously combine duration, treatments and temperature in relation to desirable effects on muscular strength. In this randomized-controlled study, fifty young women were tested for maximum isometric handgrip strength, before and after exhausting contractions. Following the fatiguing protocol, the intervention group (cryo, n = 25, 24.7 ± 2.5 years, BMI 21.7 ± 1.8 kg/m2) underwent a 6-min local cryostimulation (-160 °C) on the extensor-flexor muscles of the dominant arm, while control-matched peers sat rested in a thermo-neutral room (22 ± 0.5 °C). Handgrip tests were repeated at baseline (T0), after cryostimulation (T1), and 15 min after T1 (T2). Throughout the protocol, the AUC of the strength performance was significantly higher in the cryo- compared to control group (P = 0.006). In particular, following fatigue and cryostimulation, the cryo group preserved higher strength at T1 with respect to controls (26.8 ± 2.8 vs 23.9 ± 2.8 kg, Bonferroni's post-hoc, P < 0.01). Likewise, ventral and dorsal temperature, recorded with a thermal camera, were lower in cryo- than control group (P < 0.0001). In conclusion, a brief session of local cryostimulation may acutely preserve maximal isometric force in young women following a fatiguing protocol. These findings may have implications in orchestrating strategies of district muscular recovery.

Grip and pinch strength: Reference values for children and adolescents from India

PURPOSE

The purpose of the study was to provide reference values for grip and pinch strength for healthy children and adolescents in India.

METHODS

Grip and pinch strength were recorded for 900 participants stratified into 5 chronological age groups (5-6, 7-9, 10-12, 13-15 and 16-18 years). Grip strength was measured using a Jamar Dynamometer and pinch strength using a Martin vigorimeter.

RESULTS

The difference in grip and pinch strength between age groups was significant (p< 0.001 respectively). A linear rise in grip strength was noted from age groups of 5-6 years to 16-18 years. Moderate to strong positive association was observed between grip and pinch strength and upper extremity anthropometric characteristics (i.e., palmar width, hand span, hand length, arm length, forearm length, and upper limb length) from age groups of 5-6 years to 16-18 years. Boys demonstrated greater grip and pinch strength compared to girls in all age groups (p< 0.001). No difference was observed between the dominant and non-dominant hand in all age groups.

CONCLUSIONS

Findings from the present study provide reference values for grip strength, tip to tip, key and tripod pinch for healthy Indian children and adolescents from 5-18 years of age, which will be useful to guide rehabilitation outcomes in routine clinical practice.

S-25OHD Is Associated With Hand Grip Strength and Myopathy at 5 Years in Girls: An Odense Child Cohort Study

CONTEXT

Severe vitamin D deficiency may lead to myopathy in adults. Little is known about vitamin D and muscle strength in children.

OBJECTIVE

To test whether hand grip strength (HGS) in 5-year-old children is associated with serum 25-hydroxyvitamin D (S-25OHD).

DESIGN

Observational study in the population-based Odense Child Cohort, Denmark. At 5 years, anthropometrics, body fat percentage by skinfold measurements, HGS (n = 881), and S-25OHD2+3 (n = 499) were obtained.

RESULTS

Mean (SD) HGS was higher for boys compared with girls [8.76 (1.76) vs 8.1 (1.64) kg, P < 0.001]. Mean (SD) 5-year S-25OHD was 70.7 (24.5) nmol/L. HGS was directly associated with height in girls and with weight (directly) and body fat percentage (inversely) in both sexes (P < 0.01 for all). In girls, 5-year S-25OHD was associated with HGS, adjusting for height, weight, and body fat percentage [β = 0.011 (95% CI: 0.004; 0.019), P = 0.003]. S-25OHD ≥75 nmol/L was associated with higher HGS compared with values <50 nmol/L [adjusted β = 0.783 (95% CI: 0.325; 1.241), P = 0.001]. The odds of having myopathy (HGS <10th percentile) were reduced by approximately 70% for S-25OHD ≥50 vs <50 nmol/L [adjusted OR: 0.310 (95% CI: 0.126; 0.762), P = 0.011]. No associations were seen for boys. Pregnancy or umbilical cord S-25OHD did not associate with 5-year HGS.

CONCLUSIONS

Five-year S-25OHD was independently associated with HGS and myopathy in girls but not in boys. Muscle strength may be dependent on vitamin D status even in the higher range in preschool girls. The sex difference remains unexplained.

Association of normative values of grip strength with anthropometric variables among students, in Jiangsu Province

Handgrip strength is one of the most universal and powerful indices of nutritional and health status. This study was aimed at presenting norms of grip strength values and their association with anthropometric characters among students in Jiangsu Province. Cross-sectional studies were carried out among 255,157 males and females aged 7-22 years in 2010-2013. Weight and height were obtained and handgrip strength was measured. The sample was stratified by sex, age and residential area. Data were analyzed using chi-squared test and Spearman's correlation coefficient, calculated using SPSS version of 20.0. Grip strength increased with age and was significantly stronger in males than in females across all age groups (P < 0.001). Among males the strong association existed between grip strength and body weight (r = 0.858, P < 0.001), height (r = 0.807, P < 0.001), BMI (r = 0.508, P < 0.001), and age (r = 0.842, P < 0.001). Among females grip strength was strongly associated with weight (r = 0.748, P < 0.001), height (r = 0.730, P < 0.001), BMI (r = 0.524, P < 0.001) and age (r = 0.717, P < 0.001). The results of this study can be used for comparisons while determining benchmarks for handgrip strength.

The socially evaluated handgrip test: Introduction of a novel, time-efficient stress protocol

Most widely-used stress-induction procedures (such as the TSST and the Cold Pressor Test) require considerable effort and overhead in terms of preparation, logistics, and staff recruitment. Moreover, while known to reliably induce HPA axis activation, especially when combined with social self-threat, most conventional laboratory stressors cannot be flexibly adapted to elicit either a mainly autonomic or an additional endocrine stress response. Being a promising alternative approach, a new version of the isometric handgrip test enriched by a social-evaluative component was evaluated in the present study. On two consecutive sessions, forty participants (20 women) performed a handgrip task at both 45% (stress) and 10% (control) of maximum voluntary isometric contraction lasting for 3min. During the stress test, continuous visual feedback on performance was given. Participants in the social-evaluative condition (50%) were observed and evaluated by a previously unknown person of the opposite sex, whereas in the standard condition feedback was provided via a computer monitor. Cardiovascular measures (heart rate, blood pressure) as well as additional indices of autonomic reactivity (skin conductance, heart-rate variability) were registered before, during, and after stress induction. Moreover, changes in salivary cortisol and in subjective well-being were assessed. Relative to control, significant increases in cardiovascular and sympathetic activity were found, irrespective of experimental group. Importantly, however, additional social evaluation resulted in elevated cortisol levels. Furthermore, evidence for reduced vagal tone during sustained socially evaluated handgrip emerged. In conclusion, the socially evaluated handgrip test represents a versatile, time-efficient method to induce stress in small laboratory settings.

Valores normativos de la fuerza de puño en la población española en edad laboral. Influencia de las variables antropométricas de la mano y el antebrazo

Objetivos: Determinar si en los individuos adultos sanos existe una apertura óptima del dinamómetro para conseguir la máxima fuerza de puño y si esta se relaciona con los valores de los parámetros antropométricos del antebrazo y la mano. Saber si a través de las medidas antropométricas del antebrazo y la mano es posible predecir la fuerza de puño que puede desarrollar un persona.

Métodos: 99 hombres y 103 mujeres (20-60 años). Cada mano se testó 10 veces, utilizando 5 aperturas del dinamómetro TKK. Las medidas antropométricas tomadas fueron ancho de la mano abierta, longitud del segundo, el tercer y el cuarto dedos, anchura de la palma, longitud de la palma, longitud de la mano, longitud del antebrazo, perímetro del antebrazo y grosor de la eminencia tenar.

Resultados: Con solo 2 aperturas (5,5-6 cm en varones, 5-5,5 cm en mujeres) se consiguió la máxima fuerza de puño en más del 60% de los individuos. El tamaño de la mano y el antebrazo influyó en la posición de apertura óptima en las mujeres, no en los varones. Los parámetros antropométricos que mejor definieron la fuerza fueron diferentes según el sexo y el lado, pero en ningún caso se logró que el valor de R2 superase el 0,50.

Conclusiones: La máxima fuerza de puño se consigue utilizando las posiciones medias del dinamómetro, siendo en mujeres la apertura menor que en varones. Empleando exclusivamente los parámetros antropométricos de la mano y el antebrazo no se consigue un valor predictivo útil, como el obtenido por otros autores con otras medidas antropométricas.

Sex differences in athletic performance emerge coinciding with the onset of male puberty

BACKGROUND

Male performance in athletic events begins to exceed that of age-matched females during early adolescence, but the timing of this divergence relative to the onset of male puberty and the rise in circulating testosterone remains poorly defined.

DESIGN

This study is a secondary quantitative analysis of four published sources which aimed to define the timing of the gender divergence in athletic performance and relating it to the rise in circulating testosterone due to male puberty.

DATA

Four data sources reflecting elite swimming and running and jumping track and field events as well as hand-grip strength in nonathletes were analysed to define the age-specific gender differences through adolescence and their relationship to the rising circulating testosterone during male puberty.

RESULTS

The onset and tempo of gender divergence were very similar for swimming, running and jumping events as well as the hand-grip strength in nonathletes, and all closely paralleled the rise in circulating testosterone in adolescent boys.

CONCLUSIONS

The gender divergence in athletic performance begins at the age of 12-13 years and reaches adult plateau in the late teenage years with the timing and tempo closely parallel to the rise in circulating testosterone in boys during puberty.

BIOMECHANICAL EFFECT OF TESTING POSITIONS ON HAND GRIP STRENGTH

Hand grip strength (HGS) is a useful functional measure of the integrity of the upper extremities, however, many studies have examined it from selected positions (i.e., supine, sitting, standing), with no emphasis on other derived positions that are used in clinical setting. This study’s objective was to evaluate HGS in different body positions that are used in clinical setting by using a standard protocol. The study sample was a convenience sample of 40 healthy male participants with no history of psychiatric, neurological, or upper extremity orthopedic dysfunction. Grip strength in the dominant hand was measured with a Jamar Plus[Formula: see text] digital hand dynamometer in five positions: Supine, prone, side-lying, sitting, and standing. The HGS value in prone position was significantly lower than in standing position ([Formula: see text]) and sitting position ([Formula: see text]). However, no statistically significant difference was found in HGS among the supine, prone, and side-lying positions. Grip strength was moderately correlated with age ([Formula: see text]). This study provides useful evaluation for grip strength in different positions. In identical upper extremity positions, grip strength varies between different body positions. Grip strength is equivalent when tested from the supine, side-lying, or prone positions, thus the position can be adjusted according to the patient’s condition. Finally, age is an important determinant of hand grip evaluation, particularly when standing position is used.

Gender difference in handgrip strength of Italian children aged 9 to 10 years

Background

Handgrip strength is an index of nutritional status which correlates to morbidity and mortality in young. It differs in adults and adolescents between gender. However, it is no clear whether a difference exists also in children aged 9 to 10 years, and which are the factors influencing it. Furthermore, data of Handgrip strength of Italian schoolchildren are lacking. Aim of this study was to provide Handgrip strength value from a sample of healthy Italian schoolchildren aged 9 to 10 years and to determine which factors affect grip strength at this age.

Methods

We enrolled 137 children (boys n =66; girls n = 71) who underwent a body mass index and Handgrip strength measurement. Handgrip strength was assessed by an hydraulic hand dynamometer.

Results

The mean handgrip strength value was 13.8 ± 4.0 for girls and 15.2 ± 3.0 kg for boys (p = 0.04) thus, we found a significant difference between gender. We have not found a significant differences in anthropometric parameters between gender. In the univariate analysis Handgrip strength was associated with age, BMI, height, weight and gender (p < 0.001 for age, p < 0.001 for BMI, p < 0.001 for height, p < 0.001 for weight and p < 0.04 for gender). The Multivariate linear regression analysis showed that age, BMI and gender were all correlated to grip force.

Conclusion

We found a significant difference in grip strength between healthy Italian schoolchildren aged 9 to 10 years. This parameter seems to be primarily influenced by gender. Our investigation is important since currently data regarding the reference values of HGS for Italian children are lacking.

Relationship between grip, pinch strengths and anthropometric variables, types of pitch throwing among Japanese high school baseball pitchers

Background:

Grip and pinch strength are crucially important attributes and standard parameters related to the functional integrity of the hand. It seems significant to investigate normative data for grip and pinch strength of baseball players to evaluate their performance and condition. Nevertheless, few reports have explained the association between grip and pinch strength and anthropometric variables and types of pitch throwing for baseball pitchers.

Objectives:

The aim of this study was to measure and evaluate clinical normative data for grip and tip, key, palmar pinch strength and to assess the relationship between these data and anthropometric variables and types of pitch throwing among Japanese high-school baseball pitchers.

Materials and Methods:

One hundred-thirty three healthy high school baseball pitchers were examined and had completed a self-administered questionnaire including items related to age, hand dominance, throwing ratio of type of pitch. A digital dynamometer was used to measure grip strength and a pinch gauge to measure tip, key and palmer pinch in both dominant and nondominant side. Body composition was measured by the multi frequency segmental body composition analyzer.

Results:

Grip strength and tip and palmer pinch strength in dominant side were statistically greater than them in nondominant side (P < 0.05). There were significant associations between grip strength and height (r = 0.33, P < 0.001), body mass (r = 0.50, P < 0.001), BMI (r = 0.37, P < 0.001), muscle mass of upper extremity (r = 0.56, P < 0.001), fat free mass (r = 0.57, P < 0.001), fat mass (r = 0.22, P < 0.05) in dominant side. A stepwise multiple regression analysis revealed that fat free mass and tip, palmer, key pinch strength were predictors of grip strength in dominant side. No statistical significant correlations were found between the throwing ratio of types of pitches thrown and grip strength and tip, key, palmar pinch strength.

Conclusions:

Our result provides normative values and evidences for grip and pinch strengths in high school baseball pitchers.

The relationship of birthweight, muscle size at birth and post-natal growth to grip strength in 9-year-old Indian children: findings from the Mysore Parthenon study

Foetal development may permanently affect muscle function. Indian newborns have a low mean birthweight, predominantly due to low lean tissue and muscle mass. We aimed to examine the relationship of birthweight, and arm muscle area (AMA) at birth and post-natal growth to handgrip strength in Indian children. Grip strength was measured in 574 children aged 9 years, who had detailed anthropometry at birth and every 6-12 months post-natally. Mean (standard deviation (s.d.)) birthweight was 2863 (446) g. At 9 years, the children were short (mean height s.d. -0.6) and light (mean weight s.d. -1.1) compared with the World Health Organization growth reference. Mean (s.d.) grip strength was 12.7 (2.2) kg (boys) and 11.0 (2.0) kg (girls). Weight, length and AMA at birth, but not skinfold measurements at birth, were positively related to 9-year grip strength (β = 0.40 kg/s.d. increase in birthweight, P < 0.001; and β = 0.41 kg/s.d. increase in AMA, P < 0.001). Grip strength was positively related to 9-year height, body mass index and AMA and to gains in these measurements from birth to 2 years, 2-5 years and 5-9 years (P < 0.001 for all). The associations between birth size and grip strength were attenuated but remained statistically significant for AMA after adjusting for 9-year size. We conclude that larger overall size and muscle mass at birth are associated with greater muscle strength in childhood, and that this is mediated mainly through greater post-natal size. Poorer muscle development in utero is associated with reduced childhood muscle strength.

Grip strength at 4 years in relation to birth weight

Consistent positive relationships have been found between birth weight and grip strength in adults but evidence in children is limited. In a prospective general population birth cohort (Southampton Women's Survey), grip strength and anthropometry (height and weight) were measured in 968 children at the age of 4 years. Mean (standard deviation (s.d.)) birth weight was 3.48 (0.52) kg. Birth weight, adjusted for sex and gestational age, was positively associated with grip strength (β = 0.22 kg/s.d. increase in adjusted birth weight; 95% CI 0.11, 0.34). The relationship was attenuated after adjustment for current height and weight such that it became non-significant (β = 0.03 kg/s.d. increase in adjusted birth weight; 95% CI-0.08, 0.14), suggesting that body size may be on the causal pathway. Early influences on muscle development appear to impact on grip strength in children, as well as adults.

Quantification of the relative age effect in three indices of physical performance

The relative age effect (RAE) describes the relationship between an individual's birth month and their level of attainment in sports. There is a clustering of birth dates just after the cutoff used for selection in age-grouped sports, and it is hypothesized that such relatively older sportspeople may enjoy maturational and physical advantages over their younger peers. There is, however, little empirical evidence of any such advantage. This study investigated whether schoolchildren's physical performance differed according to which quarter of the school year they were born in. Mass, stature, body mass index, cardiorespiratory fitness, strength, and power were measured in 10 to 16 year olds (n = 8,550, 53% male). We expressed test performance as age- and sex-specific z-scores based on reference data with age rounded down to the nearest whole year and also as units normalized for body mass. We then compared these values between yearly birth quarters. There were no significant main effects for differences in anthropometric measures in either sex. Girls born in the first quarter of the school year were significantly stronger than those born at other times when handgrip was expressed as a z-score. As z-scores, all measures were significantly higher in boys born in either the first or second yearly quarters. Relative to body mass, cardiorespiratory fitness was higher in boys born in the first quarter and power was higher in those born in the second quarter. The RAE does not appear to significantly affect girls' performance test scores when they are expressed as z-score or relative to body mass. Boys born in the first and second quarters of the year had a significant physical advantage over their relatively younger peers. These findings have practical bearing if coaches use fitness tests for talent identification and team selection. Categorizing test performance based on rounded down values of whole-year age may disadvantage children born later in the selection year. These relatively younger children may be less to gain selection for teams or training programmes.

[Measuring the handgrip strength of geriatric patients]

The handgrip strength of geriatric patients can be measured when the patient is hospitalized. This article elaborates on the intrinsic and extrinsic factors which have a direct or indirect influence on handgrip strength. For the best results the tests need to be taken in the best circumstances with attention to individual differences and the age of the patient. Handgrip strength as determination of biological vitality is a key concept. Besides the physical characteristics there are many psychological factors (cognition, psyching-up, test attitude…) influencing the results. These are barely mentioned or not mentioned at all in the usual procedures. Research of handgrip strength testing theories is mostly focused on young, healthy adults and less on elderly patients. The main goal of this article is stimulating experimental research on the measurement of handgrip strength with elderly people and involving them more actively with the procedure. It is not enough to acquire insight in function and predicting characteristics of handgrip strength. Next to the aiming for the best test performance is 'working interactively with elderly patients' a goal on itself in the modern vision of health care.