Sex differences and athletic performance. Where do trans individuals fit into sports and athletics based on current research?

There are well known sex differences in parameters of physical fitness/performance due to changes occurring during sexual development. Thus, many sport and athletic events have regulations separating male and female participants. However, the inclusion or exclusion of transgender individuals in athletics has recently received outsized attention despite relatively few cases of transgender athletes. When determining which athletic gender category trans individuals should be permitted to compete in, it is important to understand the level of physical fitness/performance these individuals possess relative to their cisgender counterparts. Unfortunately, there are few studies investigating this topic, and several complications that confound this research. The current review seeks to discuss sex and gender as concepts, review sex differences in fitness/performance and how they develop, and then, consider how current evidence suggests that trans individuals compare to cis individuals. Finally, this review seeks to offer considerations for whether trans individuals should be excluded from sports and athletics, and how future research should proceed to better understand this marginalized population.

Impact of body mass index and socio-economic status on motor development in children and adolescents

This study assessed the impact of body mass index (BMI) and socioeconomic status (SES) on the Zurich Neuromotor Assessment, second version (ZNA-2), a battery of tests of motor development in typically developing children between 3 and 18 years of age. BMI measurements and international socio-economic index data were taken from the normative sample of the ZNA-2 for 321 children (158 boys, 163 girls) with a median age of 9.3 years. The age- and gender-adjusted motor performance of these children was quantified and grouped into five components: fine, pure, and gross motor tasks, static balance, and contralateral associated movements. A total score was also calculated. The associations of BMI and SES with the motor scores contribute to less than 5.1% of the total variance.Conclusion: The ZNA-2 for motor development is suitable for measuring motor abilities' development as it is largely independent of the BMI of the child and the SES of the family. What is Known: • Typical motor development, as measured with the Zurich Neuromotor Assessment, second edition (ZNA-2), is strongly dependent on age and gender. • The ZNA-2 focusses on motor performance, motor quality and simple motor skills. What is New: • Higher socio-economic status (SES) is associated with slightly better motor performance as measured by the ZNA-2 total score. • In the ZNA-2 less than 5.1% of the variability in motor performance is attributable to the combined effect of body mass index and SES.

A multilevel analysis of gross motor coordination of children and adolescents living at different altitudes: the Peruvian Health and Optimist Growth Study

BACKGROUND

Gross motor coordination (GMC) is a potential correlate of lifestyle behaviours and health outcomes in childhood and adolescence.

AIMS

The aim of this study was to examine how sex, age, biological maturation, overweight, stunting, and physical fitness are associated with GMC in children and adolescents from Peru, and to examine associations between geographical area of residence, school-level characteristics, and GMC.

SUBJECTS AND METHODS

The sample included 7408 subjects, aged 6-14 years, from sea level, Amazon and high-altitude regions of Peru. A composite marker of total coordination was derived by the sum of scores from each test (GMC_T). Overweight was identified using BMI, and biological maturation, physical fitness, and stunting were assessed. School characteristics were obtained via an objective audit.

RESULTS

Boys (β = 12.23 ± 0.90) and older children (β = 13.37 ± 0.64) had higher GMC_T than girls and younger children, respectively. Overweight was associated with lower GMC_T (β = -5.23 ± 0.80), whereas fitness was positively associated with GMC_T (β = 6.30 ± 0.25). Biological maturation was not a predictor; however, stunting was negatively associated with GMC_T (β = -3.71 ± 1.56). Subjects living in the Amazon had higher GMC_T than those at sea level (β = 16.57 ± 4.73). Five of nine school-level predictors (number of students, playground area with obstacles, multi-sports roofed, frequency and duration of Physical Education classes) were significant predictors of GMC_T.

CONCLUSIONS

Child- and school-level variables were significantly associated with GMC_T in this sample. These findings are important for the Peruvian community, especially school principals, councils and physical education teachers, helping them to define more efficient strategies and action plans to increase motor coordination in children.

Skeletal age prediction model from percentage of adult height in children and adolescents

Skeletal age (SA) is considered the gold standard to assess the degree of maturation and has been widely used in sports, education and public health areas; however, it requires sophisticated equipment and well-trained technicians. Therefore, it is important to develop non-invasive methods for its evaluation. The aim was to develop an equation to predict SA using the percentage of adult height. SA was measured by Tanner-Whitehouse-3 method, and the percentage of adult height was estimated by two methodologies: Tanner-Whitehouse-3 method (P-TW3) and Khamis-Roche method (P-KR) using 839 schoolchildren of both sexes. Linear regression was used for predicting SA from P-TW3; then P-TW3 was replaced in the equation for P-KR value. Bland-Altman graphs, interclass correlation coefficient and Kappa index were used as validation tests. Model showed a SA predictive capacity of 93.2% in boys and 96.8% in girls. The average differences between SA measured and SA predicted by P-TW3 was 0.0504 (± 0.664) in boys and 0.0144 (± 0.435) in girls (P = 0.229 and 0.667, respectively). When P-TW3 was replaced for P-KR value in the equation, the average differences were - 0.0532 in boys and 0.0850 in girls (P = 0.509 and 0.167 respectively). The present model, based on the percentage of adult height, showed an adequate estimation of SA in children and adolescents and it can be used in the absence of bone X-ray equipment, in healthy boys aged 9 to 15 and girls 8 to 13.

A multivariate multilevel analysis of youth motor competence. The Peruvian Health and Optimist Growth Study

We use a multivariate multilevel model to study the links between physical fitness (PF) and gross motor coordination (GMC) and investigate the influence of predictors affecting their levels across age. We sampled 7918 Peruvians, aged 6-15 years, from sea-level, Amazon region and high-altitude. Composite markers of GMC and PF were derived (GMC_z and PF_z , respectively). BMI, biological maturation, and stunting were assessed. School characteristics were obtained via an objective audit. School contexts explained 35% of the associations between PF_z and GMC_z , whereas children's characteristics explained 65% of the total variation. On average, with increasing age, there was a greater increase in GMC_z (β = 0.79 ± 0.04, P < .001) than in PF_z (β = 0.15 ± 0.03, P < .001); boys outperformed girls (PF_z , β = 3.25 ± 0.08, P < .001; GMC_z , β = 1.58 ± 0.09, P < .001); those with lower BMI and ahead in their maturation had higher PF_z (β = -0.13 ± 0.01, P < .001; β = 1.09 ± 0.05, P < .001, respectively) and GMC_z (β = -0.18 ± 0.01, P < .001; β = 0.39 ± 0.06, P < .001, respectively) levels. Stunting was negatively related to PF_z (β = -0.30 ± 0.07; P < .001) and GMC_z (β = -0.30 ± 0.08, P < .001) and high-altitude Peruvians had significantly lower GMC_z (β = -0.93 ± 0.33, P < .001), and those living in the Amazon region had significantly higher PF_z (β = 1.21 ± 0.58, P < .001) compared to those living at sea level. A higher number of students was negatively related to PF_z (β = -0.016 ± 0.006, P < .001) and positively with GMC_z (β = 0.005 ± 0.003, P < .001); the duration of physical education classes was positively associated with PF_z (β = 0.70 ± 0.32, P < .001) and GMC_z (β = 0.46 ± 0.15, P < .001); and the existence of policies for physical activity was only negatively associated with GMC_z (β = -1.17 ± 0.34, P < .001). In conclusion, PF_z and GMC_z were positively correlated and child- and school-level traits predicted their levels.

Effect of biological maturation on gross motor coordination in boys: a mediation analysis

Abstract Introduction: The literature emphasizes the importance of acquiring good motor coordination in the early years of life and its relationship with physical fitness and physical activity during adolescence and adulthood. Objective: To analyze the effect of biological maturation on the motor coordination in boys. Method: The sample was composed by 203 boys between 11 and 14 years old. Height, body mass, sitting height, waist circumference (WC) and skinfolds were measured. Somatic maturation (SM) was assessed by maturity offset (estimated age at peak height velocity). The gross motor coordination was evaluated by Körperkoordinationstest für Kinder (KTK) battery. Results: The SM exerted an effect on the walking backward on balance beams (WB) mediated by the WC. Conclusion: The results showed that the performance of boys in the WB was negatively influenced by the greater volume of fat in the trunk related to a more advanced state of SM.

Independent and Combined Effects of Biological Maturation and aerobic performance on the gross motor coordination in prepubertal girls

ABSTRACT The present study analyzed the effect of biological maturation on the performance in the test of gross motor coordination in girls, before and after having its effect controlled by body mass index (BMI) and aerobic performance. The sample was composed by 63 pre-pubertal girls (8.0-8.99 years). The girls who were less advanced in biological maturation presented lower body size and better physical performance in the tasks of walking backward on balance beams (t=2.706; p<0.01; d=0.70), moving sideways on boxes (t=2.128; p<0.05; d=0.48), hopping for height on one leg (t=2.076, p<0.05; d=0.54) and 20-m shuttle run (t=3.162; p <0.05; d=0.61). The maturation no longer influenced performance in the tasks of gross motor coordination when considering BMI and aerobic fitness.

Children's metabolic expenditure during object projection skill performance: New insight for activity intensity relativity

Objective: To examine children's energy expenditure (EE) during object projection skill performance at three intensity intervals. Methods: Children's (42, Mage = 8.1) average metabolic equivalents of task (METs) were calculated using a COSMED K4b2 while they repeatedly performed blocks of kicking, throwing (overhand), and striking (two-handed) during 6, 12, and 30-s interval conditions. A repeated-measures analysis of covariance examined differences in METs while controlling for skill level. Results: Data indicated a main effect for interval condition (df = 2, 123, F = 94.36, p <.001, η2 = .605). Post hoc t-tests demonstrated decreasing performance interval times yielded progressively higher METs (p <.001) across the three conditions (30s = 4.5±0.8 METs, 12s = 6.3±1.3, 6s = 8.3±1.6). There also was a main effect for sex (df = 1,120, F = 52.28, p <.001 η2 = .305). Boys demonstrated higher METs at each performance interval (p <.001). Conclusion: Skill practice with a maximum of one trial every 30s resulted in the equivalent of at least moderate physical activity (>4.0 METs) and intervals of 6s demonstrated vigorous physical activity (>7.0 METs). Practicing/performing object projection skills, even at intervals that allow for adequate instruction and feedback (i.e., 1 trial/30s), promotes MVPA in children.

Familial resemblance in gross motor coordination. The Peruvian Sibling Study on Growth and Health

BACKGROUND

The development of gross motor coordination (GMC) is governed by biological and environmental factors whose effect sizes are still unclear.

AIM

To investigate sibling resemblance in GMC, as well as biological and environmental correlates of GMC among Peruvian children.

MATERIALS AND METHODS

The sample comprised 1256 biological siblings (6-15 years old), from three geographical areas of Peru. GMC was assessed using the Korperkoordinationtest für Kinder (KTK) test battery. Anthropometry, biological maturation and physical fitness (PF) were also measured. Multilevel modelling was performed using Stata 14 software.

RESULTS

In general, sister-sister pairs (SS) showed the highest resemblance in GMC (ρ = 0.24) compared to brother-sister (BS) (ρ = 0.10) and brother-brother (BB) pairs (ρ = 0.07). On average, BB pairs had higher GMC than SS pairs and older siblings had higher GMC than younger siblings. Further, those with lower body mass index (BMI) and higher PF had higher GMC. There was also a significant interaction between age and PF with GMC. Siblings from the rainforest region demonstrated higher GMC than those from sea level and high-altitude siblings demonstrated lower GMC than their sea-level peers.

CONCLUSION

These results demonstrate statistically significant sibling resemblance in GMC. Age, BMI, PF and geographical area were significant correlates of GMC.