Association Between Physical Fitness and Bone Strength and Structure in 3- to 5-Year-Old Children

Jumping Motor Skills in Typically Developing Preschool Children Assessed Using a Battery of Tests

The preschool period is characterised by the improvement in motor skills. One of the developmental tasks in children is the ability to jump. Jumping plays an important role in the development of leg strength and balance. It is the gateway to more complex movements. In the physiotherapy clinic, we see a lot of difficulties in jumping performance in 5-7-year-old children. The aim of this study is to present the jumping ability, assessed by the Motor Proficiency Test (MOT) and the G-sensor examination of the vertical countermovement jump (CMJ) and countermovement jump with arms thrust (CMJAT) parameters. A total of 47 children (14 boys and 33 girls) were randomly recruited. The mean age was 5.5 years. The mean height was 113 cm and the mean weight was 19.7 kg. The children were divided into two groups according to their results. Children with low basic motor skills have the greatest difficulty with jumping tasks. In the CMJ jump, the take-off force was lower than in the CMJAT (p = 0.04). Most CMJAT parameters correlate with age, weight, and height. Height correlates most with children's jumping performance. This study may be useful for sport educators and developmental researchers. The topic should be further explored and the CMJ and CMJAT parameters may be established as a basis.

The Effect of Different Physical Exercise Programs on Physical Fitness among Preschool Children: A Cluster-Randomized Controlled Trial

BACKGROUND

Preschool children are in a period of rapid physical and psychological development, and improving their level of physical fitness is important for their health. To better develop the physical fitness of preschool children, it is very important to understand the behavioral attributes that promote the physical fitness of preschool children. This study aimed to determine the effectiveness of and the differences between different physical exercise programs in improving preschool children's physical fitness.

METHODS

A total of 309 preschool children aged 4-5 years were recruited from 5 kindergartens to participate in the experiment. They were cluster-randomly allocated into five groups: basic movements (BM) group, rhythm activities (RA) group, ball games (BG) group, multiple activities (MA) group, and control (CG) group. The intervention groups received designed physical exercise programs with a duration of 30 min 3 times per week for 16 weeks. The CG group received unorganized physical activity (PA) with no interventions. The physical fitness of preschool children was measured using the PREFIT battery before and after the interventions. One-way analysis of variance, a nonparametric test; generalized linear models (GLM); and generalized linear mixed models (GLMM) were used to examine differences during the pre-experimental stage among groups and to assess the differential effects of the intervention conditions on all outcome indicators. The intervention condition models were adjusted for potential confounders (baseline test results, age, gender, height, weight, and body mass index) explaining the main outcome variance.

RESULTS

The final sample consisted of 253 participants (girls 46.3%) with an average age of 4.55 ± 0.28 years: the BG group (n = 55), the RA group (n = 52), the BM group (n = 45), the MA group (n = 44), and the CG group (n = 57). The results of the generalized linear mixed model and generalized linear model analyses indicated significant differences for all physical fitness tests between groups, except for the 20 m shuttle run test and the sit-and-reach test after the interventions. Grip strength was significantly higher in the BG and MA groups than in the BM group. The scores for standing long jump were significantly higher in the MA group than in the other groups. The scores for the 10 m shuttle run test were significantly lower in the BG and MA groups than in the CG, BM, and RA groups. The scores for skip jump were significantly lower in the BG and MA groups than in the RA group. The scores for balance beam were significantly lower in the BG and MA groups than in the RA group and significantly lower in the BG group than in the BM group. The scores for standing on one foot were significantly higher in the BG and MA groups than in the CG and RA groups and significantly higher in the BM group than in the CG group.

CONCLUSIONS

Physical exercise programs designed for preschool physical education have positive effects on the physical fitness of preschool children. Compared with the exercise programs with a single project and action form, the comprehensive exercise programs with multiple action forms can better improve the physical fitness of preschool children.

Speed, agility, and musculoskeletal fitness are independently associated with areal bone mineral density in children

Background: There is still little understanding of the associations between physical fitness variables and bone health in children taking into account key confounders. Aim: The aim of this study was to analyze the associations between performance in tests of speed, agility, and musculoskeletal fitness (power of the upper and lower limbs) with bone mass of different regions in children, considering the adjustment to maturity-offset, lean percentage, and sex. Methods: Cross-sectional study design: the sample consisted of 160 children aged 6-11 years. The physical fitness variables tested were 1) speed, assessed with the running test at a maximum speed of 20 m; 2) agility, assessed through the 4×4-m square test; 3) lower limb power, assessed using the standing long jump test, and 4) upper limb power, assessed using the 2-kg medicine ball throw test. Areal bone mineral density (aBMD) was obtained from the analysis of body composition by dual-energy X-ray absorptiometry (DXA). Simple and multiple linear regression models were performed using the SPSS software. Results: In the crude regression analyses, the results indicated a linear relationship between all the physical fitness variables and aBMD in all body segments, but maturity-offset, sex, and lean mass percentage seemed to have an effect on these relationships. Except for the upper limb power, the other physical capacities (speed, agility, and lower limb power) were associated with aBMD in at least three body regions in the adjusted analyses. These associations occurred in the spine, hip, and leg regions, and the aBMD of the legs presented the best association magnitude (R ²). Conclusion: There is a significant association between speed, agility, and musculoskeletal fitness, specifically the lower limb power and aBMD. That is, the aBMD is a good indicator of the relationship between fitness and bone mass in children, but it is essential to consider specific fitness variables and skeletal regions.

Sprint and upper limbs power field tests for the screening of low bone mineral density in children

Background: The possibility of carrying out screening, with acceptable accuracy, of a child's bone mass status based on a physical fitness test can advance the concept of health-related physical fitness. In addition, the relevance of the applicability of this type of screening in educational environments is mainly due to the difficulty of direct assessments of bone health indicators. This study aimed to propose cut-off points for physical fitness tests based on children's bone health indicators. Methods: This is a two-phase cross-sectional study. Phase-1: 160 children (6-11 years-old) performed the 20-m sprint test (20-mST) and the 2 kg medicine ball throw test (2 kgMBTT). Areal bone mineral density (aBMD) and content was assessed by DXA. The area under the ROC curve greater than 70% was considered valid. Phase-2: It was carried out a secondary analysis in a sample with 8,750 Brazilians (6-11 years-old). The percentile values (identified in phase-1) were used to identify the values of the cut-off points in the unit of measurement of the tests. The validation of the cut-off points found was by odds ratio values and p ≤ 0.05. Results: Phase 1: The areas under the ROC curve were 0.710, 0.712 (boys and girls-20-mST), 0.703, and 0.806 (boys and girls-2 kgMBTT) with total spine and pelvis aBMD as the outcome. Phase 2: From percentile values, we find valid cut-off points in the Brazilian sample (OR > 3.00; p < 0.001) for boys and girls. Values ranged between 5.22 s-4.00 s to 20-mST and between 125.0 cm-160.0 cm to 2 kgMBTT. Conclusion. The 20-mST and the 2 kgMBTT presented sufficient accuracy for the screening of children aged between 6 and 11 years with greater chances of having low aBMD in the total spine and pelvis, with valid cut-off points.

Is it important to achieve physical activity recommendations at early stages of life to improve bone health?

Research in bone health during childhood is limited and important to prevent future diseases, particularly, osteoporosis. Bone parameters using DXA and pQCT in 295 Spanish children were evaluated and we found a benefit of meeting the World Health Organization physical activity recommendations in bone composition in childhood.

PURPOSE

To investigate the association between physical activity (PA) and bone health in a Spanish paediatric cohort, considering the influence of meeting/not meeting the current World Health Organization (WHO) PA recommendations and to elucidate if there are differences between boys and girls.

METHODS

In a cohort of children born in the region of Aragon (Spain) in 2009, followed until the age of 7 years, bone parameters were assessed using dual-energy X-ray absorptiometry (DXA) (whole body scan) and peripheral quantitative computed tomography (pQCT) (tibia scanned at the 8% (distal) and 38% (diaphyseal) of the total tibia length) in 295 7-year-old children (154 boys) in the last evaluation performed between 2016 and 2017. PA was assessed using GT3X Actigraph accelerometers.

RESULTS

Boys had significantly higher areal bone mineral density (aBMD), higher total bone mineral content (BMC) at the diaphyseal site and higher trabecular BMC and vBMD, and higher total bone area at the distal site than girls (p<0.01 for all of them). Both boys and girls complying with the WHO PA recommendations had significantly higher trabecular BMC than their inactive counterparts.

CONCLUSIONS

Meeting WHO PA recommendations has a beneficial effect in bone composition in childhood both in boys and in girls.

Field-based physical fitness assessment in preschool children: A scoping review

Physical fitness, which can be measured using various health- and skill-related components, is an important indicator of child development and health status. This study undertakes a scoping review on physical fitness assessment methods in preschool children to summarize the most widely used field-based physical fitness batteries and specific test items for preschool children. A search of the literature in English was undertaken using two major electronics databases, which yielded 76 literatures that met the inclusion and exclusion criteria. These literatures took the quantitative indicators of physical fitness as the outcome variables in 3-6-year-old children. This review found that of these 76 literatures analyzed, 71.1% came from Europe and 89.5% were published after 2010. The results showed six physical fitness test batteries, with the assessing FITness in PREschoolers (PREFIT) battery is the most widely used, and specific test items such as body mass index (BMI), standing long jump, handgrip, one-leg stance, sit and reach, 20 m shuttle run test (SRT)-PREFIT, and 4 × 10 m SRT are widely used in corresponding components. Therefore, we recommend that an international standard for some specific test items should be developed for preschool children to facilitate more widespread adoption and promote physical fitness assessment for preschool children.

The Impact of Diet and Physical Activity on Bone Health in Children and Adolescents

There is growing recognition of the role of diet and physical activity in modulating bone mineral density, bone mineral content, and remodeling, which in turn can impact bone health later in life. Adequate nutrient composition could influence bone health and help to maximize peak bone mass. Therefore, children's nutrition may have lifelong consequences. Also, physical activity, adequate in volume or intensity, may have positive consequences on bone mineral content and density and may preserve bone loss in adulthood. Most of the literature that exists for children, about diet and physical activity on bone health, has been translated from studies conducted in adults. Thus, there are still many unanswered questions about what type of diet and physical activity may positively influence skeletal development. This review focuses on bone requirements in terms of nutrients and physical activity in childhood and adolescence to promote bone health. It explores the contemporary scientific literature that analyzes the impact of diet together with the typology and timing of physical activity that could be more appropriate depending on whether they are children and adolescents to assure an optimal skeleton formation. A description of the role of parathyroid hormone (PTH) and gut hormones (gastric inhibitory peptide (GIP), glucagon-like peptide (GLP)-1, and GLP-2) as potential candidates in this interaction to promote bone health is also presented.

Quantitative peripheral computed tomography to measure muscle area and assess lean soft tissue mass in children

BACKGROUND

Skeletal muscle is one of the main components of lean soft tissue mass (LSTM). Low levels in children affect locomotion, posture, and increase the risk of metabolic syndrome.

AIM

(1) To evaluate the association between muscle cross-sectional area (MCSA) of the lower left leg measured by peripheral quantitative computed tomography (pQCT) and total LSTM; namely, total left leg and left lower leg LSTM assessed by dual-energy X-ray absorptiometry (DXA) in a group of children, (2) to examine if MCSA is a predictor of LSTM, (3) to determine the ability of pQCT to identify children with low LSTM.

SUBJECTS AND METHODS

Lower left leg MCSA and LSTM were measured using pQCT and DXA, respectively, in 396 children.

RESULTS

Statistically significant positive correlations were found between the lower leg MCSA - total LSTM (r² = 0.789), total leg LSTM (r² = 0.79), and lower leg LSTM (r² = 0.791) (p < .01). MCSA explained 64-68% of the variance in LSTM. Receiver operator characteristic (ROC) curves determined the capacity of the lower left leg MCSA to identify low LSTM in girls (AUC 0.95) and boys (AUC 0.87).

CONCLUSIONS

Our results showed that lower left leg MCSA, measured using pQCT, could be a tool to predict low LSTM in children.