Relationships Between Measures of Physical Fitness Change When Age-Dependent Bias is Removed in a Group of Young Male Soccer Players.

James, RS, Thake, CD, and Birch, SL. Relationships between measures of physical fitness change when age-dependent bias is removed in a group of young male soccer players. J Strength Cond Res 31(8): 2100-2109, 2017-Age-dependent bias is a key issue within talent identification of children, particularly when measures of physical fitness are used. Coaches in sport would benefit from a relatively straightforward method to remove age-dependent bias, enabling identification of children who are relatively high performers for their age. This study aimed to determine whether removal of age effects caused changes in the relationships between physical performance and anthropometric measures commonly used in talent identification and development systems. Sixty male soccer players, aged 11-17 years, underwent measures of anthropometry, muscular power, strength, sprint speed, and agility. Most absolute measures of performance were significantly correlated with each other, and all performance measures were significantly correlated with age. Age residuals were calculated, for all variables, to determine which players performed relatively well for their age and to investigate age-independent relationships between variables. In general, players with relatively fast sprint performance for their age were taller and had relatively high performance in jump power output and grip strength for their age (r > 0.25 and p < 0.025 in each case). Absolute sprint performance PC1 was significantly correlated with absolute agility performance PC1 (r = 0.473, p < 0.001). However, there was no significant relationship between age-independent measures of agility and any other measures. Usage of age residuals highlights performers that have relatively high physical fitness for their age. Such analyses may assist the talent identification and development processes as long as differential rates of physical development between players are also considered.

Can Fundamental Movement Skill Mastery Be Increased via a Six Week Physical Activity Intervention to Have Positive Effects on Physical Activity and Physical Self-Perception?

BACKGROUND: Previous research has suggested a positive relationship between fundamental movement skills (FMS) mastery and physical activity (PA) level. Research conducted on interventions to improve FMS mastery is equivocal and further research is needed. METHODS: An intervention group of 82 children (35 boys and 47 girls) and a control group of 83 children (42 boys and 41 girls) were recruited from Years 4 and 5 (mean age ± SD = 8.3 ± 0.4 years) of two schools in Central England. The intervention included a combination of circuits and dancing to music. Pre and post intervention tests were conducted. Tests included: subjective assessment of eight FMS; objective measurement of two FMS; four day pedometer step count recording; height and mass for Body Mass Index (BMI); and the completion of Harter et al.'s (1982) self-perception questionnaire. RESULTS: Following a two (pre to post) by two (intervention and control group) mixed-model ANOVA it was highlighted that the intervention group improved mastery in all eight FMS, and increased both daily steps and physical self-perception. CONCLUSIONS: It can be concluded that focussing one Physical Education (PE) lesson per week on the development of FMS has had a positive benefit on FMS, PA level and physical self-perception for the children in this study.

Comparisons in ambulatory physical activity in children from the United Kingdom and Belgium.

AIM: This study sought to examine ambulatory physical activity levels in adolescents from the UK and Belgium. METHODS: Following ethics approval, 2760 children (1247 boys, 1513 girls), aged 9-14 years from Belgium (n = 1614) and the UK (n = 1146), wore a pedometer for 4 days including at least 1 weekend day. Body mass index (BMI) was determined from height and mass. RESULTS: A 2 (gender) × 2 (country) way ANCOVA, controlling for age and BMI, revealed a significant country-by-gender interaction for steps/day (p = 0.0001). In both Belgium and the UK, boys were more physically active than girls (both p = 0.0001), but the difference between boys and girls was greater for Belgian than UK children. CONCLUSION: These results suggest there are differences in the ambulatory physical activity patterns of children in the UK and Belgium.

Environmental and school influences on physical activity in South Asian children from low socio-economic backgrounds: A qualitative study.

South Asian (SA) children are less active but have enhanced metabolic risk factors. Physical activity (PA) is a modifiable risk factor for metabolic disease. Evidence suggests that environmental factors and socio-economic status influence PA behaviour. The purpose of this study was to understand PA environments, barriers and facilitators of PA in deprived environments for children from SA backgrounds. Focus groups were conducted with 5 groups of children aged 7-9 years (n = 33; male = 16, female = 17; SA = 17, White = 8 and Black = 8) from two schools in deprived wards of Coventry, England. Thematic analysis was used to identify key themes and subthemes across all transcripts. From the results, emergent themes included school and home environment, outdoor activity, equipment, weather, parental constraints and safety. Ethnic differences were apparent for sources of beliefs and knowledge and religious practice as constraints for PA. The findings suggest that school provides a good foundation for PA attitude, knowledge and behaviour, especially for SA children. To increase PA, multi-component interventions are needed, which focus on changing the home environment (i.e. junk food and media time), encouraging outdoors activity, changing perceptions of safety and weather conditions, which provide parental constraints for children. Interventions also need to be considerate to religious practices that might constrain time.

The effect of green exercise on blood pressure, heart rate and mood state in primary school children.

The aim of this study was exploratory and sought to examine the effect on blood pressure (BP), heart rate (HR) and mood state responses in primary school children of moderate intensity cycling whilst viewing a green environment compared to exercise alone. Following ethics approval and parental informed consent, 14 children (seven boys, seven girls, Mean age ± SD = 10 ± 1 years) undertook two, 15 min bouts of cycling at a moderate exercise intensity in a counterbalanced order. In one bout they cycled whilst viewing a film of cycling in a forest setting. In the other condition participants cycled with no visual stimulus. Pre-, immediately post-exercise and 15 min post-exercise, BP, HR and Mood state were assessed. Analysis of variance, indicated significant condition X time interaction for SBP (p = 0.04). Bonferroni post-hoc pairwise comparisons indicated that systolic blood pressure (SBP) 15 min post exercise was significantly lower following green exercise compared to the control condition (p = 0.01). There were no significant differences in diastolic blood pressure (DBP) (all p > 0.05). HR immediately post exercise was significantly higher than HR pre exercise irrespective of green exercise or control condition (p = 0.001). Mood scores for fatigue were significantly higher and scores for vigor lower 15 min post exercise irrespective of green exercise or control condition (both p = 0.0001). Gender was not significant in any analyses (p > 0.05). Thus, the present study identifies an augmented post exercise hypotensive effect for children following green exercise compared to exercise alone.

Cross-validation of pedometer-determined cut-points for healthy weight in British children from White and South Asian backgrounds.

BACKGROUND: Evidence-based pedometer cut-points for health have not been sufficiently examined in the context of ethnicity. OBJECTIVE: To (1) evaluate previously described steps/day cut-points in a sample of White and South Asian British primary school children and (2) use ROC analysis to generate alternative, ethnic specific, steps/day cut-offs for children. METHODS AND PROCEDURES: Height, body mass and pedometer determined physical activity were assessed in 763 British children (357 boys and 406 girls) from White (n = 593) and South Asian (n = 170) ethnic groups, aged 8-11 years. RESULTS: The Vincent and Pangrazi cut-points significantly predicted BMI in white (p = 0.006, Adjusted R(2 )= 0.08) and South Asian children (p = 0.039, Adjusted R(2 )= 0.078). The Tudor-Locke et al. cut-points significantly predicted BMI in White children (p = 0.0001, Adjusted R(2 )= 0.079) but not South Asian children (p < 0.05). ROC analysis indicated significant alternative cut-points in White and South Asian boys and girls (all p = 0.04 or better, Adjusted R(2 )= 0.091 for White and 0.09 for South Asian children). Subsequent cut-points associated with healthy weight, when translated to steps/day were 13,625 for White boys, 13,135 for White girls, 10,897 for South Asian boys and 10,161 for South Asian girls. CONCLUSIONS: Previously published steps/day cut-points for healthy weight may not account for known ethnic variation in physical activity between White and South Asian children in the UK. Alternative, ethnic-specific, cut-points may be better placed to distinguish British children based on pedometer-determined physical activity.

The effect of exercise intensity on postresistance exercise hypotension in trained men.

The occurrence of postresistance exercise hypotension (PEH) after resistance exercise remains unknown. This study examined blood pressure and heart rate (HR) responses to an acute bout of low- and high-intensity resistance exercise, matched for total work, in trained males. Sixteen resistance-trained males (23.1 ± 5.9 years) performed an acute bout of low- (40% of 1 repetition maximum [1RM]) and high-intensity resistance exercise (80% 1RM), matched for total work, separated by 7 days and performed in a counterbalanced order. Systolic blood pressure (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), and HR were assessed before exercise, after completion of each exercise resistance exercise (3 sets of back squat, bench press, and deadlift) and every 10 minutes after resistance exercise for a period of 60 minutes. Results indicated a significant intensity × time interaction for SBP (p = 0.034, partial η(2) = 0.122) and MAP (p = 0.047, partial η(2) = 0.116) whereby SBP and MAP at 50-minute recovery and 60-minute recovery were significantly lower after high-intensity exercise (p = 0.01 for SBP and p = 0.05 for MAP in both cases) compared with low-intensity exercise. There were no significant main effects or interactions in regard to DBP (all p > 0.05). Heart rate data indicated a significant main effect for time (F(9, 135) = 2.479, p = 0.0001, partial η(2) = 0.344). Post hoc multiple comparisons indicated that HR was significantly higher after squat, bench press, and deadlift exercise compared with resting HR and HR at 40-, 50-, and 60-minute recovery (all p = 0.03). The present findings suggest that an acute bout of high intensity, but not low intensity, resistance exercise using compound movements can promote PEH in trained men.

Fundamental movement skills and weight status in British primary school children.

Weight status has been shown to have a negative impact on children's competence in performing fundamental movement skills (FMSs). Following ethics approval and informed consent, 281 children in years 2-6 from a school in central England volunteered to participate. Each child performed eight FMSs (run, hop, gallop, jump, balance, kick, throw and catch) three times, all attempts were video-recorded. Video analysis was performed (Quintic Biomechanics software) using the Process Orient Checklist (subjective measurement). Height and weight were measured to calculate body mass index (BMI) and weight status was determined. Results highlighted that year group (age) had a significant effect on seven out of the eight skills (not kick). Year 4 (aged 8-9 years) significantly scored lower in all three locomotor skills (run, hop and gallop) at this age, whereas Year 5 (aged 9-10 years) all significantly peaked at the object control skills (catch and throw) at this age. Weight status (BMI) significantly affected the run, identifying that a child with a larger BMI will have a lower mastery level of the run. Gender significantly affected the kick, throw and balance, with girls outperforming in the balance and the boys in the kick and throw. By highlighting that children at different ages will have a lower score in different skills, the effect of BMI and gender on certain FMS is important knowledge for the target of intervention in primary school children.

Overweight and reduced heart rate variability in British children: an exploratory study.

OBJECTIVE: To investigate the associations between heart rate variability (HRV) and weight status in children. METHOD: Following ethics approval, 182 children (87 males, 95 females) aged between 6 and 11 years old (Mean (SD) age 9.1 (1.4) years) were assessed for height and body mass from which body mass index (BMI, kg/m(2)) was calculated. Data were collected in Central England, March-June 2011. Resting HRV was assessed in the supine position. Time domain (RMSSD and pNN50) and frequency domain (HF and LF power (ms(2)), LF/HF ratio) measures of HRV were calculated. Pearson correlations were used to assess the associations between BMI and HRV parameters. Differences in HRV parameters according to gender or weight status were analysed using t-tests. RESULTS: BMI was significantly and inversely related to RMSSD (r=-0.23, p=0.001) and pNN50 (r=0.20, p=0.008) but not frequency domain measures of HRV (p>0.05). Overweight/obese children demonstrated lower HF power compared to normal weight children (p=0.02). RMSSD and pNN50 were significantly lower in overweight/obese children compared to normal weight children (p<0.05). Age was associated with changes in Mean R-R and RMSSD (p<0.05). CONCLUSION: This exploratory study suggests that HRV is reduced in overweight/obese children.