José Luis González-Montesinos

Percentile Values for Muscular Strength Field Tests in Children Aged 6 to 17 Years: Influence of Weight Status

Castro-Piñero, J, González-Montesinos, JL, Mora, J, Keating, XD, Girela-Rejón, MJ, Sjöström, M, and Ruiz, JR. Percentile values for muscular strength field tests in children aged 6 to 17 years: influence of weight status. J Strength Cond Res 23(8): 2295-2310, 2009-The aim of this study was to provide percentile values for 9 different muscular strength tests for Spanish children (1,513 boys and 1,265 girls) aged 6 to 17.9 years. The influence of body weight on the muscular strength level across age groups was also examined. Explosive strength was assessed by the throw ball test (upper body), standing broad jump, and vertical jump tests (lower body). Upper-body muscular endurance was assessed by push ups, bent arm hang, and pull ups tests, and abdominal muscular endurance was assessed by sit ups, curl ups in 30 seconds, and curl ups tests. Body mass index (BMI) was calculated. Participants were categorized according to the BMI international cut-off values as underweight, normalweight, overweight, and obese. Boys had significantly better scores than girls in all the studied tests, except in the 3 upper-body muscular endurance tests in the 6- to 7-year-old group and in the push ups test in the 8- to 9-year-old group. Underweight and normalweight individuals showed similar strength levels. Both underweight and normalweight children and adolescents had significantly higher performance than their overweight and obese counterparts in the lower-body explosive strength tests and in the push ups test in boys and bent arm hang test in both boys and girls. In conclusion, percentiles values of 9 muscular strength tests are provided. Percentiles values are of interest to identify the target population for primary prevention and to estimate the proportion of adolescents with high or low muscular strength levels. The overweight and obese groups had worse scores than their underweight and normalweight counterparts, whereas the underweight group had a similar performance to the normalweight group.

Percentile values for aerobic performance running/walking field tests in children aged 6 to 17 years: influence of weight status

The aim of this study was to provide percentiles values for four different aerobic performance tests in 2752 (1,261 girls) Spanish children aged 6 to 17.9 years. Aerobic performance was assessed by the shuttle run test (20 mSRT), 1-mile, 1/2-mile and 1/4-mile run/walk tests. Height and weight were measured, and body mass index was calculated. Boys had significantly better score than girls in the studied tests in all age groups, except in 1/4-mile test in 6-7 year old children. Underweight children had similar performance than their normalweight counterparts, and underweight boys had better performance than their obese counterparts. Overweight and obese children had lower performance than their normalweight counterparts. Having percentile values of the most used field tests to measure aerobic performance in youth may help to identify children and adolescents at risk for the major chronic diseases, as well as to evaluate the effects of alternative interventions.

Criterion-related validity of the one-mile run/walk test in children aged 8–17 years

Abstract We assessed the criterion-related validity of Curetons equation for estimating peak oxygen consumption ([Vdot]O2peak) from the one-mile run/walk test in endurance-trained children aged 8–17 years. Altogether, 66 physically active white children and adolescents (32 girls, 34 boys) completed a graded exercise test to volitional exhaustion and the one-mile run/walk test. Curetons equation was used to estimate [Vdot]O2peak, and was assessed using several error measures. Agreement between measured [Vdot]O2peak and estimated [Vdot]O2peak was analysed by the Bland and Altman method. The correlation coefficient between measured [Vdot]O2peak and one-mile run/walk time was −0.59 (P < 0.001) and that between measured and estimated [Vdot]O2peak was 0.70 (P < 0.001). The mean difference between measured and estimated [Vdot]O2peak was 10 ml · kg−1 · min−1 (95% CI = 9.2–11.8; P < 0.001). The standard error of the estimate was 3 ml · kg−1 · min−1, and the percentage error was 32%. There was a positive association between the measured and estimated [Vdot]O2peak difference and the measured and estimated [Vdot]O2peak mean, which indicates that the higher the [Vdot]O2peak the higher the error of the estimate. These findings did not change markedly when the analyses were performed by sex, age group or body mass status. These results suggest that Curetons equation systematically underestimates [Vdot]O2peak in endurance-trained children with high [Vdot]O2peak.

Percentile Values for Running Sprint Field Tests in Children Ages 6–17 Years: Influence of Weight Status

The aim of this study was to provide percentile values for six different sprint tests in 2,708 Spanish children (1,234 girls) ages 6–17.9 years. We also examined the influence of weight status on sprint performance across age groups, with a focus on underweight and obese groups. We used the 20-m, 30-m, and 50-m running sprint standing start and running start tests to assess sprint performance. We calculated body mass index (BMI) using and categorized participants according to the BMI international cut-off for underweight, normal weight, overweight, and obese. Boys had significantly better scores than girls in all tests, except for the 30-m running sprint standing start and running start tests in the 6–7-year-old group. The underweight group had significantly better scores than their obese counterparts, whereas there were similar levels between underweight and normal weight individuals. The normal weight group showed a significantly better performance than their overweight and obese counterparts. Overweight boys had significantly better performance than their obese counterparts. In conclusion, the percentiles values of six running tests varied by age and gender. The findings indicated that underweight youth did not have poorer sprint performance, and the obese group had lower scores than their leaner counterparts.

Percentile values for flexibility tests in youths aged 6 to 17 years: Influence of weight status

Abstract The aim of the present study was to examine the influence of weight status on flexibility performance in Spanish youths (1475 boys and 1237 girls) aged 6–17 years, and to provide percentile values for two flexibility tests. Flexibility was assessed by the sit-and-reach and shoulder stretch tests. Participants were categorized as underweight, normal weight, overweight and obese. Girls had significantly better scores than boys in all the studied tests, except in the right-shoulder stretch test in the 6–7, 14–15 and 16–17-year-old groups, and in the left-shoulder stretch test in the 6–7, 8–9 and 16–17-year-old groups. There was not a significant positive association between weight status and flexibility assessed by the sit-and-reach test. However, overweight and obese youths had significantly lower performance than their normal-weight counterparts in the shoulder stretch test. Underweight and normal-weight individuals had similar performances for both shoulder flexibility tests. In conclusion, percentiles values of the studied flexibility tests might be of interest to estimate the proportion of youths with high or low flexibility levels, as well as to evaluate the effects of alternative interventions.

Reliability and Validity of Tests to Assess Lower-Body Muscular Power in Children.

Abstract Fernandez-Santos, JR, Ruiz, JR, Cohen, DD, Gonzalez-Montesinos, JL, and Castro-Piñero, J. Reliability and validity of tests to assess lower body muscular power in children. J Strength Cond Res 29(8): 2277–2285, 2015—The purpose of this study was to analyze the reliability and the criterion-related validity of several lower-body muscular power tests (i.e., standing long jump [SLJ], squat jump, countermovement jump, and Abalakov jump) in children aged 6–12 years. Three hundred sixty three healthy children (168 girls) agreed to participate in this study. All the lower-body muscular power tests were performed twice (7 days apart), whereas the 1 repetition maximum (1RM) leg extension test was performed 2 days after the first session of testing. All the tests showed a high reliability (intertrial difference close to 0 and no significant differences between trials, all p > 0.05). The association between the lower-body muscular power tests and 1RM leg extension test was high (all p < 0.001). The SLJ and the Abalakov jump tests showed the highest association with 1RM leg extension test (R 2 = 0.700, test result, weight, height, sex, and age were added in the model). The SLJ test can be a useful tool to assess lower-body muscular power in children when laboratory methods are not feasible because it is practical, time efficient, and low in cost and equipment requirements.

Cardiorespiratory Fitness Cutoff Points for Early Detection of Present and Future Cardiovascular Risk in Children:A 2-Year Follow-up Study

Objective: To examine the association between cardiorespiratory fitness (CRF) at baseline and cardiovascular disease (CVD) risk in 6‐ to 10‐year‐olds (cross‐sectional) and 2 years later (8‐ to 12‐year‐olds [longitudinal]) and whether changes with age in CRF are associated with CVD risk in children aged 8 to 12 years. Patients and Methods: Spanish primary schoolchildren (n=236) aged 6 to 10 years participated at baseline. Of the 23 participating primary schools, 22% (n=5) were private schools and 78% (n=18) were public schools. The dropout rate at 2‐year follow‐up was 9.7% (n=23). The 20‐m shuttle run test was used to estimate CRF. The CVD risk score was computed as the mean of 5 CVD risk factor standardized scores: sum of 2 skinfolds, systolic blood pressure, insulin/glucose, triglycerides, and total cholesterol/high‐density lipoprotein cholesterol. Results: At baseline, CRF was inversely associated with single CVD risk factors (all P<.05) and CVD risk score at baseline and follow‐up (P<.001). Cardiorespiratory fitness cutoff points of 39.0 mL/kg per minute or greater in boys and 37.5 mL/kg per minute or greater in girls are discriminative to identify CVD risk in childhood (area under the curve, >0.85; P<.001) and to predict CVD risk 2 years later (P=.004). Persistent low CRF or the decline of CRF from 6‐10 to 8‐12 years of age is associated with increased CVD risk at age 8 to 12 years (P<.001). Conclusion: During childhood, CRF is a strong predictor of CVD risk and should be monitored to identify children with potential CVD risk. Abbreviations and Acronyms: AUC = area under the curve; CRF = cardiorespiratory fitness; CVD = cardiovascular disease; HDL‐C = high‐density lipoprotein cholesterol; HOMA‐IR = homeostasis model assessment for insulin resistance; OR = odds ratio; SBP = systolic blood pressure; TC = total cholesterol; TG = triglycerides; VO2max = maximum oxygen consumption

Kinematic analysis of the standing long jump in children 6- to 12-years-old

ABSTRACT The purpose of this study was to analyze the kinematic variables that determine the performance of the standing long jump in children 6- to 12-years-old. There were 121 healthy children (58 girls) recorded while they performed the standing long jump test. All kinematic variables showed a significant correlation with calculated jump distance and measured jump distance, except for the knee joint angle at maximum shoulder extension angle, ankle joint angle at maximum shoulder extension angle, and shoulder joint angle at maximum knee flexion angle. Stepwise multiple regression analysis showed that sex, age, and body mass index accounted for 51.1% of the jump distance variance. Among all the kinematic variables, take-off distance and take-off speed were accounted for the most of the variation in the jump distance. Physical education teachers and coaches should consider special attention to these anthropometrics and kinematic aspects in improving the standing long jump performance in children.