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.

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 (1 RM) 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 1 RM leg extension test was high (all p < 0.001). The SLJ and the Abalakov jump tests showed the highest association with 1 RM leg extension test (R = 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.

No 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 6Á17 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 6Á7, 14Á15 and 16Á17-year-old groups, and in the left-shoulder stretch test in the 6Á7, 8Á9 and 16Á17-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.

No abstract

The purpose of this study was to validate a new instrumented insole called ECnsole for measuring flight time during vertical jump performance. 66 participants performed 3 different jump tests (squat jump, countermovement jump and Abalakov jump) twice with flight times determined using an instrumented insole composed of 4 pressure sensors (PreECnsole) and an accelerometer sensor (AccECnsole), a laser platform (Sport Jump System Pro), and a high-speed motion capture system (HSC); the latter 2 systems are considered as reference methods. One-way analysis of variance (ANOVA), simple linear regression, and the Bland-Altman method were used to assess validity. Regardless of the jump test performed, the ECnsole system showed a systematic bias close to 0 and a low random error (average random error: ?2.8?cm; ?3.1?cm PreECnsole and AccECnsole vs. HSC system respectively and ??2.3?cm; ?2.9?cm PreECnsole and AccECnsole vs. SJS system respectively). The associations between PreECnsole and AccECnsole with the HSC were very high (R2=0.967 and 0.958 respectively). Furthermore, the associations between PreECnsole and AccECnsole with the SJS were very high (R2=0.978 and 0.966 respectively) as well. Therefore, the ECnsole system can be considered an alternative method for measuring jump height during vertical jump performance.

Despite the relationship between performance and anthropometric characteristics, strength, and endurance in the action of dinghy hiking, there is no equation to predict the position obtained in competition. The purpose of this study was to examine the effects of anthropometric characteristics, strength, and endurance on the performance of the sailor. Twenty-nine male sailors of the Laser class were evaluated according to age, navigation experience, strength and resistance tests in a simulator, body weight, size, sitting height, Body Mass Index (BMI), body fat percentage, trochanteric length, thigh length, tibial length, foot length, abdominal perimeter, and upper thigh perimeter. The results show that the variables were related to performance are age, navigation experience, height, and length of the thigh. The variables that are most related to performance are age and sailing experience. Seventy-six percent of the performance can be estimated using the following equation: 311.971 + (−1.089 × height) + (−1946 × age) + (−1.537 × thigh length). Performance in the Laser class will be determined by the tactics (age and sailing experience) and the morphological characteristics of the sailor (height and sitting height).

We assessed the criterion-related validity of Cureton's equation for estimating peak oxygen consumption (VO(2peak)) 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. Cureton's equation was used to estimate VO(2peak), and was assessed using several error measures. Agreement between measured VO(2peak) and estimated VO(2peak) was analysed by the Bland and Altman method. The correlation coefficient between measured VO(2peak) and one-mile run/walk time was -0.59 (P < 0.001) and that between measured and estimated VO(2peak) was 0.70 (P < 0.001). The mean difference between measured and estimated VO(2peak) 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 VO(2peak) difference and the measured and estimated VO(2peak) mean, which indicates that the higher the VO(2peak) 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 Cureton's equation systematically underestimates VO(2peak) in endurance-trained children with high VO(2peak).