Analysis of swimming performance from physical, physiological, and biomechanical parameters in young swimmers

The purpose of this study was to examine the influence of the energy cost of swimming, body composition, and technical parameters on swimming performance in young swimmers. Twenty-nine swimmers, 15 prepubertal (11.9 +/- 0.3 years; Tanner Stages 1-2) and 14 pubertal (14.3 +/- 1.4 years; Tanner Stages 3-4) boys participated in the study. The energy cost of swimming (Cs) and stroking parameters were assessed over maximal 400-m front-crawl swimming in a 25-m swimming pool. The backward extrapolation technique was used to evaluate peak oxygen consumption (VO2peak). A stroke index (SI; m2 . s(-1) . cycles(-1)) was calculated by multiplying the swimming speed by the stroke length. VO2peak results were compared with VO2peak test in the laboratory (bicycle, 2.86 +/- 0.74 L/min, vs. in water, 2.53 +/- 0.50 L/min; R2 = .713; p = .0001). Stepwise-regression analyses revealed that SI (R2 = .898), in-water VO2peak (R2 = .358), and arm span (R2 = .454) were the best predictors of swimming performance. The backward-extrapolation method could be used to assess VO2peak in young swimmers. SI, arm span, and VO2peak appear to be the major determinants of front-crawl swimming performance in young swimmers.     

Feasibility and reliability of a repeated sprint test in children age 6 to 8 years

This study investigated the feasibility and reliability of a 12 × 25-m repeated sprint test with sprints starting every 25-s in children aged 6-8 years (36 boys, 41 girls). In all subjects, total sprint time (TST) demonstrated high test-retest reliability (ICC: r = .98; CV: 0.7% (95% CI: 0.6-0.9)). While sprint time varied over the 12 sprints in all subjects (p < .001) with a significant increase in time for the third effort onwards compared with the first sprint (p < .001), there was no difference in performance between genders. In all subjects, TST decreased with age (p < .001) and was accompanied by an increase in estimated anaerobic power (p < .001) but also in sprint time decrement percentage (p < .001). Gender did not effect these changes. The present study demonstrates the practicability and reliability of a repeated sprint test with respect to age and gender in young children.     

The effect of pre-exercise carbohydrate supplementation on anaerobic exercise performance in adolescent males

Carbohydrate (CHO) consumption before anaerobic exercise was studied in 13 adolescent boys (15.2 ± 0.9 yrs). A within subjects design was employed where subjects consumed a 22% CHO or volume-matched placebo (PL) beverage 30-min before anaerobic exercise on two separate days. Exercise consisted of a Wingate Anaerobic Test (WAnT), ten by 10-s-sprints, and a second WAnT. Fatigue index and peak power (PP) were similar while mean power (MP) was higher (p < .025) in CHO trial; however this difference was ascribed to initial WAnT performance. PP and MP for the 10-s sprints were similar between trials. Intravenous blood glucose and insulin concentrations were higher (p < .05) in the CHO trial while lactate and catecholamine concentrations were similar. Improved performance on a single WAnT was apparent with CHO consumption before exercise; however, this strategy did not attenuate fatigue over time in adolescent boys.     

Issue Information

Murine genital tubercle (GT) initiates its outgrowth from embryonic posterior body trunk. Hoxa3-Cre-mediated Bmp4 cKO mice showed the defective GT outgrowth with reduced p63 expression. However, Shh expression was not affected in the mutant mice. This report suggests Bmp4 regulates the initiation of GT outgrowth by controlling p63 expression, which is independent of Shh signaling. Further details can be seen in the original article by Kajioka et al. in this issue.

     

The relationship between pedometer step counts and estimated VO2Max as determined by a submaximal fitness test in adolescents

The purpose of this study was to examine the relationship between pedometer step counts and estimated VO2max as determined by a submaximal exercise test. Participants (N = 115; 65 girls, 50 boys) wore pedometers for five days and completed the Queen's College Step Test (QCST). Based on these results participants were classified as HIGH, MOD, or LOW cardiorespiratory fitness. Boys accumulated more steps per day (p < .05) than girls (12,766 +/- 4,923 versus 10,887 +/- 2,656). The relationship between estimated VO2max and mean steps/day was moderate (r = .34, p < .01). Participants classified as having HIGH fitness levels accumulated more steps/day than LOW-fit adolescents (p < .05). The results from this study suggest that estimated VO2max as determined by a submaximal exercise test is moderately associated with mean steps/day in adolescents.     

Adolescent and parent factors related to fatigue in paediatric multiple sclerosis and chronic fatigue syndrome: A comparative study

Background

Fatigue is a disabling, poorly understood symptom in children and adolescents with multiple sclerosis (caMS), for which effective treatments are lacking. In paediatric Chronic Fatigue Syndrome (CFS), effective psychological interventions have been developed based on psychosocial factors associated with fatigue. This study aimed to identify potentially modifiable factors of fatigue in caMS by comparing caMS, adolescents with CFS, healthy adolescents and their parents on measures of fatigue, psychosocial factors, and neurocognitive functioning.

Psychological and school functioning of Latino siblings of children with intellectual disability

Background: Siblings of children with disabilities are at risk for internalizing psychological disorders; however, little is known about how culture influences this effect. This study examined the psychological and school functioning of Latino siblings of children with intellectual disability (ID). Methods: Participants were 100 Latino (L) and nonLatino (NL) siblings (8–15 years) of children with ID (50 LID, 50 NLID) and 100 Latino and nonLatino control siblings (50 LC, 50 NLC). Siblings, parents, and teachers completed standard questionnaires regarding sibling emotional and behavioral functioning; sibling school report cards were obtained. Analyses of variance were conducted, controlling for parent age and family income; planned contrasts compared LID siblings to the other sibling groups. Results: LID siblings reported significantly more internalizing (t(1) = 2.41, p < .05) and emotional t(1) = 3.06, p < .05) symptoms, poorer awareness of (t(1) = 2.26, p < .01) and greater reluctance to express (t(1) = 3.12, p < .01) their emotions, and more problems in personal adjustment and relationships with parents (t(1) = ?2.50, p < .05). Significantly higher percentages of LID siblings scored in the at‐risk or clinical range for internalizing and emotional symptoms, and were more likely to score above the clinical cut‐off for separation anxiety disorder and to endorse global impairment. LID siblings experienced more school absences and lower academic performance. There were no group differences in externalizing behavior problems, somatic symptoms, or teacher‐reported internalizing symptoms. Conclusions: Latino siblings of children with ID are at greater risk for internalizing psychological disorders and greater impairment in personal and school functioning. Results are discussed in terms of their sociocultural significance and clinical implications.     

The association between playfulness and coping in adolescents

This study investigated the relationship between playfulness and coping skills in adolescent males both typically developing (TD) and with severe emotional disturbance (SED). Thirty male adolescents (16 TD, 14 with SED) ranging in ages from 14 to 17 years comprised two groups. Each participant was scored on the Test of Playfulness (ToP) (Bundy, 1998) and on the Coping Inventory (Zeitlin, 1985). A significant positive correlation (r = .785; p < .01) was discovered to exist between the adolescents' level of playfulness and their coping skills. Point biserial correlations, between group (TD and SED) and the ToP scores (r = .889; p < .0001) and between group and ABIs (Coping Inventory) (r = .873; p < .0001), revealed that these adolescents came from two distinct groups. As expected, TD adolescents were rated as more playful than those with SED and scored higher in effective coping skills. This study has implications for occupational therapy intervention with adolescents. High correlations between playfulness and coping support the idea of using play and playfulness to improve coping skills particularly the ability to adapt and to approach problems and goals in a flexible manner.     

Effect of swimming on bone metabolism in adolescents

Physical activity has been shown to have a positive effect on bone metabolism among adolescents. The objective of this study was to determine the effect of swimming on bone metabolism during adolescence. Swimming, as a non-weight-bearing sport, has been considered to be insignificant in the maintenance of bone mass. We studied whether swimming is associated with a higher peak bone mass. Forty swimmers (males aged 10-17 years and females aged 9-16 years) were studied. The control group consisted of the same number of adolescents aged between 10-16 years who did not swim; distribution of male and female gender was similar in the non-swimming control group compared to the swimming group. Adolescents were matched for age, gender and pubertal stages based on Tanner staging. All subjects underwent combined measurement of bone mineral metabolism by dual-energy X-ray absorptiometry of total body calcium content, and specific biochemical markers of turnover including osteocalcin, calcium, phosphorus and alkaline phosphatase. Bone age (determined by Greulich and Pyle's Radiographic Atlas of Skeletal Development of the Hand and Wrist), weight, height, ideal body weight, ideal body weight ratio, body mass index, Tanner classification (rated by examiner), diet, history of tobacco and alcohol exposure, exercise, socioeconomic status and history of chronic illness and medications were recorded to evaluate potential mediators that would affect bone metabolism. Tanner staging was used to assess puberty, and diet was evaluated based on reported consumption of milk, yogurt and cheese and cola/caffeine beverage consumption daily. There was significant difference in bone mineral content between adolescent male swimmers and the control group males. Consumption of cola beverages were significantly higher among the control group compared with the swimmer group. Ideal body weight ratio was significantly high among the female control group compared with female swimmers. Milk consumption was significantly higher for both male and female swimmer groups, whereas yogurt consumption was only significantly higher in the male swimmer group compared with control group. These results indicate that a highly active nonimpact sport such as swimming may lead to increased bone mineral content only for male swimmers. However, dietary behaviors may be more important than swimming on bone metabolism among adolescents.     

Premonitory Urge for Tics Scale (PUTS): initial psychometric results and examination of the premonitory urge phenomenon in youths with Tic disorders

Although motor tics and/or vocal tics are the defining features of chronic tic disorder (CTD) and Tourette syndrome (TS), older youths and adults often report their tics to be preceded by an unpleasant sensation or "premonitory urge." While premonitory urge phenomena may play an important role in behavioral interventions for CTD/TS, standardized assessments for premonitory urges do not exist. The current study of 42 youths with TS or CTD presents initial psychometric data for a new, brief self-report scale designed to measure tic-related premonitory urges. Results showed that the Premonitory Urge for Tics Scale (PUTS) was internally consistent (alpha = .81) and temporally stable at 1 (r = 0.79, p < .01) and 2 (r = 0.86, p < .01) weeks. PUTS scores were also correlated with overall tic severity as measured by the Yale Global Tic Severity Scale (YGTSS; r = 0.31, p < .05) and the YGTSS number (r = 0.35, p < .05), complexity (r = 0.49, p < .01), and interference (r = 0.36, p < .05) subscales. Finally, an examination of the psychiatric correlates of the premonitory urge phenomenon yielded significant correlations between the PUTS and the Child Behavior Checklist (CBCL) anxiety/depression (r = 0.33, p < .05), and withdrawal (r = 0.38, p < .05) subscales as well as the Children's Yale-Brown Obsessive Compulsive Scale (CYBOCS; r = 0.31, p < .05). However, a cross-sectional examination of the data showed that the psychometric properties of the PUTS were not acceptable for youths 10 years of age and younger. Likewise, significant correlations found between the YGTSS subscales, CBCL subscales, CYBOCS, and the PUTS did not emerge in this younger age group. The clinical and theoretical implications of these findings are discussed.     

Effect of maturational status and training on upper limb pulse wave velocity

Cardiovascular adaptations to training may include changes in arterial distensibility, although studies involving sick and healthy individuals have yielded contradictory results. Moreover, despite the fact that endurance training frequently begins in childhood, its influence on arterial distensibility is less well characterised in children. This study was therefore to compare the upper limb pulse wave velocity (PWVUL) in highly trained prepubertal swimmers and age-matched moderately active counterparts, with that in swimmers and sedentary adults. The aim was to investigate the effects of maturation and training status on PWVUL in healthy individuals. PWVUL was evaluated by a dedicated continuous wave Doppler and photoplethysmography system. We calculated the pressure-corrected index of distensibility (Cp) which provides a measure of intrinsic structural compliance of the artery wall. PWVUL was significantly higher in highly trained child swimmers compared to moderately active ones (6.17±0.49 versus 5.20±0.38 ms^-1, P <0.05) even when mean arterial pressure was fixed as a covariate. Cp was significantly lower in child swimmers than in moderately active ones (0.15±0.03 versus 0.18±0.04, P <0.05 respectively) whereas Cp was not significantly different in either adult group. The PWVUL and Cp values of child swimmers were similar to those of adults. Conclusion: Our results confirmed an increase in pulse wave velocity with maturation implying that compliance decreases with age. An unexpected result was that swimming training performed in children over a long period led to an increase in upper limb pulse wave velocity. This change, concerning the upper limbs which are strongly involved in swimming, may be related to enhanced smooth muscle content of the arterial wall, possibly due to intermittent elevations in arterial blood pressure during repetitive swimming exercise sessions. Whether adaptations to intensive swimming training are accompanied by alterations of the cardiovascular system in prepubertal children is an important question to be dealt with in further studies.     

Effects of TRH administration on plasma leptin levels in infants, children and adolescents

The aim of this study was to investigate the effect of thyrotropin-releasing hormone (TRH) administration (standard TRH stimulation test) on plasma leptin levels in infants, children and adolescents. Plasma leptin levels were analyzed with regard to age, body mass index (BMI) and results in standard TRH stimulation test. The study population consisted of 79 infants, children and adolescents (age: 4.50 [0.04-20.49] years; BMI: 16.47 [12.46-38.32] kg/m2; BMI SDS: 0.21 [-2.97 to 3.26]) (median [range]). Plasma leptin levels significantly decreased 30 minutes after TRH administration (5 microg/kg; maximum 200 microg i.v.) (p <0.0001). No correlation was found in leptin decrease when comparing the different groups with regard to age, BMI and results in the TRH stimulation test. Positive correlation was found when comparing BMI SDS to plasma leptin levels before (r = 0.74; p <0.001) and 30 minutes after TRH injection (r = 0.73; p <0.001). There was poor correlation when age of patients was compared to plasma leptin levels before (r = 0.46; p <0.05) and 30 minutes after TRH injection (r = 0.47; p <0.05). In summary, we found that TRH administration decreases plasma leptin levels in infants and adolescents independent of age, BMI and thyroid function.     

A test to assess aerobic and anaerobic parameters during maximal exercise in young girls

The Wingate cycle test (WAnT) is a 30-s test commonly used to estimate anaerobic work capacity (AWC). However, the test may be too short to fully deplete anaerobic energy reserves. We hypothesized that a 90-s all-out isokinetic test (ISO_90) would be valid to assess both aerobic and anaerobic capacities in young females. Eight girls (11.9 ± 0.5 y) performed an exhaustive incremental test, a WAnT and an ISO_90. Peak VO2 attained during the ISO_90 was significantly greater than VO2peak. Mean power, end power, fatigue index, total work done and AWC were not significantly different between the WAnT and after 30 s of the 90-s test (i.e., ISO_30). However, 95% limits of agreement showed large variations between the two tests when comparing all anaerobic parameters. It is concluded that an ISO-90 may be a useful test to assess aerobic capacity in young girls. However, since the anaerobic parameters derived from the ISO_30 did not agree with those derived from a traditional WAnT, the validity of using an ISO_90 to assess anaerobic performance and capacity within this population group remains unconfirmed.     

Physical activity and its correlates in children and adolescents post‐liver transplant

The health benefits of PA are well established for healthy and chronically ill children. This study objectively measures physical fitness and PA levels in children PLT and explores potential correlates and perceived barriers impacting their PA. A total of 23 children (16 females, mean 14.01 ± 2.49 yrs) >1 yr PLT were assessed for peak oxygen consumption (VO₂peak), muscle strength, endurance, and flexibility. MVPA and steps/day were determined with accelerometry. Additionally, SE, perceived fatigue, and barriers and benefits of PA were examined. VO₂peak (mean 33. 2 ± 7.61 mL/kg/min; 77.0 ± 15.6% predicted) and PA (average 6841 ± 2299 steps/day) were below healthy norms. MVPA (31.6 ± 16.1 min/day) was lower than national guidelines. Six participants (30%) attained criterion standards for abdominal strength and one participant (5%) for push‐ups. Fatigue and SE were lower than reported levels in healthy children. A commonly perceived barrier to PA was “I am tired.” A positive correlation was shown between SE and MVPA (r = 0.57, p = 0.007), SE and fatigue (r = 0.54, p = 0.01), and PELD score and fatigue (r = 0.66, p = 0.007). Children PLT demonstrate below normal levels of PA and aerobic capacity. SE is a modifiable correlate of their PA. Further investigation of the impact of PA correlates can guide the development of future innovative PA intervention strategies in children PLT.     

Reliability and validity of the Harris Infant Neuromotor Test

OBJECTIVE: To examine the reliability and validity of the Harris Infant Neuromotor Test (HINT), a screening tool that can be administered and scored in <30 minutes, with the goal of identifying neuromotor differences in infants aged 3 to 12 months. STUDY DESIGN: Infants, aged 3 to 12 months (n = 54), were assessed in 2 high-risk infant follow-up programs in Vancouver, British Columbia. Inter-rater, test-retest, and intra-rater reliability were examined. Concurrent and predictive validity of the HINT with the Bayley Scales of Infant Development-II (BSID-II) were evaluated by using the Pearson product-moment correlation. RESULTS: Intraclass correlation coefficients for reliability for the Total HINT Score ranged from 0.98 to 0.99. Concurrent validity of the HINT with the BSID-II Mental Scale during the first year was r = -0.73 (P <.01), and with the BSID-II Motor Scale, r = -0.89 (P <.01). The predictive relationships between the HINT and the BSID-II at 17 to 22 months were r = -0.11 for the BSID-II Mental Scale and r = -0.49 (P <.01) for the BSID-II Motor Scale. CONCLUSIONS: The HINT is reliable for screening infant neuromotor performance and has strong concurrent validity with the Bayley-II Mental and Motor Scales. HINT scores during the first year accounted for 24% of the variance of Bayley-II Motor scores at 17 to 22 months.     

Sodium and Potassium in Red Blood Cells of Premature Infants during the First Few Days: Risk of Hyperkalaemia

ABSTRACT. Erythrocyte sodium and potassium were studied in 64 newborn infants including 21 very low birthweight infants (birthweight < 1500 g) during the first three days after birth. Erythrocyte sodium showed a positive correlation with gestational age ( r =0.63, p <0.01) and birthweight ( r =0.66, p <0.01). Erythrocyte potassium was negatively correlated with birthweight ( r = -0.33, p <0.05). The Na/K ratio in red blood cells showed a positive correlation with gestational age ( r =0.60, p <0.01) and birthweight ( r =0.65, p <0.01). In VLBW infants plasma potassium rose significantly ( p <0.01) from 0–6 h to 12–30 h and decreased from 12–30 h to 30–60 h ( p <0.05). Erythrocyte potassium decreased slightly from 0–6 h to 12–30 h, but not significantly. A new finding that "more immature infants have higher potassium and lower sodium concentration in RBC" may suggest a potential risk of hyperkalaemia in tiny infants.     

Early pituitary-adrenal responses and retinopathy of prematurity in very low birth weight infants

This longitudinal prospective study aimed to investigate the relationship between pituitary-adrenal responses and severity of retinopathy of prematurity (ROP) in 92 preterm, very low birth weight infants < or = 30 wk gestation. The human corticotropin releasing hormone stimulation test was performed on these infants at D 7 and 14 of postnatal life. Univariate analysis revealed significant associations between severity of ROP and gestational age (r = -0.53, p < 0.0001), birth weight (r = -0.56, p < 0.0001), Apgar score at 1 min (r = -0.27, p < 0.05), Clinical Risk Index for Babies score (r = 0.48, p < 0.0001), duration of mechanical ventilation (r = 0.48, p < 0.0001), oxygen dependency (r = 0.48, p < 0.0001), and length of hospitalization (r = 0.49, p < 0.0001). The stage of ROP was also significantly associated with the basal and peak plasma ACTH (r > -0.22, p < 0.05) and peak serum cortisol (r = -0.21, p = 0.05) at d 7. Multivariate analysis using the classification and regression trees indicated that the two most influential risk factors affecting the development of advanced stages of ROP (> or = stage 3) were i) birth weight and ii) oxygen dependency at 28 d of life or at 36 wk postconceptional age. Our findings suggest that early endogenous or stimulated pituitary-adrenal responses are not independent risk factors associated with the development of severe ROP. Low birth weight and prolonged oxygen exposure are likely to be important factors that influence the degree of damage inflicted on the retina.     

Evaluation of the built environment at a children's convalescent hospital: development of the Pediatric Quality of Life Inventory parent and staff satisfaction measures for pediatric health care facilities

In preparation for the design, construction, and postoccupancy evaluation of a new Children's Convalescent Hospital, focus groups were conducted and measurement instruments were developed to quantify and characterize parent and staff satisfaction with the built environment of the existing pediatric health care facility, a 30-year-old, 59-bed, long-term, skilled nursing facility dedicated to the care of medically fragile children with complex chronic conditions. The measurement instruments were designed in close collaboration with parents, staff, and senior management involved with the existing and planned facility. The objectives of the study were to develop pediatric measurement instruments that measured the following: (1) parent and staff satisfaction with the built environment of the existing pediatric health care facility, (2) parent satisfaction with the health care services provided to their child, and (3) staff satisfaction with their coworker relationships. The newly developed Pediatric Quality of Life Inventory scales demonstrated internal consistency reliability (average alpha = 0.92 parent report, 0.93 staff report) and initial construct validity. As anticipated, parents and staff were not satisfied with the existing facility, providing detailed qualitative and quantitative data input to the design of the planned facility and a baseline for postoccupancy evaluation of the new facility. Consistent with the a priori hypotheses, higher parent satisfaction with the built environment structure and aesthetics was associated with higher parent satisfaction with health care services (r =.54, p <.01; r =.59, p <.01, respectively). Higher staff satisfaction with the built environment structure and aesthetics was associated with higher coworker relationship satisfaction (r =.53; p <.001; r =.51; p <.01, respectively). The implications of the findings for the architectural design and evaluation of pediatric health care facilities are discussed.     

Sex effect on catecholamine responses to sprint exercise in adolescents and adults

The purpose of this study was to clarify the effect of sex on plasma catecholamine responses to sprint exercise in adolescents and adults. Thirty-six untrained participants took part in this study-9 girls and 10 boys (Tanner Stage 4) and 9 women and 8 men. Each participant performed a 6-s sprint test on a cycle ergometer. Plasma adrenaline (A) and noradrenaline (NA) concentrations were determined successively at rest (A0 and NA0), immediately after the 6-s sprint test (AEX and NAEX), and after 5 min of recovery (A5 and NA5). Peak power, expressed in absolute values or relative to body weight and fat-free mass, was significantly higher in boys than in girls and higher in men than in women (p < .001). No sex effect was observed in AEX in the adolescents, but the NA increase was significantly higher in boys in response to the 6-s sprint (p < .05). In adults, no sex difference was found in NAEX, but AEX was significantly higher in men than in women (p < .05). NAEX was significantly higher in women than in girls (p < .05), and AEX was significantly higher in men than in boys (p < .01). The results of this study suggest that male and female adolescents and young adults might exhibit different catecholamine responses to sprint exercise.     

Correlation between 6‐min walk test and exercise stress test in healthy children

Aim: To investigate the correlation between 6‐min walk test (SMWT) and incremental treadmill exercise stress test (EST) as indicators for the functional capacity in children. Methods: Healthy children aged 9–12 years were included. The anthropometric data, SMWT and EST were prospectively measured using the standard protocols. Various parameters were analysed to define the correlation between SMWT and EST. Results: A total of 100 subjects (53 boys) aged 10.3 ± 1.0 years participated in the study. The SMWT distance was 586.1 ± 44.0 m. Height (r = 0.59, R² = 35%), length of the leg (r = 0.64, R² = 41%), heart rate at the end of SMWT (r = 0.59, R² = 35%) and heart rate difference at the end of SMWT (r = 0.71, R² = 50%) were found to have significant correlation with SMWT distance. The estimated maximal oxygen consumption (eVO2) obtained during the EST tended to be greater in boys than in girls. Among the parameters obtained during EST, maximal heart rate (r = 0.33, R² = 11%) and the eVO2 (r = 0.54, R² = 53%) were found to have significant correlation with SMWT. Conclusions: SMWT distance is significantly correlated with the eVO2 obtained during the EST. This indicates that SMWT is also one of the predictive markers for EST performance.