Anaerobic performance in 5- to 7-yr-old children of low birthweight

Impact of preterm birth on muscle mass and function: a systematic review and meta-analysis

Individuals born preterm present lower exercise capacity. Along with the cardiopulmonary responses and activity level, muscle strength is a key determinant of exercise capacity. This systematic review aimed to summarize the current knowledge on the impact of preterm birth on skeletal muscle mass and function across the lifespan. The databases PubMed, MEDLINE, EBM, Embase, CINAHL Plus, Global Index Medicus, and Google Scholar were searched using keywords and MeSH terms related to skeletal muscle, preterm birth, and low birth weight. Two independent reviewers undertook study selection, data extraction, and quality appraisal using Covidence review management. Data were pooled to estimate the prematurity effect on muscle mass and function using the R software. From 4378 studies retrieved, 132 were full-text reviewed and 25 met the inclusion/exclusion criteria. Five studies presented a low risk of bias, and 5 had a higher risk of bias due to a lack of adjustment for confounding factors and presenting incomplete outcomes. Meta-analyses of pooled data from homogenous studies indicated a significant reduction in muscle thickness and jump test (muscle power) in individuals born preterm versus full-term with standardized mean difference and confidence interval of - 0.58 (0.27, 0.89) and - 0.45 (0.21, 0.69), respectively.    Conclusion: Overall, this systematic review summarizing the existing literature on the impact of preterm birth on skeletal muscle indicates emerging evidence that individuals born preterm, display alteration in the development of their skeletal muscle mass and function. This work also highlights a clear knowledge gap in understanding the effect of preterm birth on skeletal muscle development. What is Known: • Preterm birth, which occurs at a critical time of skeletal muscle development and maturation, impairs the development of different organs and tissues leading to a higher risk of comorbidities such as cardiovascular diseases. • Preterm birth is associated with reduced exercise capacity. What is New: • Individuals born preterm display alterations in muscle mass and function compared to individuals born at term from infancy to adulthood. • There is a need to develop preventive or curative interventions to improve skeletal muscle health in preterm-born individuals.

Low birth weight and its relation to physical fitness parameters in children: Its negative effect on muscle strength and cardiorespiratory endurance

BACKGROUND

There is increasing evidence that low birth weight has a negative effect on physical fitness, muscle strength, and cardiorespiratory endurance, although the findings are inconsistent.

OBJECTIVES

This study aimed to evaluate whether birth weight acts as a prenatal determinant of physical fitness parameters and to determine the role of environmental or biological variables on this effect.

METHODS

One hundred and sixty-seven children aged 6-14 years were included in this study. The anthropometric data, physical activity index, standing long jump, flexibility, handgrip strength, and cardiorespiratory fitness were evaluated.

RESULTS

A positive correlation was found between birth weight and cardiorespiratory fitness (r = .349; p < .001), right handgrip strength (r = .337; p < .001), and left handgrip strength (r = .320; p < .001), suggesting that children with low birth weight had the worst performance in both cardiorespiratory endurance and grip strength tests. These findings remained significant after adjustment for prematurity, sex, age, physical activity index, and body mass index (BMI). Stepwise multiple regression analyses revealed a significant interaction of high birth weight, older age, and low BMI in predicting better cardiorespiratory endurance (R² = .308). When handgrip strength was tested as the dependent variable, we found that high birth weight, male sex, and older age emerged as important determinants for both sides.

CONCLUSION

Children aged 6-14 years born with a birth weight < 2.5 kg have low handgrip strength and cardiorespiratory fitness, which seems to be mediated partially by influences of both prenatal environment (e.g., birth weight) and biological variables (e.g., age, sex, BMI).

Physical Activity in 6.5-Year-Old Children Born Extremely Preterm

Physical activity (PA) can prevent cardiovascular diseases. Because of increased risks of impairments affecting motor activity, PA in children born preterm may differ from that in children born at term. In this prospective cohort study, we compared objectively measured PA in 71 children born extremely preterm (<27 weeks gestational age), to their 87 peers born at term, at 6.5 years of age. PA measured with accelerometer on the non-dominant wrist for 7 consecutive days was compared between index and control children and analyzed for associations to prenatal growth, major neonatal brain injury, bronchopulmonary dysplasia and neonatal septicemia, using ANOVA. Boys born extremely preterm spent on average 22 min less time per day in moderate to vigorous physical activity (MVPA) than control boys (95% CI: -8, -37). There was no difference in girls. Amongst children born extremely preterm, major neonatal brain injury was associated with 56 min less time in MVPA per day (95%CI: -88, -26). Subgroups of children born extremely preterm exhibit lower levels of physical activity which may be a contributory factor in the development of cardiovascular diseases as adults.

Physical fitness of non-disabled school-aged children born with extremely low birth weights

BACKGROUND

The assessment of long-term outcomes in survivors born with extremely low birth weights (ELBWs) has become increasingly important. However, little has been reported on the physical fitness of non-disabled school-aged children born with ELBWs.

AIMS

To assess the physical fitness of non-disabled school-aged children born with ELBWs.

STUDY DESIGN

Retrospective cohort study.

SUBJECTS

We analyzed 169 ELBW infants without cerebral palsy or intellectual disability (based on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) Full Scale intelligence quotient (IQ) test < 70).

OUTCOME MEASURES

Physical fitness was assessed using the grip strength, sit-up repetitions, sit & reach, side steps, standing long jump, and softball throw tests. T-scores were calculated using national survey data.

RESULTS

The T-scores for the grip strength, sit-up repetitions, sit & reach, side steps, standing long jump, softball throw tests, and the overall T-score were 43.7 ± 7.5, 44.2 ± 10.5, 46.0 ± 9.7, 40.9 ± 8.0, 40.0 ± 9.8, 42.4 ± 8.1, and 42.9 ± 5.5, respectively. After adjusting for other age-related factors, the height (SD score), WISC-III Performance IQ score, and percent predicted forced vital capacity (FVC) independently predicted the overall T-scores. Their standardized partial regression coefficients (β) were 0.334 (p = 0.009), 0.190 (p = 0.022), and 0.187 (p = 0.032), respectively.

CONCLUSIONS

Our cohort's physical fitness at approximately 8 years of age was significantly impaired compared to average Japanese children of the same age. Height, FVC, and Performance IQ independently predicted physical fitness, with height being the strongest predictor.

Comparison of physical activity and body composition in a cohort of children born extremely preterm or with extremely low birth weight to matched term-born controls: a follow-up study

OBJECTIVES

To compare physical activity and body composition in a cohort of children born extremely preterm/extremely low birth weight (EP/ELBW) with term-born (TB) controls.

METHODS

A regional cohort of children born during 1999-2000 at gestational age <28 weeks or with birth weight <1000 g and their individually matched TB controls were examined in 2010-2011. Information on physical activity was obtained from parental questionnaires, and body composition was determined by anthropometry and dual X-ray absorptiometry.

RESULTS

Fifty-seven EP/ELBW and 57 TB controls were included at a mean age of 11.6 years. Compared with the TB children, the EP/ELBW-born children exercised less often (22% vs 44% exercised more than 3 days per week), had lower physical endurance and poorer proficiency in sports and play and were less vigorous during exercise (p<0.05). They also had lower values (mean; 95 % CI) for muscle mass (0.9; 0.3-1.5 kg), total bone mineral density z-score (0.30; 0.13-0.52 units) and fat mass ratio (0.14; 0.06-0.21 units). The association between physical activity and bone mineral and skeletal muscle mass accrual was significantly weaker for the EP/ELBW-born than the TB children.

CONCLUSIONS

The EP/ELBW-born children were less physically active, had signs of an unfavourable body composition with less muscle mass and lower bone mineral density than the TB controls. The association between physical activity and the measures of body composition was weaker in the group of EP/ELBW-born children.

Body Structure, Function, Activity, and Participation in 3- to 6-Year-Old Children Born Very Preterm: An ICF-Based Systematic Review and Meta-Analysis

BACKGROUND

The World Health Organization's International Classification of Functioning, Disability, and Health framework, Children and Youth Version (ICF-CY), provides a valuable method of conceptualizing the multidomain difficulties experienced by children born very preterm (VP). Reviews investigating motor outcomes at preschool age across ICF-CY domains are lacking.

PURPOSE

The purpose of this review is to identify and compare motor outcomes of 3- to 6-year-old children born VP and children born full-term (FT) within the ICF-CY framework.

DATA SOURCES

Four electronic databases and reference lists of included and key articles were searched.

STUDY SELECTION

Studies comparing motor outcomes of 3- to 6-year-old children born VP (<32 weeks' gestation or birth weight <1500 g) with peers born FT were included.

DATA EXTRACTION

Two independent authors extracted data and completed quality assessments.

DATA SYNTHESIS

Thirty-six studies were included. Activity motor performance of children born VP was consistently poorer compared with peers born FT: standardized mean difference (SMD) was -0.71 (95% CI = -0.80 to -0.61; 14 studies, 2056 participants). Furthermore, children born VP had higher relative risk (RR) of motor impairment (RR = 3.39; 95% CI = 2.68 to 4.27; 9 studies, 3466 participants). Body structure and function outcomes were largely unable to be pooled because assessment tools varied too widely. However, children born VP had higher RR of any neurological dysfunction (Touwen Neurological Examination) (RR = 4.55; 95% CI = 1.20 to 17.17; 3 studies, 1363 participants). There were no participation outcome data.

LIMITATIONS

Limitations include the lack of consistent assessment tools used in VP follow-up at preschool age and the quality of the evidence.

CONCLUSIONS

Children born VP experience significant motor impairment across ICF-CY activity and body structure and function domains at preschool age compared with peers born FT. Evidence investigating participation in VP preschool-age populations relative to children born at term is sparse, requiring further research.

Leisure time physical activity in 9- to 11-year-old children born moderately preterm: a cohort study

BACKGROUND

Physical activity is one of the best documented activities with impacts on health in children and adults. Children born preterm show reduced physical and psychosocial function compared to children born at term. This may influence their level of physical activity. Reports on moderately preterm children's physical activities during childhood are limited. Thus, the aim of this study was to compare the leisure time physical activity at age 9-11 years of moderately preterm children with that of children born at term.

METHODS

Data from 4941 mother-child pairs from the Aarhus Birth Cohort (1989-91) were used. The cohort gathered clinical information, including gestational age at delivery. Information about parental socio-demographic and lifestyle factors was obtained from questionnaires completed during the second trimester of pregnancy. Information about children's physical activities was reported in a 9- to 11-year follow-up questionnaire completed by parents detailing how many times per week their child participated in sports activities outside of school, hours spent per week playing outside, and hours per week engaged in sedentary activities. Data were analysed using multiple logistic regression with the lowest activity group as a reference group.

RESULTS

A total of 158 children (3.2%) were born moderately preterm, i.e., between 32 and 36 completed weeks. Children born moderately preterm participated in sports activities as often as their peers born at term; they also participated in frequent sports activities (≥ 4 times per week) as often as their peers. There were no differences in hours per week spent playing outside or in sedentary activities between the two groups.

CONCLUSIONS

Nine- to 11-year-old moderately preterm children participated in sports activities outside school to a similar extent as their peers and engaged in outdoor activities and sedentary activities for the same duration of time per week as their peers born at term.

The level of physical fitness in children aged 6-7years with low birthweight

BACKGROUND

Level of physical fitness is related to the functional status of most of the bodily functions and so it appears to be very important to identify perinatal factors influencing physical fitness.

AIM

The purpose of this study was to determine the influence of birth weight on the level of physical fitness in children 6-7years of age.

SUBJECTS AND METHOD

Physical fitness was assessed using EUROFIT tests in 28,623 children, aged 6-7years, from rural areas in Poland. Children below the 10th percentile for birth weight for gestational age were defined as small for gestational age (SGA). The influence of birth weight on parameters of fitness was assessed by means of covariance analysis.

RESULTS

With the controls of age, sex and body size, children of low birth weight have shown significantly lower levels of body flexibility and running speed. The leg strength of children with SGA turned out to be significantly lower only in 7-year-old boys.

CONCLUSION

This study has revealed the significant influence of birth weight on physical fitness. The results suggest the importance of early intervention and its possible benefits for developing and maintaining the proper level of physical fitness further in life.

Physical activity outcomes following preterm birth

Physical activity (PA) is an important mediator of health and disease. Many correlates may play an important role in explaining differences in PA between populations; however, the role of birth outcomes such as prematurity on levels of PA is relatively poorly represented in the literature. Children born preterm may be at risk for reduced levels of PA as they have increased respiratory symptoms as well as decrements in lung function and exercise capacity. Emerging evidence suggests that the effects are prevalent across the whole range of gestational age. This review summarises the current literature in regards to levels of PA in preterm-born children and also explores PA in cohorts of young adults in order to contextualise the possible impact on long term risks to respiratory health.

Can exercise training rescue the adverse cardiometabolic effects of low birth weight and prematurity?

Being born preterm and/or small for gestational age are well-established risk factors for cardiometabolic disease in adulthood. Physical activity has the potential to mitigate against the detrimental cardiometabolic effects of low birth weight from two perspectives: (i) maternal exercise prior to and during pregnancy; and (ii) exercise during childhood or adulthood for those born small or prematurely. Evidence from epidemiological birth cohort studies suggests that the effects of moderate-intensity physical activity during pregnancy on mean birth weight are small, but reduce the risk of either high or low birth weight infants. In contrast, vigorous and/or high-intensity exercise during pregnancy has been associated with reduced birth weight. In childhood and adolescence, exercise ability is compromised in extremely low birth weight individuals (< 1000 g), but only marginally reduced in those of very low to low birth weight (1000-2500 g). Epidemiological studies show that the association between birth weight and metabolic disease is lost in physically fit individuals and, consistently, that the association between low birth weight and metabolic syndrome is accentuated in unfit individuals. Physical activity intervention studies indicate that most cardiometabolic risk factors respond to exercise in a protective manner, independent of birth weight. The mechanisms by which exercise may protect low birth weight individuals include restoration of muscle mass, reduced adiposity and enhanced β-cell mass and function, as well as effects on both aerobic and anaerobic muscle metabolism, including substrate utilization and mitochondrial function. Vascular and cardiac adaptations are also likely important, but are less well studied.

Preterm birth and leisure participation: a synthesis of the literature

Leisure participation has been associated with happiness and well-being in children. Individuals born preterm are at greater risk for motor, cognitive and behavioral difficulties which may contribute to difficulties participating in leisure activities. This systematic review examined the current knowledge on participation in leisure activities in individuals born preterm throughout the lifespan as compared to term born controls. An electronic search of eight databases for articles published up to October 2011 was conducted. The quality of each study was assessed using a standardized checklist. Thirteen studies met the selection criteria. In school-age children, no significant differences were found in activity levels between children born prematurely and term born controls. In adolescents, leisure scores in social activities, hobbies and sports were statistically significantly lower compared to controls. In young adults, differences in frequency and intensity of physical activity were reported compared to term controls. Promoting participation in leisure activities should be encouraged at a young age and continued to adulthood by minimizing the gaps between capabilities and the demands of the tasks and the environment.

Lower conditioning leisure-time physical activity in young adults born preterm at very low birth weight

Background

Adults born preterm at very low birth weight (VLBW, <1500 g) have elevated levels of risk factors for cardiovascular diseases and type 2 diabetes. Preliminary observations suggest that this could partly be explained by lower rates of physical activity. The aim of this study was to assess physical activity in healthy young adults born preterm at very low birth weight compared with term-born controls.

Methodology/Principal Findings

We studied 94 unimpaired young adults, aged 21–29 years, born at VLBW and 101 age-, sex-, and birth hospital-matched term-born controls from one regional center in Southern Finland. The participants completed a validated 30-item 12-month physical activity questionnaire and the NEO-Personality Inventory based on the Big Five taxonomy, the most commonly used classification of personality traits. Yearly frequency, total time, total volume and energy expenditure of conditioning and non-conditioning leisure-time physical activity (LTPA) and commuting physical activity were compared between VLBW and term-born subjects. A subset of participants underwent dual-energy x-ray absorptiometry for body composition measurement. Data were analyzed by multiple linear regression. Compared with controls, VLBW participants had lower frequency [−38.5% (95% CI; −58.9, −7.7)], total time [−47.4% (95% CI; −71.2, −4.1)], total volume [−44.3% (95% CI; −65.8, −9.2)] and energy expenditure [−55.9% (95% CI; −78.6, −9.4)] of conditioning LTPA when adjusted for age, sex, body mass index, smoking, parental education and personality traits. Adjusting for lean body mass instead of body mass index attenuated the difference. There were no differences in non-conditioning LTPA or commuting physical activity.

Conclusions/Significance

Compared with term-born controls, unimpaired VLBW adults undertake less frequent LTPA with lower total time and volume of exercise resulting in lower energy expenditure. Differences in personality that exist between the VLBW and term-born groups do not seem to explain this association.

Physical activity and fitness in children with developmental coordination disorder: a systematic review

Developmental coordination disorder (DCD) is a neurodevelopmental condition characterized by poor motor proficiency that interferes with a child's activities of daily living. Activities that most young children engage in such as running, walking, and jumping are important for the proper development of fitness and overall health. However, children with DCD usually find these activities challenging. A systematic review of the literature was conducted to synthesize the recent available data on fitness and physical activity in children with DCD, and to understand the extent of the differences between children with DCD and their typically developing peers. Systematic searches of electronic databases and reference lists identified 40 peer-reviewed studies meeting the inclusion criteria. These studies were reviewed in terms of: (a) study design, (b) population, (c) assessment tools, (d) measures, and (e) fitness and physical activity outcomes. It has been demonstrated that body composition, cardiorespiratory fitness, muscle strength and endurance, anaerobic capacity, power, and physical activity have all been negatively associated, to various degrees, with poor motor proficiency. However, differences in flexibility were not conclusive as the results on this parameter are mixed. Studies' limitations and the impact of results on future work are discussed.

Does birth weight influence physical activity in youth? A combined analysis of four studies using objectively measured physical activity

Animal models suggest growth restriction in utero leads to lower levels of motor activity. Furthermore, individuals with very low birth weight report lower levels of physical activity as adults. The aim of this study was to examine whether birth weight acts as a biological determinant of physical activity and sedentary time. This study uses combined analysis of three European cohorts and one from South America (n = 4,170). Birth weight was measured or parentally reported. Height and weight were measured and used to calculate Body Mass Index (BMI). PA was objectively measured using accelerometry for ≥3 days, ≥10 hours day. Data was standardized to allow comparisons between different monitors. Total physical activity was assessed as counts per minute (cpm), with time spent above moderate activity (MVPA) >2,000 counts and time spent sedentary (<100 counts). There was no evidence for an association between birth weight and total physical activity (p = 0.9) or MVPA (p = 0.7). Overall there was no evidence for an association between birth weight and sedentary time (p = 0.8). However in the Pelotas study we did find an association between higher birth weight (kg) and lower overall physical activity (cpm) (β = -31, 95%CI: -58, -46, p = 0.03) and higher birth weight and greater sedentary time (mins/day) (β = 16.4, 95%CI: 5.3, 27.5, p = 0.004), although this was attenuated and no longer significant with further adjustment for gestational age. Overall this combined analysis suggests that birth weight may not be an important biological determinant of habitual physical activity or sedentary behaviour in children and adolescents.

Fat-free mass mediates the association between birth weight and aerobic fitness in youth

OBJECTIVE

To investigate whether birth weight acts as a biological determinant of later aerobic fitness, and whether fat-free mass may mediate this association.

METHODS

The European Youth Heart Study (EYHS) is a population-based cohort of two age groups (9 and 15 years) from Denmark, Portugal, Estonia and Norway. Children with parentally reported birth weight >1.5 kg were included (n = 2 749). Data were collected on weight, height, and skinfold measures to estimate fat mass and fat-free mass. Aerobic fitness (peak power, watts) was assessed using a maximal, progressive cycle ergometer test. Physical activity was collected in a subset (n = 1 505) using a hip-worn accelerometer and defined as total activity counts/wear time, all children with >600 minutes/day for ≥3 days of wear were included.

RESULTS

Lower birth weight was associated with lower aerobic fitness, after adjusting for sex, age group, country, sexual maturity and socio-economic status (ß = 5.4; 95% CI: 3.5, 7.3 W per 1 kg increase in birth weight, p < 0.001). When fat-free mass was introduced as a covariate in the model, the association between birth weight and aerobic fitness was almost completely attenuated (p = 0.7). Birth weight was also significantly associated with fat-free mass (ß = 1.4; 95% CI: 1.1, 1.8, p < 0.001) and fat-free mass was significantly associated with aerobic fitness (ß = 3.6; 95% CI: 3.4, 3.7, p < 0.001). Further adjustment for physical activity did not alter the findings.

CONCLUSION

Birth weight may have long-term influences on fat-free mass and differences in fat-free mass mediate the observed association between birth weight and aerobic fitness.

Adults born at very low birth weight exercise less than their peers born at term

OBJECTIVE

To study the effects of very low birth weight (VLBW, <1500 g) birth on physical activity, an important protective and modifiable factor.

STUDY DESIGN

VLBW participants (n=163) with no major disability and 188 individuals born at term (mean age, 22.3 years; range, 18.5-27.1) completed a standardized questionnaire of physical activity.

RESULTS

VLBW participants reported less leisure-time conditioning physical activity. They were 1.61-fold more likely to "not exercise much," 1.61-fold more likely to exercise infrequently (once a week or less), 2.75-fold more likely to exercise with low intensity (walking), and 3.11-fold more likely to have short exercise sessions (<30 minutes). The differences were present even in subjects with no history of bronchopulmonary dysplasia or asthma and were only slightly attenuated when adjusted for height, parental education, lean body mass, and percent body fat.

CONCLUSIONS

Unimpaired adults who were VLBW exercise less during their leisure time than adults born at term. Promoting physical activity may be particularly important in the VLBW population to counteract the risks of chronic disease in adult life.

Birth size, infant weight gain, and motor development influence adult physical performance

PURPOSE

Adult physical performance is recognized as a marker of both current physical capacity and future health. The aim of the study was to examine the independent influences of birth weight, infant weight gain, and infant motor development on a variety of adult physical performance outcomes, in terms of muscular strength, muscular endurance, and aerobic fitness.

METHODS

The study population consisted of 4304 individuals from the Northern Finland Birth Cohort 1966 (NFBC 1966) with anthropometry measured at birth and at 1 yr. Infant motor development at age 1 yr was assessed by parentally reported age at first walking supported and standing unaided. At follow-up, aged 31 yr, muscle strength was measured using a handgrip dynamometer, muscle endurance was measured using a timed trunk extension test, and aerobic fitness was estimated from heart rate immediately after a standardized step test.

RESULTS

Birth weight was positively associated with muscle strength and aerobic fitness at age 31 yr, and these associations were independent of adult body size (P < 0.001). Greater infant weight gain between 0 and 1 yr was associated with lower muscle endurance (P = 0.004) and poorer aerobic fitness (P = 0.002); these associations seemed to be mediated by adult body size. Independent of infant birth weight and adult body size (height and weight), earlier infant motor development was associated with greater adult muscle strength (P < or = 0.001), muscle endurance (P < 0.001), and aerobic fitness (P < 0.001).

CONCLUSIONS

Higher birth weight, lower infant weight gain, and earlier infant motor development independently predict higher levels of adult physical performance for muscle strength, muscle endurance, and aerobic fitness at age 31 yr.

Motor coordination difficulties and physical fitness of extremely-low-birthweight children

Motor coordination difficulties and poor fitness exist in the extremely low birthweight (ELBW) population. This study investigated the relative impact of motor coordination on the fitness of ELBW children aged 11 to 13 years. One hundred and nine children were recruited to the study: 54 ELBW participants (mean age at assessment 12y 6mo; 31 male, 23 female; mean birthweight 769g, SD 148g; mean gestational age 26.6 weeks, SD 2.1 weeks) and 55 comparison children (mean age at assessment 12y 5mo; 28 males, 27 females; at least 37 weeks' gestation). All children completed the Movement Assessment Battery for Children (MABC), functional tests of postural stability and strength, growth measures, and tests of respiratory function. Maximal oxygen uptake (VO(2)max) was calculated from a 20m shuttle run test as a measure of fitness. The ELBW group had greater problems with postural stability (p=0.001) and motor coordination (p=0.001), with 70% rated as having a definite motor problem on the MABC brackets (those who scored less than the 5(th) centile on the MABC). The ELBW was also less fit than the comparison group (p=0.001), with 45% below the 10th centile for VO(2)max. There were differences between the groups for growth, strength, and particularly respiratory function. However, respiratory function did not significantly correlate with VO(2)max in the ELBW group. Motor coordination was the most powerful predictor of VO(2)max in both the ELBW (p=0.001) and the comparison groups (p=0.001).

Are muscular and cardiovascular fitness partially programmed at birth? Role of body composition

OBJECTIVE

To determine whether birth weight is associated with handgrip strength and cardiovascular fitness in adolescence and, if so, how these associations are influenced by current body composition.

STUDY DESIGN

A total of 1801 adolescents (983 females), age 13 to 18.5 years, from the AVENA (Alimentación y Valoración del Estado Nutricional de los Adolescentes Españoles [Food and Assessment of the Nutritional Status of Spanish Adolescents]) study were evaluated. Handgrip strength and cardiovascular fitness were assessed using the handgrip test and the 20-m shuttle run test, respectively.

RESULTS

Birth weight was positively associated with handgrip strength in females after controlling for current age, gestational age, breast-feeding, and adolescent body mass index (P = .002), body fat percentage (P < .001), or waist circumference (P = .005), but not after controlling for fat-free mass. The associations were similar yet weaker in males. Females with high birth weight (>90th percentile) had greater handgrip strength than those with normal (10th to 90th percentile) or low (<10th percentile) birth weight, after adjusting for body fat percentage (P = .004). All of the differences became nonsignificant after adjusting for adolescent fat-free mass. Birth weight was not associated with cardiovascular fitness.

CONCLUSIONS

High birth weight is associated with greater handgrip strength in adolescents, especially in females, yet these associations seem to be highly explained by fat-free mass.

Clinical exercise testing in children and adolescents with cystic fibrosis

PURPOSE

To review the most common field and laboratory exercise tests available for children and adolescents with cystic fibrosis (CF).

METHODS

Relevant studies for this review were identified by electronic search of Medline and PubMed databases between the years 1958 and 2008. The bibliographies of all accessed publications were also searched. Key descriptors were cystic fibrosis, exercise testing, aerobic fitness, children, and adolescents.

RESULTS

Five field tests were selected for presentation, including discussion of their strengths and weaknesses. Laboratory tests measuring aerobic and anaerobic responses to exercise in children with CF were also selected for presentation and discussed along with a summary of safety considerations for exercise testing of children with CF.

CONCLUSION

Exercise testing is regarded an important prognostic tool in CF care. However, despite its beneficial effects, clinical exercise testing seems underused. Clinicians and their staff should encourage patients with CF to be physically active and recommend exercise testing annually.

Motor impairment and low achievement in very preterm children at eight years of age

AIM

To examine the concurrence of motor impairment and academic underachievement in a group of very preterm children at 8 years of age.

METHODS

All surviving children with a gestational age less than 30 weeks, admitted to the neonatal intensive care unit between 1987 and 1997, were prospectively enrolled in developmental follow-up. Children with a neurosensory disability or a low intelligence score (FSIQ < or = 75 points) were excluded. At 8 years of age the Bruininks Oseretsky Test of Motor Proficiency and standardised tests of academic achievement were administered to a sample of 323 very preterm children.

RESULTS

One hundred and one (31.3%) of these very preterm children were identified as having Developmental Coordination Disorder (DCD). Of the children with DCD, 54.4% also had underachievement in literacy and/or numeracy. As the severity of motor impairment increased so too did the severity and complexity of underachievement. Significantly fewer children with motor impairments participated in after-school sporting activities. Children with DCD required more mechanical ventilation support during their hospital admission.

CONCLUSIONS

This study demonstrated that a significant proportion of children born very preterm find both motor and academic skills difficult in early school years.

Physical fitness in children with developmental coordination disorder

The protective effects of physical activity and fitness on cardiovascular health have clearly been shown among normally developed children. However data are currently lacking pertaining to children with developmental coordination disorder (DCD). The purpose of this study was to examine differences in fitness measures, body composition, and physical activity among children with and without DCD. A cross-sectional design was implemented examining 261 children (118 girls, 143 boys) ages 4-12 years (mean age 7.8 +/- 1.9 years). Children were categorized as having DCD if they scored less than or equal to the 5th percentile (n=71) or between the 6th and the 15th percentile (n=5) on the Movement Assessment Battery for Children (MABC; Henderson & Sugden, 1992). The typically developing children had scores between the 16th and the 50th percentile (n=16) or above the 50th percentile (n=3) on the MABC. The age-related body mass index was used to characterize body composition. Physical fitness was assessed with a 6-min run, 20-m sprint, jump-and-reach test, medicine ball throw, curl-ups, and sit-and-reach test. Physical activity was estimated with a questionnaire. The percentage of overweight and obese children ages 10-12 years were significantly higher in the DCD groups (severe: 50%, moderate: 23.1%) than in the typically developing groups (medium: 5.6%, high: 0%; p < .05). Significant interactions (MABC x Age Group) were found for the fitness tests (p values < .05), except flexibility; whereby specifically, compared to the children in the typically developing groups children in the DCD groups ages 4-6 years achieved significantly worse results for the 20-m sprint, and children of the DCD groups ages 10-12 years achieved significantly worse results for the 6-min run, jump-and-reach test, and medicine ball throw. The study demonstrates poorer performance in fitness tests with high demands on coordination in children with DCD compared to their typically developing peers. Furthermore, the differences in fitness increased with age between children in the DCD groups versus the typically developing groups.

Glucose regulation in young adults with very low birth weight

BACKGROUND

The association between small size at birth and impaired glucose regulation later in life is well established in persons born at term. Preterm birth with very low birth weight (<1500 g) is also associated with insulin resistance in childhood. If insulin resistance persists into adulthood, preterm birth with very low birth weight also may be associated with an increased risk of disease in adulthood. We assessed glucose tolerance and insulin sensitivity and measured serum lipid levels and blood pressure in young adults with very low birth weight.

METHODS

We performed a standard 75-g oral glucose-tolerance test, measuring insulin and glucose concentrations at baseline and at 120 minutes in 163 young adults (age range, 18 to 27 years) with very low birth weight and in 169 subjects who had been born at term and were not small for gestational age. The two groups were similar with regard to age, sex, and birth hospital. We measured blood pressure and serum lipid levels, and in 150 very-low-birth-weight subjects and 136 subjects born at term, we also measured body composition by means of dual-energy x-ray absorptiometry.

RESULTS

As compared with the subjects born at term, the very-low-birth-weight subjects had a 6.7% increase in the 2-hour glucose concentration (95% confidence interval [CI], 0.8 to 12.9), a 16.7% increase in the fasting insulin concentration (95% CI, 4.6 to 30.2), a 40.0% increase in the 2-hour insulin concentration (95% CI, 17.5 to 66.8), an 18.9% increase in the insulin-resistance index determined by homeostatic model assessment (95% CI, 5.7 to 33.7), and an increase of 4.8 mm Hg in systolic blood pressure (95% CI, 2.1 to 7.4). Adjustment for the lower lean body mass in the very-low-birth-weight subjects did not attenuate these relationships.

CONCLUSIONS

Young adults with a very low birth weight have higher indexes of insulin resistance and glucose intolerance and higher blood pressure than those born at term.

Early gross motor development of preterm infants according to the Alberta Infant Motor Scale

OBJECTIVE

To systematically examine gross motor development in the first 18 months of life of preterm infants.

STUDY DESIGN

A total of 800 preterm infants (356 boys), ages between 1 and 18 months and corrected for degree of prematurity, were assessed with the use of the Alberta Infant Motor Scale.

RESULTS

Comparison of the mean Alberta Infant Motor Scale scores of the preterm infants with the norm-referenced values derived from term infants revealed that as a group, the preterm infants scored significantly lower at all age levels, even with full correction for degree of prematurity.

CONCLUSIONS

In general, preterm infants exhibit different gross motor developmental trajectories compared with term infants in the first 18 months of life. The gross motor developmental profile of preterm infants may reflect a variant of typical gross motor development, which seems most likely to be specific for this population. As a consequence, adjusted norms should be used for proper evaluation and clinical decision-making in relation to preterm infants.

Aerobic and lung performance in premature children with and without chronic lung disease of prematurity

OBJECTIVE

This study intended to identify pulmonary and exercise-related effects of chronic lung disease of infancy (CLD) versus prematurity (PRE) without CLD in children 5 to 7 years old who were born prematurely (24-30 weeks of gestation) with very low and extremely low birthweight of 500 to 1500 g (VLBW, ELBW).

SUBJECTS

Seventeen CLD and 14 PRE were compared with 24 term controls (CON). The premature children had no overt manifestations of a neuromuscular disease.

METHODS

Pulmonary function at rest and following exercise, and aerobic exercise performance were measured.

RESULTS

Peak [latin capital V with dot above]O2 and maximal aerobic power were not different among the groups, but O2 uptake at a given mechanical power was higher in the CLD than in PRE and in CON (P < 0.05). At rest, forced vital capacity was significantly lower in CLD than in PRE (P < 0.05) and CON (P < 0.0005), and FEV1 and FEF25-75 were lower in CLD than CON (P < 0.0005 and P < 0.005, respectively). Exercise-induced bronchoconstriction (EIB) was more prevalent among the 2 premature groups (P < 0.05).

CONCLUSIONS

Our children 5 to 7 years old born at VLBW or ELBW, with or without CLD, have some degree of pulmonary dysfunction at rest and following exercise and a higher prevalence of EIB with no reduction in maximal aerobic exercise performance. The findings suggest that the pulmonary limitations are associated with low birthweight even in the absence of CLD. The higher O2 uptake at a given mechanical power in the CLD group may cause early fatigability during prolonged exercise, even when aerobic performance is normal.

Anaerobic exercise in pediatric cystic fibrosis

Anaerobic fitness is important for daily functioning of children with cystic fibrosis (CF). The aim of this study was to assess the determinants of anaerobic performance in CF. Anaerobic performance was measured in 39 children with CF (mean age, 13.2 +/- 1.8 (SD) years, forced expired volume in 1 sec (FEV(1)) 81.6 +/- 22.1% predicted), using a Wingate anaerobic test. Significant associations were found for peak power (PP) and mean power (MP) with fat-free mass (FFM) body weight, body mass index, maximal isometric muscle force, and aerobic capacity. Pulmonary function was correlated with anaerobic indices when controlled for FFM. Multiple regression analysis indicated that FFM and FEV(1) accounted for 82% and 86% of the variability in PP and MP, respectively. Patients with moderate CF (FEV(1) < 80%), as compared to mild CF (FEV(1) >/= 80%), had higher PP (difference = 85 W, 95% CI = 27-144 W) and MP (difference = 53 W, 95% CI = 42-63 W) at equivalent FFM. Our results indicate that FFM and pulmonary function are important determinants of anaerobic exercise performance in children with CF. With progression of pulmonary disease, anaerobic performance may be enhanced.

Head size and motor performance in children born prematurely

PURPOSE

The objective of this study was to determine the relationship between head circumference (HC) and motor performance in 6- to 12-yr-old children born prematurely (PRE: birthweight < or = 1500 g, gestational age < or = 32 wk) and in children born at term (CON).

METHODS

Thirty-three PRE and 21 CON without an apparent neurological deficit participated in this study. HC was measured on the day of testing and was rated as small HC (SHC, HC more than 1 SD below the 50th percentile of reference data) or as normal HC (NHC). Subjects were examined by an experienced neuropediatrician, and whole-body coordination was assessed by the Körper-Koordinationstest für Kinder (KTK). Peak exercise performance was determined by a Wingate test and an incremental cycling test to volitional fatigue. Net oxygen cost of cycling was measured during four different tasks lasting 5-7 min each. Subjects pedaled at an intensity corresponding to 30% and 60% of peak oxygen uptake ([OV0312]O(2peak)) at a cadence of 36 and 76 rpm, respectively.

RESULTS

Prematures with SHC showed no statistically significant difference in their neurological examination and whole-body coordination compared with prematures with NHC. Wingate test performance and [OV0312]O(2peak) relative to body mass were similar among SHC, NHC, and CON. In SHC, but not in NHC and CON, net oxygen cost of cycling increased significantly (P < 0.05) when cadence was increased from 36 to 76 rpm.

CONCLUSION

At the age of 6-12 yr, SHC have a higher oxygen cost of cycling in exercise tasks requiring high velocity, which might be explained-at least in part-by an impaired neural control of intra- and intermuscular coordination.

Relationships of equipment use and play positions to motor development at eight months corrected age of infants born preterm

PURPOSE

The purpose of this study was to determine the relationship between both use of infant equipment and play positions and motor development of infants born preterm who were classified as high risk. Subjects were 60 parent-infant dyads attending a developmental follow-up clinic.

METHODS

Parents reported the duration of infant equipment use and the predominant positions in which their infants played in the previous month. Infants were assessed using the Alberta Infant Motor Scale (AIMS).

RESULTS

Equipment use was not related to motor development; however, the duration of carrying was negatively related to the sit subscale of the AIMS (r = -0.31, p < 0.05). As a group, the infants in this sample spent more time in the relatively less active play positions of sitting and supine than in the positions of prone and standing.

CONCLUSIONS

Therapists should consider the use of equipment and specific play positions to enhance motor development of infants born preterm and work with parents to promote an understanding of the importance of providing their infants with opportunities to develop early motor competencies.

Exercise and the child born prematurely

With the increase in survival rates of children born prematurely, issues related to their active pursuits and responses to exercise have been gaining increasing attention. In some preterm children with an extremely low birthweight, bronchopulmonary dysplasia or cerebral palsy exercise capacity may be limited, especially in tasks requiring good neuromotor coordination. Deficiencies in aerobic and anaerobic performance, strength and coordination may even occur in children without overt manifestations of a neuromuscular or pulmonary disease. However, as a rule, children born prematurely may engage in physical activities and competitive sports without limitations. Exercise is safe in almost all such children as long as precautions are taken to avoid exercise-induced bronchoconstriction. However, to date there are no studies that have determined the efficacy of training. A wide variety of activities should be encouraged in all children born prematurely at an early age, to support the development of skills and to compensate for the possible effects of their premature birth on coordination.