Secular Trends in Gross Motor Coordination: A Study of Peruvian Children Living at High Altitude.

PURPOSE: To (1) describe secular trends in gross motor coordination (GMC) scores by sex and age; (2) investigate GMC trends adjusted for concomitant secular trends in height, weight, and overall physical fitness; and (3) examine trends in children's frequencies within different GMC categories. METHOD: The sample comprises 1562 Peruvian children (690 in 2009 and 872 in 2019), aged 6-11 years, from Junín (a high-altitude region). GMC was assessed with the KörperkoordinationsTest für Kinder. Physical fitness was assessed with handgrip strength, standing long jump, and shuttle-run test. Height and weight were measured with standardized protocols. Analysis of variance, covariance, and logistic regression were used. RESULTS: A negative secular trend in GMC (based on raw scores) for boys and girls aged 6-8 years was observed. However, a positive trend was observed at 11 years of age but only in boys. Finally, there were no significant changes in the likelihood of children having below-normal GMC from 2009 to 2019. CONCLUSIONS: Secular trends in GMC were negative in Peruvian children, especially at 6-8 years of age. Further, body size and physical fitness trends did not affect the negative secular trend. A high prevalence of children had below-normal GMC in both 2009 and 2019.

Is there an association between proficiency in fundamental movement skills and mderate-to-vigorous physical activity in childhood on weekdays and weekends? The REACT project.

OBJECTIVE: The present study probes into the association between children's fundamental movement skills (FMS) and moderate-to-vigorous physical activity (MVPA) during weekdays and weekends. METHODS: This cross-sectional sample included 1014 children aged 6-10 years from the REACT project. Physical activity was assessed with accelerometry, and five FMS (stationary dribble, kick, catch, overhand throw, and underhand roll) were assessed with the digital platform Meu Educativo®. Three groups were formed based on the frequency of FMS that each child mastered: group 1 (wizard level in four or five FMS); group 2 (wizard level in two or three FMS); and group 3 (wizard level in at most one skill). Multilevel models were used to analyze the data treating children (level-1) nested within schools (level-2). RESULTS: Compared to group 1, groups 2 (-12.9 ± 2.3 min day-1) and 3 (-23.9 ± 2.4 min day-1) were less physically active during weekdays and weekends (group 2: -14.7 ± 2.7 min day-1 and group 3: -22.4 ± 2.9 min day-1), independent of age and sex. There was a decline in MVPA during the weekend. Further, on average, boys were more active than girls, and with increasing age, children were less active. CONCLUSION: On average, children with higher FMS levels are generally more physically active than their peers with lower FMS levels. Even though MVPA tends to decline on weekends, FMS proficiency is a significant factor in maintaining 60 min of MVPA on weekends.

Profile of leisure-time physical activity and sedentary behavior in adults in Brazil: a nationwide survey, 2019.

OBJECTIVES: to estimate the prevalence of leisure-time physical activity and sedentary behavior in adults in Brazil. METHODS: this was a cross-sectional, population-based study carried out in a sample of 88,531 Brazilians, using data from the 2019 National Health Survey; leisure-time physical activity (overall and aerobic exercise) was measured according to the World Health Organization guidelines; the weighted prevalence and respective 95% confidence intervals (95%CI) of physical activity, physical inactivity and sedentary behavior were estimated. RESULTS: according to the selected sample, 26.4% (95%CI 25.9;27.1) of Brazilian adults were physically active, 14.0% (95%CI 13.5;14.4) were insufficiently physically active and 59.5% (95%CI 58.8;60.2) were physically inactive; sedentary behavior ≥ 6 hours was reported by 30.1% (95%CI 29.5;30.8) of the population; only 8.6% (95%CI 8.2;8.9) met the recommendations for muscle-strengthening activities. CONCLUSION: most Brazilian adults were physically inactive and did not meet international recommendations for leisure-time physical activity and reduction in sedentary behavior.

Flower-inducing technology facilitates speed breeding in cassava.

Cassava is a tropical crop that provides daily carbohydrates to more than 800 million people. New cassava cultivars with improved yield, disease resistance, and food quality are critical to end hunger and reduce poverty in the tropics. However, the progress of new cultivar development has been dragged down by difficulties obtaining flowers from desired parental plants to enable designed crosses. Inducing early flowering and increasing seed production are crucial to improving the efficiency of developing farmer-preferred cultivars. In the present study, we used breeding progenitors to evaluate the effectiveness of flower-inducing technology, including photoperiod extension, pruning, and plant growth regulators. Photoperiod extension significantly reduced the time to flowering in all 150 breeding progenitors, especially late-flowering progenitors which were reduced from 6-7 months to 3-4 months. Seed production was increased by using the combination of pruning and plant growth regulators. Combining photoperiod extension with pruning and the PGR 6-benzyladenine (synthetic cytokinin) produced significantly more fruits and seeds than only photoperiod extension and pruning. Another growth regulator, silver thiosulfate, commonly used to block the action of ethylene, did not show a significant effect on fruit or seed production when combined with pruning. The present study validated a protocol for flower induction in cassava breeding programs and discussed factors to consider in implementing the technology. By inducing early flowering and increasing seed production, the protocol helped move one step further for speed breeding in cassava.

Sibling Resemblance in Physical Activity Levels: The Peruvian Sibling Study on Growth and Health.

Physical activity is associated with a host of positive health outcomes and is shaped by both genetic and environmental factors. We aim to: (1) estimate sibling resemblance in two physical activity phenotypes [total number of steps∙day-1 and minutes for moderate steps per day (min∙day-1)]; and (2) investigate the joint associations of individual characteristics and shared natural environment with intra-pair sibling similarities in each phenotype. We sampled 247 biological siblings from 110 nuclear families, aged 6-17 years, from three Peruvian regions. Physical activity was measured using pedometers and body mass index was calculated. In general, non-significant variations in the intraclass correlation coefficients were found after adjustment for individual characteristics and geographical area for both phenotypes. Further, no significant differences were found between the three sib-ship types. Sister-sister pairs tended to take fewer steps than brother-brother (ß = -2908.75 ± 954.31). Older siblings tended to walk fewer steps (ß = -81.26 ± 19.83), whereas body mass index was not associated with physical activity. Siblings living at high-altitude and in the Amazon region had higher steps/day (ß = 2508.92 ± 737.94; ß = 2213.11 ± 776.63, respectively) compared with their peers living at sea-level. In general, we found no influence of sib-types, body mass index, and/or environment on the two physical activity phenotypes.

Secular Trends in Physical Fitness of Peruvian Children Living at High-Altitude.

The physical fitness of children is an important marker of health, and monitoring its temporal changes provides important information for developing interventions. We aimed to: (1) describe secular trends in physical fitness across age, within each sex, in Peruvian schoolchildren; and (2) verify if these trends are also present when adjusted for changes in height and weight. We sampled 1590 children (707 in 2009; 883 in 2019), aged 6-11 years. Physical fitness was assessed with four tests from the EUROFIT battery. ANOVA and ANCOVA statistical models were used. Results showed that with increasing age, girls and boys were significantly stronger in all PF tests, except for the case of flexibility in girls. In 2019, girls were stronger (handgrip) and more flexible than in 2009; but lower values were evident in standing long jumps in both sexes. Age-by-year interactions were statistically significant for agility in both sexes, with significant differences occurring at different ages. These trends did not change when adjusted for temporal changes in height and weight. Our research provides important data for local governments to implement public policies and practices to improve physical fitness levels in children.

Perfil de atividade física no tempo livre e tempo sedentário em adultos no Brasil: inquérito nacional, 2019 / Profile of leisure-time physical activity and sedentary behavior in adults in Brazil: a nationwide survey, 2019 / Perfil de la actividad física en el tiempo libre y sedentario em adultos en Brasil: encuesta nacional, 2019

Objetivos: estimar a prevalência de atividade física no tempo livre e comportamento sedentário em adultos no Brasil. Métodos: estudo seccional, populacional, na amostra de 88.531 brasileiros da Pesquisa Nacional de Saúde de 2019; a atividade física (geral e modalidades aeróbias) no tempo livre foi mensurada conforme as diretrizes da Organização Mundial da Saúde; estimaram-se as prevalências ponderadas, e respectivos intervalos de confiança de 95% (IC95%), de atividade física, inatividade física e tempo sedentário. Resultados: a partir da amostra selecionada, 26,4% (IC95% 25,9;27,1) dos adultos brasileiros eram fisicamente ativos, 14,0% (IC95% 13,5;14,4) eram insuficientemente ativos e 59,5% (IC95% 58,8;60,2) eram inativos; o tempo sedentário ≥ 6 horas foi relatado por 30,1% (IC95% 29,5;30,8) da população; apenas 8,6% (IC95% 8,2;8,9) atenderam às recomendações de atividade física para fortalecimento muscular. Conclusão: a maioria dos brasileiros adultos era inativa e não atendeu às recomendações internacionais de atividade física no tempo livre e restrição de tempo sedentário.

Objectives: to estimate the prevalence of leisure-time physical activity and sedentary behavior in adults in Brazil. Methods: this was a cross-sectional, population-based study carried out in a sample of 88,531 Brazilians, using data from the 2019 National Health Survey; leisure-time physical activity (overall and aerobic exercise) was measured according to the World Health Organization guidelines; the weighted prevalence and respective 95% confidence intervals (95%CI) of physical activity, physical inactivity and sedentary behavior were estimated. Results: according to the selected sample, 26.4% (95%CI 25.9;27.1) of Brazilian adults were physically active, 14.0% (95%CI 13.5;14.4) were insufficiently physically active and 59.5% (95%CI 58.8;60.2) were physically inactive; sedentary behavior ≥ 6 hours was reported by 30.1% (95%CI 29.5;30.8) of the population; only 8.6% (95%CI 8.2;8.9) met the recommendations for muscle-strengthening activities. Conclusion: most Brazilian adults were physically inactive and did not meet international recommendations for leisure-time physical activity and reduction in sedentary behavior.

Objetivos: estimar la prevalencia de actividad física en el tiempo libre y comportamiento sedentario de adultos en Brasil. Métodos: estudio seccional, poblacional, de la muestra de la Encuesta Nacional de Salud de 2019 a partir de lo cual, se estimó la prevalencia ponderada (porcentaje e intervalo de confianza del 95%) de actividad física (general y aeróbica), la inactividad física y el comportamiento sedentario. Resultados: según la muestra elegida, 26,4% (IC95% 25,9;27,1) son físicamente activos, 59,5% (IC95% 58,8;60,2) son inactivos, 14,0% (IC95% 13,5;14,4) son insuficientemente activos y 30,1% (IC95% 29,5;30,8) pasan ≥6 horas sedentarios en su tiempo libre; sólo el 8,6% (IC95% 8,2;8,9) de los adultos cumple con las recomendaciones de actividad física para fortalecimiento muscular. Conclusión: la mayoría de los adultos brasileños son inactivos, no cumplen con las recomendaciones internacionales de actividad física en el tiempo libre y la restricción del tiempo sedentario.

Metabolic syndrome predictors of brain gray matter volume in an age-stratified community sample of 776 Mexican- American adults: Results from the genetics of brain structure image archive.

Introduction: This project aimed to investigate the association between biometric components of metabolic syndrome (MetS) with gray matter volume (GMV) obtained with magnetic resonance imaging (MRI) from a large cohort of community-based adults (n = 776) subdivided by age and sex and employing brain regions of interest defined previously as the "Neural Signature of MetS" (NS-MetS). Methods: Lipid profiles, biometrics, and regional brain GMV were obtained from the Genetics of Brain Structure (GOBS) image archive. Participants underwent T1-weighted MR imaging. MetS components (waist circumference, fasting plasma glucose, triglycerides, HDL cholesterol, and blood pressure) were defined using the National Cholesterol Education Program Adult Treatment Panel III. Subjects were grouped by age: early adult (18-25 years), young adult (26-45 years), and middle-aged adult (46-65 years). Linear regression modeling was used to investigate associations between MetS components and GMV in five brain regions comprising the NS-MetS: cerebellum, brainstem, orbitofrontal cortex, right insular/limbic cluster and caudate. Results: In both men and women of each age group, waist circumference was the single component most strongly correlated with decreased GMV across all NS-MetS regions. The brain region most strongly correlated to all MetS components was the posterior cerebellum. Conclusion: The posterior cerebellum emerged as the region most significantly associated with MetS individual components, as the only region to show decreased GMV in young adults, and the region with the greatest variance between men and women. We propose that future studies investigating neurological effects of MetS and its comorbidities-namely diabetes and obesity-should consider the NS-MetS and the differential effects of age and sex.

Prevalence and Associated Factors of Excessive Recreational Screen Time Among Colombian Children and Adolescents.

Objectives: Excessive recreational screen time (RST) is associated with detrimental effects for physical, psychological and cognitive development. This article aims to describe the prevalence of excessive RST among Colombian preschoolers, children and adolescents and explore its factors associated. Methods: We analyzed data from the National Survey of Nutrition 2015. The sample included 4,503 preschoolers, 5,333 school-aged children and 6,623 adolescents. Poisson regression models with robust variance were conducted to estimate prevalence ratios and determine associated factors of excessive RST. Results: Fifty percent of preschoolers, 61% of school-aged children and 73% of adolescents in Colombia had excessive RST. Positive associations were observed with the availability of TV in the child's bedroom, the availability of video games at home, and eating while using screens. A negative association with rural area was observed for all age groups. Conclusion: The majority of Colombian children and adolescents have excessive RST. Younger preschoolers, older school-aged children, wealthiest children and those from urban areas should be targeted by interventions to decrease RST. These interventions should promote limiting the availability of electronic devices in children's bedrooms and not eating in front of screens.

Sibling Resemblances in Physical Fitness in Three Distinct Regions in Peru: The Peruvian Sibling Study on Growth and Health.

We estimated sibling resemblance in health-related physical fitness (PF) and examined how individual characteristics and shared natural environment accounted for sibling similarities. The sample comprised 656 sibling pairs and 102 triplets (6-15 years of age), from three geographical areas of Peru. PF components included morphological (waist circumference, sum of skinfolds), muscular (handgrip strength, standing long jump), and motor (shuttle-run). Body mass index (BMI) and somatic maturation were also assessed. In general, sibling intraclass correlations differed significantly across sib-ship types for waist circumference and handgrip strength but were the same for sum of skinfolds, standing long jump, and shuttle-run. Further, in general, both individual characteristics and geographical area of residence significantly influenced the magnitude of sibling resemblance as well as the mean levels of PF. In conclusion, individual characteristics and shared natural environment jointly influenced the expression of PF in Peruvian siblings, revealing the importance of these features when designing individualized programs promoting fitness.

Regional variation in growth status. The Peruvian health and optimist growth study.

OBJECTIVE: This study aims to (1) investigate differences in weight, body mass index (BMI), and waist circumference (WC) among Peruvian children and adolescents living in three areas located at different altitudes; (2) compare age- and sex-specific height, weight, and BMI within each site with US reference data. METHODS: We sampled 8753 subjects (4130 boys), aged 4 to 17 years from sea level, rainforest, and high-altitude. Height, weight, and WC were measured and BMI was calculated. Analysis of variance was used to compare variables across geographic regions, and the Hoff and Blackburn procedure was used to compare the Peruvian results with US reference data. RESULTS: Participants living at sea level were taller, heavier, had greater BMI and WC relative to those living at high-altitude and in the rainforest. Peruvian schoolchildren of both sexes from the three geographical areas were shorter and lighter than their American peers. Boys and girls living in the rainforest and at high-altitude had lower BMI, whereas WC values of American schoolchildren are higher than those of the Peruvian children by age and gender. CONCLUSIONS: Peruvians living at different altitudes differ in their growth indicators (height, weight, BMI, and WC), with significant differences between those living at sea level relative to their peers from other regions. Further, Peruvian schoolchildren of both sexes from the three geographical areas significantly differ from their US counterparts.

[Association between the consumption of breakfast and the recommendation of physical activity and the nutritional status in children]. / Associação entre o consumo de café da manhã com a recomendação de atividade física e o estado nutricional em crianças.

The scope of this article is to associate breakfast consumption (BC) with moderate to vigorous physical activity (MVPA) intensity and the nutritional status of children aged 9-11. The sample consisted of 432 children from São Caetano do Sul participating in the International Study of Childhood Obesity Lifestyle and the Environment. Data were collected between 2012 and 2013. The weekly BC was obtained using the self-reported method. To measure MVPA, children used accelerometers and were classified into two groups (<60 versus ≥60 min/day). The nutritional status was presented by body mass index (BMI). Logistic regression models were used, adjusted for gender, age, race, parental educational level and eating score. The mean BC was 5.25 (CI95%: 5.1-5.4) days/week and the MVPA was 59.29 (CI95%: 57.3-61.7) min/day. In the total sample, 55.8% of the children did not perform ≥60 min/day of MVPA and 50.2% were overweight or obese. The daily BC was not associated with MVPA, however, it reduced the odds of children being overweight or obese (OR: 0.51; CI95%: 0.34-0.76; p=0.001). Daily BC reduced the odds of excess weight or obesity in children, though it did not increase the chances of children meeting the recommendations of MVPA. Public policies should encourage daily BC to prevent excess weight or obesity.

O objetivo deste artigo é associar o consumo do café da manhã (CM) com atividade física de moderada à vigorosa (AFMV) e estado nutricional de crianças entre 9 e 11 anos. A amostra foi composta por 432 crianças de São Caetano do Sul participantes do International Study of Childhood Obesity Lifestyle and the Environment. Os dados foram coletados entre 2012-2013. O consumo do CM semanal foi obtido pelo método autorreferido. Para mensuração da AFMV, as crianças utilizaram acelerômetro e foram classificadas em dois grupos (<60 versus ≥60 min/dia). O estado nutricional foi apresentado pelo Índice de Massa Corporal (IMC). Foram utilizados modelos de regressão logística. A média do consumo de CM foi de 5,25 (IC95%: 5,1-5,4) dias/sem e da AFMV foi de 59,29 (IC95%: 57,3-61,7) min/dia. No total, 55,8% das crianças não realizavam ≥60 min/dia de AFMV e 50,2% apresentavam excesso de peso ou obesidade. O consumo diário do CM não se associou com a AFMV, porém, diminuiu o risco de terem excesso de peso ou obesidade (OR: 0,51; IC95%: 0,34-0,76; p=0,001). O consumo diário do CM reduziu as chances de excesso de peso ou obesidade em crianças, mas não aumentou a chance das crianças cumprirem as recomendações de AFMV. Politicas públicas devem incentivar o consumo diário do CM para assim prevenir o excesso de peso ou obesidade.

Prevalence and Correlates of Active Transportation to School Among Colombian Children and Adolescents.

BACKGROUND: In Colombia, active transportation has been assessed in multiple local and regional studies, but national data on active transportation are scarce. This study aims to describe the prevalence and factors associated with active transportation to/from school among Colombian children and adolescents. METHODS: The authors analyzed nationally representative data from the National Survey of Nutrition 2015, with a sample of 11,466 children and adolescents aged between 3 and 17 years. Descriptive statistics were calculated, and prevalence ratios were estimated using Poisson regression multivariable models with robust variance. RESULTS: Approximately 70% of Colombian children and adolescents reported engaging in active transportation to/from school over the last week. There were no differences by sex among preschoolers nor school-aged children. Fewer adolescent females than males used active transportation. Preschoolers and school-aged children living in Bogota were more likely to report active transport than children from other regions (prevalence ratios for other regions ranged from 0.59 to 0.86). School-aged children and adolescents with a lower wealth index were more likely to use active transportation than their counterparts (prevalence ratios = 1.32 and 1.22, respectively). CONCLUSIONS: The wealthiest children and adolescents, adolescents from rural areas, and female adolescents should be a focus for future interventions. Actions need to be implemented to improve the involvement in active transportation to/from school in Colombia.

Biological and environmental influences on motor coordination in Peruvian children and adolescents.

This study investigated the associations between biological and environmental factors and gross-motor coordination (GMC) in Peruvian children and adolescents. The sample comprised 7401 boys and girls, aged 6-14 years, recruited from three geographical regions: sea-level, Amazon and high-altitude. Biological variables included age, sex, height, BMI, physical fitness, stunting, and maturational status. Environmental influences included geographical region and school characteristics. Gross-motor coordination was tested with the Körperkoordinationstest für Kinder and the data analyzed by multilevel logistic regression. Results showed a high prevalence of below normal GMC scores. Sex, age, geographical area, biological maturation, BMI (normal versus overweight/obesity), and stunting were all significant predictors of GMC. There was also an interaction between age, sex, and geographical area indicating that older girls who lived at sea-level and high-altitude were more likely to display below normal GMC scores. The school context was less important in predicting GMC problems than the interplay between biological characteristics and geographical region. These results suggest that early identification, as well as educational and pediatric care interventions, are of importance in reducing below normal GMC among Peruvian children and adolescents.

Prevalence and Correlates of Meeting Physical Activity Guidelines Among Colombian Children and Adolescents.

BACKGROUND: Global estimates have shown that a small proportion of children and adolescents are physically active. However, the evidence on physical activity (PA) among Colombian children and adolescents is limited. The objective of this study was to describe the prevalence and correlates of meeting PA guidelines among Colombian children and adolescents. METHODS: Data were collected as part of the National Survey of Nutrition 2015. A national sample of 16,612 children and adolescents (3-17 y) was included. Prevalence estimates of meeting PA and active play guidelines were calculated, and Poisson regression models were conducted to identify correlates of PA. RESULTS: Low proportion of Colombian children and adolescents met the PA guidelines. Low engagement in active play was observed among preschoolers. Correlates varied by age group. Female sex was a consistent negative correlate of meeting PA guidelines across all age groups. CONCLUSIONS: Urgent actions are needed to promote active play and PA among Colombian children and adolescents. The correlates identified in our study can help inform the development of actions to overcome the disparities and provide opportunities for children to achieve their full potential for healthy growth and development.

The Use of Thoracic Ultrasound to Predict Transudative and Exudative Pleural Effusion.

Objectives: Pleural effusion is a common reason for hospital admission with thoracentesis often required to diagnose an underlying cause. This study aimed to determine if the imaging characteristics of TUS effectively differentiates between transudative and exudative pleural fluid. Methods: Patients undergoing TUS with pleural fluid analysis were retrospectively identified at a single center between July 2016 and March 2018. TUS images were interpreted and characterized by established criteria. We determined diagnostic performance characteristics of image criteria to distinguish transudative from exudative pleural effusions. Results: 166 patients underwent thoracentesis for fluid analysis of which 48% had a known malignancy. 74% of the pleural effusions were characterized as exudative by Light's Criteria. TUS demonstrated anechoic effusions in 118 (71%) of samples. The presences of septations on TUS was highly specific in for exudative effusions (95.2%) with high positive predictive values (89.5%) and likelihood ratio (2.85). No TUS characteristics, even when adjusting for patient characteristics such as heart failure or malignancy, were sensitive for exudative effusions. Conclusions: Among our cohort, anechoic images did not allow reliable differentiation between transudative and exudative fluid. Presence of complex septated or complex homogenous appearance was high specific and predictive of exudative fluid.

A multilevel analysis of gross motor coordination of children and adolescents living at different altitudes: the Peruvian Health and Optimist Growth Study.

BACKGROUND: Gross motor coordination (GMC) is a potential correlate of lifestyle behaviours and health outcomes in childhood and adolescence. AIMS: The aim of this study was to examine how sex, age, biological maturation, overweight, stunting, and physical fitness are associated with GMC in children and adolescents from Peru, and to examine associations between geographical area of residence, school-level characteristics, and GMC. SUBJECTS AND METHODS: The sample included 7408 subjects, aged 6-14 years, from sea level, Amazon and high-altitude regions of Peru. A composite marker of total coordination was derived by the sum of scores from each test (GMCT). Overweight was identified using BMI, and biological maturation, physical fitness, and stunting were assessed. School characteristics were obtained via an objective audit. RESULTS: Boys (ß = 12.23 ± 0.90) and older children (ß = 13.37 ± 0.64) had higher GMCT than girls and younger children, respectively. Overweight was associated with lower GMCT (ß = -5.23 ± 0.80), whereas fitness was positively associated with GMCT (ß = 6.30 ± 0.25). Biological maturation was not a predictor; however, stunting was negatively associated with GMCT (ß = -3.71 ± 1.56). Subjects living in the Amazon had higher GMCT than those at sea level (ß = 16.57 ± 4.73). Five of nine school-level predictors (number of students, playground area with obstacles, multi-sports roofed, frequency and duration of Physical Education classes) were significant predictors of GMCT. CONCLUSIONS: Child- and school-level variables were significantly associated with GMCT in this sample. These findings are important for the Peruvian community, especially school principals, councils and physical education teachers, helping them to define more efficient strategies and action plans to increase motor coordination in children.

Patterns of physical performance spurts during adolescence: a cross-cultural study of Canadian, Brazilian and Portuguese boys.

BACKGROUND: Data relating physical performance to the timing of the adolescent growth spurt are limited. Aim: This study identifies: (i) age-at-peak height velocity (APHV), (ii) physical performance spurt patterns aligned to APHV; and (iii) cross-cultural and time patterns in Canadian, Brazilian and Portuguese boys. Subjects and methods: A total of 512 boys (131 Canadian, 250 Portuguese and 131 Brazilian), 8-17 years of age were followed serially using longitudinal data. APHV was identified and five physical performance measures velocities [trunk extension (TE), trunk flexion (TF), standing long jump (SLJ), curl-ups (CU) and handgrip strength (HG)] were aligned at 6-month intervals, 4 years around the attainment of PHV. Velocities were estimated using a non-smooth mathematical procedure. Results: APHV was 13.9 ± 1.0, 13.4 ± 1.6 and 13.0 ± 0.8 years for Canadian, Brazilian and Portuguese boys, respectively. Maximal velocity in SLJ was attained between 12 and 6 months prior to PHV. For HG, peaks were attained 12-24 months after PHV. Maximal velocity in TE occurred between 12 and 0 months prior to PHV, while CU peaked between PHV and 6 months after PHV. Conclusion: Patterns of spurts in physical performance have remained relatively the same and do not appear to be influenced by cross-cultural differences.

Effect of Pruning Young Branches on Fruit and Seed Set in Cassava.

Flowering in cassava is closely linked with branching. Early-flowering genotypes branch low and abundantly. Although farmers prefer late flowering genotypes because of their erect plant architecture, their usefulness as progenitors in breeding is limited by their low seed production. In general, the first inflorescence aborts in cassava. Preventing this abortion would result in early production of seeds and make cassava breeding more efficient. The objective of this study was to assess if pruning young branches prevents the abortion of first inflorescences and promotes early fruit and seed set. Four genotypes with early, late, very late, and no flowering habits were grown under an extended photoperiod (EP) or normal dark night conditions (DN). Additional treatments included pruning young branches at the first or second flowering event and spraying (or not) benzyladenine (BA) after pruning. One genotype failed to flower and was not considered further. For the remaining genotypes, EP proved crucial to induce an earlier flowering, which is a pre-requisite for pruning. Total production of seeds in EP plots was 2,971 versus 150 in DN plots. For plants grown under EP, the average number of seeds per plant without pruning was 3.88, whereas those pruned produced 17.60 seeds per plant. Pruning at the first branching event led to higher number of seeds per plant (26.25) than pruning at the second flowering event (8.95). In general, applying BA was beneficial (38.52 and 13.98 seeds/plant with or without spraying it, respectively). The best combination of treatments was different for each genotype. Pruning young branches and applying BA in the first flowering event not only prevented the abortion of inflorescences but also induced the feminization of male flowers into hermaphrodite or female-only flowers. The procedures suggested from this study (combining EP, pruning young branches, and spraying BA), allowed the production of a high number of seeds from erect cassava genotypes in a short period. The implementation of these procedures will improve the breeding efficiency in cassava.