Factors associated with achieving physical activity guideline in Japanese adolescents / 体力科学

Understanding factors associated with physical activity (PA) is important to promote PA. The purpose of the present study was to investigate factors associated with achieving PA guideline in 293 Japanese adolescents (140 boys and 153 girls). Time spent in moderate to vigorous PA (MVPA) was accessed by using accelerometers. Based on MVPA, the participants were classified as “Active” (≥60 min/day of MVPA) or “Inactive” (<60 min/day of MVPA). Anthropometry, age, screen time, mental health, participation in after-school sport activities, sleep status, and breakfast status were measured as factors potentially associated with achieving PA guideline. Adjusted logistic regression analyses revealed that after-school sports activities were positively associated with the probability of being Active for both sexes (odds ratios [ORs] [95% confidence intervals (CI)] = 3.90 [1.13-13.49] for boys, 4.80 [1.80-12.81] for girls). In addition, body fat was negatively associated with a reduced likelihood of being Active for girls (ORs [95%CI] = 0.93 [0.87-0.97]). Two factor ANOVA revealed that those in Inactive group had significantly lower PA levels than those in Active group on both regular curriculum and extra-curriculum (F _{(1, 138)} = 152.50 for boys, F _{(1, 151)} = 181.95 for girls, p < 0.001). In addition, for girls, there was a significant interaction effect between domain (regular curriculum vs. extra-curriculum) and after-school sport activities (F _{(1, 151)} = 4.91, p = 0.028), suggesting that obtaining higher PA levels on extra-curriculum might be difficult for those who do not belong to any after-school sport activities. Therefore, promoting PA on regular curriculum (i.e., physical education lessons and recess) might be alternative ways to increase PA levels for those individuals. Furthermore, special attention may be needed for girls who have higher body fat to promote PA.

Physical Activity monitors: Limitations to measure physical activity in the free-living environment / Monitores de Actividad Física: limitaciones para medir la actividad física en la vida cotidiana

Teniendo en cuenta las limitaciones de los métodos de auto informe para medir patrones de actividad física con precisióny la forma poco práctica de la observación directa, a través de los años investigadores han desarrollado medidas objetivas que son válidasy confiables para estimar la actividad física. Acelerómetros y podómetros proporcionan estimaciones precisas de la actividad física en ambientes controlados y en la vida cotidiana. Sin embargo, estos dispositivos tienen limitaciones que deben ser consideradas antes de su uso. Acelerómetros proporcionan una gran cantidad de información (por ejemplo, actividad, intensidad, las estimaciones de gasto de energía), sin embargo, son caros y requieren un gran conocimiento y habilidad técnica para ser utilizados con éxito. Podómetros requieren menos habilidad técnica y son menos costosos, pero la mayoría se limitan al número de pasos dados por un individuo.

Considering the limitations of self-report methods to accurately measure physical activity patters, and how impractical direct observation is, researchers have developed objective measures to estimate physical activity that are valid and reliable. Accelerometers and pedometers provide accurate estimates of physical activity in controlled and free-living environments. However, these devices have limitations that must be considered prior to their use. Accelerometers provide the most information (e.g. activity, intensity, energy expenditure estimates); however, they are expensive and require significant technical knowledge and skill for successful use. Pedometers require less technical skill and are less expensive, but their output data is limited to the number of steps taken by an individual.

Associações entre actividade física, habilidades e coordenação motora em crianças portuguesas / Association between physical activity and motor skills and coordination in Portuguese children

Actualmente, existe na literatura a evidência unânime, que a prática actividade física (AF) regular é benéfica para a saúde. A variação na AF nas crianças é resultado de vários factores, nos quais se incluem as habilidades motoras fundamentais (HMF) e a coordenação motora (CM).Analisar a relação entre a AF habitual e as HMF, e a CM em crianças de ambos os sexos com idades de 6 e 7 anos. A amostra foi constituída por 21 crianças com uma idade média de 6,38±0,50. A actividade física habitual foi avaliada por acelerometria, as habilidades motoras fundamentais usando o Test of Gross Motor Development (TGMD-2) e a coordenação motora através do Körperkoordination Test für Kinder (KTK). As crianças deste estudo cumprem as recomendações internacionais de AF regular. No KTK, a maioria das crianças (52,4%) apresentou perturbações da CM e insuficiências coordenativas,47,6% valores correspondentes a uma CM normal, nenhum sujeito apresentou uma CM boa ou muito boa; no TGMD-2, para a avaliação locomotora, 76,2% das crianças situam-se acima do percentil 50 (P50), na avaliação do controlo de objectos, 28,6% atingem o P50 ou superior, e para o score total do teste, 38,1% alcançam o P50 ou superior. A AFhabitual correlacionou-se positivamente com o TGMD-2 controlo de objectos. Estas crianças apresentaram resultados baixos, indiciadores de possíveis insuficiências do desenvolvimento coordenativo e de pobre desenvolvimento das HMF, pelo que se considera que deviam seralvo de uma especial intervenção, nomeadamente na área da Educação Física.

Nowadays, there is growing evidence in literature that Health benefits from regular physical activity (PA). The variance in PA among children is caused by a number of factors including their motor abilities and coordination. The aim of the study was to analyse the relation between usual PA and gross motor abilities and motor coordination in children aged 6 to 7 years. The sample comprised 21 children, aged in average 6,38±0,50 years. Physical activity was accessed by accelerometry, gross motor abilities by using the Test of Gross Motor Development (TGMD-2) and motor coordination by using the Körperkoordination Test für Kinder (KTK). Subjects met the international recommendations for daily PA; in motor coordination 47,6% of children met normal coordination, nobody reach good or very good coordination, the majority (52,4%) revelled disturbances or insufficiencies of coordination; in locomotion TGMD-2 76,2% of the children met percentile 50 or superior (P50), in objectcontrol TGMD-2 28,6% of the children reach P50 or superior, in total TGMD-2 38,1% of the children met P50 or superior. PA was positively correlated with TGMD-2 object control. Low performance attributed to the children in TGMD-2 and KTK tests could be an indicative of insufficient in the development of coordination and gross motor abilities; therefore we believe that this kind of intervention should be targeted at school children mainly in Physical Education classes.

Accelerometers for Measuring Physical Activity Behavior in Indian Children.

Objective: To examine the validity of accelerometers for characterizing habitual physical activity patterns in Indian children. Design: Cohort study. Setting: Holdsworth Memorial Hospital, Mysore. Subjects: Children (N=103, mean age 6.6 years) selected from an ongoing birth cohort study. Methods: Physical activity was measured over 7 days using accelerometers (MTI Actigraph) and concurrent parent-maintained activity diaries. Actigraph counts per minute representing sedentary (<10), light (<400), moderate (<3000) and vigorous (≥3000) activity were determined using a structured activity session in a separate group of 10 children. In 46 children chosen for validating accelerometers, time spent in different activity levels according to diaries was determined. Energy Expenditure (EE) was calculated from diaries using a factorial method. Results: Ninety-eight children wore the monitor for ≥4 days. Total counts and time spent in different activity levels were similar in boys and girls (P>0.2). Among 46 children chosen for comparisons, time spent in sedentary (r =0.48, P=0.001), light (r=0.70, P<0.001) and moderate activities (r=0.29, P=0.054) according to diaries correlated with those derived from counts, and total Actigraph counts correlated with EE (r=0.42, P=0.004). Bland-Altman analysis showed systematic bias, and wide limits of agreement between these methods for time spent in different activity levels. Conclusions: Accelerometers are a well tolerated and objective way of measuring activity behavior in free-living children. Though accelerometer counts correlate with time spent in activity of varying intensity and energy expenditure derived from parent-maintained diaries, wide limits of agreement show that the limitations of accelerometers need to be recognized in interpreting the data that they generate.

Synergistic control of forearm based on accelerometer data and artificial neural networks

In the present study, we modeled a reaching task as a two-link mechanism. The upper arm and forearm motion trajectories during vertical arm movements were estimated from the measured angular accelerations with dual-axis accelerometers. A data set of reaching synergies from able-bodied individuals was used to train a radial basis function artificial neural network with upper arm/forearm tangential angular accelerations. The trained radial basis function artificial neural network for the specific movements predicted forearm motion from new upper arm trajectories with high correlation (mean, 0.9149-0.941). For all other movements, prediction was low (range, 0.0316-0.8302). Results suggest that the proposed algorithm is successful in generalization over similar motions and subjects. Such networks may be used as a high-level controller that could predict forearm kinematics from voluntary movements of the upper arm. This methodology is suitable for restoring the upper limb functions of individuals with motor disabilities of the forearm, but not of the upper arm. The developed control paradigm is applicable to upper-limb orthotic systems employing functional electrical stimulation. The proposed approach is of great significance particularly for humans with spinal cord injuries in a free-living environment. The implication of a measurement system with dual-axis accelerometers, developed for this study, is further seen in the evaluation of movement during the course of rehabilitation. For this purpose, training-related changes in synergies apparent from movement kinematics during rehabilitation would characterize the extent and the course of recovery. As such, a simple system using this methodology is of particular importance for stroke patients. The results underlie the important issue of upper-limb coordination.