Muscle contraction acutely increases glucose transport in both healthy and type 2 diabetic individuals. Since glucose uptake during muscle contraction has been observed in the absence of insulin, the existence of an insulin-independent pathway has been suggested to explain this phenomenon. However, the exact mechanism behind the translocation of GLUT4 vesicles through the sarcolemma during muscle contraction is still unknown. Some substances, such as AMPK and calcium activated proteins, have been suggested as potential mediators but the exact mechanisms of their involvement remain to be elucidated. A hypothetical convergence point between the insulin cascade and the potential pathways triggered by muscle contraction has been suggested. Therefore, the earliest concept that two different routes exist in skeletal muscle has been progressively modified to the notion that glucose uptake is induced by muscle contraction via components of the insulin pathway. With further consideration, increased glucose uptake and enhanced insulin sensitivity observed during/after exercise might be explained by a metabolic- and calcium-dependent activation of several intermediate molecules of the insulin cascade. This paper aimed to review the literature in order to examine in detail these concepts behind muscle contraction-induced glucose uptake.

The objective of the present study was to evaluate and compare the neuromuscular, morphological and functional adaptations of older women subjected to 3 different types of strength training. 58, healthy women (67±5 year) were randomized to experimental (EG, n=41) and control groups (CG, n=17) during the first 6 weeks when the EG group performed traditional resistance exercise for the lower extremity. Afterwards, EG was divided into three specific strength training groups; a traditional group (TG, n=14), a power group (PG, n=13) that performed the concentric phase of contraction at high speed and a rapid strength group (RG, n=14) that performed a lateral box jump exercise emphasizing the stretch-shortening-cycle (SSC). Subjects trained 2 days per week through the entire 12 weeks. Following 6 weeks of generalized strength training, significant improvements occurred in EG for knee extension one-repetition (1RM) maximum strength (+19%), knee extensor muscle thickness (MT, +15%), maximal muscle activation (+44% average) and onset latency ( − 31% average) for vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) compared to CG (p<0.05). Following 6 more weeks of specific strength training, the 1RM increased significantly and similarly between groups (average of +21%), as did muscle thickness of the VL (+25%), and activation of VL (+44%) and VM (+26%). The onset latency of RF (TG=285±109 ms, PG=252±76 ms, RG=203±43 ms), reaction time (TG=366±99 ms, PG=274±76 ms, RG=201±41 ms), 30-s chair stand (TG=18±3, PG=18±1, RG=21±2) and counter movement jump (TG=8±2 cm, PG=10±3 cm, RG=13±2 cm) was significantly improved only in RG (p<0.05). At the end of training, the rate of force development (RFD) over 150 ms (TG=2.3±9.8 N·s^− 1, PG=3.3±3.2 N·s^− 1, RG=3.8±6.8 N·s^− 1, CG=2.3±7.0 N·s^− 1) was significantly greater in RG and PG than in TG and CG (p<0.05). In conclusion, rapid strength training is more effective for the development of rapid force production of muscle than other specific types of strength training and by consequence, better develops the functional capabilities of older women.

To describe and analyze the trends of occurrence of underweight, overweight, and obesity in schoolchildren. This was a longitudinal study of trends conducted in a voluntary sample of Brazilian children and adolescents. The sample was grouped by year of collection (period I: 2005 and 2006; period II: 2007 and 2008, and period III: 2009-2011), age category (children: 7 to 10 years, and adolescents: 11 to 14 years), and stratified by gender. The body mass index was used to classify the nutritional profile. Trend analysis was verified using multinomial logistic regression (p<0.05). Mean occurrences were 2.11% for underweight, 22.27% for overweight, and 6.8% for obesity. There was a decrease of underweight in male adolescents from period I to II, as well as an increase in female children from period II to III. Regarding overweight, there was an increase followed by a decrease in male children. Regarding obesity, there was an increase from period I to II in all age groups and for both genders. The prevalence of underweight was less than 5% in all categories of age and gender. However, the categories of overweight and obesity showed higher values, and together comprised almost 30% of the young Brazilian population; moreover, a trend toward increase in prevalence of obesity was observed up to the year 2008, followed by the maintenance of these high prevalence rates.

Surveillance of health-related physical fitness can improve decision-making and intervention strategies promoting health for children and adolescents. However, no study has comprehensively analyzed surveillance/monitoring systems for physical fitness globally. This review sought to address this gap by identifying: (1) national-level surveillance/monitoring systems for physical fitness among children and adolescents globally, (2) the main barriers and challenges to implementing surveillance/monitoring systems, and (3) governmental actions related to existing surveillance/monitoring systems. We used a scoping review to search, obtain, group, summarize, and analyze available evidence. Our review involved three stages: (1) identification of surveillance systems through a systematic literature review, with complementary search of the grey literature (e.g., reference lists, Google Scholar, webpages, recommendations), (2) systematic consultation with relevant experts using a Delphi method to confirm/add systems and to gather and analyze information on the barriers and challenges to implementing systems, and (3) Web searches for public documents on government sites and surveillance/monitoring system pages, and direct internet searches to identify relevant governmental actions related to surveillance systems. A total of 15 fitness surveillance/monitoring systems met our inclusion criteria. Experts identified a lack of government support and funding, and the low priority of fitness on the public health agenda as the main barriers/challenges to implementation. Several governmental actions related to surveillance systems were identified, including policies, strategies, programs, and guidelines. We propose a Global Observatory of Physical Fitness to help address these issues.