Recess Behaviors of Urban Children 16 Months After a Green Schoolyard Renovation.

BACKGROUND: Green schoolyard renovations lead to immediate positive changes in moderate to vigorous physical activity (MVPA) and social behavior. This pilot study examines whether these benefits are equally distributed across gender and age and maintained 16 months postgreening. METHODS: Physical activity and social interactions during recess were recorded at control (n = 389) and experimental (n = 642) Title I urban elementary schools with direct observation and accelerometers. RESULTS: Activity profiles were similar to 4-month postgreening and to baseline for experimental girls and boys, respectively. There was no difference in MVPA minutes between sexes (girls = 11.8; 95% confidence interval [CI], 11.1 to 12.5]; boys = 12.8; 95% CI, 12.0 to 13.4) and no difference in sitting minutes between age groups (first to fourth = 2.0; 95% CI, 1.5 to 2.6; fifth to sixth = 1.8; 95% CI, 1.1 to 2.4) in green areas. Experimental students spent more time in MVPA (11.2 min; 95% CI, 10.6 to 11.8 vs 8.9 min; 95% CI, 8.3 to 9.3), in small groups (10.6 min; 95% CI, 10.2 to 11.0 vs 9.2 min; 95% CI, 8.5 to 9.9), and engaged in more prosocial interactions (5.5; 95% CI, 5.1 to 6.3 vs 3.7; 95% CI, 3.0 to 4.2) than control students. CONCLUSIONS: Green schoolyard renovations result in persistent changes to recess behavior that are characteristic of a more collaborative community and counteract age-related declines in MVPA, particularly for girls.

Physical Activity and Social Behaviors of Urban Children in Green Playgrounds.

INTRODUCTION: Nature exposure is associated with many wellbeing benefits. However, the influence of green space on the physical activity and social behaviors of children is not completely understood. The purpose of the study was to complete a stepwise impact evaluation of a large-scale playground greening project at a Title 1 elementary school in Los Angeles, California. METHODS: Physical activity and social interaction data were collected with direct observation and accelerometers pre-, immediately post-, and 4 months post-greening at control (students enrolled=393) and experimental (students enrolled=538) locations from 2016 to 2017. Effects of relevant variables on recess behavior were analyzed with linear mixed models in 2018. RESULTS: Zone popularity and recess behaviors did not change for control students during the study (p>0.05). Areas replaced by green space became the most popular for experimental students who transitioned from traditional playground games/sports to tag/chasing, gymnastics, climbing/jumping, and creative play. The percentage of students observed as sedentary decreased by 10.0% (95% CI=4.9%, 15.0%) at 4 months, p=0.003. Vigorous activity participation increased pre to post at the individual (48.5%, 95% CI=29.1%, 67.9%, p<0.001) and population level (41.2%, 95% CI=27.3%, 55.1%, p=0.003) and remained higher than pre-greening at 4 months (p<0.05) for girls in the experimental group only. The moderate to vigorous physical activity differential between green space and hardscape was greater for fifth graders than all other grades, p=0.002. Student physical and verbal conflict rates decreased below pre-greening rates after 4 months for the experimental group, p<0.001. CONCLUSIONS: Results suggest that adding green space to asphalt-covered schoolyards helps expose children to nature, increases daily activity levels, and promotes social wellbeing in sex- and age-dependent ways.

Dose- and time-dependent benefits of iPad technology in an undergraduate human anatomy course.

This study examined the impact of iPad integration on performance in an undergraduate gross anatomy course. Two out of six course sections were assigned to one of the following conditions: control (no iPad, n = 61); limited access (laboratory iPads, n = 58); and unlimited access (personal iPads, n = 47). Student knowledge was assessed over time during the semester with two practical examinations in laboratory and four multiple choice/essay examinations in lecture. The same PowerPoint presentations and examinations were utilized for all conditions. Mixed ANOVA analysis identified an interaction effect between time and condition for both laboratory (F2,153  = 16.12; P < 0.05) and lecture (F6,462  = 5.47; P < 0.05) performance. Between laboratory examinations, student performance was lower by 4.2% and higher by 3.0% in control and unlimited access conditions, respectively. Unlimited access students scored higher than control and limited access (82.8 ± 2.2 vs 71.5 ± 2.6 and 74.3 ± 1.7%; P < 0.05) and higher than control students (78.7 ± 2.1 vs 70.6 ± 2.0%; P < 0.05) on the third and fourth lecture examination, respectively. Postsemester surveys completed by experimental students (89.5% response rate) indicated that a greater percentage of unlimited vs limited access students agreed that laboratory (84.8 vs 56.3%, P < 0.05) and lecture (58.7 vs 14.6%, P < 0.05) performance was enhanced with the iPad. Results suggest that if students are given the opportunity to overcome the technology learning curve, tablet devices and relevant applications can be useful tools in human anatomy courses. Anat Sci Educ 9: 367-377. © 2015 American Association of Anatomists.

Evidence for the involvement of CaMKII and AMPK in Ca2+-dependent signaling pathways regulating FA uptake and oxidation in contracting rodent muscle.

Calcium-calmodulin/dependent protein kinase II (CaMKII), AMP-activated protein kinase (AMPK), and extracellular signal-regulated kinase (ERK1/2) have each been implicated in the regulation of substrate metabolism during exercise. The purpose of this study was to determine whether CaMKII is involved in the regulation of FA uptake and oxidation and, if it is involved, whether it does so independently of AMPK and ERK1/2. Rat hindquarters were perfused at rest with (n = 16) or without (n = 10) 3 mM caffeine, or during electrical stimulation (n = 14). For each condition, rats were subdivided and treated with 10 muM of either KN92 or KN93, inactive and active CaMKII inhibitors, respectively. Both caffeine treatment and electrical stimulation significantly increased FA uptake and oxidation. KN93 abolished caffeine-induced FA uptake, decreased contraction-induced FA uptake by 33%, and abolished both caffeine- and contraction-induced FA oxidation (P < 0.05). Caffeine had no effect on ERK1/2 phosphorylation (P > 0.05) and increased alpha(2)-AMPK activity by 68% (P < 0.05). Electrical stimulation increased ERK1/2 phosphorylation and alpha(2)-AMPK activity by 51% and 3.4-fold, respectively (P < 0.05). KN93 had no effect on caffeine-induced alpha(2)-AMPK activity, ERK1/2 phosphorylation, or contraction-induced ERK1/2 phosphorylation (P > 0.05). Alternatively, it decreased contraction-induced alpha(2)-AMPK activity by 51% (P < 0.05), suggesting that CaMKII lies upstream of AMPK. These results demonstrate that regulation of contraction-induced FA uptake and oxidation occurs in part via Ca(2+)-independent activation of ERK1/2 as well as Ca(2+)-dependent activation of CaMKII and AMPK.

Evidence for the regulation of contraction-induced fatty acid oxidation via extracellular signal-regulated kinase 1/2 activation independent of changes in fatty acid uptake.

Data show that extracellular signal-regulated kinase 1/2 (ERK1/2) may be involved in the regulation of fatty acid (FA) uptake during muscle contraction via stimulation of CD36 translocation to the plasma membrane. The perfused hind limb model was used to determine (1) the importance of ERK1/2 signaling on contraction-induced FA uptake and (2) the effect of ERK1/2-mediated FA uptake on contraction-induced FA oxidation. We perfused rat hind limbs with 8 mmol/L glucose, 550 micromol/L palmitate, and no insulin at rest in the absence of inhibitor and during moderate-intensity electrical stimulation and dose-dependent pharmacologic inhibition of ERK1/2 using increasing concentrations of PD98059 (P1 = none, P2 = 10 micromol/L, P3 = 20 micromol/L, P4 = 50 micromol/L). Increasing PD98059 concentration resulted in a gradual decrease in contraction-induced ERK1/2 phosphorylation, and this was accompanied by a decrease in contraction-induced FA uptake (concentration required for 50% inhibition [IC(50)] = 15.8 +/- 1.6 mumol/L) and in plasma membrane CD36 content (IC(50) = 8.7 +/- 0.3 micromol/L) (P < .05). Percent FA oxidation was significantly lower in P3 and P4 compared with P1 and P2. Based on IC(50) values, FA oxidation demonstrated a greater sensitivity than FA uptake to changes in ERK1/2 phosphorylation (IC(50) = 5.4 +/- 0.3 micromol/L) (P < .05). A positive correlation was found between FA uptake and plasma membrane CD36 content (R(2) = 0.85, P < .05). Plasma membrane CD36 content, FA uptake, and FA oxidation each shared a positive correlation with ERK1/2 phosphorylation (R(2) = 0.64, 0.66, and 0.71, respectively; P < .05). These results suggest that during moderate-intensity muscle contraction, ERK1/2 phosphorylation is required for translocation of CD36 to the plasma membrane and the subsequent increase in FA uptake. In addition, these data suggest that ERK1/2 signaling may be involved in the regulation of FA oxidation independently of its effects on FA uptake.

Regulation of contraction-induced FA uptake and oxidation by AMPK and ERK1/2 is intensity dependent in rodent muscle.

Muscle contraction activates AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK1/2), two signaling molecules involved in the regulation of muscle metabolism. The purpose of this study was to determine whether activation of AMPK and/or ERK1/2 contributes to the regulation of muscle fatty acid (FA) uptake and oxidation in contracting muscle. Rat hindquarters were perfused during rest (R) or electrical stimulation (E) of increasing intensity by manipulating train duration (E1 = 25 ms, E2 = 50 ms, E3 = 100 ms, E4 = 200 ms). For matched FA delivery, FA uptake was significantly greater than R during E1, E2, and E3 (7.8 +/- 0.7 vs. 14.4 +/- 0.3, 16.9 +/- 0.8, 15.2 +/- 0.5 nmol.min(-1).g(-1), respectively, P < 0.05), but not during E4 (8.3 +/- 0.3 nmol.min(-1).g(-1), P > 0.05). FA oxidation was significantly greater than R during E1 and E2 (1.5 +/- 0.1 vs. 2.3 +/- 0.2, 2.5 +/- 0.2 nmol.min(-1).g(-1), P < 0.05) before returning to resting levels for E3 and E4 (1.8 +/- 0.1 and 1.5 +/- 0.2 nmol.min(-1).g(-1), P > 0.05). A positive correlation was found between FA uptake and ERK1/2 phosphorylation from R to E3 (R(2) = 0.55, P < 0.05) and between FA oxidation and ERK1/2 phosphorylation from R to E2 (R(2) = 0.76, P < 0.05), correlations that were not maintained when the data for E4 and E3 and E4, respectively, were included in the analysis (R(2) = 0.04 and R(2) = 0.03, P > 0.05). A positive correlation was also found between FA uptake and FA oxidation and AMPK activity for all exercise intensities (R(2) = 0.57, R(2) = 0.65 respectively, P < 0.05). These results, in combination with previous data from our laboratory, suggest that ERK1/2 and AMPK are the predominant signaling molecules regulating FA uptake and oxidation during low- to moderate-intensity muscle contraction and during moderate- to high-intensity muscle contraction, respectively.

AMPK activation is not critical in the regulation of muscle FA uptake and oxidation during low-intensity muscle contraction.

To determine the role of AMP-activated protein kinase (AMPK) activation on the regulation of fatty acid (FA) uptake and oxidation, we perfused rat hindquarters with 6 mM glucose, 10 microU/ml insulin, 550 microM palmitate, and [14C]palmitate during rest (R) or electrical stimulation (ES), inducing low-intensity (0.1 Hz) muscle contraction either with or without 2 mM 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR). AICAR treatment significantly increased glucose and FA uptake during R (P < 0.05) but had no effect on either variable during ES (P > 0.05). AICAR treatment significantly increased total FA oxidation (P < 0.05) during both R (0.38 +/- 0.11 vs. 0.89 +/- 0.1 nmol x min(-1) x g(-1)) and ES (0.73 +/- 0.11 vs. 2.01 +/- 0.1 nmol x min(-1) x g(-1)), which was paralleled in both conditions by a significant increase and significant decrease in AMPK and acetyl-CoA carboxylase (ACC) activity, respectively (P < 0.05). Low-intensity muscle contraction increased glucose uptake, FA uptake, and total FA oxidation (P < 0.05) despite no change in AMPK (950.5 +/- 35.9 vs. 1,067.7 +/- 58.8 nmol x min(-1) x g(-1)) or ACC (51.2 +/- 6.7 vs. 55.7 +/- 2.0 nmol x min(-1) x g(-1)) activity from R to ES (P > 0.05). When contraction and AICAR treatment were combined, the AICAR-induced increase in AMPK activity (34%) did not account for the synergistic increase in FA oxidation (175%) observed under similar conditions. These results suggest that while AMPK-dependent mechanisms may regulate FA uptake and FA oxidation at rest, AMPK-independent mechanisms predominate during low-intensity muscle contraction.