Effects of Different Teaching Approaches on Proxy Measures of Physical Fitness of Italian Kindergarten Children.

Developing physical fitness (PF) behaviors early in life enhances physical development and facilitates sustained participation in physical activity and sports across childhood. This study addressed the effect of different teaching approaches on precursors of PF in kindergarten children. A total of 178 children (5.45 ± 0.40 years, female = 92) from 11 classes were organized into three groups. Group 1 (structured activity + free play) and Group 2 (only free play) attended the same playground (PrimoSport0246) for one hour/week for 10 weeks. Group 3 (structured activity + free play in kindergarten) followed their standard physical education curriculum at school. PF tests (standing long jump, medicine ball throw, and 20 m running speed) were administered pre- and post-intervention. Factorial ANOVA was implemented using a percentage change in PF performance (PFC) as the dependent variable, and teaching approaches, gender, and age as factors. Group 1 demonstrated significant improvements in fitness performance compared with Groups 2 and 3. Moderate to large effect sizes (Cohen's d range: 0.68-1.40) were noted in both males and females. Six-year-old demonstrated the greatest improvement in composite PFC compared to Groups 2 and 3. A structured teaching plan, even with a limited dose of once per week, supported the development of PF attributes in kindergarteners.

Effects of Free Play and Partly Structured Playground Activity on Motor Competence in Preschool Children: A Pragmatic Comparison Trial.

Both the indoor and the outdoor environments and their organization exert pronounced influence upon physical activity behavior and motor development of preschool children. The aim of this study was to explore whether partly structured activity or free play in a specific playground had different impacts on motor competence development in 4-6-year-old preschoolers. The study had a pretest-post-test design, with two intervention groups and one control. Sixty-two children were included in a partly structured activity group and forty-three children in a free-play group. Both groups participated in playground activities consisting of 10 sessions (once a week), each lasting 1 h, in a specific playground setting. For the partly structured activity group, activities in each session consisted of a combination of both structured and free activity while the free-play group were engaged in unstructured play only. The control group did not attend the playground activities (N = 36). To assess levels of motor skills, each child completed pre- and post-tests using the Movement Assessment Battery for children (MABC-2), the Test of Motor Competence (TMC) and two playground-specific tests. A 3 (study group) and X 2 (gender) ANCOVAs were conducted on post-test scores on each of the test items from TMC, MABC-II and playground tests, with pre-test scores as covariates. Post hoc pairwise multiple comparisons were conducted with the alpha Bonferroni corrected, and the partial eta-squared (η2p) was applied as a measure of effect size. The results indicate no significant differences in motor competence measured by the TMC or the MABC-2 between groups. On the contrary, a significant improvement in performance in the playground-specific tests was observed in the partly structured activity group compared to the free-play and control groups.

Comparing Free Play and Partly Structured Play in 4-5-Years-Old Children in an Outdoor Playground.

The aim of this study was to compare how the organization of a movement session as partly structured play or free play influenced the physical activity engagement in 4-5 years old pre-schoolers. The partly structured playgroup consisted of 46 children and the free playgroup consisted of 33 children. The playground activities consisted of 10 sessions each lasting 1 h, executed once per week in the period Mars to May 2017 at a specific playground setting. The partly structured playgroup conducted a movement activity session that included a combination of both structured- and free play activities. The free playgroup engaged in unstructured play, only. To detect the intensity of the physical activity each child carried an accelerometer 1 h the first week and last week of the intervention. Results indicate a significant difference in physical activity level between the two groups for the 5-year-old in the favor of the partly structured playgroup. There was a significant difference between the four-and 5-year-old in relation to physical activity level. No significant difference between the activity in March and May for the whole group was found.

Expression of small-conductance calcium-activated potassium channels (SK3) in skeletal muscle: regulation by muscle activity.

The type 3 small conductance calcium-activated potassium channel (SK3) is expressed in embryonic and adult denervated skeletal muscles where it contributes to hyperexcitability. This study aimed at determining the role of muscle activity in regulating SK3 channels. Soleus muscles of adult rats were denervated by cutting the sciatic nerve. In reinnervation studies, the soleus nerve was crushed: in one group, muscles were reinnervated with electrically silent axons, by chronic sciatic nerve perfusion with tetrodotoxin. Several groups of denervated muscles were subjected to chronic direct electrical stimulation, using either fast (100 Hz) or slower patterns (20 or 30 Hz). The SK3 mRNA and protein levels in soleus muscle were determined by reverse transcriptional-PCR, Western blot and immunofluorescence. Both denervated and reinnervated-paralysed soleus muscles displayed similar up-regulation of SK3 mRNA and protein. Reinnervation with electrically active axons instead inhibited SK3 up-regulation. Chronic muscle direct stimulation in vivo, irrespective of the pattern used, reversed the denervation-induced up-regulation of SK3 expression or prevented it when initiated at the time of denervation. Chronic electrical stimulation of denervated muscles also completely prevented the development of the after-hyperpolarization (AHP) following the action potential, normally induced in the muscle fibres by denervation. We conclude that action potential activity evoked by motor neurones in muscle fibres is both necessary and sufficient to account for the physiological down-regulation of SK3 channels in the non-junctional membrane of skeletal muscle.

Sub-chronic nicotine-induced changes in regional cerebral blood volume and transversal relaxation time patterns in the rat: a magnetic resonance study.

This preliminary study describes magnetic resonance imaging (MRI) data on the effects of sub-chronic nicotine administration in rats. Nicotine 0.4 mg/kg s.c. free base was given once a day for 4 days to Wistar adult male rats. On day 5, anaesthetized subjects were observed using an MRI tomography system. Regional cerebral blood volume (rCBV) and transversal relaxation time (T2) MRI parameters were measured. Nicotine treatment increased T2 values, with a significant effect in the cingulate cortex. A trend to increase was also observed in the prefrontal cortex and nucleus accumbens. Similarly, the effect of nicotine on rCBV was a significant increase in values compared to saline treatment. Post hoc analysis showed a significant effect of nicotine in the prefrontal cortex, cingulate cortex, mediodorsal thalamus and lateral posterior thalamus. This study showed for the first time that sub-chronic nicotine administration can induce changes in MRI pattern which are (i) similar to human MRI studies, and (ii) common to those described for markers of neuronal metabolic activation in corticolimbic brain regions known to be involved in nicotine dependence.