Physical activity impacts resting skeletal muscle myosin conformation and lowers its ATP consumption.

It has recently been established that myosin, the molecular motor protein, is able to exist in two conformations in relaxed skeletal muscle. These conformations are known as the super-relaxed (SRX) and disordered-relaxed (DRX) states and are finely balanced to optimize ATP consumption and skeletal muscle metabolism. Indeed, SRX myosins are thought to have a 5- to 10-fold reduction in ATP turnover compared with DRX myosins. Here, we investigated whether chronic physical activity in humans would be associated with changes in the proportions of SRX and DRX skeletal myosins. For that, we isolated muscle fibers from young men of various physical activity levels (sedentary, moderately physically active, endurance-trained, and strength-trained athletes) and ran a loaded Mant-ATP chase protocol. We observed that in moderately physically active individuals, the amount of myosin molecules in the SRX state in type II muscle fibers was significantly greater than in age-matched sedentary individuals. In parallel, we did not find any difference in the proportions of SRX and DRX myosins in myofibers between highly endurance- and strength-trained athletes. We did however observe changes in their ATP turnover time. Altogether, these results indicate that physical activity level and training type can influence the resting skeletal muscle myosin dynamics. Our findings also emphasize that environmental stimuli such as exercise have the potential to rewire the molecular metabolism of human skeletal muscle through myosin.

Anthropometry, DXA, and leptin reflect subcutaneous but not visceral abdominal adipose tissue on MRI in 197 healthy adolescents.

BackgroundAbdominal fat distribution is associated with the development of cardio-metabolic disease independently of body mass index (BMI). We assessed anthropometry, serum adipokines, and DXA as markers of abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) using magnetic resonance imaging (MRI).MethodsWe performed a cross-sectional study that included 197 healthy adolescents (114 boys) aged 10-15 years nested within a longitudinal population-based cohort. Clinical examination, blood sampling, DXA, and abdominal MRI were performed. SAT% and VAT% were adjusted to total abdominal volume.ResultsGirls had a higher SAT% than did boys in early and late puberty (16 vs. 13%, P<0.01 and 20 vs. 15%, P=0.001, respectively), whereas VAT% was comparable (7% in both genders, independently of puberty). DXA android fat% (standard deviation score (SDS)), suprailiac skinfold thickness (SDS), leptin, BMI (SDS), waist-to-height ratio (WHtR), and waist circumference (SDS) correlated strongly with SAT% (descending order: r=0.90-0.55, all P<0.001) but weakly with VAT% (r=0.49-0.06). Suprailiac skinfold was the best anthropometric marker of SAT% (girls: R2=48.6%, boys: R2=65%, P<0.001) and VAT% in boys (R2=16.4%, P<0.001). WHtR was the best marker of VAT% in girls (R2=7.6%, P=0.007).ConclusionsHealthy girls have a higher SAT% than do boys, whereas VAT% is comparable, independently of puberty. Anthropometry and circulating leptin are valid markers of SAT%, but not of VAT%.

[Changes in self-referent emotions during inpatient psychotherapy: the role of mindfulness and acceptance]. / Veranderung von selbst-bezogenen Emotionen im therapeutischen Prozess: Die Rolle von Achtsamkeit und Akzeptanz.

OBJECTIVES: Current theoretical and clinical approaches conceive the avoidance and acceptance of emotions as critical factors in the maintenance and alleviation of psychological problems. This study investigates the role of mindfulness, experiential avoidance (EA), and positive and negative meta-emotions (emotional reactions towards the emotional self) on the symptoms and psychological well-being of inpatients. METHOD: Changes of mindfulness measured during a 6-week stay at a psychosomatic clinic were explored in a sample of 293 inpatients with diverse psychological problems. Multivariate analyses were performed to determine the predictive power of mindfulness and acceptance on symptoms and psychological well-being. RESULTS: Staying on an inpatient ward was associated with reductions in EA and negative meta-emotions as well as improvements in mindful awareness and positive meta-emotions, i.e., participants reported greater acceptance of their own emotional reactions. These aspects were associated with a reduction in symptom severity and greater psychological well-being. A differentiation of meta-emotions allowed the meaningful identification of possible processes of change. CONCLUSIONS: Anger and contempt seem to have distinctive functions in self-regulation. Reducing the amount of contempt/shame for one's own emotions and generating greater interest were associated with symptom reduction and greater psychological well-being. Self-compassion was negatively associated with symptoms, though it had no association with psychological well-being. The theoretical implications are discussed.