Effects of aging on Type II muscle fibers: a systematic review of the literature

The authors conducted a systematic review of the literature for scientific articles in selected databases to determine the effects of aging on Type II muscle fibers in human skeletal muscles. They found that aging of Type II muscle fibers is primarily associated with a loss of fibers and a decrease in fiber size. Morphological changes with increasing age particularly included Type II fiber grouping. There is conflicting evidence regarding the change of proportion of Type II fibers. Type II muscle fibers seem to play an important role in the aging process of human skeletal muscles. According to this literature review, loss of fibers, decrease in size, and fiber-type grouping represent major quantitative changes. Because the process of aging involves various complex phenomena such as fiber-type coexpression, however, it seems difficult to assign those changes solely to a specific fiber type.     

Burnout and Mental Health in Swiss Vocational Students: The Moderating Role of Physical Activity

Few studies have focused on burnout among vocational students. This study examined the association between burnout and mental health among 56 Swiss vocational students (29 males, 27 females, M = 18.1, SD = 1.2 years) and tested whether recommended levels of moderate‐to‐vigorous physical activity (MVPA) attenuate this relationship. Burnout was strongly associated with increased depressive symptoms and decreased levels of life satisfaction, mental toughness, and quality of sleep. Students above recommended levels of MVPA reported lower burnout and higher mental health. No significant moderator effects were observed. Symptoms of burnout were associated with increased mental health problems. Physical activity should be promoted to prevent burnout, because nearly half of the students did not meet MVPA recommendations.     

Fast Equilibrium Selection by Rational Players Living in a Changing World

We study a coordination game with randomly changing payoffs and small frictions in changing actions. Using only backwards induction, we find that players must coordinate on the risk‐dominant equilibrium. More precisely, a continuum of fully rational players are randomly matched to play a symmetric 2×2 game. The payoff matrix changes according to a random walk. Players observe these payoffs and the population distribution of actions as they evolve. The game has frictions: opportunities to change strategies arrive from independent random processes, so that the players are locked into their actions for some time. As the frictions disappear, each player ignores what the others are doing and switches at her first opportunity to the risk‐dominant action. History dependence emerges in some cases when frictions remain positive.