Selectively breeding for high voluntary physical activity in female mice does not bestow inherent characteristics that resemble eccentric remodeling of the heart,but the mini-muscle phenotype does

Physical activity engagement results in a variety of positive health outcomes,including a reduction in cardiovascular disease risk partially due to eccentric remodeling of the heart.The purpose of this investigation was to determine if four replicate lines of High Runner mice that have been selectively bred for voluntary exercise on wheels have a cardiac phenotype that resembles the outcome of eccentric remodeling.Adult females(average age 55 days)from the 4 High Runner and 4 non-selected control lines were anaesthetized via vaporized isoflurane,then echocardiographic images were collected and analyzed for structural and functional differences.High Runner mice in general had lower ejection fractions compared to control mice lines(2-tailed p=0.0236)and tended to have thicker walls of the anterior portion of the left ventricle(p=0.065).However,a subset of the High Runner individuals,termed mini-muscle mice,had greater ejection fraction(p=0.0006),fractional shortening percentage(p<0.0001),and ventricular mass at dissection(p<0.0027 with body mass as a covariate)compared to non-mini muscle mice.Mice from replicate lines bred for high voluntary exercise did not all have inherent positive cardiac functional or structural characteristics,although a genetically unique subset of mini-muscle individuals did have greater functional cardiac characteristics,which in conjunction with their previously described peripheral aerobic enhancements(e.g.,increased capillarity)would partially account for their increased VO2max.

Quantifying Neuromuscular Electrical Stimulation Dosage after Knee Arthroplasty

Recovering functional ability after total knee arthroplasty （TKA） requires recovery of strength and voluntary activation. Short-term recovery of strength and activation are enhanced following a protocol combining strength training with neuromuscular electrical stimulation （NMES）. The purpose of the study was to determine if a dose response curve could be constructed for patients who received NMES as part of their treatment after TKA. NMES dosage was quantified as the electrically evoked knee extensor torque, expressed as a percentage of the subject＇s maximal voluntary contraction. Dose-response curves were generated, with the associations between NMES training intensity and quadriceps strength, voluntary activation, and lean muscle cross-sectional area examined using Pearson Product-Moment Correlation Coefficients. Significantly, linear correlations were observed between NMES training intensity and both quadriceps strength and voluntary activation, but not lean muscle cross-sectional area. These results suggest that maximizing the elicited training force during rehabilitation will enhance short-term recovery following TKA.

Changes in Citizen Participation in Japanese Civil Society

Japan experienced the retrenchment of the welfare state. The purpose of this study was to deepen the understanding of the impact these policy changes had on citizens’ organized activities. It focused on the 2016 revision of Long-Term Care Insurance （LTCI） system, which urged citizens to organize activities to support the frail seniors in their communities. Researchers conducted interviews in the Tokyo from February-March 2016. The subjects were six local officers in charge of LTCI implementation and 10 community members who led the voluntary activities organized as a response to the 2016 systemic revision. This study found that those leading voluntary activities were primarily baby boomers, who were born between 1947 and 1949. They were actively involved in “new voluntary activity movements” in the 1980s, as interacting with a wide range of citizens. However, as they reached the age of 65 or older, they became more focused on developing a comfortable space and collaborating with those similar to them： those who were college graduates, middle- to upper-class, and held white-collar jobs. The disparity based on income level seemed to be emphasized also because the way the 2016 revision of LTCI system was designed.

Downhill running impairs peripheral but not central neuromuscular indices in elbow flexor muscles

The purpose of this study was to examine the effects of a 1-h downhill running exercise on the elbow flexor muscles’neuromuscular functions.Seventeen adults(Control[CON]:n=9;Experimental[EXP]:n=8)completed this study.The CON rested for 30 min while the EXP performed the downhill running.Before,10 min,24 h,and 48 h after the interventions,dependent variables(knee extensor muscle soreness,elbow flexion and knee extension isometric strength,elbow flexion resting twitch and voluntary activation[VA],and the biceps surface electromyography[EMG]amplitude)were measured.Knee extensor muscle soreness was significantly greater in the EXP than the CON group following the intervention throughout the entire 48 h.This was accompanied by the greater decline in the knee extension strength in the EXP than the CON(mean±SD:-6.9±3.4%vs.1.0±3.2%,p=0.044).The elbow flexion strength,VA,and EMG amplitude were not affected by the exercise.However,the decline of the elbow flexion resting twitch was greater in the EXP than the CON(±19.6±6.3%vs.8.7±5.9%,p=0.003).Therefore,the downhill running impaired the remote elbow flexor muscles at a peripheral level.