Mid-life cyclists preserve muscle mass and composition: a 3D MRI study.

Physical activity and a healthy lifestyle are crucial factors for delaying and reducing the effects of sarcopenia. Cycling has gained popularity in the last decades among midlife men. While the cardiovascular benefits of cycling and other endurance exercises have been extensively proved, the potential benefits of lifelong aerobic exercise on muscle health have not been adequately studied. Our aim was to quantify the benefits of cycling in terms of muscle health in middle-aged men, using magnetic resonance imaging. We ran a cross-sectional study involving two groups of middle-aged male adults (mean age 49 years, range 30-65) that underwent Dixon MRI of the pelvis. The groups consisted of 28 physically inactive (PI) and 28 trained recreational cyclists. The latter had cycled more than 7000 km in the last year and have been training for 15 years on average, while the PI volunteers have not practiced sports for an average of 27 years. We processed the Dixon MRI scans by labelling and computing the fat fraction (FF), volume and lean volume of gluteus maximus (GMAX) and gluteus medius (GMED); and measuring the volume of subcutaneous adipose tissue (SAT). We found that the cyclists group had lower FF levels, a measure of intramuscular fat infiltration, compared to the PI group for GMAX (PI median FF 21.6%, cyclists median FF 14.8%, p < 0.01) and GMED (PI median FF 16.0%, cyclists median FF 11.4%, p < 0.01). Cyclists had also larger GMAX and GMED muscles than the PI group (p < 0.01), after normalizing it by body mass. Muscle mass and fat infiltration were strongly correlated with SAT volume. These results suggest that cycling could help preserve muscle mass and composition in middle-aged men. Although more research is needed to support these results, this study adds new evidence to support public health efforts to promote cycling.

Wear of dual-mobility cups: a review article.

Dual-mobility (DM) cups have been clinically used in hip surgery in Europe for more than 35 years and continue to gain popularity worldwide due to promising results at reducing instability. Concerns related to polyethylene wear apply as in conventional standard bearings but are accentuated by the larger-diameter articulations with multiple surfaces. We critically reviewed the reported literature regarding the in vivo and in vitro wear occurring on all surfaces involved. We looked for patterns to create a rational classification of sites of wear and to identify areas for future research. Wear was a significant problem for first-generation designs and appeared to be design related. Improved polyethylene, thinner and smoother trunnions, chamfered rims and eccentric configuration of insert and shell seem to enhance outcome performance; however, long-term clinical evidence and retrieval studies are needed to better understand the balance of benefit and risk when opting for DM bearings.