Emil Rydell Högelin

I am a resident physician (ST-läkare) in internal medicine and cardiology at Höglandssjukhuset in Eksjö, and since 2022 a doctoral student at Linköping University in the field of muscle physiology.

Skeletal muscle underpins most of the body's capacity for movement and is at the same time one of its largest metabolic organs. It is strikingly plastic: mechanical loading drives growth, whereas inactivity, illness and advancing age lead to atrophy and loss of function, often more rapidly than the muscle is subsequently rebuilt. Muscle mass and strength are also among the strongest predictors of physical function and health across the lifespan. My research concerns the adaptation of skeletal muscle to physical training, with a particular focus on resistance exercise in children and adults. In the randomised intervention trial KidREx, we examine how muscle volume, muscle thickness and muscle function change over time, using magnetic resonance imaging and ultrasound as the principal measurement methods, complemented by functional testing. By following both structure and function repeatedly across the intervention, we are able to describe the time course of hypertrophy and to examine the extent to which increases in muscle size actually translate into gains in strength and performance. The evidence base is particularly limited in children, where the training response must also be interpreted against a background of ongoing growth and maturation. In the longer term, the work aims to clarify what loading is required to build and preserve muscle mass a question that matters both for healthy individuals and for patient groups with atrophy secondary to immobilisation, chronic disease or ageing. The research is carried out at Linköping University in collaboration with colleagues at Karolinska Institutet, among others.