Published: 12-06-2017 16:57 | Updated: 14-05-2019 08:57

Trained and untrained individuals wanted (35-50 years)

How are muscles affected by long-term training? The purpose of this study is to compare individuals with different training backgrounds compared with non-trained individuals in order to understand how muscle and fat tissue are changed following years of training.

Inclusion criteria

- Age: 35-50

- Fit into one of the following groups:

  • Individual with over 15 years of regular endurance training experience (at the elite/sub-elite level)
  • Individual with over 15 years of regular strength training experience (at the elite/sub-elite level)
  • Individual with limited to no previous training experience
  • Not overweight
  • Non-smoker
  • Do not use (or have not previously used) performance enhancing drugs -Be healthy (no ongoing infection or chronic disease)


If you fit the inclusion criteria, please contact us with the information provided below.

Participation in this study involves two visits. During the first visit you will fill out a health questionnaire and perform two physiological tests (one for endurance - VO2 max cycling test, and one for strength - maximal knee extension test). This visit takes about 60 minutes.

If the results of your physiological tests meet our inclusion criteria, you will be included in the study. If included, you will come back to the lab for a whole-body MRI then we will take skeletal muscle biopsies from the thigh from both legs (at most 4 from each leg). A fat tissue biopsy will also be taken from the abdomen. This visit takes about 60-90 minutes.

Participants in this study will receive 2500kr upon completion.

You will also receive results from your physiological tests and information about your muscles (i.e. fiber type composition).

Contact information

If you are interested in participating, please contact Mark Chapman, PhD, Department of Physiology and Pharmacology Karolinska Institutet.


Phone: 08-524 868 74

Read more about Molecular exercise physiology


The study has all the permits required.