For Participants

Participation begins with a screening phase that takes place up to four weeks before the start of the study. During this stage, the study physician reviews the inclusion and exclusion criteria and assesses medical, physical, and cognitive suitability for participation. If eligibility is confirmed and written informed consent is provided, participants are enrolled and assigned to one of the study groups.

At T1, the baseline assessment is carried out.This includes cognitive testing, questionnaires, anthropometric measurements, body composition assessment, physical performance and strength testing, and the collection of biological samples.

The main intervention phase lasts 18 weeks. During this period, participants receive the intervention according to their group allocation. Depending on the group, this may include supplementation, resistance training, or a combination of both.

At T2, after 18 weeks, the final assessment is performed. The same examinations carried out at baseline are repeated at this time point.

Core participation lasts 18 weeks, with baseline (T1) and end-of-study (T2) assessments.

Optionally, some groups can continue with an additional 12‑week speed‑power training module after the initial 18 weeks, on a voluntary basis.

Participants in Group 2 and Group 4 are asked not to undertake any additional strength training during the intervention phase, as this could influence the study intervention. Other forms of physical activity, especially endurance-based activities such as jogging or cycling, are generally not a problem. It is important that you maintain your usual lifestyle as far as possible during the study period. If you have any questions about sport or physical activity during this time, please contact the study team.