Trial in Elderly With Musculoskeletal Problems Due to Underlying Sarcopenia - Faeces to Unravel Gut and Inflammation Translationally

Inclusion Criteria: * Male or female persons without probable, confirmed or severe sarcopenia according to the European Working Group on Sarcopenia in Older People (EWGSOP2): no reduced muscle strength measured by chair stand test or hand grips strength * 65 years or older * Community-dwelling elderly or assisted living * Dutch speaking Exclusion Criteria: * Impairments/diseases that affect performance of daily activities * Persons who are systematically physically active (e.g. routine or organized sports activities) or who followed a physical activity training program (e.g., rehabilitation program) in the last 6 months (systematically = twice or more/week) * Diagnosis of diabetes mellitus, measured by fasting glucose ≥126 mg/dL or HbA1C ≥ 6.5% at screening or in recent (maximum 3 months old) lab report * Use of antibiotics in the last 3 months * Gastrointestinal cancer (active or treated in the last 5 years) * No freezer at home available After the screening visit, included persons will be invited for a test visit.