Inclusion Criteria:  No subjective symptoms during physical exertion Stable weight and dietary behaviour Body Mass Index (BMI) between 18.5 and 24.9 No extensive strength/endurance sports so far (less than 3 h/week) No complaints during strenuous physical activity  Exclusion Criteria:  Circumstances that impair/prevent sporting activity (e.g. chronic heart disease, arrhythmia, heart valve disease, arthritis etc.) Intolerance/aversion to animal protein Arterial hypertension (high blood pressure) (syst > 200 mmHg and/or diast > 105 mmHg) at rest Presence of insulin-dependent diabetes mellitus Liver and/or kidney disease that precludes a high protein load Collagen supplementation or regular intake of other dietary supplements in the last 6 months.