Energy metabolism
Three energy systems provide ATP for muscle contraction. Phosphagen system (explosive), glycolysis (anaerobic), oxidative phosphorylation (aerobic), time frame and intensity determine which dominates.
Auch bekannt als: ATP-Synthese, Energiesysteme, aerober Stoffwechsel, anaerober Stoffwechsel
ATP, the only energy currency
Muscles can only use adenosine triphosphate (ATP) directly for contraction, not fat, not glucose directly. All three energy systems serve ATP resynthesis. The body only has ~80-100g of ATP stored, enough for ~2-3 seconds of maximal work.
1. Phosphagen system (ATP-PCr)
- Energy: Phosphocreatine → ADP + Pi → ATP
- Capacity: 5-15 seconds maximum intensity
- Advantage: immediately available, no oxygen required
- Relevance: sprints, maximum weights, explosive movements
- Creatine supplementation increases PCr stores by ~20%
2. Glycolysis (anaerobic-lactacid)
- Glucose → pyruvate → lactate + 2 ATP (fast) or pyruvate → acetyl-CoA (aerobic)
- Capacity: 15 seconds, 2 minutes
- Lactate is not a “waste product”, it is an energy source (Cori cycle)
- Relevance: 200-800m run, intense sets of 8-15 reps
3. Oxidative phosphorylation (aerobic)
- Glucose, fatty acids, amino acids → CO₂ + H₂O + 30-32 ATP
- Capacity: minutes to hours
- Main energy system at continuous load < 70% VO₂max
- Relevance: endurance training, basal metabolic rate, regeneration
Sources
- Hargreaves M, Spriet LL. Skeletal muscle energy metabolism during exercise. Nat Metab. 2020. PubMed
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