Fictional power levels often overshoot what biology can handle, but Captain America is written in a narrower lane. His feats sit near the theoretical ceiling of human performance rather than in the realm of broken physics. When compared with an Olympic decathlete on an absolutely optimized day, the gap is smaller than fans expect.
Human muscle physiology, especially motor unit recruitment and fast twitch fiber output, can already generate extreme power when supported by high maximal oxygen uptake and efficient cardiac output. The super soldier serum is usually framed as pushing all of those levers to their genetic upper bound, not rewriting actin myosin chemistry or inventing a new kind of tissue. That framing keeps his sprint speed, jump height, and strike force within an extrapolated range of known biomechanics, including tendon elasticity and ground reaction forces seen in elite jumpers and sprinters.
Olympic decathletes already balance speed, strength, coordination, and recovery across multiple events while operating near limits defined by metabolic pathways such as anaerobic glycolysis and oxidative phosphorylation. Captain America is essentially portrayed as an athlete with consistently perfect recovery, injury resistance, and neuromuscular control, with reaction times and lactate clearance shifted toward the edge of plausible human variance. A truly superhuman character would require violations of tissue stress tolerance, bone compressive strength, and energy conservation that current physiology does not support, which is not how this character is usually described.
