There’s a 'magic number' in all animal muscles that evolved to perfectly balance power and efficiency.
March 19, 2026
Original Paper
Molecular-scale, nonlinear actomyosin binding dynamics drive population-scale adaptation and evolutionary convergence
arXiv · 2603.17183
The Takeaway
Scientists found a specific mathematical constant (3.85) that governs how muscles contract across almost all moving species on Earth. By simulating millions of years of competition, researchers proved that evolution inevitably lands on this exact number because it is the physical 'sweet spot' for survival.
From the abstract
Biological actuators -- from myosin motors to muscles -- follow Hill's model where a dimensionless parameter $\alpha$ captures the nonlinear coupling between contraction rate and force generation. Our prior work identified a characteristic $\alpha^* = 3.85 \pm 2.32$ across natural muscles and showed that $\alpha^*$ optimizes a power-efficiency tradeoff, potentially explaining its prevalence in nature. However, those results reflected short-term actuation tasks whereas phenotypic distributions in