Why does strength training improve endurance performance?

Abstract

Objective: The specificity of training principle holds that adaptations to exercise training closely match capacity to the specific demands of the stimulus. Improvements in endurance sport performance gained through strength training are a notable exception to this principle. While the proximate mechanisms for how strength training produces muscular adaptations beneficial to endurance sports are increasingly well understood, the ultimate causes of this phenomenon remain unexplored. Methods: Using a holistic approach tying together exercise physiology and evolution, I argue that we can reconcile the apparent "endurance training specificity paradox."Results and Conclusions: Competing selective pressures, inherited mammalian biology, and millennia of living in energy-scarce environments constrained our evolution as endurance athletes, but also imparted high muscular plasticity which can be exploited to improve endurance performance beyond what was useful in our evolutionary past.

The evolution of human fatigue resistance

“…Although physiological trade-offs between endurance and strength and power are well established, there is abundant evidence that strength and power training can also improve endurance capacity and fatigue resistance. The reasons for this effect are not particularly obvious, although one enticing suggestion is that our survival in energy-scarce environments constrained our evolution for endurance, and in so doing endowed us with skeletal muscle plasticity so that improvements in endurance, and hence fatigue resistance could be gained through an additional mechanism (Best 2020 ). Thus, the endurance-strength/power trade-off is skewed toward endurance in humans, which also involved the evolution of mechanisms to resist fatigue.…”

Adaptations, Safety Factors, Limitations and Trade-Offs in Human Exercise Performance

“…Improvements in endurance capacity resulting from resistance training can also be explained from an evolutionary perspective. As outlined recently by Best (2020), strength and endurance training results in more favourable endurance performance because the inherent plasticity of human skeletal muscle is skewed toward enhanced endurance and fatigue resistance. Tradeoffs also exist to balance the cost of future reproduction with the cost of survival.…”