Favorite
Please login to bookmark Close

In response to NYTimes: How Hard Do You Have to Push Yourself to Get Stronger?

Quick Summary

  • Muscle growth isn’t just about micro-damage and soreness—it’s a more complex process involving multiple mechanisms.

  • Energy depletion (like glycogen store exhaustion) is a key muscle-growth signal and supports better metabolic health, including insulin sensitivity.

  • The popular “Reps in Reserve” (RIR) concept can be helpful, but most people underestimate how many reps they can truly do.

  • Instead, tuning into “stimulating reps”—those last few reps that feel meaningfully hard—can be a more intuitive and effective guide for effort.

In response to the May 6, 2025 New York Times article How Hard Do You Have to Push Yourself to Get Stronger?

The idea that “challenging your muscles creates micro-damage, which causes them to change,” and that working to failure creates more extreme damage—and therefore more soreness—isn’t always borne out. While it’s true that muscle damage can be part of the adaptation process, the connection between training and growth is more complex than it’s often portrayed.

Researchers who study muscle growth closely now suggest that although they understand the types of stimulus that promote muscle growth, the exact mechanisms behind it remain unclear. Micro-damage and subsequent repair are one part of the story, but other factors play significant roles as well.

One such factor is energy depletion. The “fuel tank” metaphor for muscle fatigue is not purely symbolic—our skeletal muscles actually store glycogen, a form of sugar. When we train to fatigue, we deplete these glycogen stores. In response, the body may expand its capacity to store glycogen, which can contribute to muscle growth. Importantly, this process also plays a key role in improving insulin sensitivity and overall metabolic health. By regularly emptying and refilling our glycogen stores through exercise, we enhance our muscles’ ability to clear glucose from the bloodstream, which supports better blood sugar regulation and long-term metabolic function.

And of course the myokines (signaling molecules released by muscles during contraction) are part of the picture, communicating with various tissues throughout the body, including other muscles and the working muscle itself. These chemical messengers likely contribute to the adaptation process as well.

Another point worth noting is that post-workout soreness often has more to do with novelty than intensity. When someone introduces a new movement or pattern, they’re more likely to be sore, regardless of how hard they worked. Once someone has established a consistent training routine, they can train very hard without experiencing much soreness at all—though of course, individual responses may vary.

Fortunately, in our community, we’re all about good form, so we can confidently apply the idea of “technical failure”—stopping before form breaks down. Whether or not working to failure is appropriate often depends on the specific exercise. For example, taking a barbell back squat to failure is probably not a good idea without a lot of safety mechanisms in place, whereas doing so on a leg press machine may be safer and more practical.

Finally, the Reps in Reserve (RIR) concept has gotten really popular lately, but in my experience, most of us are not great at estimating how many reps we can do! As in, most of us will dramatically underestimate it (this has been studied too). The “stimulating reps” idea is an inverse way of looking at it – an early sign that we’re getting to the end of what we can do, but we haven’t hit the wall yet. it’s nice because it’s an actual thing we can experience, rather than something we have to speculate about.

  • Schoenfeld, Brad J. “The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training.” Journal of Strength and Conditioning Research, vol. 24, no. 10, 2010, pp. 2857–2872.
    — Offers a foundational overview of muscle growth mechanisms beyond just muscle damage, including metabolic stress and mechanical tension.

  • Haun, Cameron T., et al. “A Critical Evaluation of the Biological Construct Skeletal Muscle Hypertrophy: Size Matters but So Does the Measurement.” Frontiers in Physiology, vol. 10, 2019, article 247.
    — Highlights that mechanisms of hypertrophy include energy substrate depletion (e.g., glycogen) and other systemic adaptations.

  • Pedersen, Bente Klarlund, and Mark A. Febbraio. “Muscles, Exercise and Obesity: Skeletal Muscle as a Secretory Organ.” Nature Reviews Endocrinology, vol. 8, no. 8, 2012, pp. 457–465.
    — Describes the role of myokines—molecules secreted by muscles—in mediating exercise’s effects throughout the body.