Why your muscles grow (and what doesn't help)
Load-induced human skeletal muscle hypertrophy: Mechanisms, myths, and misconceptions
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Unilateral training showed identical muscle growth in both arms despite one arm having 4–5 times higher post-exercise testosterone levels.
It directly contradicts the belief that hormonal surges drive muscle growth—proving mechanical tension alone is sufficient.
Practical Takeaways
Focus on progressive overload: increase weight, reps, or sets over time—don’t chase pumps, burns, or post-workout hormone surges.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Unilateral training showed identical muscle growth in both arms despite one arm having 4–5 times higher post-exercise testosterone levels.
It directly contradicts the belief that hormonal surges drive muscle growth—proving mechanical tension alone is sufficient.
Practical Takeaways
Focus on progressive overload: increase weight, reps, or sets over time—don’t chase pumps, burns, or post-workout hormone surges.
Publication
Journal
Journal of Sport and Health Science
Year
2025
Authors
Derrick W. Van Every, Matthew J Lees, Brandan Wilson, Jeff Nippard, Stuart M. Phillips
Related Content
Claims (10)
Your muscles grow bigger mainly because of how much total force they feel over time—not whether you do your workouts all at once or spread out over the week.
Your muscles grow bigger mainly because of how much total force they feel over time—not whether you do your workouts all at once or spread out over the week.
When you lift weights, it's the pulling force on your muscles—not the tears or burn—that makes them grow bigger, and scientists think a specific molecular signal inside the muscle cells is behind this growth; other things like soreness or muscle burn probably don't cause the growth on their own.
When muscles get bigger from working out, it’s not really because they’re storing more water or sugar—those changes don’t last or help much. What really matters is that the actual muscle fibers grow thicker.
Even if you make your muscles feel that burning, swollen 'pump' feeling during a workout by boosting certain chemicals, it doesn't actually make your muscles grow bigger—studies show muscle growth doesn't happen just from that sensation.