Does Physiological Elevation of Endogenous Hormones Enhance Training Adaptation? An 11-Week Within-Subject Trial
Rønnestad BR, Nygaard H, Raastad T
Evidence is still limited and needs further study
Summary
Training one arm after leg exercise (high-hormone) and the other arm alone for 11 weeks yielded slightly greater relative 1RM gains and hypertrophy at the peak-CSA site of the biceps in the leg-combined arm. One of the few studies supporting the acute-hormone hypothesis.
Key findings
- 1
Testosterone and GH rose significantly with the leg-combined (L+A) arm; no change with the arm-only (A) condition
- 2
The L+A arm showed greater relative 1RM gains and greater hypertrophy at the biceps peak-CSA site
- 3
But n=9 is very small and effects were limited (e.g., only at the peak-CSA site)
- 4
Its conclusion runs opposite to the similarly designed West (2010), positioning it as an outlier
Related research
Are Post-Exercise Anabolic Hormone Elevations Required for Hypertrophy? A 15-Week Within-Subject Trial
Journal of Applied Physiology, 2010
Training one arm alone (low-hormone) and the other arm with added leg exercise (high-hormone) in the same men for 15 weeks produced no difference in muscle cross-sectional area or strength gains. Elbow flexors in young men.
Post-Exercise Hormone Elevations and Hypertrophy/Strength in 49 Trained Men: A 12-Week Study
Journal of Applied Physiology, 2016
In 49 resistance-trained young men, post-exercise acute elevations in testosterone, GH, IGF-1, and cortisol showed no significant correlation with gains in muscle size or strength. Acute hormones are not a marker of adaptation.
Articles featuring this study
- Research vs Bro-science
Does Higher Testosterone Always Mean More Muscle? Hormones and Hypertrophy — What the Research Shows
"Higher testosterone means more muscle" — this belief has dominated bodybuilding culture for decades. The acute testosterone spike after training was thought to directly drive hypertrophy, but RCTs from the 2010s onwards have challenged this assumption. The relationship between testosterone and muscle growth is far more complex than commonly believed.
Shingo Yoshizaki
- Research vs Bro-science
'You Can't Get Big Without Training Legs' — Myth vs Research
'Skip leg day and your upper body won't grow either,' 'the growth hormone and testosterone from squats and deadlifts build your whole body,' 'legs are your foundation, so without them you won't build a frame.' Leg-day devotion runs deep in gym culture. But is training legs really the key to upper-body growth? Using research on hormones and muscle mass, we separate what's right from what's wrong in this belief.
Hirotsugu Yoshimura
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