Research
Energy balance
Concurrent training (combining endurance and strength) can impair strength adaptations and muscle hypertrophy, potentially due to a significant caloric deficit and negative energy balance rather than just molecular interference (AMPK/mTORC1).
If you combine cardio and weights, watch your calorie intake. The 'interference' effect is often due to not eating enough to support muscle growth, not just molecular conflicts. Ensure you are in energy balance or a slight surplus to maintain strength gains.
GoodQualifiesHIGH confidence
The resulting 4000 kcal per week difference in energy expenditure could easily underlie the difference in muscle size and strength.
Why this rating
Cites the classic Hickson study and energy expenditure data, though notes molecular mechanisms (AMPK/mTORC1) may not fully explain it.
Source
Adaptations to Endurance and Strength Training
David C. Hughes et al. · Cold Spring Harbor Perspectives in Medicine · 2017
DOI 10.1101/cshperspect.a029769
narrative_reviewCited 525×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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