Research

Hormonal

Performing endurance exercise before resistance exercise attenuates the mRNA response of IGF-IEa (a growth factor) compared to performing resistance exercise before endurance exercise.

If you do cardio before weights, your body's expression of IGF-IEa (a growth factor) is reduced by 42% compared to doing weights first. If your goal is maximizing muscle growth signaling, prioritize resistance training before cardio in the same session.

GoodRefutesHIGH confidence
However, the increase in IGF-IEa mRNA was attenuated when cycling preceded resistance exercise (CYC1-REX2, -42%, ES = 0.4; Fig. 4A)
Vernon G. Coffey et al. · Journal of Applied Physiology · 2009

Why this rating

Same study strengths/limitations. Statistically significant attenuation.

Source

Consecutive bouts of diverse contractile activity alter acute responses in human skeletal muscle

Vernon G. Coffey et al. · Journal of Applied Physiology · 2009

DOI 10.1152/japplphysiol.91221.2008

crossover · n=8Cited 115×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →