After damaging eccentric exercise, 1 g/kg of alcohol roughly doubles the strength loss measured 36 hours later; an undamaged muscle is unaffected
Key Findings
With 1 g/kg alcohol after 300 maximal eccentric contractions, strength loss at 36 h was 34% / 40% / 34% (isometric / concentric / eccentric) against 12% / 28% / 19% without alcohol.
Eleven healthy men performed 300 maximal eccentric quadriceps contractions with one leg, then drank 1 g/kg ethanol (vodka and orange juice) or isocaloric orange juice.
Peak strength loss at 36 h without alcohol: 12% isometric, 28% concentric, 19% eccentric. With alcohol: 34%, 40% and 34%.
Creatine kinase and muscle soreness did not differ between conditions.
A companion study by the same group (Barnes 2010, Eur J Appl Physiol, DOI 10.1007/s00421-009-1311-3, N = 10) repeated the result for average peak torque (28.7/31.9/25.9% vs 40.9/42.8/44.8%) and found no change in the non-exercised leg.
Practical Application
After unusually damaging work — a long descent, a race, a first heavy leg session — a night of drinking (about 1 g/kg) may deepen the loss of leg strength over the next two to three days: keep the next quality session further away, or keep the night small.
Soreness will not warn of it: perceived soreness was the same with and without alcohol.
It does not show that alcohol weakens a muscle that was not damaged.
Limitations
N = 10–11, men, one research group, one dose; isolated knee-extensor torque, not endurance performance.
A systematic review of alcohol after resistance exercise (Lakićević 2019, DOI 10.3390/jfmk4030041, 12 studies) found force, power and soreness unmodified overall — the effect here belongs to an extreme eccentric model.
Abstract only was read.