High doses of anti-inflammatory drugs compromise muscle strength and hypertrophic adaptations to resistance training in young adults.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 28834248 · doi:10.1111/apha.12948
What was done
Thirty-one healthy men and women aged 18–35 years were randomly assigned to daily consumption of either ibuprofen (1200 mg; n = 15) or acetylsalicylic acid (aspirin, 75 mg; n = 16) for 8 weeks. Participants completed supervised knee-extensor resistance training where one leg performed maximal volitional effort on a flywheel ergometer and the other leg performed conventional work-matched weight-stack training. Quadriceps muscle volume was assessed before and after training by MRI, muscle strength was measured, and muscle biopsies were analyzed for gene and protein expression of muscle growth regulators.
What was found
Quadriceps muscle volume increase (averaged across legs) was significantly lower in the ibuprofen group (3.7%) than in the aspirin group (7.5%), with a group difference of 34 cm³ (P = 0.029). Weight-stack strength improved similarly across groups (11–20%). Flywheel leg strength increases (10–23%) were significantly greater for aspirin compared to ibuprofen (interaction P < 0.05). In molecular analyses, the only group interaction was downregulated mRNA expression of IL-6 in the ibuprofen group (P < 0.0001).
Why it matters
This trial demonstrates that maximal over-the-counter doses of ibuprofen blunt hypertrophic and strength adaptations to resistance training in healthy young adults.
Limits
The sample size was small (n = 31). The study used low-dose aspirin as an active comparator rather than an inert placebo. The training protocol was restricted to isolated knee-extensor exercise over 8 weeks, leaving whole-body adaptations and longer-term outcomes unassessed.