Influence of acetaminophen and ibuprofen on skeletal muscle adaptations to resistance exercise in older adults.
Level 2 - randomized trial
Individual randomized, double-blind, placebo-controlled trial
PubMed 21160058 · doi:10.1152/ajpregu.00611.2010
What was done
Thirty-six older adults were randomized in a double-blind, placebo-controlled fashion into three groups during 12 weeks of progressive knee extensor resistance training: placebo (67 ± 2 years, n = 12), acetaminophen (64 ± 1 years, n = 11; 4 g/day), and ibuprofen (64 ± 1 years, n = 13; 1.2 g/day). Compliance was monitored (including digital video observation for drug consumption). Outcomes included knee extensor muscle volume, muscle strength, size of non-trained hamstring muscles, and vastus lateralis muscle biopsy measures of protein content, water content, myosin heavy chain distribution, and COX-1 and COX-2 enzyme levels.
What was found
Compliance with training was 100% and drug consumption was 94% across all groups. Controlling for baseline values, drug consumption resulted in greater increases (P < 0.05) in muscle volume (acetaminophen: 109 ± 14 cm3, 12.5%; ibuprofen: 84 ± 10 cm3, 10.9%) and strength (acetaminophen: 19 ± 2 kg; ibuprofen: 19 ± 2 kg) compared to placebo (volume: 69 ± 12 cm3, 8.6%; strength: 15 ± 2 kg). Biopsy analysis showed no drug effect on muscle protein content, water content, myosin heavy chain distribution, or COX-1 and COX-2 levels (P > 0.05), though training increased COX-1 by 32 ± 8% across groups (P < 0.05). Untrained hamstring size was unchanged (P > 0.05).
Why it matters
Contrary to assumptions that COX inhibitors impair training adaptations in older adults with sarcopenia, regular therapeutic doses of acetaminophen or ibuprofen enhanced resistance-training-induced hypertrophy and strength.
Limits
The sample size was small (n = 36 total, 11-13 per group) and limited to a single 12-week knee extension protocol. The abstract does not report clinical safety outcomes, gastrointestinal or cardiovascular tolerance, or results for whole-body resistance training.
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