Effects of essential amino acid supplementation on musculotendinous recovery following eccentric plantar flexor exercise: a randomized controlled trial
Study Details
This new study examined whether essential amino acid supplementation improved musculotendinous recovery after damaging eccentric calf exercise in 36 recreationally active men 🔍
Participants consumed either…
1️⃣ 10 g EAAs
2️⃣ 10 g maltodextrin placebo
3️⃣ no supplement
EAAs were consumed 30 min before and immediately after exercise, then repeatedly across the 72-hour recovery period ⏱️
Key Findings
🦵 The eccentric plantar-flexor protocol successfully increased soreness, calf muscle thickness and circumference, while reducing pain-pressure threshold
😣 At 24 hours, worst pain was ~51% lower with EAAs than placebo
📉 Current pain was ~50% lower and average pain ~48% lower with EAAs versus placebo at 24 hours
↔️ These soreness differences were no longer clearly present at 48 or 72 hours
💪 Calf muscle thickness increased after exercise in both supplemented groups, reflecting exercise-induced swelling
✅ Muscle thickness had returned to baseline by 72 hours in the EAA group
⚠️ In contrast, calf muscle thickness remained elevated at 72 hours with placebo, suggesting faster resolution of swelling with EAAs
📏 Calf circumference increased through 72 hours in both groups, with no meaningful between-group differences
🧠 Pain-pressure threshold decreased during recovery but was not influenced by EAA supplementation
🦶 Achilles tendon thickness temporarily decreased immediately after eccentric exercise
↔️ EAAs did not influence Achilles tendon thickness or its recovery
Conclusion
Greater amino acid availability, particularly leucine, may support early muscle repair, although MPS and mTOR signalling were not directly measured in this study 🧐
Plus, no functional performance or strength outcomes were measured, so it remains unclear whether these changes translated into faster restoration of muscle function ⚠️
Overall, EAAs provided modest early recovery benefits, mainly reduced soreness at 24 hours and faster resolution of muscle swelling ✅
Reference
https://www.tandfonline.com/doi/full/10.1080/15502783.2026.2726619
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