Objectives: We compared the effect of 12 weeks lesser mealworm-based (Alphitobius diaperinus) protein supplementation to whey protein and placebo supplementation on Exercise-Induced Muscle Damage (EIMD) after long-distance walking in older adults.

Methods: in this randomized controlled trial, 70 physically active older adults (>60 years) were randomly allocated to the following groups: I) lesser mealworm protein, II) whey protein or III) iso-caloric placebo. Participants received supplements 11 weeks before and 1 week during a 3-day long-distance walking challenge (30-50 km per day). Blood concentrations of creatinine kinase (CK) and lactate dehydrogenase (LDH), handgrip strength and muscle soreness were measured pre-exercise and directly after each walking bout.

Results: Significant elevations of CK concentrations (103 [76-161] U/l to 758 [342-1104] U/l, p < 0.001) and LDH concentrations (202 [175-220] to 283 [252-339] U/l, p < 0.001) were observed following 7h45 min ± 11 min of walking exercise per day, but the magnitude of this effect did not differ among suppletion groups. Hand grip strength decreased significantly (p < 0.001) while muscle soreness increased (p = 0.002) after the first walking day compared to pre-exercise, with no group differences.

Conclusion: 12-weeks of lesser mealworm-based protein supplementation (30 g/day) does not attenuate exercise induced muscle damage in older adults following three days of prolonged walking exercise in comparison to placebo or whey protein.