Beyond the Limits of Human Muscle Growth
A Mr Olympia competitor case-study.
A professional bodybuilder preparing for the Mr Olympia loses muscle thickness across every major muscle group during his cut, and new ultrasound data from Italian researchers shows that muscle quality also takes a hit, even as body fat barely moves.
Researchers from the University of Bologna tracked a 38-year-old IFBB Pro League Open bodybuilder (128.7 kg, 176 cm, 25 years of training experience, three-time Mr Olympia competitor) through his bulking phase and into his cutting phase, 10 days before competition. They measured muscle thickness and corrected echo intensity (cEI) — a measure of muscle quality — via ultrasound across nine muscle groups, while also analysing his full food and training logs.
The Setup
The athlete was assessed during his bulking phase (week 8 of 14) in February 2025, and again during his cutting phase (week 9 of 11) in June 2025.
The training program remained nearly identical across both phases: five training days per week, the same split, the same set-and-rep structure, with every set taken to technical failure. The only addition during the cut was one session per week of 30 minutes of fast walking.
The real change was in the diet. Caloric intake dropped 44%, from roughly 5,620 calories per day in the bulking phase to 3,140 per day during the cut.
Carbohydrates took the biggest hit, cut by 62% from 820 g/day to 320 g/day. Protein was held steady throughout, landing at the upper end of current recommendations for athletes in a caloric deficit at 330 g/day (~2.7 g/kg).
Results: Body Composition
The athlete dropped 6.4 kg total, from 128.7 kg down to 122.3 kg. Fat-free mass fell by 4.72%, while the sum of the three skinfolds decreased by only 0.7 mm. Body fat went from 6.1% to 5.9% — a change of just 0.7 kg of actual fat.