Doing 14 sets vs. 21 sets doesn’t make your muscles look any different on ultrasound—even though you lifted more total weight in the 21-set version.
Scientific Claim
In trained males, resistance training volume does not produce differential effects on muscle thickness or echo-intensity between 14 and 21 sets, despite higher volume load in the 21-set condition.
Original Statement
“The 14 and 21-SETS conditions resulted in greater volume load (VL) (p < 0.05). No condition or condition-by-time effects were observed for MT, EI, or 10RM-VL (p > 0.05).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The authors report no significant differences between 14 and 21 sets for MT/EI despite higher VL, and use appropriate non-causal language.
Evidence from Studies
Supporting (1)
Don’t Sweat the Swelling: Exercise Volume’s Transient Effects in Trained Males
Even when guys did more sets of squats, their thigh muscles didn’t get noticeably bigger or change in texture compared to doing fewer sets — so doing more work didn’t give them extra muscle gains in this case.