1.) You are not changing Enough
Consistent change is essential to maintaining consistent growth — especially for gym rats. “The longer someone has been training the more frequently they need to change things up,” Clayton explains.
But a key thing to remember is that the term “change” extends beyond exercise selection. “Changing things up can mean anything from a squat type to an exercise to a rep scheme,” he adds. “Even if someone is doing the right exercises [for bigger legs] they might be doing three sets of 10 across the board.”
Things like giant sets, dropsets, extended sets, supersets, pyramids, and varying your rest periods other things you can use to make your next workout differ from the previous one
2.) Your Legs arn't Strong
You might hear people complain that their legs are strong but not big. To determine whether that’s the case the word “strong” needs to be defined — and Clayton’s definition might differ from yours.
“I’d consider strong legs the ability to squat two times your bodyweight and deadlift two-and-a-half times your bodyweight,” Clayton says. “If you can squat and deadlift that and your legs are still skinny, it’s probably just lousy genetics. But I don’t see too many people who can do those percentages of squats and deads with skinny legs.”