From Longman Dictionary of Contemporary Englishmuscleboundmus‧cle‧bound /ˈmʌsəlbaʊnd/ adjective MIDShaving large stiff muscles because of too much physical exercise musclebound weight-lifters
Examples from the Corpus
musclebound• a muscle-bound man• Obese mice, diabetic mice, musclebound mice, even knockout mice.• The lifeguard raised his shoulders in a musclebound shrug and tugged at the whistle around his neck. 