sinewy in WordNet English dictionary

1. (of a person) possessing physical strength and weight; rugged and powerful
   "a hefty athlete"; "a muscular boxer"; "powerful arms"
   brawny  hefty  muscular  powerful  sinewy 
   
2. (of meat) full of sinews; especially impossible to chew
   fibrous  sinewy  stringy  unchewable 
   
3. consisting of tendons or resembling a tendon
   tendinous  sinewy