Genetics explain a lot of the differences in strength and muscularity between person to person. Specifically, the size of your frame, how many muscle fibres you’re born with and how well you respond to training essentially separate you from your gym buddy or someone who can squat 454kg.
Video: All the curls in the world won’t build your biceps if you aren’t eating enough protein. But how does the food you eat benefit your strength? This video breaks down what’s happening in your body when you down that post-workout shake.