The amount of work done by compound exercises like squats or deadlifts on specific muscles can be calculated as a fraction of the total exercise volume in a workout.

To really know how much each muscle is being worked during the week, we should count exercise volume based on how much each move actually hits that muscle — not just how many sets and reps you do.

Multi-joint exercises that engage both the biceps and triceps add a significant amount to the overall workload these muscles experience during a workout.

Exercises like bench presses and pull-downs add a large portion of the overall workload for the muscles in the arms during strength training.

When the number of weekly resistance training sets for a muscle group is increased from 8 to 12, muscle size increases by about 0.9% compared to the lower volume.

A new way of measuring workout volume—by giving less weight to exercises that are not the main focus—better predicts muscle growth and strength gains than simply counting all sets. This suggests that the type of exercise matters more than just how many sets are done.