What matters most for burning calories during weightlifting is whether you’re using big muscles like legs or small ones like chest—not how long you rest or how fast you lift.

When you lift a weight you can do 15 times, for 5 sets of 10 reps, your body’s energy burn depends mostly on how much muscle you use and how tired you get—not how fast you lift or how heavy the weight is relative to your max.

Whether you rest 1 minute or 3 minutes between sets, you burn about the same total calories—rest time doesn’t change your overall energy burn in these workouts.

To know how many calories you burn during a weightlifting session, you have to measure your breathing for at least 90 minutes after you finish—most of the burn happens after you’re done lifting.

Resistance training is energetically inefficient in terms of total caloric expenditure due to predominant eccentric muscle actions and prolonged inter-set rest periods.

Whether you lift heavy weights for fewer reps or light weights for more reps—as long as you push until you can’t do another rep—your muscles grow about the same amount.