In strength training, volume is a term used to describe how much work you do, such as the number of repetitions (and sets) you perform in an exercise. Intensity describes the difficulty of the exercise, usually depending on the weight you are lifting. Let's take the deadlift as an example. If you do five reps with a 50 kg barbell and increase to 10 reps with the same barbell, you will increase the volume. If you do five reps, but increase the weight of the barbell to 75 kg, you will increase the intensity.