This really depends on how many sets per exercise you do, but ultimately you will want to do more exercises for the major body parts than the smaller ones. Typically 4 exercises per large body part like your chest, back, shoulders, quads, and hamstrings will suffice; and 2 exercises for your smaller body parts like your triceps, biceps, abs, and calves will provide excellent results.
Different exercises may work the same body part, but oftentimes, different exercises will hit different angles and different parts of that particular muscle group. For instance, a bench press and an incline dumbbell press both place most of its emphasis on the chest. While they both work the triceps and deltoids as well, the main focus is on the pectoralis. On the other hand, the incline press predominantly works the upper part of the chest while the flat bench works the lower part of the chest.
That is why under H.I.S.T., you are supposed to perform one intensity set throughout multiple exercises. One intensity set, as dictated by Mike Mentzer’s H.I.T., will only work out part of the muscle and there is no one exercise that hits every part of the muscle at once with the same intensity. For example, in a leg workout, a squat emphasizes different parts of the leg from a deadlift, yet both serve an important purpose in sometimes performing them on the same day. You need to throw in multiple exercises per body part; however, you do not want to do overdo it. Remember, you must not stay in the gym for over one hour.
Such a simple thing as over-training could sound harmless, but it can be followed by an injury for a long time depriving you of a possibility to train. You have to aspire to your dream by means of careful consideration and revision of the routines and methods which seemed great to you at first sight.
It is scientifically proven that for maximum results, your major body parts (i.e.- chest, back, hamstrings, quads, deltoids) need 6 to 8 days to recuperate between workouts if it has been taxed appropriately and your small muscle groups need 48 hours to 4 days to recuperate (i.e.- triceps, biceps, abs, calves). It could seem unrealistic to be able to grow your chest bigger by taking so much time off, and for many trainees, they cave mentally to go into the gym to work out too often only to see their physique transition into a somewhat worse form.
And having heard about overtraining for the first time, I thought that either they are crazy or something is wrong with the world. Yeah, it’s really hard to comprehend if your usual split is “4 days on one day off” and each body part is totally pumped twice a week. Yet, when I was younger, I could not understand the reason why my muscles hit plateaus very frequently and why I felt exhausted very often. Not only that, but I’ve injured several body parts from pushing myself too hard, namely my shoulders.