Many a time the question is asked about how many exercises a workout should contain, how many sets of each exercise should be done and finally how many reps each of these sets should have. The answer really depends on your goals and what you want to get out of your workout.
Before going into the details, here is the summary of the answer:
- If your focus is on weight loss and the gain of definition, then the recommendation is to go for 4 to 6 exercises when working out a body part, e.g the chest. Each of these exercises should contain 4 sets. Each set 12 to 15 reps.
- If your focus is on gaining muscle mass, then go for 4 to 5 exercises again per workout. An exercise should have 4 sets while each set should have 8 to 12 reps with 10 being the magic number.
- Lastly, if your goal is to gain strength, then your workout should have 3 to 4 exercises. Each exercise 3 sets instead of 4 and each set should be 6 to 8 reps.
It is very important to note that for each of the 3 recommendations above, your weights should be picked in a way that you barely make the last 2 reps of each set of each exercise. As in, you reach the point of failure by the end of each set on your own.
You can have an extra set of hands to avoid any accidents but not to help you with the weights. This clearly means that you will be carrying heavier weights at an overall smaller number of reps for strength training while your weights will be lighter at a higher number of reps for definition with the gain of muscle mass being in between.
The main reason lies in the different types of fiber muscles are made out of. Muscle fibers are divided mainly in two: a) slow twitching b) fast twitching whereas there are two sub types of the later: IIa and IIb. Regardless the type, muscle fibers are responsible for the contraction of the muscles.
So for muscles to contract and perform, they require energy. Energy comes from burning fuel. Fuel is food, nutrition: There are 3 main types of food from a fuel burning perspective: carbohydrates, fats, proteins whereas proteins are used for maintaining and repairing damaged muscle and the former two are used for providing energy.
Depending on the type of activity, its intensity and duration, different muscle fibers are used. For slow, low-intensity activities the slow twitching fiber step in triggering aerobic metabolism, meaning that the body will rely on burning fat with the help of oxygen. The composition of slow twitching fibers makes them efficient in leveraging oxygen to extract energy out of fat.
This leads to light weights, slow easy movements and a high number of reps to be ideal for burning fat. Oxygen can burn up carbs much faster and free needed energy for faster, more intense movements. Now let's step aside for one moment and discuss muscle growth and then tie it all together: It might seem contradictory at first but muscle building is all about muscle destruction!
When muscles lift heavy weight in a repetitive manner, the resistance leads to tearing the muscle tissues. The organism being genetically coded to perform re-generation of certain tissues, goes ahead and starts replacing the torn tissue and overcompensates to be better equipped for "future shocks" and voila! The muscle grows. When using heavy weights, the fast twitching fibers set in after the slow twitching ones are exhausted.
Fast twitching fibers go a different energy pathway, triggering anaerobic metabolism. Anaerobic metabolism means that energy is provided without the help of oxygen, as this is a much faster process. However these are bursts of energy that only last for a few seconds.
Generally speaking any exercise will utilize both types of fiber in different ratios and resort to all sources of energy, again in different ratios depending on the activity. So you will always burn fat, carbs and use up protein for repairing damaged muscle, however in different ratios depending on the intensity and duration of your exercise which takes us back to the first section of this article.