At the most fundamental level resistance builds muscle. As your muscle adapts to increasingly difficult resistance levels, it adapts to the new stimulus and grows in response. This is however a very simplistic view as we know that nutrition, rest, and recovery are equally important factors for muscle growth.
The question then is provided that nutrition, rest, and recovery are at adequate levels, what workout techniques can be used to enhance muscle growth.
If the main goal is muscle growth then we need to follow the principles of hypertrophy. Note that training for hypertrophy is different from training for strength. A fact quite evident when looking at bodybuilders vs powerlifters. Powerlifters typically can lift way heavier weights while bodybuilders actually look more muscular.
The main difference between the two different types of training is when training for strength the emphasis is on moving the heaviest weight possible from point A to point B and back in the most efficient way possible, while when training for hypertrophy the focus is on moving the weight in a controlled fashion to create as much tension in the muscles as possible.
Basically, muscle size is affected through two types of growth: myofibrillar and sarcoplasmic. Myofibrillar growth refers to the increase in the size of muscle fibers, and sarcoplasmic refers to an increase in the volume of fluid in your muscles. Both types of growth however might be related so its best to not think of them in isolation and waste time trying to target one vs the other.
There are three primary mechanisms for creating muscle growth: muscle tension, metabolic stress, and muscle mechanical damage.
Muscle tension is achieved by progressive overloading of weights being pushed/pulled by that muscle or by increasing the volume of the total weights being moved in that session by increasing the number of reps per set, or the number of sets. We need to make sure that the muscles are under consistent strain throughout the rep, squeezing the muscle during the concentric portion of the rep, and stretching the muscle during the eccentric portion of the rep.Metabolic stress is achieved through continuous tension of the muscles using contracted consistency position exercises. It's that burn feeling you get when your muscles are exhausted and there is a lack of oxygen going to your muscles and blood can't leave your muscles fast enough and gets trapped and metabolic byproducts like lactate builds up along with the blood. This triggers cellular swelling through more fluids being pulled into the muscle cells.Muscle mechanical damage is caused through lifting weights that cause micro-tears in the muscles, forcing it to repair itself and grow to become denser and bigger. It can be achieved through eccentric overload, by slowing down the eccentric movement (the portion of the rep where the weight is lowered back to its original position), or by modifying the workout to focus on the eccentric portion of the rep.