When everyone steps foot into a gym or undertakes any sort of resistance training, one of their goals tend to be to grow lean muscle mass or "Muscle Hypertrophy". But what do we mean when we talk about muscle hypertrophy? and what do we need to do to achieve it?
Muscle Hypertrophy is the result of an increase in size of muscle mass due to a rise in the length and thickness of each muscle cell without greater muscle cell numbers. This occurs when the skeletal muscle is subjected to an overload of stimulus eg. weight training, which will in turn change the diameter of muscle fibres and subsequently an increase in the cross-sectional area.
So how do we achieve muscle hypertrophy? and what factors affect muscle growth? There are 3 factors that come in to play and are therefore responsible for initiating muscle hypertrophy during resistance exercise: Mechanical Tension, Metabolic Stress and Muscle Damage.
Mechanical Tension is the tension that is produced by force generation and stretch, both of which are essential for muscle growth. It should be seen as lifting the with the highest intensity possible with the greatest amount of weight, safely, every time you step foot into a gym, thus creating large amounts of mechanical tension throughout the muscle. Although mechanical tension alone can produce muscle hypertrophy and it has been shown it needs to be paired with at least one of the other 3 factors to see not only an increase in neural adaptations, but also muscle hypertrophy.
The second is Metabolic Stress, although it has been shown to not have a significant impact on muscle growth, as it results from exercise that relies on anaerobic glycolysis for ATP production, which results from a buildup of things such as lactate, hydrogen ions, phosphate, creatine etc. The longer that these by products stay in the muscle the harder they are for the body to remove and replace with good nutrients. Therefore the greater metabolic stress not only affects the body's ability to remove these from the body but then mediates and limits the hypertrophic response.
And third but not final is Muscle Damage, a direct result from exercise training that causes localised damage to muscle tissue, and is theorised to generate a hypertrophic response. The inflammatory response to damaged muscle fibres caused by resistance training, is believed to lead to the release of various growth factors, which will then promote muscle hypertrophy.
The key here and the key overall to gaining muscle and muscle hypertrophy would be to have all of these 3 factors in sync, being able to create the most amount of muscle tension during a session, creating "good" muscle damage that comes from resistance exercise, and decreasing metabolic stress on the body so it is able to remove the by products of exercise such as hydrogen ions and lactate etc, so that it is able to replenish the muscle as soon as possible and kick start muscle hypertrophy to see maximum muscle growth.
By Ethan Clark