What is the definition of hypertrophy?
This is the term we give for the enlargement of organ or tissue cells. Regarding skeletal muscle, it is the increase in myofibrillar proteins within a muscle . To achieve hypertrophy, we put muscle fibres under mechanical tension, metabolic stress and muscular damage .
Mechanical tension is the amount of load (weight) you put onto the muscle through its concentric (muscle shortening), eccentric (muscle lengthening) and isometric phase (constant tension). Time under tension also plays a part in hypertrophy.
Metabolic stress is the build-up of metabolites when the energy demand for the muscle is supplied by anaerobic glycolysis. This will include cell swelling, reduced venous return and the build-up of metabolites (such as inorganic phosphate, lactate and hydrogen ions). Hypoxia (lack of oxygen) also plays a part in metabolic stress.
Resistance training can cause tears to the muscle cells. The body treats this stress in the muscle fibres as an injury and sets out to rebuild so the damage doesn’t happen again. This means the myofibrils inside the fibres increase in density.
Increasing muscle mass has numerous benefits to the body:
- Your metabolic rate will increase just by having more muscle on the body
- You will get stronger and bigger
- Reduces the risk of injury
- Improves confidence
- Improves mood
- Improves the immune system
Reps and hypertrophy
Recent studies have suggested rep ranges don’t matter when it comes to increasing muscle . As long as you train near to failure. It’s best to choose a rep range that’s suitable for you.
Sets and hypertrophy
Volume is an essential factor for muscular hypertrophy  as higher workloads causes the breakdown of muscle tissue, causing the body to adapt. The minimum number of sets for improvement in hypertrophy is around 10 sets per week, per body part .
Intensity and hypertrophy
People respond differently to training intensities, so it’s wise to include periods of lifting heavy mixed with periods of low loads, as long as low loads are taken to near failure. Lifting heavy weights, your body will adapt and improve its ability to lift heavy and vice-versa with light weights, you will improve muscular endurance. Remember training to failure all the time, the body will fatigue quickly and stop your ability to train efficiently.
 MacDougal et al. 1984. Schoenfield, 2010
 Ozaki et al. 2015. Schoenfeld, 2010
 Weiss et al. 2000, Compos et al. 2000, Schoenfeld et al. 2014 and 2015. (https://www.strongerbyscience.com/the-new-approach-to-training-volume/)
 Schoenfeld et al. 2019 – https://journals.lww.com/acsm-msse/Fulltext/2019/01000/Resistance_Training_Volume_Enhances_Muscle.13.aspx Schoenfeld et al. 2017 – https://www.ncbi.nlm.nih.gov/pubmed/27433992) https://www.youtube.com/watch?v=qwv3JqOUqWs