Gaining muscle seems simple, but the process is actually guided by specific mechanisms. Learning what these mechanisms are can help you use your time more effectively in the gym by focusing on what matters most.
The method behind building muscle is simple at its core: train, eat, sleep, and grow. However, the science behind growth is one of the most sought-after topics in the fitness industry, with often differing methods to help aspiring lifters get the results they want.
The goal of this article is to simplify and summarize the key things you should focus on if your goal is muscle hypertrophy, ie. muscle growth.
Mechanisms of Muscular Hypertrophy
Muscle growth comes from a specific stimulus. In order to increase your muscle size, it's important to first understand which mechanisms are believed to play a role:
Mechanical Tension
Metabolic Stress
Muscle Damage
You can think of these as muscle growth “pathways,” and they can be heightened or lessened by how you train. For example, heavy weightlifting emphasizes progressive mechanical tension and muscle damage. Working with lighter weights and higher rep ranges, however, emphasizes metabolic stress, especially when the rest times in between sets are relatively short.
Mechanical Tension
created by the actin-myosin cross-bridges of muscle fibers. In other words, muscle
hypertrophy occurs when enough biomechanical tension is created by the muscle fibers
that their structural integrity is compromised. As an adaptive response to this stress, the
muscle fibers undergo changes in their structure, including growth of the muscle fibers
to be able to produce more tension in the future.
The most effective way to do this is to increase the amount of weight you’re lifting over time.
Metabolic Stress
In addition to mechanical tension, metabolic stress has been proposed as a possible
mechanism of muscle growth. Metabolic stress refers to the accumulation of metabolic
hypoxia, i.e. the oxygen shortage, during exercise. Metabolic stress is particularly high during exercise with a large demand for glucose and you feel it in part as ‘the burn’ in your muscles.
There is no direct evidence that metabolic stress itself plays an important role in muscle growth independent of mechanical tension.
Muscle Damage
heavy exertion, muscles can become damaged as a result of the mechanical tension
imposed on them, especially when the muscles are lengthened, which makes them
more susceptible to micro-tears. It's important to think of muscle damage as a potential byproduct of training and not necessarily something that should be sought out in isolation. Excessive damage can impair your ability to impose mechanical tension on our muscles in future workouts, which is much more established as a primary cause of muscle growth.
Muscle damage is not something you should actively seek out but rather minimize. Muscle damage is not required for muscle growth and muscle damage does not correlate with muscle growth.
Summary
Research shows that out of each of these pathways, progressive mechanical tension is the most important for muscle growth. In other words, if you want to build muscle as quickly as possible, you want to ensure you’re progressively adding weight to the bar over time. That’s why one of your primary goals as a natural trainee should be getting stronger over time with the same exercises, in a moderate repetition range.
You can build muscle with both heavy and light loads but, if you want to maximize muscle growth, you should emphasize training with heavy loads and atleast a moderate training volume.
A well-designed workout program does three things for each major muscle group in your body:
It emphasizes compound heavy weightlifting wherever possible.
It keeps you within your individual training volume tolerance, ie. your weekly amount of total working sets for each muscle group.
It allows you to continue to progress by either adding weight to the bar, or increasing the amount of reps you can do with a given weight.
A larger muscle has the ability to produce more force due to its increased CSA (cross sectional area). If you are training with a sufficent volume and getting stronger with the same exercises over time, there is a high probability you are growing muscle. If you arn't getting stronger over time, you almost certainly arn't growing muscle. Monitoring your progression in strength over time is one of the most practical methods we have of assessing progress.
Is your strength improving over time?
References:
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2. West DW, Burd NA, Staples AW, Phillips SM. Human exercise-mediated skeletal muscle hypertrophy is an intrinsic process. Int J Biochem Cell Biol. 2010;42(9):1371-1375. doi:10.1016/j.biocel.2010.05.012
3. Schoenfeld BJ. Potential mechanisms for a role of metabolic stress in hypertrophic adaptations to resistance training. Sports Med. 2013;43(3):179-194. doi:10.1007/s40279-013-0017-1
4. Schoenfeld BJ. The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res. 2010;24(10):2857-2872. doi:10.1519/JSC.0b013e3181e840f3
5. Flann KL, LaStayo PC, McClain DA, Hazel M, Lindstedt SL. Muscle damage and muscle remodeling: no pain, no gain?. J Exp Biol. 2011;214(Pt 4):674-679. doi:10.1242/jeb.050112
6. Damas F, Phillips SM, Libardi CA, et al. Resistance training-induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage. J Physiol. 2016;594(18):5209-5222. doi:10.1113/JP272472
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