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Hypertrophy is merely a fancy word for an increase in muscle mass. This usually manifests itself as an increase in muscular size and strength, often as a result of resistance training. Many struggle to put on muscle for a number of reasons, namely; programming, nutrition, lifestyle, consistency etc. The principle is simple (in essence), the application is often the hard bit.

“Muscular adaptations are predicated on a net protein balance over time. The process is mediated by intracellular anabolic and catabolic signalling cascades.” (Schoenfeld).

Sounds fiddly – yeah kinda! Hypertrophy requires a system that’s going to help induce the above, and adherence to give it the consistency it thrives off. Before delving deeper into this, let’s have a look at the mechanisms that underpin hypertrophy.

 

The Mechanisms of Hypertrophy.

Increases in protein accretion following resistance training has been put down to three key mechanisms;

Mechanical tension – exposure to heavy load (>75% 1RM). Muscle is highly responsive to alterations in mechanical loading. Researchers have surmised that mechanical tension is one of the primary driving forces behind training induced hypertrophy, initiating critical hypertrophy related intracellular signalling post resistance training.

Metabolic stress – also considered to be of particular relevance to exercise induced anabolism. Simply put, it’s an exercise induced accumulation of metabolites, particularly lactate. Evidence suggests that various metabolites can directly influence the hypertrophic response.

Muscle damage - exercise induced muscle damage (EIMD) can be specific to small tears, or manifest as large tears. However, hypertrophy can exist without noticeable muscular damage. The evidence implies that micro-trauma enhances the adaptive response that mediates anabolism.

 

The Role of the Variables

Volume – the amount of exercise performed over a period of time. There is compelling evidence that indicates that higher training volumes are necessary to maximise anabolism. Multi-set protocols favouring high volumes of resistance training optimise the hypertrophic response.

Frequency – the number of sessions performed in a given period of time e.g. number of times a muscle group is worked per week. Split routines are the preferred method, allowing for a greater volume of work per muscle week (x2-3), therefore, enhancing muscular adaptations.

Intensity – the load or weight of the lift, widely considered as the most important factor in the hypertrophy response. Training across a wide range (1-20+ reps) is recommended to maximise all avenues of muscular development, with specific focus within the 6-12 rep range.

Rest - the time taken between sets. Short rest periods (30 seconds or less) have been shown to markedly increase metabolite accumulation. However, despite the commonly accepted belief that hypertrophy orientated routines benefit from moderate rest (60-90 seconds), holding at least 120 seconds between multi-joint is more favourable, and 60-90 for isolation.

 

Nutrition for Hypertrophy

Energy Balance, the net difference between energy intake and energy expenditure, has been known to have a profound effect on the capacity to build muscle. Are you consuming more than you’re expending? Short term bouts of calorie restriction have been shown to interfere with molecular signalling, favouring catabolism over anabolism. Alterations in signalling are consistent with research that calorie deficits have an adverse impact on muscle protein synthesis.

In addition to energy balance, the consumption of macronutrients plays a key role in driving muscular adaptations. Protein, the building blocks, however, only 20 of the amino acids (essential aminos) actually serve as the true building blocks of bodily proteins.

“The anabolic effects of nutrition are primarily driven by the transfer and incorporation of amino acids obtained from dietary protein sources into bodily tissues.” (Schoenfeld)

Exercise potentiates the anabolic effect of protein intake, heightening both the magnitude and duration of the response. Post training, protein synthesis rates are rapidly elevated initially (45-150 mins), however, given the increase post exercise, net protein balance remains negative without nutritional intervention. So, you don’t need to smash your protein shake while you’re still perspiring, but consumption of protein within the first hour post training, and then regularly throughout the day is favourable.

The RDA for protein is 0.8g/kg of body mass, however, daily requirements for those seeking to maximise muscle mass need substantially more (1.6g/kg-2.2g/kg). While proteins are the building blocks, the other macros, namely carbs and fats, also play a crucial role in the hypertrophy process. Carbs help fuel sessions and replenish muscle glycogen post training. Glycogen is known to have a direct influence on muscle hypertrophy by mediating intramuscular signalling. Carbs also and have a direct impact on hormone production. Individuals who consistently consume a higher carb intake have been shown to have greater testosterone concentrations and a more favourable testosterone:cortisol profile.

Research indicates between 4-7g/kg/day, but these recommendations don’t take individual differences into consideration. A minimum of 3g/kg/day is seen to be a reasonable starting point. Once the protein has been prioritised, and carbs have been established, the remainder of the meal should be comprised of dietary fats – mainly polyunsaturated. A minimum of 1g/kg/day is known to be optimal at preventing any negative hormonal changes.

What about nutrient timing? And the infamous “anabolic window?” There’s plenty of research that will back the efficacy of timing for increasing protein synthesis rates post resistance training. Exercise causes the depletion of a number of stored fuels (glycogen and amino acids), and breakdown of protein balance, therefore, replenishing the body within an hour post training is advisable to promote a net protein balance and optimise the hypertrophic response. Given the anabolic effect of protein, for those seeking to maximise hypertrophy, spread protein intake out throughout the day (~0.4-0.55g/kg/ meal), across a number of meals every 4 hours or so (1.6g/kg-2.2g/kg/day).

For more info about hypertrophy orientated programming from the AEI continuum, check out Evolve – it’ll cater for all your hypertrophy needs.

 

References

Abernethy, PJ, Jurimae, J, Logan, PA, Taylor, AW, and Thayer, RE. Acute and chronic response of skeletal muscle to resistance exercise. Sports Med. 17; 22-38, 1994.

Alway, SE, Gonyea, Wj, and Davies, ME. Muscle fiber formation and fiber hypertrophy during the onset of stretch overload. Am. J. Physiol. 259: C92-102, 1990.

Dungan, CM, Murach, KA, Frick, KK, Jones, SR, Crow, SE, England, DA, Vechetti, IJ. Elevated Myonuclear density during skeletal muscle hypertrophy in response to training is reserved during pretraining. Am. J. Physiol. 316: 649-654, 2019.

Goldspink, G. Impairment of IGF-I gene splicing and MGF expression associated with muscle wasting. Int. J. Biochem Cell Biol. 38: 481-489, 2006.

Gunderson, K. Excitation prescription coupling in skeletal muscle; the molecular pathways of exercise. Bio. Rev. Camb. Philos. 86: 564-600, 2011.

McCroskery, S, Thomas, M, Maxwell, L, Sharma, M, and Kambadur, R. Myostatin negatively regulates satellite cell activation and self-renewal. J. Cell. 162: 1135-1147, 2003.

Rooney, KJ, Herbert, RD and Balanve RJ. Fatigue contributes towards to the strength training stimulus. Med. Sci. Sport Exercise, 26: 1160-1164, 1994.

Vierck, J, O’Reilly, B, Hossner, K, Antonio, J, Byrne, K, Bucci, L, and Dobson M. Satelite cell regulation following myotrauma caused by resistance training. Cell Biol. Int. 24: 263-272, 2000.

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