Strength, Hypertrophy & (Some) Nutrition
Why only ‘some’ nutrition?!
Because there is A LOT we could get into. And we will, in different blogs over the coming months. But I wanted this blog to a) focus on the fundamentals of protein and carbs, and b) be short enough to not cause a deep intake of breath and a ‘no way’ as you open it!!
So here we go …
Resistance Training & Exercise Physiology: 101
Food is the fuel to train and the fuel and building blocks to recover and adapt to our training. So, to understand the food we need, we do need to understand a bit about what our training is designed to achieve, and what it does to our body.
Strength and hypertrophy is achieved through resistance training. Whether your poison could be the weight machines, the barbell, dumbbells or odd objects, you are using “resistance to muscular contraction to build the strength, anaerobic endurance and / or size of the muscle”. Aka moving heavy stuff!!
Your training is designed to achieve this exercise physiology …
Your energetic capacity is your ability to produce the energy to lift the weights. The high intensity anaerobic system is dominant in resistance training; however the aerobic system plays some role. Your force generating capacity is the strength, power and size of your muscles. In particular, your fast twitch muscles. Neuromuscular coordination is the ability of your muscle contractions to coordinate so you can a) complete a movement and b) do it correctly (e.g. not bopping yourself on the head in an overhead lift). Bodyweight is shown because, as load lifts load, a heavier individual is considered to have an inherent advantage against a smaller individual. So, if you compete in a strength based sport you typically compete in a weight class, or have your results adjusted by some factor of weight, to correct for this. So in these sports the goal is really to maximise strength: bodyweight ratio.
Strength vs Hypertrophy
There are, at least currently, no significant differences between protein and carbohydrate recommendations for strength or hypertrophy focussed athletes (once training volume has been accounted for). However, it is important to recognise that although strength and hypertrophy are linked, they are also distinct from one another.
Strength refers to the capacity to exert FORCE. This could be absolute (total weight lifted), relative (e.g. to bodyweight), strength-power (how much weight, how fast) and / or strength-endurance (how much, for how long).
Muscle hypertrophy refers to the addition of mass and volume to muscle. It could be measured by muscle fibre diameter, total weight, cross sectional area, volume and / or thickness.
Strength and hypertrophy do potentiate one another; however, they can also result from adaptation that can be uncoupled. The more advanced a strength athlete you are, the more likely it is that further increases in strength will require some addition of muscle mass, but strength does not always require a concomitant and equivalent increase in muscle size.
An increase in strength can occur in the absence of hypertrophy due to altered neuromuscular function, energy stores or production, muscle fibre type, density or architecture, and / or changes in the structure of connective tissue. And hypertrophy can occur in the absence of significant increases in strength because of changes in muscle fibre size or architecture, sarcoplasmic volume, and / or energy stores or production.
What happens in training?
Understanding this helps us understand a little more about why we might need the food we do for our training. And it is summarised in this graphic:
Resistance training exerts force on muscles. This mechanical load is detected by the muscle directly, and causes the release of growth factors (hormones that can activate growth and adaptation of the muscle). The load is also a mechanical (force) stress on the muscle, and a metabolic (energy + by-products of producing force) stress. This damages the muscle and causes fatigue, causing the cell to release inflammatory and stress signals.
Many mechanisms play a role in what happens next, however central to them is what we call ‘mTORC1’. This is like a central governor of growth and repair in the body, including the muscle. All these signals I have just described converge and activate mTORC1, which can then drive the repair, adaptation and growth of the muscle.
Importantly from a food perspective, mTORC1 will only fully activate and remain activated in the presence of sufficient energy (and ideally glucose, aka carbs) and certain amino acids (aka protein). Plus, of course, the repair, adaptation and growth of the muscle itself requires fuel and building blocks in the form of energy and amino acids. Hence, we can see that to recover and adapt, i.e. to get stronger and / or bigger, requires sufficient energy (calories) and protein to be available in the body. And this ultimately comes from our diet, particularly if we are lean and do not have a lot of energy stored in the form of fat.
Okay, so now we are ready to think about protein and carbs …
Protein: Total, Type & Timing
Protein is required to repair and build muscle. The TOTAL amount of protein appears to be the most important, followed by the TYPE, with TIMING perhaps providing some refinement around the edges.
So total … current recommendations are to consume 1.2-2.0g/kg bodyweight daily to support maximal muscle mass and strength (ISSN, ACSM and IOC position stands and guidance). This range is consistent with recent meta-analyses by Morton et al (2018) and Tagawa et al (2020). Recommended total protein intake may increase to >2.3g/kg bodyweight when you are on a diet to lose weight. This is because high protein intakes may help preserve muscle mass during weight loss (i.e. help ensure more of the weight loss is fat compared to muscle). It is worth noting that plant protein, unless in a purified form, may not be digested as effectively as animal protein as it becomes trapped in the fibre of the plant. Therefore plant based diets may require 5-10% higher protein intake than the recommendations above derived from animal protein or protein powder based studies.
Now, type … protein is made up of amino acids. There are about 22 amino acids different amino acids. Of these approximately 8 are ESSENTIAL amino acids. This means they cannot be produced in the body from other amino acids and must be consumed in the diet. A protein that contains all the essential amino acids in sufficient quantities is called a COMPLETE protein. We need all the essential amino acids to effectively make all the proteins we need in the body, which is why we focus on eating complete protein at every meal. Animal proteins are complete proteins. Plant proteins are typically not complete. This is not a problem, it just means we need to pair complementary plant proteins (i.e. ones low in different essential amino acids) to create a complete protein. As a 101: legumes pair with wholegrains, corn, nuts or seeds to create a complete protein!
A further word on type of protein. Research studies have historically been performed using purified protein powders, like whey. This is not because it is thought that powders are inherently superior to whole foods, but because they are simple. They ONLY contain protein, so if you find an increase in strength or muscle mass or whatever you can conclude that the protein is the apparent cause. Whereas if you use whole foods it could be the protein, fat, vitamins etc. More recently however studies have started to be performed using whole food proteins and the results are very interesting. There seems to be, in some cases at least, a superior response in the body from the whole food even when the total amount of protein or calories are matched with the powder or isolated protein. There seems to be something about the food matrix of the whole food that is superior. This has been found for whole eggs versus egg whites, and whole milk versus whey for example. Watch this space!
Now, timing! Protein is unlike fats and carbohydrates. Fats and carbs can be stored for later use after we eat them. Fats in our fat, and carbs as glycogen in our liver and muscle. Protein is different. Protein cannot sit around in the body waiting to be used. It is either used after we eat it, or converted to other things … like fats and carbs. This means to provide a steady supply of protein to the body for repair and recovery of, for example, the muscle we expect to need to eat protein in regular intervals throughout the day. It also seems that the amount of protein at each interval is important. This is perhaps a combination of the fact there needs to be sufficient amounts of the amino acid leucine in each meal to support full activation of mTORC1 (leucine is the key amino acid required for mTORC1 activation). Plus, you need to have a total amount of protein that can supply the amount of protein synthesis needed! So what does this all mean practically? We typically recommend having at least 20g protein per meal, around every 4-5 hours if practical.
Carbs: More important than you think?
As we flagged right at the start, the anaerobic system is the dominant energy system for resistance training, and this system is fuelled by carbohydrates.
Multiple studies have consistently show that a heavy resistance training session may use up 30-40% of the glycogen (carbohydrates) stored in the muscle. This is certainly not insignificant! Particularly when we think about the fact that it is unlikely that muscle glycogen stores are like a glass of water where it is as easy to access when the glass is half full as half empty. It is probably more like a gas canister, where the ease with which the muscle can access and use the glycogen decreases as levels deplete.
More recently, this year in fact, the story seems to have got even more interesting (Hokken et al., 2021). All previous studies have looked at total muscle glycogen. In this study, they looked specifically at the glycogen used in fast twitch fibres that are the driving force for resistance training, strength and hypertrophy. And more than that they looked at exactly where WITHIN the fast twitch muscle fibres the glycogen was used. They found that certain regions of these fibres were depleted of glycogen by as much as 54%.
So, in short, carbohydrates are important to fuel training.
As we currently have no specific data around resistance training, we draw our carbohydrate recommendations from broader recommendations based on the amount of training we do per day. These are:
· 3-7g/kg bodyweight for ~1 hour per day moderate intensity training
· 6-10g/kg bodyweight for 1-3 hours per day moderate to high intensity training
So, in summary, if you are resistance training current recommendations are:
· Eat 1.2-2.0g complete protein per kg bodyweight daily
· Divide this into regular doses of 20-40g (or more?) across the day
· Don’t forget carbs fuel your training! Eat according to training load … around 3-7g/kg bodyweight for moderate training loads of 1-2 hours a day, increasing to >6g/kg bodyweight as training increases beyond 1-3hrs.
Hokken et al. (2021). Subcellular localization and fibre type dependent utilization of muscle glycogen during heavy resistance training in elite power and olympic lifters. Acta Physiologica, 231: e13561
Morton et al (2018). A systematic review, meta-analysis and metaregression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52, 376 – 384
Tagawa et al (2020). Dose-response relationship between protein intake and muscle mass increase: a systematic review and meta-analysis of randomised control trials. Nutrition Reviews, 79 (1), 66-75