I owe a big thank you to a number of people for the ideas contained in this post, notably Dr Brad Schoenfeld for his fantastic literature review on skeletal muscle hypertrophy, Dr Ben Rosenblatt for introducing me to occlusion training, Paul Carter for his writing on compensatory acceleration training, Dante Trudel for devising DC training, and many others. Thank you.
Ask the average rugby player why they lift weights and almost unanimously they will respond with wanting to get big or gain weight. They want to be strong, look big and feel big too. Similarly the most popular question I get asked is always about how to gain muscle for rugby. Though size and strength are often different things, particularly if you have been training a long time, it is true to say that in general a bigger athlete is a stronger athlete. Likewise a bigger athlete is typically more effective in collisions. A bigger athlete is also usually a more confident athlete, and more intimidating athlete to his or her opponents- not a bad thing in a tough, contact sport like rugby.
So hypertrophy training is definitely valid part of rugby strength and conditioning in itself. But perhaps more importantly it lays an important foundation for strength development down the road in a player’s training. Not only this but it will also build connective tissue strength, helping to reduce the risk of injuries to these structures. Some coaches also liken muscle hypertrophy to body armour that can also help prevent injuries elsewhere within the body, for example bone or internal organs.
What is hypertrophy and what causes it?
When we talk about getting big or gaining lean weight we are describing skeletal muscle hypertrophy- an increase in the cross-sectional area of the muscle via a combination of increased contractile protein and also increased cellular fluid and stored energy substrates. Muscle hypertrophy is our body’s response to the resistance load placed upon them. This can take many forms e.g. bodyweight, bands, manual resistance and, of course, the awesome stuff that turns you into a real man and makes women weak at the knees: barbells and dumbbells.
It goes without saying that many roads lead to Rome and that there are a number of successful ways to develop muscle hypertrophy in the weight room. However hypertrophy arises thanks to a combination of three mechanisms. All the different forms of hypertrophy training are trying to emphasise one or more of the following:
Muscular tension- the physical act of muscle creating tension to overcome the load of the resistance. The science suggests that by creating muscular tension you are switching on the genes responsible for synthesising new muscle and slowing the breakdown of existing muscle.
Muscular damage- the physical effects on the muscle of overcoming that resistance. By creating damage, the tissue floods with white blood cells which promote an inflammation response, triggering the release of chemicals that stimulate growth. The swelling of muscle cells may also have a direct effect on building new muscle, as the cell tries to protect itself from the potentially damaging effects of the swelling i.e. it doesn’t want to burst!
Metabolic stress- the physiological effects of overcoming that resistance. This includes molecules like lactate, hydrogen ions and creatine amongst others, which stimulate the release of muscle building hormones like testosterone and growth hormone. There may be an additional effect of stimulating more blood flow to the working area, which in turn increases swelling, turning up the signal for muscle growth via muscular damage.
There is no one factor that is going to result in maximal muscle hypertrophy as there are plenty of examples of high tension weights programmes or other exercise modalities which produce a ton of metabolic stress (running the 400m for example) which produce little to no hypertrophy. Likewise I can smack your legs with a baseball bat for a few hours and create huge amounts of damage, but you won’t get any bigger. The research appears to indicate that all three are necessary for optimal muscle hypertrophy.
Hypertrophy training variables
Obviously we want to try and maximise all three mechanisms in order to increase muscle size as muscle as possible. There are a number of different variables that we can manipulate in the weight room. They include:
Minimum effective load (% of 1RM)
Repetition range (reps per set)
Rest periods (how long between sets)
Total volume (weight x reps x sets)
Time under tension (repetition length)
I will also cover a bonus topic in the form of Kaatsu training
Minimum effective load (% of 1RM)
Like any physical ability we train for, there has to be a minimum amount of stress that we expose the body to in order to force it into adapting- it is impossible to get big sat on your arse doing nothing. Research suggests that the bare minimum that must be used to trigger hypertrophy is 65% of your one rep max. Any less than this and your brain will not recruit the muscle fibres that have the greatest capacity to grow (fast twitch fibres). However this can drop to as low as 30-50% of your max if you are utilising hypoxic training methods (discussed later).
So make sure you are utilising at least 65% of your max, but do not get tempted into using the highest percentages of your max whenever possible. Firstly you will accumulate a large amount of fatigue, and soon reach an overtrained state. But secondly you will not be able to perform the number of reps per set that appears to result in the greatest amount of muscle gain:
Repetition range (reps per set)
The magic zone for hypertrophy appears to be sets of 6-12 reps. This is because it strikes a good balance between a load that is heavy enough to tap into all muscle fibres, with one that creates a high amount muscle damage and metabolic stress (something that isn’t possible with very light or very heavy loads). Likewise you are able to tap into a broad range of faster and slower twitch fibres with a moderate rep range.
Some additional science: research suggests that training promoting high levels of lactate stimulate cellular swelling and will tax glycogen reserves, resulting in further swelling when that glyocgen gets replenished. A 6-12 rep range will create this physiological environment nicely.
The science here definitely appears validated by conventional wisdom where bodybuilders are typically more muscular than powerlifters, despite powerlifters being far stronger with lower reps. Stick with the body building wisdom if you want to get big: get as strong as you can within the 6-12 rep range. One method that I am fond of is to start at the lower end of the rep range, then spend several weeks building up to the top end, before adding weight. For example:
Week 1: 5*6 squats with 140kg
Week 2: 5*8
Week 3: 5*10
Week 4: 5*12
Week 6: back to 5*6 with 145kg (or deload as necessary)
This is not to say that super high rep sets (likely to maximise metabolic stress) are not useful. If they weren’t, bodybuilders would not do them so much. However if you want to maximise hypertrophy the 6-12 range should be your highest priority, with higher rep sets coming later in the session.
Note: should you go to failure? Taking sets to failure will definitely increase recruitment of muscle fibres and increase metabolic stress, however there is a psychological and physical cost to be paid. Continual use of sets to absolute failure will probably result in overreaching and stagnation, so they should be cycled in and out of the programme on regular basis.
Generally speaking short rest periods of around 30s appear to create the highest amounts of metabolic stress- that’s why they suck so much. The problem with short rest periods is that often the rest is too short for you to recover sufficiently to tap into your fast twitch muscle fibres on subsequent sets. This is a bad thing as they have the biggest capacity to grow.
Long rest periods allow to generate high levels of muscular tension, but the metabolic stress element of the equation is greatly reduced. This is why moderate rest periods of 60-90s are generally considered optimal for hypertrophy as you hit the happy medium between muscular tension and metabolic stress, as evidenced by the research.
The research here is fairly unequivocal: higher volume, multiple set programmes produce more muscle gains than lower or single set routines. This is because they significantly increase signal of all three muscle building mechanisms: muscular tension, muscular damage sustained during the session and also the total metabolic stress of the session. This is probably why we see such huge legs on track cyclists, speed skaters and other such athletes- volume!
Though some popular programmes utilise very high volumes- for example German Volume Training- between 4 and 6 sets per exercise appears sufficient to maximise hypertrophy. It goes without saying that GVT was designed with genetically well selected, drug using elite weightlifters. So it might not be the most applicable programme in the world for normal, unenhanced rugby players!
Time under tension
Time under tension essentially describes the speed at which the resistance is moved during a rep. It appears that on the whole that rep speed his little or no effect on total hypertrophy if % of 1RM, rep range and total volume are appropriate. However some papers have investigated the effect of varying rep speed during both the concentric (lifting) and the eccentric (lowering) phases.
They mostly found that performing the concentric phase as quickly as possible resulted in more muscle growth by tapping into a greater pool of muscle fibres. However the reverse may be true in the eccentric portion, where lowering the load more slowly increases muscle damage and metabolic stress within a selected number of muscle fibres. Feel free to introduce some tempo work to your sets, but don’t get hung up on it. It doesn’t appear to be that significant of a variable.
Last but not least it would be good to mention an alternative Japanese hypertrophy technique called Kaatsu, which involves the use of cuffs, wraps or ligatures to cut off the blood flow to muscles during weight training. The rationale for Kaatsu is that by depriving the muscles of blood, by products like lactate and hydrogen ions accumulate faster, and are cleared more slowly, creating a stronger signal for muscle growth. There may also be a super compensation effect of even higher blood flow when the restriction is removed, heightening muscle swelling and promoting even more growth.
Using this technique it is possible to generate significant hypertrophy using as little as 30-50% of 1RM. In one study Kaatsu resulted in as much hypertrophy as non-hypoxic weight training with 85% of 1RM. There are a number of protocols that may be used when implementing Kaatsu, but my preferred method is one that I stole from Ben Rosenblatt at the English Insititute of Sport: 3 sets to failure with 30% of 1RM with 60s rest between sets, making sure to keep the tension on the arms/legs between sets. This is the same protocol we used for London Irish centre Fergus Mulchrone during his broken foot at Rotherham Titans, and I have even heard of some of the British Olympic kayakers using this method for 50 rep sets of wide arm chins!
If you are going to give Kaatsu training a try, get yourself some standard knee wraps and make sure to use a decent amount of tension. I would say “firm” but not “my leg is going to fall off”. You can use this technique for both upper and lower body, tying the wraps around just below the armpit and just below the backside respectively. Keep the wraps on during your rest periods and only take them off at the end of the last set, when you think your legs/arms are about to fall off. Here is a sample video of someone performing the technique:
Even if you do not have wraps available you can still approximate Kaatsu training by performing all your reps for a given exercise without locking out. Doing so maintains muscular tension throughout the set, severely restricting blood flow to the muscle and increasing the release of lactate and other growth factors- a trick that bodybuilders have instinctively been doing for decades.
There are some additional things you may want to consider in your training if you are trying to gain lean muscle mass. One of them is the use of multi joint versus single joint exercise. Whilst some coaches are adamant that multi joint exercises like the squat, bench press, deadlift, row and press are all that is needed to get as big as possible, there is a place for single joint exercises like curls, extensions, and raises within a muscle building programme.
It is true that multi joint exercises create much higher amounts of muscular tension than isolation type exercises. However they spread the muscle damage and metabolic stress over multiple muscle groups which means that individual muscles or muscle groups might not receive the targeted stimulus they need for growth. The use of single joint exercises should enable a more targeted and intense muscle building stimulus. It is for these same reasons that (anecdotally) body part split training sessions are more effective for muscle building, whereas whole body or upper/lower split programmes are more effective for strength development.
There may also be some muscle gaining benefit to heavy stretching. Though the research is currently limited to animals only, scientists have been able to significantly increase muscle building when muscles have been placed under loaded stretches- presumably by creating additional muscle damage and by stimulating the same gene pathways switched on by the tension of muscle contraction. This is a feature of the popular “Dogg Crapp” training method devised by body builder Dante Trudel and anecdotally is quite effective.
Lastly do not forget the role of nutrition, hydration and recuperation in muscle building: as outlined in the first few paragraphs hypertrophy is simply the body’s response to the stress of muscular resistance. To facilitate that response the body needs excess calories (about 500-1000 extra calories per day), excess protein (about 1g per lb of bodyweight), lots of water and and lots of recovery in the form of sleep and a stress free environment. These factors are just as important as resistance training in the development of hypertrophy and are worthy of an article in themselves. The world’s best hypertrophy programme with a bad diet and lifestyle produces zero results no matter who you are. Try to put as much effort into these factors as you do your training in the gym.
To sum up, here are the general rules you should stick to if you are trying to maximise muscle gain in your training:
Don’t forget: you need a combination of muscular tension, muscular damage and metabolic stress to maximise muscle gain.
Exercise with a minimum of 65% of your 1 repetition maximum.
Perform the majority of your training in the 6-12 repetition range, occasionally taking sets to failure.
Most of your rest periods should be between 60-90s long. Rest longer within this range when lifting lower reps, less when lifting higher reps.
Stick to higher volume, multiple set routines. About 4-6 sets per exercise is a good number.
Lift the bar as explosively as possible, then lower the bar under control for around 2-3s per rep.
Your programme may also benefit from Kaatsu/Hypoxic training or other methods which restrict blood flow to the muscle, particularly during training periods where you are unable to utilise heavy loads e.g. following an injury or during heavy in-season periods.
Utilise a mixture of multi joint and single joint exercises to maximise muscular tension and damage, and metabolic stress respectively.
To maximise hypertrophy train in a body part split fashion. For strength focus more on whole body or upper/lower split programmes.
Heavy loaded stretching may be a useful addition in maximising muscle gain. Read up more about it here.
Eat, hydrate, sleep and recover just as hard as you train in the gym to maximise lean muscle gain.