Understanding The Differences Between Training For Strength and Hypertrophy
Not a day goes by when I’m asked the question. It’s a question I used to plug into Google when I first started training.
‘What is the difference between strength training and hypertrophy?’
If, like me, you’ve asked Google this question too, it likely responded with a version of the following: ‘Strength training is anything between 1-5 reps, and hypertrophy training is anything between 6-12 reps.’
There’s some truth to this, but it requires more explanation. Let’s start with hypertrophy training.
Myofibrillar vs. Sarcoplasmic Hypertrophy Training
We know from the research that there are two main drivers of muscle growth: mechanical tension and metabolite accumulation. We used to think that muscle damage was also a contributing factor; however, we now know muscle damage is more an inevitable by-product of hard training. Some muscle damage is inevitable. Too much of it, however, can impede recoverability. So we shouldn’t strive for it as a driver of hypertrophy in itself.
Mechanical tension-based training is predominantly myofibrillar: it aims to increase the cross-sectional area (CSA) of the target muscles by growing and multiplying the myofibrils (the contractile elements of the muscle) inside each muscle fibre.
This is different to metabolic training which is more sarcoplasmic: it doesn’t grow the CSA of the target muscle fibres but is accomplished by the growth of the fluid area inside the muscle fibre.
Image taken from Stronger By Science - https://www.strongerbyscience.com/sarcoplasmic-vs-myofibrillar-hypertrophy/
Practically, mechanical tension-based training looks like a traditional hypertrophy training program:
A1. Bench Press 3x6
B1. Incline DB Press 3x8
C1. Tricep Pushdown 3x10
Whereas, sarcoplasmic or metabolic training might be a CrossFit WOD or look like this, where each exercise is performed back-to-back with little rest:
A1. Chest Press 3x10
A2. Costal Chest Fly 3x10
A key difference between the two styles of training is the work:rest ratio. With the mechanical tension-based program, I’d emphasise longer tempos and perform the exercises with strict form whilst not skimping the lengthened portion of the movement. The rest between sets will be moderate. On the other hand, rest between sets for sarcoplasmic training will be low to non-existent, and therefore the loads will be lighter.
Understanding this, we can polarise training from block to block, or week to week, to drive more specific training outcomes.
But how does this relate to strength training?
I like this sliding scale because it demonstrates visually that strength training and hypertrophy training exist on a continuum and therefore there will always be a degree of overlap. All we can ever really do with training is bias it towards a specific outcome. We can’t exclusively train for strength and not for hypertrophy; and vice versa. But we can bias training towards a strength-related outcome versus a muscle growth one.
Strength Training
Strength training is a demonstration of the force a muscle/the body produces in specific movements. We usually think about specific exercises when talking about strength: the squat, the deadlift, and the bench press are the big three. But we can also express strength in various ways, positions, and movements.
One of the key differences between strength training and training for muscle growth is the motor skill component. Strength training improves movement skill, inter- and intra-muscular coordination, and motor unit recruitment.
Training for hypertrophy will primarily revolve around mechanical tension-based protocols, whereas training to improve strength will focus on improving muscular coordination, movement competency and skill, and motor unit recruitment. This is why training for either should look different, despite the overlap.
Improving movement competency and muscular coordination comes with practice, and improving motor unit recruitment requires heavier loads than we typically use for hypertrophy training.
Let’s try a metaphor: I want you to imagine that each muscle in your body is a factory. In each factory, you have 100 employees. The factory only requires as many employees as necessary to complete a job - it doesn’t want to waste money by employing more workers than necessary to complete the task. One day, the employees are trained on how to be better at their jobs; their individual output increases. Now the factory can produce the same amount of work with even fewer employees, freeing up the others to do further work. Thus, the ceiling of the factory’s potential output rises. It’s now a more productive factory.
Your muscles aren’t factories filled with workers, but structures made up of muscle fibres. Similar to the factory, a muscle will only recruit as many muscle fibres as is necessary to complete a task. Raising a glass of water with your hand won’t require many, but lifting a heavy barbell from the ground will.
Strength training (ie. training with heavier loads, typically above ~85% 1RM) forces the muscles to recruit more muscle fibres to complete the task/exercise. As our muscles adapt to heavier loads, the ceiling of our strength potential rises.
If the mechanisms through which hypertrophy and strength improvements occur are different, then the training must also look different. Both hypertrophy training and strength training are essential to being resilient, athletic, and strong. Understanding the differences between them will help with programming exercises and establishing an overall goal for your future training blocks.
