What You Think You Know About Muscle Soreness Is Wrong
I'm sure that you've heard that muscle soreness means you had a good workout. I'm also sure you've heard that when we train muscles, training creates microtears and microtrauma in our tissue, and that is how, in the repair process, we build new muscle. I'm also pretty sure you've put in a workout and been a bit disappointed because you weren't sore after the session. So, I want to break this down, discuss soreness, and explain to you why getting sore probably isn't something that you should be aiming for.
But to do this, we need to talk a little bit about muscle damage and recovery, because it's really important to understand why soreness probably isn't what you need to focus on.
First up, there are two types of muscle recovery. Let's say:
Tissue Remodelling: This occurs when you've created so much structural damage to the muscle fibre (what is called the sarcomere) that the structural components of that unit have to be fully rebuilt and remodelled. What was a totally functional sarcomere has now had to be rebuilt. That is a really big waste of resources and energy.
Tissue Repair: This is what I think more people are used to hearing about. This is the repair of muscle fibres and the organisation of the fibres back into contractile lines, so the muscle can pull in a linear fashion to create muscle contraction. That's a very normal part of the repair process when muscle is damaged.
But here's the thing: damage, tissue repair, and the muscle damage itself are not what causes muscles to grow. It's part of the process of building muscle, but it's not the primary driver of creating extra, larger muscles. And that's the part that most people (and that includes personal trainers) get wrong and do not understand.
How Muscle is Built
Let's talk about how muscle is built. Muscle fibres are not just one big muscle; there are lots of bundles of sarcomeres bound together. When we put stimulus, effort, and load through the muscles, this places mechanical tension onto the bundle of muscle fibres. If that mechanical tension is higher than was previously encountered, this signals to the brain a pathway called mTOR, in which the body's response is to make structural changes to ensure that the tissue, the muscle fibre, has the capacity to tolerate the same level of mechanical tension next time.
Part of that process is repairing the muscle fibres that were damaged, but the laying down of new fibres has nothing to do with that damage. The brain determines if it needs to increase the amount of muscle fibres across the bundle to increase muscle fibre thickness, or along the muscle to increase the length. And this seems to be dependent on the forces, and occurs in a fairly non-uniform manner.
So, it's the presence of a stimulus, which would mean effectively more load or more reps, that's greater than the previous stimulus, over time, that is progressed, that makes the body lay down new muscle fibre. And it's also worth stating, because I've mentioned on this podcast before, that increasing muscle fibre thickness is not the only thing that happens. We also have other changes: changes to the fascia, connective tissue, and capillary supply; altered nerves. Many things are happening at once, and it is a gross oversimplification to think that muscle damage alone is what causes or triggers muscle growth. It's way more complex than that.
Why the Delay in Soreness?
Let's circle back to soreness. To be honest, the truth is we don't actually know exactly why there is this delay to the onset of soreness. Soreness can start 12 to 24 hours after training. It can take up to 72 hours to start, and it can last for two to three days, or one to three days, depending on the severity of the training bout. What's really interesting is that some research shows, or suggests, let's say (because it's only a couple of pieces of research), that the tissue repair and tissue remodelling, even after really extremely damaging training protocols, the actual muscle fibre itself seems to be completely repaired after 24 hours. But this delay can take up to days, so it's days after the repair has already happened.
So why does this happen? I don't actually know. There are hypotheses, but this bit isn't fully understood. It's often suggested that it could be inflammation, lack of pressure, or damage to the connective tissue itself. There's something called the enzyme flux theory, but the truth is, we don't actually know why there is this big delay.
What Causes Soreness?
But we do know what types of training create more muscle damage and soreness, and I think that's really important to point out. So, the things guaranteed to make you sore are:
Anything Novel and New: As I sort of mentioned already, we adapt to the stresses that we place upon our bodies. So any new movement in a direction or pattern we haven't done before will cause soreness instantly.
The Lengthening Phase (Eccentric Phase): That would be the lowering of a squat, or as a dumbbell goes down towards the floor on a bicep curl. That lengthening phase, also called the eccentric phase, is the most taxing part on the muscle. So, training muscles to work at longer lengths, or focusing on the eccentric portion, can create more muscle damage and therefore more soreness.
High Number of Contractions: Just a very high number of contractions, so lots and lots of reps of an exercise, or the same movement patterns. Let's say you're doing your thighs, quadriceps, leg press, lunges, squats, and leg extensions all in the same workout, which works your knee extension. That repeated amount of contraction would also cause a lot of soreness.
Flip Your Mindset on Soreness
I want to completely flip your mindset on soreness and think of it as the other way around. Think of this example: novelty, as I mentioned, is the No. 1 thing guaranteed to make someone sore. If I just want to make someone miserably painful, I'll ask them what they've been doing in their last six weeks of training, and I'll not pick any of those exercises and just give them a brand new bunch of exercises. They're going to be wicked sore.
Let's take a split squat, for example, a rear foot elevated Bulgarian split squat, because that emphasises training into long muscle length. And let's say you haven't done that for over a year. Now, you put them in; the first two or three weeks are hell, and after that, you can hardly walk. But you probably won't even be lifting that much weight at first. But by week six, you're probably lifting 25% more weight and doing more reps per set. So you're doing more total load and more total volume per set, so your overall volume load is much higher. But here's the thing: in week six, it's not hurting you, but in week one to three, it's making you very, very sore.
You've already heard that muscles adapt, or muscles are being built, because the brain is responding to that increased mechanical tension over time. So, week-on-week progression has built muscle to the point where you are no longer getting sore. But that initial soreness then is entirely irrelevant. It's an annoying part of the process, not the process itself.
The hard truth is that the people who love getting sore and actively chase soreness, often by doing novel things, constantly bringing in new exercises all the time, they're creating lots of tissue remodelling, or the need for tissue remodelling. There's no real laid progression, and therefore no increase in mechanical tension. They're spending a lot of time getting sore, but that's it; they're not actually building any muscle. It's a really great way to spend a lot of time in the gym without getting very far.
So, to finish up, a little bit of soreness is fine; it's what we expect at the start of a training phase or block. But I'd actively encourage you to try and limit soreness, because, like I said at the beginning, the title states, "Soreness is not doing what you think it is." And if you do find yourself getting sore all the time in your training and want to create a training programme that is much more efficient and effective for your goals, I am available for online one-on-one training.
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