For as long as there have been gyms, there have been sit-ups. For good reason. They can be performed with no equipment and they’re relatively easy to complete.
But are these really ‘good’ reasons?
You’ll notice the benefits are more about convenience and a low barrier to entry than they are about sit-ups actually being a ‘good’ exercise.
But first, a comment on that word, ‘good’. Of course, it’s all relative. Maybe instead of ‘good’, we should use the word ‘better’. And sure doing sit-ups is better than doing nothing at all, but all exercise exists on a continuum – and our job is to move as far along that continuum as possible. The ultimate aim is in finding exercises that are not only convenient and simply to perform, but are also safe and effective.
Let’s talk about why maybe sit-ups don’t deserve the popularity they have.
Firstly, sit-ups are not an effective method of ‘burning stubborn tummy fat’. Now that’s out of the way… the other biggest reason people do sit-ups is to either build a six pack, or to achieve the health benefits of having more strength and stamina around their midsection. As our focus is on health, not aesthetics, we won’t comment on the ‘six pack’, but we will discuss abdominal strength and stamina.
From a health perspective, the primary role of our abdominal muscles is actually not to create movement, but to resist movement. They’re less about pulling our ribs down towards our pelvis, and more about stopping our back hyperextending. A strong midsection should act as a stable foundation for our body to perform other movements.
Once we understand this stabilising function, we can start to find fault in the sit-up. Sit-ups don’t resist movement, they create movement – going against the primary stabilising role of this group of muscles.
Ok, let’s get all scientific for a moment. Your back is made of of bony vertebrae, with discs between them. The core of the disc is called the ‘nucleus’, and the tissue surrounding that is called the ‘annulus’. Think of it like a jam donut. The nucleus is the jam, the annulus is the dough.
Over time, excessive and repetitive flexion of the spine (like you’d experience in sit-ups) can squeeze the ‘jam’ (nucleus) out of the ‘dough’ (annulus). This can then press against nerves, causing pain and dysfunction. A study by the United States Military attributed 56% of all injuries sustained during their fitness testing to sit-ups.
“WHAT!? Sit-ups can kill my back!? I’m never doing them again!”
Not so fast. We’re definitely not trying to say that sit-ups are the devil – just that they’re grossly over used. In fact, it’s important to be able to do a sit-up. Trying to go from lying on your back into a standing position (definitely an important skill to have)? You will almost certainly involve some sort of sit-up. But there are other ways to train this movement without doing thousands upon thousands of sit-ups over your life (we’ll cover those soon).
We’re also not saying that movement of the spine is bad in all situations. In fact, it’s important to have a mobile spine (as long as it’s also stable). It’s would be hard to function if your spine were replaced with a steel rod. But the issue with sit-ups is that it’s not just movement, it’s also loading. Research by Dr. Stuart McGill – a leading global authority on back health, has found compressive forces of 340kg on the spine when bent in flexion during a sit-up. It’s ok to flex your spine, just do it passively, not with added load.
So we know that we should limit the number of sit-ups we do. What should we do instead? Here are some ideas:
Focus on abdominal movements that resist movement, instead of creating it.
As we’ve discussed, the primary function of the abdominal muscles is stabilisation – resisting movement. Static exercises therefore great alternatives to sit-ups, things like hollow holds, L-sits and bridges.
Train your abs without ‘ab exercises’.
Just about every compound movement we do uses our abs. A compound movement is one that uses multiple joints and multiple muscle groups. The best way to train your abs is to use them while you’re performing the movements you actually need them for. Heavy squats, deadlifts, Olympic weightlifting and strongman style movements have some of the highest abdominal muscle activation patterns (more than a lot of isolated ‘ab exercises’).
Reduce the number of repetitions.
Bret Contreras from Auckland University of Technology recommends we keep spinal flexion exercises (like sit-ups) to a maximum of 60 repetitions per session. More reps equals more loading.
Replace sit-ups with other similar (but still different) movements.
If you NEED to do a sit-up type movement (that involves flexion of the trunk), add in some variety. Imagine you’re trying to break a piece of wire. You can’t just snap it, but if you repeatedly bend it forward and back, it will eventually weaken and break. This is similar to the long term effect of sit-ups. But if you bend the wire in different places in different ways, it won’t break as quickly. Of course, this isn’t ideal (we don’t want it to break at all), but more variety and different versions of trunk flexion (like toes to bar) may be an option for you. Variety is key.