Why cant I do any situps without someone holding my feet

Question

At the Gym I use an abdominal machine to do stomach crunches and over time I've increased the weight and made steady progress. However I have just started a Taekwondo class and as part of the warm-up we have to do sit-ups, I cannot even do a single sit-up without someone holding my feet. I can lift my upper back of the floor but not the bottom half of my back. For what it's worth, in case there is a genetic component, neither can my son.

I can do the other exercises including press-ups, I'm surprised I cannot do them at all since I have made progress on the abdominal machine. Will doing them with my feet held strengthen the correct muscles so that over time I can do them unaided, or is there a particular muscle/mechanical issue that will continue to prevent me doing them unaided?

Answer 1

The problem is not that your core muscles are not strong enough to lift your chest up. It looks like you are facing another (bigger problem) : physics.

Actually, it is not weird not to be able to do what you are trying to do. In the position that you are in (supposedly with your feet close to your butt), your center of gravity is located above the waist. So whenever you try to lift up your chest, you will simply more or less roll on your back.

Two ways of solving this :

• Stick you feet under something heavy (furniture, children, wife, whatever is available)

• Simply lift your feet like this

Actually, what you are currently doing will mostly target your upper abs. So you don't need to go all the way.

Answer 2

It is possible that you're using your leg muscles to push yourself up in the sit-ups. I know I had that problem at one point. If you're feeling tension in your legs while doing the sit-ups, there's a decent change you're engaging the legs. If so, doing them with your feet held will have more limited use since you're diluting your effort with your legs. That said, they're generally still of some use since you have to use your stomach some.

The two ways in which I trained myself into it was a) tapering off the amount of weight on my feet by putting them under progressively smaller chairs (I know... it sounds silly, but it worked by providing me some support, but giving me a warning sign that I was using my legs whenever the chair started tipping up) and b) doing negatives, starting up in the completed position, feet on the floor and unsupported, and trying to lower myself as slowly as possible. Eventually, I got the hang of it.

Answer 3

It is because when you've used the machine at the gym you haven't had to activate the hip flexors, that is the muscle group connecting your legs to pelvis and abdomen. These are activated when you do a classic crunch on the ground and move your upper body all the way up towards your knees.

Really the only way to do crunches without anchoring your feet is to at your own pace try to mentally focus on activating your core and keep your feet down while doing your crunches. Don't anchor your feet under something else like someone suggested, that way the hip flexors are over exaggerated and a resistance is created from where they can pull, and they're not tensed and released for every crunch which is what you want if you want to strengthen them.

There is no advice that will work instantly just because you "do the crunch right", you have to be patient. Over time you will have to strengthen those muscles and you will be able to do crunches without anchoring your feet.

Good luck!

Answer 4

Sometimes it's not about strength and as mentioned in earlier posts it's just physics.

It's similar to a seesaw, it's all relative to weight and distance from the pivot point. If two equal weights are positioned at each end of a seesaw, at equal distances from the pivot point, then it is perfectly balanced. However if you increase one of the weights or move it further from the pivot point (such as a long torso) then the other end (feet) will lift up.

The only ways to prevent the feet lifting up are; Reduce weight to torso, increase weight to legs or get someone to hold your legs... or any combination of these.

Answer 5

I do pilates and sit-ups, as well as the reverse lowering down from the sit-up position in a slow a controlled way, are major parts of my pilates session. I am able now to do a controlled rollback, however the sit up with legs straight is a struggle. Weirdly if my instructor holds the tips of my fingers without even pulling me up, I have no difficulty doing a sit up legs straight and in a slow controlled way. I was thinking is there a psychological thing going on. Well major breakthrough at yesterdays class, in that another instructor put a small lumber support pillow thing under my lower back and as they say here in New Zealand, land of cows and sheep. I could do sit-ups until the cows come home now. So I'm not crazy maybe some lower back muscle strength needed or it may be physics too in terms of a fulcrum. I fantasise that my legs are long however maybe my torso is longer. Hope this helps you can find lumber support things here https://www.thebodyworkshop.co.nz/products.html. Or maybe just roll up a towel and stick it under your lower back - that's called the number 8 wire approach in NZ.