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 Post subject: Sit ups vs leg raises...
PostPosted: Fri Jun 19, 2009 3:52 am 
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Hi,

I am just wondering,
What is the difference between sit ups and leg raises?
Does one work them more or less efficiently than the other?

Reason i'm asking it because I read somewhere that the leg raises work mostly the hips than the abs, that true?

Thanks


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PostPosted: Fri Jun 19, 2009 7:43 am 
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Silhorn wrote:
Hi,

I am just wondering,
What is the difference between sit ups and leg raises?
Does one work them more or less efficiently than the other?

Reason i'm asking it because I read somewhere that the leg raises work mostly the hips than the abs, that true?


Both sit-ups and leg raises are hip flexor exercises. Unless you flex your spine (think crunches) during the movements, your abs will get no work except as stabilizers.


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PostPosted: Fri Jun 19, 2009 5:50 pm 
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Yea leg raises are just hip flexors. Crunches are just abs and situps are both.


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PostPosted: Sat Jun 20, 2009 9:23 pm 
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I thought leg raises was lower abs? I know reverse crunches are lower abs because I defiantly feel it there. Leg raises, you have to keep your back flat the whole time. If done right, you feel it in the lower abs. Whenever my lower back starts coming off the ground, thats when the hip flexors take over.


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PostPosted: Sat Jun 20, 2009 10:24 pm 
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caangelxox wrote:
Leg raises, you have to keep your back flat the whole time. .


If you keep your back flat, you won't be working your abs directly. The muscular function of the abs is toflex the thoracic spine.


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 Post subject:
PostPosted: Sat Jun 20, 2009 10:29 pm 
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Stephen Johnson wrote:
caangelxox wrote:
Leg raises, you have to keep your back flat the whole time. .


If you keep your back flat, you won't be working your abs directly. The muscular function of the abs is toflex the thoracic spine.


I thought that is how you perform leg raises by laying flat on the ground (back, head, butt on ground) and bringing your legs up and down trying to keep lower back on ground the whole time.

and if I crunched up and was not holding my neck, my neck would feel strain as it always does in crunches when I am not stabilizing my head. I don't really do leg raises though anyway. I like reverse crunches better. I can really feel my lower abs working with reverse crunches.


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 Post subject:
PostPosted: Sun Jun 21, 2009 6:44 am 
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caangelxox wrote:
I thought leg raises was lower abs? I know reverse crunches are lower abs because I defiantly feel it there. Leg raises, you have to keep your back flat the whole time. If done right, you feel it in the lower abs. Whenever my lower back starts coming off the ground, thats when the hip flexors take over.


You may feel it in the "lower abs" but that's because it's hitting the hip flexors. There is no distinction between upper and lower abs. It's all one muscle. As long as you're moving your hips closer to your chest, you're working your abs. If you're just moving your legs, you are working your hip flexors.


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 Post subject:
PostPosted: Sun Jun 21, 2009 2:05 pm 
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Let me go into more detail about what Stu posted. The fibers of the rectus abdominus run the length of the muscle from top to bottom. So you contract the whole of each fiber. You can't contract part of a fiber. The second issue is that there is just the one neural connection. You would need separate fibers and motor nerves to control just half of it.


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 Post subject:
PostPosted: Sun Jun 21, 2009 4:38 pm 
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what is your opinion on reverse crunches? I defiantly feel the abs in these when I bring my lower back off the ground (keeping my knees close to my chest)


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PostPosted: Sun Jun 21, 2009 8:53 pm 
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caangelxox wrote:
what is your opinion on reverse crunches? I defiantly feel the abs in these when I bring my lower back off the ground (keeping my knees close to my chest)


I'm not sure about what a reverse crunch is. Is it similar toIncline Leg Hip Raises, done without the incline? If it is, you're good to go for ab work.

By comparison, Lying Leg Raises target the hip flexors:

Quote:
Rectus Abdominis and Obliques only contract dynamically if actual waist flexion occurs. With no waist flexion, Rectus Abdominis and External Oblique will only act to stabilize the pelvis and waist during hip flexion. It may be necessary to completely flex the hips before waist flexion is possible; see Weighted Incline Leg-Hip Raise. Also see Spot Reduction Myth and Lower Ab Myth.


Many women develop lower ab pouches after childbirth. They mistakenly think that doing "lower ab exercises" will spot reduce these pouches. Sadly, that isn't the case.


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 Post subject:
PostPosted: Sun Jun 21, 2009 9:15 pm 
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yes it is except that its done on the floor (flat ground).

What is better? the incline or the flat floor?


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PostPosted: Sun Jun 21, 2009 9:28 pm 
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caangelxox wrote:
yes it is except that its done on the floor (flat ground).

What is better? the incline or the flat floor?


The incline version is more challenging, but they both work the same muscles pretty much the same way. If you find the flat version too easy, it is better to increase the incline (and make the exercise harder) than to increase the number of reps for the flat version. Once the inclines get easy, add weights.


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 Post subject:
PostPosted: Sun Jun 21, 2009 10:00 pm 
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yeah I think I will go to incline because I can easily add weights if I need to. I am going to look around at my gym tomorrow and find one of these incline benches. Hopefully I can find one. I have not payed attention into look around for one of those yet. I know there are a bunch of different kind of incline benches/boards around though. I'll need to find one that I can performed this exercise on that is long enough.


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 Post subject:
PostPosted: Mon Jun 22, 2009 5:46 am 
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Thanks for your replies.
I just thought that since one movement is moving from the hip and one from the waist i would need both to fully work my core like reading something here about fully working the hamstrings through both knee and hip flexion...
btw:
Does anyone know of any good ways I can test how strong/usable my abs are?


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 Post subject:
PostPosted: Mon Jun 22, 2009 5:54 am 
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Stephen Johnson wrote:
caangelxox wrote:
Leg raises, you have to keep your back flat the whole time. .


If you keep your back flat, you won't be working your abs directly. The muscular function of the abs is toflex the thoracic spine.


Oh one more thing.
I just noticed your reply.
So does this mean that when doing sit ups it is better to curl your way up rather than keep your back straight as possible while your pulling yourself up?
If you do keep your back straight what are you more likely to be training?


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