I started doing planks in the hopes that stronger abs would help me with my lower back pain, however, after I started doing them my legs have become uncomfortably sore. The areas that ache are the front and back of my thighs, as well as the area right above my achilles tendon.

Is this a result of bad form, or is it a normal result from doing planks? I am doing the exercise in front of a mirror, and as far as I can tell, I am successfully keeping my back straight. Are there any variations of this exercise which will allow me to strengthen my abs without being in pain when I'm walking?

  • Are your quadriceps strong? Can you squat properly?
    – Freakyuser
    Oct 23, 2013 at 17:28
  • how is this relevant to his question? OP's talking about planks. Even though squatting is a core intensive movement, I think your question is vague in your prose to discuss what is going on with OP's body. Nor does he express any discomfort in his quads, so by definition, if you're going the route I think you're going, the hamstrings would be weak not the quads.
    – Hituptony
    Oct 23, 2013 at 17:42
  • I have exactly the same issue and pretty sure my body is straight and bums not sticking in the air
    – Brian
    Sep 11, 2017 at 14:08

1 Answer 1


This is a result of bad form. Your butt is probably sticking up the air.

Your achilles tendon and hamstrings are becoming sore because they are being stretched during your holds.

First of all look at your body position.

to start, lay down chin towards the floor, toes downward, directly downward, and rest on your elbows using your shoulder girdle to support your neck.

when you lift and get into positionput your weight directly on your elbows which should be ok, stick your legs straight out and remain on your tip toes, do not try and force the sole of your foot to the ground, the most that should touch is your fore-foot. Nothing more.

Furthermore, you should be able to set a broomstick on your back and it should remain parallel with the floor and you. Your butt should be in line with your body, and you should be bracing your core, tucking your hips in.

I saw a similar case of the same regions being sore, when my girlfriend tried to do burpees during some HIIT for the first time. She just wasn't jumping down far enough, the result was her butt stuck up in the air, hamstrings and back of shins were sore for a week.

Make some adjustments to your form, straighten out, brace your core, and tuck your hips, it's not just your back that needs to be straight it needs to fall in line with the rest of your body to promote thoracic extension.

Best of luck.

  • Ah, I hadn't thought about that. Your assessment that my butt is sticking up too much is probably correct. Thanks for the advice! There's one thing I'm not sure about, though. What exactly does tucking my hips in mean? I've got a rough idea where the hip region is but I've no idea what kind of motion "tucking" implies.
    – GJIG
    Oct 23, 2013 at 19:14
  • Here is a list of exercises you can use to understand how your core is worked and engaged. You might need help "feeling" your core engagement, if so have a personal trainer look at you for an hour or so and watch what you're doing, they can usually direct you. Til then practice these. acefitness.org/acefit/…
    – Hituptony
    Oct 23, 2013 at 19:24
  • specifically the supine pelvic tilts!!!
    – Hituptony
    Oct 23, 2013 at 19:26

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