Basic abdominals: bent knee fall out

Level: Beginner

Basic abdominals: bent knee fall out is the simplest tummy exercise you can do on the roller. It is an abdominal exercise that is perfect for beginners, as it is teaches you how to activate your deep abdominal muscles  and core muscles. This is largely due to the fact that the roller is an inherently unstable surface and, as such,  if you don’t activate the correct muscles, you will fall off!

Please check out the basic roller set up if you are using a roller for the first time or unsure of any of the terms used below.

Set up:

  • supine on the roller, head resting at one end, bottom at the other,
  • feet and knees hip width apart, lower back in neutral position, deep tummy engaged at about 25% of a contraction, ie draw belly button in towards spine gently (see correct core activation if you are unsure),
  • gently tuck chin and have shoulder blade muscles slightly contracted,
  • forearms resting lightly on the floor,
  • breathe normally down into your diaphragm.

basic start position on a roller


  1. slowly move your right knee out to the right side ( somewhere between 1 and 2 o’clock if you think of a clock analogy) and then return to starting position,
  2. then move the left knee out to somewhere between 10 and 11 o’clock and then return to starting position,
  3. Repeat 10 times each side, alternating sides.



bent knee fallout on a roller



  • Tummy contraction should remain at a low 25% of a contraction throughout exercise,
  • there should be no rocking or rotation of pelvis or loss of neutral back position,
  • remember to breathe normally throughout so that upper abdominal muscles remain relaxed, with no rib flaring.
  • you should be breathing with each leg movement ie as your bent knee moves out, breathe in;  breathe out as you move your bent knee back. Or vice versa. There are no rules. You just need to keep breathing and not hold your breath.
  • keep neck and shoulders relaxed.

Make it harder:

  • progress to only elbow support on floor,
  • progress to no arms on floor, hands resting lightly on stomach,
  • perform basic abdominals: bent knee fall out with theraband around the tops of knees.

bent knee fallout no arm supporttop view bent knee fall outbent knee fall out with resistance


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