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Flexion Leg Sit Up (Straight Arm)

A sit-up performed with legs flexed and arms held straight overhead-forward, lengthening the lever to make the trunk flexion harder without external load.

AbsBodyweightTrunk flexion
GoLightWeight mediaflexion-leg-sit-up-straight-arm

Demonstration coming soon

Primary

Rectus abdominis

Secondary

Hip flexorsObliquesSerratus anterior

Equipment

Bodyweight

Pattern

Trunk flexion

Setup

  1. 01Lie on your back on a mat with knees bent and feet flat on the floor.
  2. 02Extend both arms straight overhead so they are in line with the torso.
  3. 03Press the lower back gently toward the floor and set the ribs down.
  4. 04Keep the feet unanchored or lightly anchored, whichever lets the abs lead.

Execution

  1. 01Exhale and sweep the straight arms forward as the trunk curls off the floor.
  2. 02Roll up one segment at a time until the torso is upright over the hips.
  3. 03Keep the arms straight and reaching toward or past the knees at the top.
  4. 04Lower back down under control, letting the spine uncurl vertebra by vertebra.

Checkpoints

  • -Arms stay straight for the entire rep, not bending to cheat momentum.
  • -The trunk curls segmentally rather than hinging as one stiff plank.
  • -Feet stay quiet; the heels do not slam down to counterbalance.
  • -The lowering phase takes at least as long as the way up.

Common mistakes

  • -Throwing the arms to generate momentum instead of curling with the abs.
  • -Yanking the neck forward at the sticking point.
  • -Letting the lower back arch off the floor at the start position.
  • -Dropping back to the floor instead of controlling the eccentric.

Programming notes

  • -Use 2 to 4 sets of 8 to 15 controlled reps as a main trunk flexion exercise.
  • -If full reps are too hard, shorten the arm lever by crossing arms on the chest, then progress back.
  • -Slow 3 second eccentrics add difficulty without adding load.

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