The captain’s chair knee raise is an abdominal exercise done on the upright station with a back pad, two arm pads and handles. You hold yourself up on your forearms with the legs hanging, lift the knees until the hips curl up off the pad, and lower slowly. The back pad is what separates it from a hanging knee raise: it stops you swinging.
Nobody is credited with inventing the exercise or naming the station; the name is borrowed from the armchair. Brolic lists it as Knee Raise (Captain’s Chair), with “Captain’s Chair Knee Raise” as an alias, and keeps the straight-leg version as its own entry, Leg Raise (Captain’s Chair). Both are logged as two-sided exercises in reps.
Muscles worked
Brolic tags the abdominals as the only muscle group for both entries. Live Lean TV says the knee raise, done correctly, “will primarily work the lower abdomen”, and that raising the knees only to a 90° angle “will mainly work your hip flexors”. Andy Frisch says the same in his own words: the rectus abdominis is one sheet of muscle, but you can emphasise its lower part, and bringing the knees up and down without the hips moving is a hip flexor exercise.
The best-known measurement is an ACE-commissioned study by Peter Francis and Jennifer Davis at San Diego State University, published in ACE FitnessMatters in 2001, not a peer-reviewed journal. Thirty people aged 20 to 45 did 13 abdominal exercises while electrodes recorded the rectus abdominis, the external obliques and the rectus femoris as a hip-flexor check. The captain’s chair, described as slowly lifting the knees in toward the chest, ranked second for the rectus abdominis (212% of a crunch) and first for the obliques (310%). Two caveats: the hip flexors were busy too, since the report calls the exercise-ball crunch “arguably” the best overall for producing far less rectus femoris activity; and Francis noted that the average exerciser appeared unable to recruit the upper and lower abdominals separately, so “lower abs” is a cue, not a measured fact. A PubMed search on October 7, 2026 for “captain’s chair” and “hanging knee raise” found no peer-reviewed study.
Set up in the chair
Back firmly against the pad, forearms on the arm pads, hands on the handles. Live Lean TV’s starting position; the ACE study’s instruction was the same, with the lower back pressed lightly to the pad.
Let the legs hang straight down. Live Lean TV has you fully extend the legs beneath you before each rep.
Brace before every rep. Live Lean TV’s cue is to exhale and tighten the abdominals “as if you were about to be punched in the stomach”, and to start each repetition from that contraction rather than from a swing.
Lift the knees, then the hips
Keep lifting past the right angle. Live Lean TV has you bend the hips until the knees are above the waist, because stopping at 90° works the hip flexors. Frisch’s version of the same cue is “get your butt up off this pad”: the hips lift and the pelvis and tailbone curl up toward the sternum. The legs are along for the ride, “not just flailing the legs”, as he puts it.
Lower as slowly as you can. Live Lean TV extends the legs back to the start under control. Frisch calls the lowering the hardest part and has you lock the abdominals in and fight gravity on the way down; in his view even two or three slow, controlled lowerings make you stronger quicker than more fast ones.
No swing. Live Lean TV: do not use inertia or swinging to complete the lift. Frisch names the swing as the second of the two common mistakes, after knees-only lifting, and says momentum is the enemy.
Knee raise, leg raise and hanging knee raise
| Captain’s chair knee raise | Captain’s chair leg raise | Hanging knee raise | |
|---|---|---|---|
| Support | Forearms on the pads, back on the pad | The same | Hands on a bar, nothing behind you |
| Knees | Bent | Straight | Bent |
| Swing | Limited by the back pad | Limited by the back pad | Yours to control |
Live Lean TV places the chair below the hanging knee raise: the back pad makes the exercise easier by limiting the swing. The leg raise is the progression the other way: straight legs are a longer lever, so the same hip curl is harder. Frisch’s cue does not change for it: flat on the floor, hanging from a bar, in ab straps or on the chair, the pelvis and tailbone curl up toward the chest. No trial compares the three for muscle growth.
Logging
Brolic logs Knee Raise (Captain’s Chair) and Leg Raise (Captain’s Chair) as separate entries in reps. Count only reps where the hips came off the pad and the lowering was controlled; a set of knee lifts that stop at the right angle is, by both coaches’ account, a different exercise. Neither coach gives a rep target, so stop the set when the hips no longer leave the pad or the lowering turns into a drop. If you hold a dumbbell between the feet, record its weight. The free workout log has room for those notes, and the weekly set tally shows what your abdominals already get.
Common questions
Knees to 90° or higher? Higher. Both coaches say that stopping with the thighs level and the hips still on the pad trains the hip flexors; the rep is the hip curl at the top.
When do I move to the leg raise? When every knee-raise rep lifts the hips and lowers slowly. Nothing establishes that straight legs build more muscle; they make the same movement harder. If the lower back or hips complain, shorten the range, slow the lowering and keep the back against the pad; if it still hurts, stop. Pain is not a cue to work through.
Sources and method
- Live Lean TV Daily Exercises: Captain’s Chair Knee Raise — the starting position, the brace, knees above the waist, the 90° point, the controlled lowering and the no-swing rule; captions.
- Nutrient Health: Andy Frisch, captain’s chair leg raises — the two mistakes, the hips off the pad, the slow lowering and the pelvis-to-sternum cue; automatic captions.
- ACE FitnessMatters, May/June 2001: “New Study Puts the Crunch on Ineffective Ab Exercises” — Mark Anders’s report of the Francis and Davis study: method, rankings and caveats; also in ACE’s press release.
- Brolic catalog — names, aliases, logging mode and muscle tags for both entries.
The ACE figures are percentages of a crunch’s muscle activity in one session, not a measure of muscle growth; the report counts only exercises at least 25% above the crunch as notably different.
