How many reps of the TRX suspended knee tuck should you do when you are new to the exercise?

Start with 2 sets of 8 reps, adding a full one-second pause at the knees-in position on each rep. Once the pause feels steady and the hips stop swinging between reps, add a third set before you add a longer pause.

What can I use instead of a TRX for the suspended knee tuck?

Gymnastic rings set to the same height work identically, since both give a moving, unstable base. Without any suspension equipment, the slider or towel plank knee tuck trains the same lower-ab and anti-extension pattern from a fixed base.

What is the TRX suspended knee tuck good for, and when should you skip it?

It layers shoulder and chest stability on top of a lower-ab flexion move, since the moving straps demand constant upper-body control. Skip it if shoulder pain shows up under load, or if plain plank holds are not yet steady, since the instability will amplify any weakness there.

Intermediate

TRX Suspended Knee Tuck

From a suspended plank you pull both knees toward your chest, forcing the rectus abdominals to flex the spine and control a swinging base. It hits the lower-ab region hard while the shoulders and chest work overtime to keep you stable. A core staple that scales by slowing the tempo or adding a pause at the knees-in position.

Equipment: TRX
Body part: Abs
Type: Balance, Strength
Browse by muscle: Lower Rectus Abdominals, Upper Rectus Abdominals
Browse by movement: Core Brace

How to do it

1
Place both feet in the foot cradles and press up into a high plank on your hands.
2
Set the shoulders directly over the wrists and brace the whole trunk.
3
Keep a straight line from head to heels to start.
4
Draw both knees toward your chest by curling the pelvis under.
5
Pause briefly with the knees tucked and the abs fully contracted.
6
Extend the legs back to the plank slowly without letting the hips pike or sag.

Tips

Round the lower back slightly as you tuck to bias the abs over the hip flexors.
Keep the shoulders stacked over the wrists so the plank stays stable.
Control the return; the eccentric is where the core works hardest.

Variations

Common mistakes

The straps swing side to side between reps instead of settling still, so each tuck starts from a slightly different, less stable position.
The pause at the knees-in position gets skipped entirely, turning a controlled hold-and-return into a continuous bouncing motion.
The hands press so far forward of the shoulders that the plank turns into an incline push-up position instead of a level one.
Letting the hips sag toward the floor as the legs extend back out gives away the anti-extension work right as the set gets tiring.
The knees stop tracking straight toward the chest and drift out to one side, loading the hips unevenly on a movement that should stay symmetrical.

Frequently asked

How many reps of the TRX suspended knee tuck should you do when you are new to the exercise?: Start with 2 sets of 8 reps, adding a full one-second pause at the knees-in position on each rep. Once the pause feels steady and the hips stop swinging between reps, add a third set before you add a longer pause.
What can I use instead of a TRX for the suspended knee tuck?: Gymnastic rings set to the same height work identically, since both give a moving, unstable base. Without any suspension equipment, the slider or towel plank knee tuck trains the same lower-ab and anti-extension pattern from a fixed base.
What is the TRX suspended knee tuck good for, and when should you skip it?: It layers shoulder and chest stability on top of a lower-ab flexion move, since the moving straps demand constant upper-body control. Skip it if shoulder pain shows up under load, or if plain plank holds are not yet steady, since the instability will amplify any weakness there.

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