Should I master a floor plank before trying the TRX Pendulum?

Yes. A study of 25 healthy adults found core muscles worked together less on a suspension trainer than on the floor during push-ups, bridges and planks (the pendulum was not tested), and the authors advise mastering the floor versions first. Build up with the Plank and TRX Plank.

How far should my legs swing?

Swing only as far as you can keep your hips level and your shoulders square, which for most people is well short of horizontal. Coaches often use about 45 degrees to each side as a target and let the arc grow as control improves.

How do I make the TRX Pendulum easier?

Shorten the swing or bend the knees, which both make the load on your trunk smaller. You can also practice the Side Plank and Lying Windshield Wipers to learn the rotational control on the floor.

How is the TRX Pendulum different from the TRX Body Saw?

The TRX Body Saw moves the body forward and back on the forearms, so it mainly resists extension, while the pendulum swings the legs sideways on straight arms and loads the obliques more.

How many reps should I do?

Beginners to this move often struggle to finish five clean swings, so start with a few controlled reps per set. Add reps only while your hips stay level and the legs pass through the center without a jerk.

TRX Pendulum

What Is the TRX Pendulum?

TRX Pendulum is a compound exercise that primarily targets the core and also engages the shoulders, hips and lower back. It is an advanced-level movement: you hold a straight-arm plank with both feet in the suspension cradles and swing your legs from side to side like the hand of a clock.

The swing is driven and controlled by the obliques, while the rectus abdominis and spinal muscles stop the hips from sagging and the trunk from twisting. The shoulders and the muscles around the shoulder blades hold you up on straight arms, and the hip muscles on the outside of the thigh help guide the legs. Because the feet are suspended, every inch of the arc has to be controlled, which makes it a demanding test of anti-rotation and lateral core strength.

Difficulty changes with the size of the arc and the length of the lever. A small swing is far easier than a wide one, and bending the knees shortens the lever. Compared with the TRX Plank or TRX Mountain Climber, which keep the legs in line with the body, the pendulum adds side-to-side movement that loads the obliques much more.

It suits trainees who can already hold a long, solid plank and want a harder rotational core challenge. If it is too hard, build up with the Plank, Side Plank, TRX Plank and TRX Jack Knife before swinging the legs. It works well early in a session, when the shoulders and trunk are fresh.

Muscles Worked

MuscleActivation

External Oblique: Primary
Deltoid: High
Rectus Abdominis: High
Erector Spinae: Medium
Gluteus Medius: Medium
Serratus Anterior: Medium
Tensor Fasciae Latae: Medium
Adductor Longus: Low
Rectus Femoris: Low
Triceps Brachii (Long Head): Minimal

Instructions

Set the straps to about mid-calf height so the foot cradles hang just above the floor.
Kneel facing away from the anchor point, place your hands on the floor directly under your shoulders, and slide one foot at a time into the cradles.
Straighten your arms and legs into a high plank with your feet together and your body in one straight line from head to heels.
Brace your abs, squeeze your glutes and press the floor away so your shoulders stay stable.
Keeping your arms straight and your shoulders square, swing both legs together to one side in a smooth arc until they are about 45 degrees from center.
Use your obliques to pull your legs back through the center without letting your hips drop or twist.
Continue the swing to the other side in the same controlled way. One swing to each side is one rep.
To finish, lower your knees to the floor and take your feet out of the cradles one at a time.

Common Mistakes

Sagging hips
Letting the hips drop as the legs swing loads the lower back, so keep the glutes and abs braced and the body in one straight line.
Swinging too wide too soon
A big arc before you can control it turns the move into a momentum swing, so start with a small arc and widen it only while the hips stay level.
Using momentum
Flinging the legs to one side and letting them drop back removes the work from the obliques, so move at a slow, steady pace through the center.
Bending the knees or separating the feet
Loose legs shorten the lever and take the challenge away, so keep the legs straight and the feet together.
Sinking into the shoulders
Letting the chest drop between the shoulder blades strains the shoulders, so keep the arms straight and press the floor away.
Twisting the upper body
Rotating the shoulders and chest with the legs means the trunk is not resisting the swing, so keep the shoulders square over the hands.

Injuries

TRX Pendulum is a medium risk exercise when performed with proper technique. It puts a long lever on the trunk and holds your body weight on straight arms, so the lower back, shoulders and wrists carry most of the stress.

The most common strain point is the lower back, which arches when the hips sag or the ribs flare as the legs swing. The shoulders can also get irritated if you sink between the shoulder blades, and the wrists take load through the whole set. To protect them, keep the swing small enough that the hips stay level, press the floor away, and stop each set when the arc gets sloppy rather than grinding through it.

If you cannot keep the hips level, regress by bending the knees or shortening the swing, or go back to the TRX Plank and Side Plank. Once the movement is smooth, progress by widening the arc or slowing the swing. Skip this exercise during an acute low back injury, shoulder impingement or wrist pain, and stop if you feel sharp pain in the back or shoulders.

Overview

Primary Focus: Core
Equipment: Suspension trainer and body weight
Modality: Strength
Difficulty: Advanced

Alternative Exercises

Frequently Asked Questions

Q: Should I master a floor plank before trying the TRX Pendulum?: Yes. A study of 25 healthy adults found core muscles worked together less on a suspension trainer than on the floor during push-ups, bridges and planks (the pendulum was not tested), and the authors advise mastering the floor versions first. Build up with the Plank and TRX Plank.
Q: How far should my legs swing?: Swing only as far as you can keep your hips level and your shoulders square, which for most people is well short of horizontal. Coaches often use about 45 degrees to each side as a target and let the arc grow as control improves.
Q: How do I make the TRX Pendulum easier?: Shorten the swing or bend the knees, which both make the load on your trunk smaller. You can also practice the Side Plank and Lying Windshield Wipers to learn the rotational control on the floor.
Q: How is the TRX Pendulum different from the TRX Body Saw?: The TRX Body Saw moves the body forward and back on the forearms, so it mainly resists extension, while the pendulum swings the legs sideways on straight arms and loads the obliques more.
Q: How many reps should I do?: Beginners to this move often struggle to finish five clean swings, so start with a few controlled reps per set. Add reps only while your hips stay level and the legs pass through the center without a jerk.