Why is it called the Hundred?

Because of the arm beats. You pump the arms one hundred times in total, taken as ten cycles of five pumps while breathing in and five while breathing out, and the set ends when the count does.

Should my legs be straight or bent in tabletop?

Both are taught, and the right one is whichever keeps your lower back flat on the carriage. An EMG study of young men doing the Hundred on the mat measured more core muscle activity with the knees straight than with them bent to 90 degrees, so tabletop asks less of the core and is the easier place to start, while the straight, low legs shown here are the harder position.

How long does it take, and how many sets should I do?

One set of one hundred pumps takes roughly 60 to 90 seconds at a steady beat, and one set is all the exercise asks for. It is normally done once, near the start of the session, rather than repeated.

Is the Hundred enough abdominal work on its own?

Not on its own. When researchers used ultrasound to measure deep abdominal thickness in women performing five mat Pilates exercises, the dead bug produced a larger increase than the hundred did, and they suggested the hundred fits best as a warm-up before harder work. Follow it with something like Dead Bug or Hollow Hold.

Can I do it with my head down on the carriage?

Yes, and it is the standard fix when the neck tires before the stomach does. Lowering the head and shoulders takes out the neck work and most of the upper abdominal curl, but holding the legs and pumping the straps still loads the core, so it stays a useful version while you build up.

What spring setting should I use?

Enough tension that the straps stay taut from the first pump to the last, and light enough that you can hold the carriage still while your arms move. Spring colors mean different things on different reformers, so go by how the strap feels rather than by the color other studios name.

Pilates Reformer Hundred

What Is the Pilates Reformer Hundred?

Pilates Reformer Hundred is an isolation exercise that primarily targets the core and also engages the hip flexors, lats, and shoulders. It is an intermediate-level movement in which you hold a curled, face-up position on the carriage with the legs extended while both hands pump the reformer straps, so the abdominal wall works without moving for the whole count.

The Hundred opens the classical Pilates repertoire, and on the reformer it usually sits at the start of a session, often straight after footwork, as the piece that links the breath to the abdominal work that follows. The count is where the name comes from: one hundred arm beats, taken as ten cycles of five pumps on an inhale and five on an exhale. That is why it is programmed as one timed effort rather than as sets of reps, and why the goal is to hold the shape for the full count rather than to add load.

Almost all of the work sits in the front of the trunk. The curl holds the ribs toward the pelvis, and the straight legs act as a long lever the lower abdominals have to resist, so the lower you carry the legs the harder the exercise gets and the higher you carry them the easier it gets. Bending the knees to tabletop shortens that lever further and is the standard way to make the position manageable. At the other end of the body, the arms press the straps down with the lats and triceps, and the spring load decides how much of the total effort goes there.

It suits anyone who can already hold a curled trunk position for the length of the count without the neck taking over the job. If the neck fatigues first, leave the head and shoulders down on the carriage and pump the arms from there, or build the shape up with Hollow Hold and Dead Bug before putting your hands in the straps.

The breath is what makes the exercise worth the time it takes. Keeping the pumps small and the inhale and exhale even is what stops the shoulders and neck from gripping, and it asks the abdominal wall to stay drawn in instead of pushing out every time you breathe. On the reformer there is a second piece of feedback the mat cannot give you: if your center lets go, the carriage starts to shuttle under you.

Muscles Worked

MuscleActivation

Rectus Abdominis: Primary
Rectus Abdominis (Lower): Primary
External Oblique: High
Rectus Femoris: High
Latissimus Dorsi: Medium
Serratus Anterior: Medium
Triceps Brachii (Long Head): Medium
Deltoid: Low
Sternocleidomastoid: Low
Vastus Lateralis: Low

Instructions

Set a spring load that keeps the straps under tension the whole way through the exercise. Spring colors differ between reformer brands, so use the setting your studio teaches for hands in the straps.
Lie face up on the carriage with your head at the pulley end, your shoulders against the shoulder rests, and your spine long.
Take a handle in each hand, straighten your elbows, and turn your palms down so the straps are taut with your arms raised above your hips.
Draw your knees in, then extend both legs straight and pressed together at about 45 degrees above the carriage, with the feet pointed.
Curl your head, neck, and upper back off the carriage, looking down the line of your legs, and leave about a fist of space between your chin and your chest.
Press both straight arms down beside your body until the handles reach your hips, and settle the carriage so it stops moving.
Pump the straight arms up and down in a short, brisk range, moving only at the shoulders and keeping the rest of you still.
Breathe in for five pumps and out for five pumps, and repeat that cycle ten times to reach one hundred.
Keep your lower back flat against the carriage throughout, and raise the legs higher the moment it starts to arch.
Finish by bending your knees, lowering your head and shoulders to the carriage, and returning the handles to their hooks.

Common Mistakes

Curling from the neck
Leading the lift with the chin instead of drawing the ribs toward the pelvis, which leaves the neck burning long before the abdominals do.
Legs carried too low
Dropping the legs below the height at which your lower back can stay flat, so the lumbar spine arches off the carriage for the rest of the count.
Letting the carriage shuttle
Pumping hard enough to drag the carriage back and forth instead of holding it still with the trunk and arms.
Pumping from the elbows
Bending and straightening the elbows to make the beat rather than moving the whole straight arm from the shoulder.
Bouncing the torso
Letting the head and chest bob up and down with every pump instead of holding the curl steady while only the arms move.
Losing the breath count
Holding the breath or breathing at random rather than taking five pumps in and five pumps out, which is what keeps the pace honest.

Injuries

Pilates Reformer Hundred is a low risk exercise when performed with proper technique. Nothing is held over your body, you are supported by the carriage the whole time, and the position can be made easier at any moment without getting off the machine.

The neck is the first place it goes wrong. Holding the head up for a full hundred counts is tiring, and once the chin leads the curl instead of the ribs, the neck flexors take over a job the abdominals should be doing and start to burn. Keep the curl coming from the ribs, leave a fist of space under the chin, and lower the head and shoulders to the carriage as soon as the neck rather than the stomach is what is failing. The other strain point is the lower back. With the legs straight and low, the pelvis is being pulled into a tilt for the whole count, and the lumbar spine will arch off the carriage if the abdominals cannot hold it. Raising the legs toward the ceiling shortens the lever and settles the back down again.

Bend your knees to tabletop if straight legs are still too much, or keep the head down and pump the arms only while you build the position. From there, progress by lowering the legs a little at a time rather than by adding springs, and build up to the full hundred counts in blocks of twenty or forty. Hollow Hold and Dead Bug train the same shape on the floor and are useful on days when the reformer is busy.

Stop the set if your lower back lifts and will not settle, if your head starts bobbing with each pump, or if the abdominal wall domes into a ridge down the middle. Sustained trunk flexion like this is usually left out in later pregnancy and after abdominal surgery, so check with your doctor or physical therapist before doing it in either case.

Overview

Primary Focus: Core
Equipment: Pilates reformer
Modality: Strength
Difficulty: Intermediate

Alternative Exercises

Frequently Asked Questions

Q: Why is it called the Hundred?: Because of the arm beats. You pump the arms one hundred times in total, taken as ten cycles of five pumps while breathing in and five while breathing out, and the set ends when the count does.
Q: Should my legs be straight or bent in tabletop?: Both are taught, and the right one is whichever keeps your lower back flat on the carriage. An EMG study of young men doing the Hundred on the mat measured more core muscle activity with the knees straight than with them bent to 90 degrees, so tabletop asks less of the core and is the easier place to start, while the straight, low legs shown here are the harder position.
Q: How long does it take, and how many sets should I do?: One set of one hundred pumps takes roughly 60 to 90 seconds at a steady beat, and one set is all the exercise asks for. It is normally done once, near the start of the session, rather than repeated.
Q: Is the Hundred enough abdominal work on its own?: Not on its own. When researchers used ultrasound to measure deep abdominal thickness in women performing five mat Pilates exercises, the dead bug produced a larger increase than the hundred did, and they suggested the hundred fits best as a warm-up before harder work. Follow it with something like Dead Bug or Hollow Hold.
Q: Can I do it with my head down on the carriage?: Yes, and it is the standard fix when the neck tires before the stomach does. Lowering the head and shoulders takes out the neck work and most of the upper abdominal curl, but holding the legs and pumping the straps still loads the core, so it stays a useful version while you build up.
Q: What spring setting should I use?: Enough tension that the straps stay taut from the first pump to the last, and light enough that you can hold the carriage still while your arms move. Spring colors mean different things on different reformers, so go by how the strap feels rather than by the color other studios name.