Hundred on Reformer: A Complete Guide
Quick Intro
Hundred on Reformer is a reformer Pilates exercise performed lying on the back on the carriage, straps in the hands with the arms long at the sides, curling the head and shoulders up, extending the legs to 45 degrees and pumping the arms in small, fast beats against the spring resistance. Inhaling for five counts and exhaling for five counts, the pattern continues to 100 total pumps, and the spring adds an upper-back and shoulder-blade stability demand that the mat version lacks.
Equipment Needed
A Pilates Reformer is required for this exercise, since the spring-loaded straps are what give it its extra resistance. The straps and the carriage are all that is used.
Why It Matters
Sustaining a curled position through 100 continuous pumps against spring tension builds staying power, on top of the coordination needed to time the arm pump against the resistance. A deep core muscle that wraps around the torso like a corset (transverse abdominis) and the abdominal muscles running down the front of the stomach (rectus abdominis) hold the curled spine steady for the full set, and a muscle along the side of the ribcage (serratus anterior) and a large back muscle (latissimus dorsi) work together to draw the straps against the spring with each pump. The deep hip flexor (hip flexors, iliopsoas) keeps the extended legs from dropping, and the front of the shoulder cap (deltoid, anterior) helps drive the pump itself.
When to Do It
Hundred on Reformer works well as the opening exercise of a reformer session, mirroring the order of the classical mat work and warming the powerhouse (the Pilates term for the deep core) against resistance from the first move. Two to three sessions a week is a reasonable pace for building this loaded version of the pattern.
Anyone with a current neck, lower back or shoulder issue should get individual guidance before adding this exercise, since holding a curled position for 100 spring-loaded counts places sustained demand on all three.
Getting Ready
A few rounds of the arm pump without the leg extension or the curl preview the spring’s resistance before the full pattern is added. Curling up for just ten or so pumps checks how the neck and lower back feel that day before committing to a full 100 count.
Step-by-Step Instructions
1. The setup. Lie supine on the carriage, straps in hand, arms long at the sides, legs extended and raised to a 45-degree angle.
2. The curl. Curl the head, neck and shoulders up off the headrest.
3. The pump. Pump the arms against the spring in small, fast beats, five beats on the inhale and five on the exhale.
4. The count. Keep the breath-paced pump going until 100 total beats are reached, then lower the head and legs to rest.
How Many, How Often
Hundred on Reformer is dosed by breath cycles, with the classical target being ten full cycles of five inhale-pumps and five exhale-pumps, 100 pumps total.
| Level | Where you’re at | What to do |
|---|---|---|
| Beginner | New to holding the curl against spring resistance | 3 to 5 breath cycles, with the legs in tabletop |
| Intermediate | The curl and pump feel steady against the spring | 6 to 8 breath cycles |
| Advanced | Comfortable holding the full curl for 100 counts | The full 10 cycles |
Keeping the torso still against the spring’s pull matters more here than finishing all 100 pumps, since a torso that rocks with each pump is the clearest sign the spring has added more resistance than the powerhouse is currently bracing against.
Modifications and Variations
As an easier version, Hundred Reformer — Legs at 90 raises the legs to a steeper 90-degree angle, reducing the load on the hip flexors and the lower back while the spring-loaded arm pump is learned.
As a harder version, Hundred Reformer — Legs at 30 Degrees lowers the legs to a shallower 30-degree angle, adding load to the hip flexors on top of the spring resistance already working the arms.
Common Mistakes to Avoid
Letting the torso rock with each arm pump. Allowing the spring’s resistance to pull the shoulders or torso along with the arms, without staying anchored, breaks the stillness this exercise depends on. The powerhouse should brace hard enough that only the arms move.
Letting the lower back arch off the carriage. Allowing the lower back to lift as the legs and pump continue shifts the load onto the hip flexors and spine instead of the deep abdominals. Pressing the lower back down, even if that means raising the legs higher, keeps the target muscles working.
Pumping from the elbow instead of the shoulder. Bending the elbows against the spring turns a small, controlled shoulder movement into a looser, less precise one. Keeping the arms straight and the pump small and fast from the shoulder is what the reformer version, like the mat version, trains.
After Your Set
Hugging both knees into the chest for a few breaths releases the lower back after a set built around a sustained curled hold against spring load. Rolling the shoulders back and down a few times eases any tension the pump against the straps left in the upper back.
Going Deeper
The spring resistance adds a shoulder-blade and upper-back demand to the classical opener that the mat version, with no load on the arms, can’t create. As the spring pulls back on each pump, the torso is often the first thing to give in and start rocking to help keep the arms moving. Bracing the powerhouse hard enough to keep the torso still, even if that means fewer pumps at first, builds strength faster than letting the spring rock the whole body.
Someone new to this exercise generally learns a stable curl against spring resistance within the first few sessions, then works up to the full 100-count set over two to four weeks.
How to Know You’re Improving
- A torso that stays anchored against the spring’s pull, letting only the arms move
- A lower back that stays pressed down into the carriage for the full set
- An arm pump that stays small, fast and driven from the shoulder
- A full 100-count set completed without the torso rocking or the lower back lifting
A torso that stays still against the spring matters more than the number of pumps completed.
Muscles Worked
- Transverse Abdominis (a deep core muscle that wraps around the torso like a corset, holding the curl steady while the carriage springs resist)
- Rectus Abdominis (the abdominal muscles running down the front of the stomach, maintaining the curl against the carriage’s spring tension)
- Serratus Anterior (a muscle along the side of the ribcage, working with the back to draw the straps against the spring)
- Latissimus Dorsi (a large back muscle, working with the ribcage muscle to draw the straps against the spring)
- Iliopsoas (the deep hip flexor, keeping the extended legs from dropping)
- Anterior Deltoid (the front of the shoulder cap, helping drive the pump)
FAQ
Is this the same exercise as The Hundred on the mat? It shares the same classical pattern, breath count and curled position, but the straps add spring tension, which brings in an upper-back and shoulder-blade demand. The Hundred is the mat exercise, done with no load on the arms.
Why does this feel harder than the mat version even at the same leg angle? The spring adds resistance the mat version doesn’t have, so the arms and upper back work against load on every pump instead of moving through the air.
Is some neck, ab or upper-back fatigue after this exercise normal? Yes, a burning fatigue through the abdominals and upper back, plus some neck tiredness by the end of a full 100 count, is expected. A sharp, localized pain in the neck or lower back is a different matter, worth stopping for and mentioning to a doctor or physical therapist if it doesn’t settle.
How often should Hundred on Reformer be practiced? Two to three sessions a week, as the opener of a broader reformer routine, suits most people well.
Is a lighter spring acceptable if the full load feels like too much? Yes, using a lighter spring is a reasonable way to build the curl and pump pattern before working up to the standard load, the same approach used in Footwork — Lighter Spring.
Related to Hundred Reformer — Legs at 90 as the easier version with the legs raised higher and Hundred Reformer — Legs at 30 Degrees as the harder version with a lower leg angle.