Coordination — Three Opens: A Complete Guide

Quick Intro

Coordination — Three Opens is a reformer Pilates exercise that runs the same four-phase sequence as the base exercise, curling up to pull the straps to the hips while the legs extend to 45 degrees, but adds a third leg-opening repetition at full extension before the knees hug back in. The extra opening extends how long the curled-up position and the extended legs must hold together, raising the coordination and endurance demand past what two openings ask for.

Equipment Needed

A Pilates Reformer is required, since the strap resistance on the arms remains the mechanism this extended sequence works against. The straps stay in the hands through all three openings.

Why It Matters

Adding a third leg opening at the same width and speed as the first two takes precision, and sustaining the curled-up position for that extra repetition asks for staying power on top of the strength the extended legs and pulled straps already demand. The deep core muscle that wraps around the torso like a corset (transverse abdominis) and the long muscle running down the front of the abdomen (rectus abdominis) hold the curled-up position through all four phases and the extra opening, and the muscle group at the front of the hip (hip flexors, iliopsoas) lifts and controls the extended legs. The inner thigh muscles (adductors) drive the legs back together after each of the three openings, and a large back muscle (latissimus dorsi) pulls the straps down to the hips. A muscle along the side of the ribcage (serratus anterior) helps stabilize the shoulder blades as the arms extend, and the muscles along the sides of the waist (obliques) work harder to keep the trunk steady through the longer hold.

When to Do It

Coordination — Three Opens works well once Coordination already feels steady through a full set of its standard two openings. Two to three sessions a week is a reasonable pace for building this extended sequence.

Anyone with a current neck or low-back issue should get individual guidance before adding this exercise, since the curled-up position is sustained even longer here than in the base version.

Getting Ready

Curling up with the knees bent to the chest and holding for a few breaths, without the straps moving yet, checks the abdominal hold this longer sequence depends on. Running through the standard two-opening version once first previews the timing before the third opening is added.

Step-by-Step Instructions

1. The setup. Lie supine, a strap in each hand, knees drawn to the chest, curling the head and shoulders up.

2. The extension. Pull the arms down toward the hips against the spring tension as the legs extend out together to 45 degrees.

3. The three opens. Open and close the legs three times while the arms and the curled-up position both stay steady, keeping each opening the same width and speed as the first.

4. The reverse. Draw the knees back toward the chest as the straps ease off, settling back into the starting curl with control.

How Many, How Often

Coordination — Three Opens is dosed by reps, with each full sequence including all three leg openings counting as one.

The third opening matching the first two in width and speed matters more here than how many reps get completed, since a shrinking third opening is the clearest sign fatigue has started to erode the hold before the sequence finishes.

Modifications and Variations

As an easier version, Coordination runs the same four-phase sequence with two leg openings, shortening the sustained hold while the base pattern is learned. Coordination — No Leg Opening leaves the openings out.

Common Mistakes to Avoid

Letting the third opening shrink compared to the first two. Allowing fatigue to narrow the leg opening by the third repetition, when it should match the first, breaks the consistency this exercise is built to train. Matching the width of all three openings is what makes the extra repetition worth doing.

Letting the curled-up position sag as the openings continue. Allowing the head and shoulders to drop back down partway through the third opening breaks the sustained hold this exercise depends on even more than the base version does. Keeping the curl steady through every opening is what makes the sequence count.

Rushing through the extra opening. Speeding up the third opening to get through it faster turns a controlled sequence into an uneven one. Keeping the same pace across all three openings protects the coordination demand this exercise is built around.

After Your Set

Hugging both knees to the chest for a few extra breaths releases the low back after the longer sustained curl. Rolling the shoulders slowly and drawing a few full breaths into the ribs eases out the arms and trunk that held the sequence together through the extra repetition.

Going Deeper

A third opening keeps the curl and the extended legs working together for longer than the two-opening sequence does. The third opening tends to narrow as the curl fatigues, when the sequence asks for the most consistency. Slowing the whole sequence down for now, with all three openings staying even, builds endurance faster than a quick set with a shrinking third opening.

Someone new to this exercise generally manages two full-width openings and a smaller third within the first few sessions, then works toward three even openings over the following couple of weeks.

How to Know You’re Improving

1. A curled-up position that holds through all three openings without sagging
2. A third opening that matches the first two in both width and speed
3. Arms and legs that stay synchronized through every one of the three phases
4. A sequence that flows smoothly from start to reverse without slowing down for the extra opening

Three even openings matter more than how many reps get completed.

Muscles Worked

• Transverse Abdominis (a deep core muscle that wraps around the torso like a corset, holding the curled-up position through all four phases and the extra opening)
• Rectus Abdominis (the long muscle running down the front of the abdomen, holding the curled-up position through all four phases and the extra opening)
• Iliopsoas (the muscle group at the front of the hip, holding the extended legs steady across three separate opens)
• Adductors (the inner thigh muscles, driving the legs back together after each of the three openings)
• Latissimus Dorsi (a large back muscle, pulling the straps down to the hips)
• Serratus Anterior (a muscle along the side of the ribcage, helping stabilize the shoulder blades as the arms extend)
• Obliques (the muscles along the sides of the waist, working harder to keep the trunk steady through the longer hold)

FAQ

Why does one extra leg opening change this exercise so much? Extending the curled-up hold for a third repetition asks the abdominals and hip flexors to sustain the same position for longer, an increase over what two openings require even though the movement doesn’t change.

Is a steady two-opening sequence needed before adding the third? A full sequence with two even leg openings that already holds together comes first, since the third opening only helps once that timing is in place.

Is some abdominal or hip-flexor fatigue after this exercise normal? Yes, a worked feeling through the abdominals and the front of the hips after a full set is expected, more so than after the base version. A sharp ache confined to one spot in the neck or low back is different, worth a pause and a word with a doctor or physical therapist if it doesn’t fade.

Is going back to two openings acceptable if the third keeps breaking down? Yes, running the sequence with two leg openings is a reasonable way to build the timing and endurance first, and Coordination is built that way.

How often should the three-opens version be practiced? Two to three times a week, once the base two-opening sequence feels steady through a full set, suits most people building toward this extended version.

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Related to Coordination as the easier version performed with two leg openings.