Iliocostalis Exercises: Strengthen Your Outer Back Extensors

The iliocostalis is the most lateral (outer) column of the erector spinae muscle group. Running along the sides of your spine and attaching to your ribs, it plays essential roles in spinal extension, side bending, and breathing mechanics. Understanding this muscle helps complete your knowledge of back anatomy and function.

Understanding the Iliocostalis

The iliocostalis has three regional portions:

Iliocostalis Lumborum

• Lower portion
• Runs from the iliac crest (pelvis) to the lower ribs
• Largest section

Iliocostalis Thoracis

• Middle portion
• Runs between the lower and upper ribs
• Spans the thoracic region

Iliocostalis Cervicis

• Upper portion
• Runs from upper ribs to cervical vertebrae
• Extends into the neck

Position in Erector Spinae:

• Iliocostalis (lateral/outer) — this muscle
• Longissimus (middle)
• Spinalis (medial/inner)

Functions of the Iliocostalis

Bilateral (Both Sides):

• Spinal extension (arching/straightening the back)
• Maintaining upright posture
• Controlling forward bending (eccentric control)

Unilateral (One Side):

• Lateral flexion (side bending) to the same side
• Assists breathing by elevating ribs (accessory respiratory muscle)

Unique Rib Attachment: Unlike the other erector spinae columns, the iliocostalis attaches directly to the ribs, giving it a role in:

• Rib cage stability
• Breathing mechanics
• Lateral trunk control

Why Train the Iliocostalis

Complete Back Development

• Often undertrained compared to middle back
• Important for lateral stability
• Balances the entire erector spinae group

Side Bending Control

• Primary lateral flexor of the spine
• Important for rotational sports
• Prevents excessive side-to-side movement

Rib and Breathing Function

• Supports rib position
• Assists in deep breathing
• Important for athletes with high respiratory demands

Exercises for the Iliocostalis

General Back Extension Exercises

All back extension work trains the iliocostalis as part of the erector spinae group:

Bird Dog

1. On hands and knees
2. Extend opposite arm and leg
3. Keep spine neutral
4. Hold 5 seconds, switch sides
5. 3 sets of 10 each side

Superman

1. Lie face down, arms overhead
2. Lift arms, chest, and legs
3. Hold 3-5 seconds
4. Lower with control
5. 3 sets of 10-12 repetitions

Back Extension (45-Degree or Roman Chair)

1. Position in back extension apparatus
2. Lower torso toward floor
3. Extend back to starting position
4. 3 sets of 12-15 repetitions

Lateral Emphasis Exercises

Side Plank

1. Lie on side, forearm and feet on floor
2. Lift hips to create straight line
3. Hold position
4. Iliocostalis works to maintain lateral alignment
5. 3 sets of 20-30 seconds each side

Side-Lying Lateral Flexion

1. Lie on side on a back extension bench
2. Lower upper body toward floor (lateral flexion)
3. Lift back to neutral using side muscles
4. 3 sets of 12 repetitions each side

Standing Side Bend

1. Stand tall holding weight in one hand
2. Bend away from the weight
3. Return to neutral (don't lean toward weight)
4. 3 sets of 12 repetitions each side

Pallof Press Hold

1. Stand sideways to cable or band
2. Press hands forward, hold position
3. Resist rotation—iliocostalis helps stabilize
4. 3 sets of 20-30 seconds each side

Quadratus Lumborum and Iliocostalis Together

Suitcase Carry

1. Hold weight in one hand
2. Walk while staying upright
3. Don't lean toward or away from weight
4. 3 sets of 30-40 steps each side

Side-Lying Hip Abduction with Upper Body Hold

1. Lie on side, prop upper body on elbow
2. Maintain side plank position
3. Lift top leg (hip abduction)
4. 3 sets of 12 repetitions each side

Stretching the Iliocostalis

Seated Side Bend

1. Sit tall, raise one arm overhead
2. Bend toward opposite side
3. Feel stretch along raised arm's side
4. Hold 30 seconds each side

Standing Side Stretch

1. Stand with feet wide
2. Slide one hand down thigh
3. Reach other arm overhead
4. Feel stretch along reaching side
5. Hold 30 seconds each side

Thread the Needle

1. Start on hands and knees
2. Reach one arm under body toward opposite side
3. Let shoulder lower toward floor
4. Feel stretch in thoracic spine and lateral back
5. Hold 30 seconds each side

Child's Pose with Side Reach

1. Start in child's pose
2. Walk hands to one side
3. Feel stretch along opposite side
4. Hold 30 seconds each side

Foam Rolling

Lateral Back Roll

1. Lie on side with foam roller under armpit area
2. Roll from armpit down to lower ribs
3. Keep arm overhead for better access
4. 1-2 minutes each side

Thoracic Roll (Standard)

1. Lie on back over foam roller
2. Roll mid-back region
3. This addresses all erector spinae
4. 1-2 minutes

The Erector Spinae as a Unit

While we can discuss iliocostalis separately, remember:

• All three erector columns work together
• You can't truly isolate one from the others
• Training back extension trains all three
• Lateral work emphasizes iliocostalis somewhat more

The Three Columns: | Muscle | Position | Primary Attachment | |--------|----------|-------------------| | Iliocostalis | Lateral | Ribs | | Longissimus | Middle | Transverse processes | | Spinalis | Medial | Spinous processes |

Programming Considerations

For General Back Health:

• Include back extensions 2-3x weekly
• Add lateral work (side planks, side bends)
• Balance with core (front) work

For Athletic Performance:

• Include rotational and anti-rotation work
• Single-leg and single-arm exercises challenge lateral stability
• Sport-specific movement patterns

For Posture:

• Daily postural awareness
• Isometric holds
• Frequent movement breaks from sitting

Relationship to Other Muscles

Other Erector Spinae:

• Longissimus and spinalis work in concert
• All three contribute to extension

Quadratus Lumborum:

• Also performs lateral flexion
• Works with iliocostalis for side stability

Obliques:

• Provide opposite-side lateral flexion
• Balance the iliocostalis for lateral control

Intercostals:

• Both attach to ribs
• Both assist breathing
• Work together for rib cage function

When to Seek Help

Consult a healthcare provider if you experience:

• Pain along the side of your back
• Pain that radiates around the ribs
• Difficulty breathing with movement
• Significant lateral spine curvature
• Persistent back pain with side bending

Summary

The iliocostalis is the lateral column of your erector spinae, with unique rib attachments that involve it in breathing and lateral trunk control. While you can't truly isolate it from the other back extensors, including lateral-focused work like side planks, side bends, and carries will emphasize this muscle. Combined with general back extension exercises, stretching, and attention to posture, you'll develop balanced, functional erector spinae muscles that support your spine through all planes of movement.