Internal Obliques: Anatomy, Function, and Effective Exercises

How Do You Flex Internal Obliques?

Flexing the internal obliques primarily involves actions that rotate the torso to the same side (unilaterally) or contribute to spinal flexion and compression of the abdominal contents (bilaterally), often in conjunction with controlled breathing and core bracing.

Understanding the Internal Obliques: Anatomy & Function

The internal oblique muscles are a pair of deep abdominal muscles situated beneath the external obliques. Their muscle fibers run diagonally upwards and medially, contrasting with the external obliques whose fibers run downwards and medially. This unique fiber orientation dictates their specific roles in core movement and stability.

Key Functions of the Internal Obliques:

• Unilateral Action (One Side Contracts):
  • Ipsilateral Rotation: When the internal oblique on one side contracts, it rotates the trunk to the same side. For example, the right internal oblique contracts to rotate the torso to the right. This is a crucial distinction from the external obliques, which rotate the trunk to the opposite side.
  • Lateral Flexion: Both internal and external obliques on one side work together to bend the trunk sideways (e.g., right internal and external obliques contract to bend to the right).
• Bilateral Action (Both Sides Contract):
  • Spinal Flexion: Working with the rectus abdominis, they contribute to bending the trunk forward (e.g., a crunch).
  • Compression of Abdominal Contents: They play a vital role in increasing intra-abdominal pressure (IAP), which is essential for spinal stability, forced exhalation (e.g., coughing, sneezing), and defecation.
  • Core Stabilization: Along with the transversus abdominis, they are key deep stabilizers of the lumbar spine and pelvis, providing a "corset-like" effect.

The Challenge of Isolating the Internal Obliques

While you can perform exercises that emphasize the internal obliques, true isolation is difficult due to the synergistic nature of the core musculature. The internal obliques nearly always work in concert with the external obliques, rectus abdominis, and transversus abdominis.

Why "Feeling" Them Can Be Difficult:

• Deep Location: They are not superficial muscles, making tactile feedback challenging.
• Synergistic Action: Other, larger muscles often dominate the "feeling" of an exercise.
• Stabilizing Role: Often, their primary role is subtle stabilization rather than powerful, visible movement.

Key Principles for Activating the Internal Obliques

To effectively target the internal obliques, focus on the quality of movement, breathing, and specific muscle actions.

• Controlled Exhalation and Bracing: As muscles involved in forced exhalation and increasing intra-abdominal pressure (IAP), contracting them is often facilitated by exhaling forcefully. Think about "drawing your navel towards your spine" or "bracing for a punch" during the movement. This action directly engages the internal obliques and transversus abdominis.
• Spinal Position: Maintain a neutral or slightly flexed spinal position. Avoid excessive lumbar extension, which can disengage the core.
• Slow, Deliberate Movement: Avoid momentum. Focus on the muscle contraction throughout the entire range of motion.
• Mind-Muscle Connection: Consciously try to "feel" the contraction in your deep side abdominal wall during rotation or lateral flexion.
• Emphasis on Unilateral Rotation: Exercises that involve rotating the torso to the same side as the contracting oblique are particularly effective.

Effective Exercises for Targeting the Internal Obliques

Here are exercises that effectively engage the internal obliques, focusing on their specific actions.

• Side Plank:
  • Execution: Lie on your side, supporting your body on your forearm and the side of your foot. Keep your body in a straight line from head to heels.
  • Internal Oblique Focus: This exercise primarily emphasizes the lateral stability function. You can increase the challenge by performing Side Plank Hip Dips, lowering and raising your hips, which enhances the lateral flexion component.
• Bicycle Crunch (Controlled):
  • Execution: Lie on your back, hands behind your head, knees bent. Bring one elbow towards the opposite knee while extending the other leg. Alternate sides.
  • Internal Oblique Focus: The key here is slow and controlled rotation. As your right elbow moves towards your left knee, your right external oblique and left internal oblique are working to rotate your torso. When your left elbow moves towards your right knee, your left external oblique and right internal oblique are active. Avoid fast, jerky movements that rely on momentum.
• Russian Twist (Controlled):
  • Execution: Sit on the floor, knees bent, feet flat or slightly elevated. Lean back slightly, maintaining a straight back. Rotate your torso from side to side, touching your hands to the floor beside your hips.
  • Internal Oblique Focus: Again, emphasis on slow, deliberate rotation. As you twist to the right, the right internal oblique assists in that rotation. As you twist to the left, the left internal oblique assists. Avoid excessive speed or using a heavy weight that compromises form.
• Dead Bug with Abdominal Bracing:
  • Execution: Lie on your back, knees bent 90 degrees over hips, arms extended straight up. Slowly lower one arm and the opposite leg towards the floor without letting your lower back arch. Return to start and alternate.
  • Internal Oblique Focus: Before initiating movement, perform a deep abdominal brace by drawing your navel in and bracing your core as if preparing for a punch. This engages the deep core unit, including the internal obliques, to maintain spinal stability as your limbs move. The internal obliques contribute significantly to this bracing action.
• Pallof Press:
  • Execution: Stand sideways to a cable machine or resistance band anchored at chest height. Grasp the handle with both hands and press it straight out in front of you, resisting the rotational pull of the cable/band.
  • Internal Oblique Focus: This is an anti-rotation exercise. The internal obliques (along with external obliques and transversus abdominis) work isometrically to prevent your torso from twisting towards the anchor point. It's excellent for developing their stabilizing role.

Common Mistakes to Avoid

• Relying on Momentum: Swinging through movements, especially in exercises like Russian twists or bicycle crunches, reduces muscle activation and increases injury risk.
• Over-Recruiting Hip Flexors: If you feel exercises primarily in your hip flexors (front of the hips), your core might not be adequately engaged. Focus on pelvic tilt and abdominal bracing.
• Holding Your Breath or Shallow Breathing: Proper breathing, especially controlled exhalation, is crucial for internal oblique activation and intra-abdominal pressure.
• Ignoring Core Bracing: Simply moving through an exercise without actively bracing your core will limit internal oblique engagement.

Integrating Internal Oblique Training into Your Routine

Incorporate 2-3 exercises targeting the internal obliques into your weekly routine. Aim for 2-3 sets of 10-15 repetitions, or hold isometric exercises like the side plank for 30-60 seconds. Focus on quality over quantity. Strengthening these muscles contributes significantly to:

• Improved Spinal Stability: Reducing the risk of lower back pain.
• Enhanced Rotational Power: Beneficial for sports involving twisting movements (e.g., golf, tennis, throwing).
• Better Posture: Supporting a strong, upright posture.
• Effective Respiration: Aiding in forced exhalation.

When to Consult a Professional

If you experience persistent pain during core exercises, have difficulty activating your core muscles, or are recovering from an injury, consult with a qualified healthcare professional, physical therapist, or certified personal trainer. They can provide personalized guidance, assess your movement patterns, and ensure you are performing exercises safely and effectively.