What are the primary muscles that lift the legs during leg raises?

The primary muscles responsible for lifting the legs during leg raises are the hip flexors, including the iliopsoas and rectus femoris.

What is the role of abdominal muscles in leg raises?

Abdominal muscles primarily act as stabilizers during leg raises, preventing the lower back from arching and maintaining pelvic stability.

How can I ensure my abs are properly engaged during leg raises?

To properly engage your abs, focus on preventing your lower back from arching by maintaining pelvic control, performing controlled movements, and exhaling on effort.

Which abdominal muscles are involved in stabilizing the core during leg raises?

The rectus abdominis, obliques, and transversus abdominis are the key abdominal muscles involved in stabilizing the core and protecting the spine during leg raises.

What common mistakes should be avoided when doing leg raises?

Common mistakes to avoid include arching the lower back, using momentum, hyperextending the knees, and lacking control during the downward phase of the movement.

What part of abs do leg raises work?

Leg raises primarily work the hip flexor muscles, such as the iliopsoas and rectus femoris. While the abdominal muscles, particularly the rectus abdominis and obliques, are engaged, their role is primarily as stabilizers to prevent the lower back from arching and to maintain pelvic stability, rather than being the prime movers of the leg movement.

Understanding the Core: A Brief Anatomical Review

To fully grasp the mechanics of the leg raise, it's essential to understand the key muscles of the core and their functions. The "abs" are often generalized, but they comprise several distinct muscles, each with a specific role:

Rectus Abdominis: This is the superficial "six-pack" muscle, running vertically from the sternum to the pubic bone. Its primary action is spinal flexion (bringing the rib cage closer to the pelvis, or vice versa).
External Obliques and Internal Obliques: Located on the sides of the torso, these muscles are involved in spinal rotation, lateral flexion (side bending), and also assist in spinal flexion and stability.
Transversus Abdominis (TVA): The deepest abdominal muscle, the TVA acts like a natural corset, wrapping around the entire midsection. Its primary role is to stabilize the lumbar spine and pelvis by increasing intra-abdominal pressure.

Beyond the abdominal wall, another crucial group of muscles for leg raises are the hip flexors, which include:

Iliopsoas: Comprising the iliacus and psoas major, this is the strongest hip flexor, originating from the lumbar spine and pelvis and inserting on the femur.
Rectus Femoris: One of the quadriceps muscles, it crosses both the hip and knee joints, acting as a hip flexor and knee extensor.
Sartorius and Pectineus: Other muscles that contribute to hip flexion.

The Primary Movers: Hip Flexors

When you perform a leg raise, the action of lifting your legs towards your torso is predominantly driven by your hip flexor muscles. These muscles are responsible for reducing the angle between your torso and your thighs. As your legs are relatively heavy levers, the hip flexors must generate significant force to lift them against gravity.

How the Abs (Indirectly) Engage: The Stabilizer Role

While the hip flexors are the prime movers, the abdominal muscles play a critical, albeit indirect, role in the leg raise. Their primary function is to act as stabilizers, particularly for the lumbar spine and pelvis.

Preventing Lumbar Hyperextension: As the hip flexors contract strongly to lift the legs, they have a tendency to pull the pelvis into an anterior tilt (arching the lower back). This can place excessive stress on the lumbar spine. The rectus abdominis and obliques counteract this by contracting isometrically (without changing length) or concentrically (by slightly flexing the spine) to keep the pelvis stable and the lower back pressed towards the floor (or a neutral position if hanging). This is often referred to as maintaining a "posterior pelvic tilt" or "core bracing."
Pelvic Stabilization: The transversus abdominis works synergistically with the other core muscles to create intra-abdominal pressure, further stiffening the torso and providing a stable base from which the hip flexors can operate more efficiently. Without this abdominal bracing, the movement would be less controlled and potentially harmful to the spine.

Therefore, while leg raises don't directly "work" the abs in the same way a crunch works the rectus abdominis (through spinal flexion), they demand significant stabilizing strength from the entire core to control the movement and protect the spine.

Optimizing Abdominal Engagement During Leg Raises

To maximize the stabilizing role of your abdominal muscles during leg raises and ensure they are adequately challenged, consider these points:

Focus on Pelvic Control: The key to engaging your abs is to prevent your lower back from arching. Before lifting your legs, actively press your lower back into the floor (for lying leg raises) or ensure your pelvis is tucked slightly (for hanging leg raises). This is a posterior pelvic tilt.
Controlled Movement: Avoid using momentum. Lift and lower your legs slowly and with control. The eccentric (lowering) phase is crucial for building strength and control in the stabilizing muscles.
Range of Motion: Only lower your legs as far as you can without your lower back arching. For many, this means not going all the way to the floor, especially with straight legs.
Exhale on Effort: Exhale as you lift your legs. This helps to engage the transversus abdominis and improve core stability.
Mind-Muscle Connection: Actively think about "bracing" your core and pulling your navel towards your spine throughout the movement.

Common Mistakes to Avoid

Arching the Lower Back: The most common mistake. This disengages the abs and places undue stress on the lumbar spine.
Using Momentum: Swinging the legs reduces the work done by the muscles and makes the exercise less effective.
Hyperextending the Knees: For straight leg raises, avoid locking out your knees excessively, which can strain the hamstrings. A slight bend is often advisable.
Lack of Control on the Downward Phase: Dropping the legs quickly negates the benefits of the eccentric contraction and increases injury risk.

Conclusion

Leg raises are an effective exercise primarily for strengthening the hip flexors. While they do not directly target the "abs" for spinal flexion, they are a powerful tool for developing core stability and anti-extension strength in the rectus abdominis, obliques, and transversus abdominis. By focusing on proper form, controlled movement, and maintaining pelvic stability, you can ensure that your abdominal muscles are significantly challenged in their crucial role of protecting and stabilizing your spine during this demanding exercise. Integrate leg raises into a balanced core routine that also includes exercises for direct spinal flexion (like crunches) and rotation (like Russian twists) for comprehensive abdominal development.

Leg Raises: Understanding Muscle Engagement, Core Stability, and Proper Form