Leg Raises vs Sit-Ups: Which Exercise Is Better for Abs?

Key Takeaways

• Sit-ups provide the most significant abdominal muscle activation while minimizing lower limb involvement.
• Leg raises are superior for targeting the lower rectus abdominis and hip flexors.
• Both exercises can be problematic for those with lower back issues if performed incorrectly, requiring proper modifications and attention to form that maintains neutral spine positioning.
• SOLE's Equipment Mat provides the cushioned surface essential for both exercises protecting your lower back and tailbone during floor-based ab work.

The Truth About Ab Exercises

The battle for ab exercise supremacy has raged in gyms for decades. In one corner, we have the classic sit-up, the military and martial arts standby. In the other corner stands the leg raise, beloved by gymnasts and calisthenic athletes worldwide. 

But which truly delivers better results? The answer isn't as straightforward as fitness influencers might have you believe.

The abdominal wall consists of four main muscles: the rectus abdominis (the "six-pack" muscle), internal and external obliques (side muscles), and the transverse abdominis (the deep core stabilizer). 

An effective ab routine must target all these muscles through various movement patterns, not just focus on one signature exercise.

What many fitness enthusiasts don't realize is that core exercises also heavily involve other muscle groups. Sit-ups and leg raises both recruit the hip flexors (iliopsoas and rectus femoris) to varying degrees. This recruitment pattern creates both challenges and opportunities depending on your training goals. 

Leg Raises: The Complete Breakdown

Leg raises have earned their reputation as an effective core builder among gymnastics and calisthenics communities through extended time under tension and lower ab emphasis.

Proper Form and Technique

To maximize benefits while minimizing risk of injury with leg raises, proper execution is essential. Begin by lying flat on your back with legs extended and hands either at your sides or under your glutes for lower back support. 

Keeping legs straight (or slightly bent for beginners), raise them until perpendicular to the ground while maintaining contact between your lower back and the mat.

The key to effective leg raises lies in controlled movement. Avoid using momentum by lowering the legs slowly (3–4 second eccentric phase) until they hover just above the ground before initiating the next repetition. 

This controlled eccentric phase dramatically increases abdominal activation while reducing strain on the lower back. 

For those with existing back issues, modifications can help make leg raises more accessible. Bending the knees reduces leverage and decreases strain on the lower back. Additionally, performing the movement on a decline bench allows for a more controlled range of motion for beginners.

Muscles Targeted and Activation Patterns

Leg raises create distinct activation patterns across the core musculature. While they effectively engage the lower rectus abdominis, they also significantly activate the iliopsoas and rectus femoris—key hip flexors that connect the spine, pelvis, and femur. 

This activation pattern explains why leg raises are particularly favored in sports requiring hip flexor strength.

What's particularly interesting is how the transverse abdominis activates during leg raises. This deep stabilizing muscle works isometrically throughout the movement to maintain pelvic position and spine neutrality. 

The external obliques also engage as stabilizers, especially when preventing rotational movement during the exercise.

Variations to Progress Your Training

• Hanging Leg Raises: Performed from a pull-up bar, this advanced variation adds the challenge of stabilization and increased range of motion. 
• Captain's Chair Leg Raises: Using a captain's chair apparatus allows for proper form with back support while increasing the challenge through gravitational resistance. 
• Single Leg Raises: By alternating legs, you can focus on unilateral development while reducing overall intensity. 
• Toes-to-Bar: The most advanced progression requires not just lifting the legs to parallel but continuing the movement until the toes touch the bar overhead.

Common Mistakes That Reduce Effectiveness

The most prevalent error during leg raises is excessive lower back arching. This compensation shifts work away from the abdominals and can place unhealthy stress on the lumbar spine. 

Maintaining posterior pelvic tilt (slightly tucked pelvis) throughout the movement is crucial for both effectiveness and safety. Another common mistake is using momentum rather than controlled movement, which significantly reduces time under tension and muscular development.

Sit-Ups: Beyond the Basics

The traditional sit-up has been a cornerstone of fitness assessments and training programs for generations, producing significant activation of the rectus abdominis and external obliques.

Correct Execution for Maximum Results

The optimal sit-up begins with lying supine, knees bent at approximately 90 degrees, and feet either flat on the floor or secured under a stable anchor. Place hands lightly behind the ears or crossed over the chest to avoid neck strain. 

Initiate the movement by drawing the chin slightly toward the chest, then proceed to roll up through the spine, actively contracting the abdominals throughout the movement.

The key distinction between an effective and ineffective sit-up lies in the controlled eccentric phase. Rather than dropping back to the starting position, lower your torso vertebra by vertebra, maintaining tension in the abdominals throughout. 

This controlled descent significantly increases time under tension and muscular development. Breathing should be coordinated with the movement; exhale during the upward phase and inhale during the lowering phase.

Primary and Secondary Muscles Worked

Sit-ups effectively activate the upper and lower rectus abdominis along with the external obliques. Unlike leg raises, sit-ups create a more balanced activation between the abdominal muscles and the hip flexors. 

The internal obliques and transverse abdominis also engage isometrically throughout the movement to maintain pelvic stability. Interestingly, the eccentric phase of sit-ups shows particularly high activation of the rectus abdominis, suggesting this portion of the exercise may be most valuable for development.

Effective Sit-Up Variations

• Weighted Sit-Ups: Holding a weight plate or medicine ball against your chest increases resistance and muscle activation throughout the movement. 
• Decline Sit-Ups: Performed on a decline bench, this variation increases the range of motion and resistance through leverage, intensifying the work on the abdominals. 
• Bicycle Sit-Ups: Combining rotation with flexion, this variation engages both the rectus abdominis and the obliques for comprehensive core development.

Why Many Trainers No Longer Recommend Traditional Sit-Ups

Despite their effectiveness for abdominal development, traditional sit-ups have faced criticism in recent years due to concerns about lumbar spine stress. 

The movement creates approximately 3,300 newtons of compressive force on the spine, which can potentially contribute to disc issues in susceptible individuals. 

This has led many physical therapists and trainers to recommend alternative exercises that maintain abdominal activation while reducing spinal compression.

Another concern involves the significant recruitment of the hip flexors during sit-ups. For individuals with existing muscle imbalances (particularly tight hip flexors), this recruitment pattern can potentially reinforce anterior pelvic tilt and contribute to lower back discomfort. 

However, these concerns can be largely mitigated through proper form and appropriate programming based on individual needs and limitations.

Quick Comparison: Leg Raises vs Sit-Ups

Build Complete Core Strength With SOLE Equipment

The Equipment Mat provides essential cushioning for floor-based ab exercises protecting your lower back.

The SOLE Equipment Mat provides the cushioned surface essential for both exercises, protecting your lower back, tailbone, and hips during extended floor-based ab training sessions. 

The generous 36.5" x 78" size accommodates all body positions during both exercises—whether performing leg raises with full leg extensions or sit-ups with proper knee positioning and controlled spinal rolling. The non-slip surface prevents body sliding during leg raises, crucial for maintaining proper lower back contact preventing arching that reduces abdominal engagement.

For comprehensive conditioning complementing ab-focused training, the SR550 rowing machine provides a full-body engagement, strengthening the entire core through compound pulling movements. The dual air and magnetic resistance creates progressive challenge while the low-impact nature protects your spine during high-volume phases.

The free SOLE+ App delivers structured core training programs. The app provides exercise demonstrations showing proper form, tracks your core performance metrics, and adjusts programming based on your adaptation rate—all without expensive monthly subscriptions, saving hundreds of dollars annually.

Ready to build complete core strength through strategic ab training? Check out SOLE fitness equipment today!

Frequently Asked Questions (FAQs)

How many leg raises or sit-ups should I do per workout?

Rather than targeting arbitrary numbers, focus on quality and proper progression. For beginners, 2–3 sets of 8–12 repetitions with perfect form is a suitable starting point for either exercise. Intermediate trainees might benefit from 3–4 sets of 12–15 repetitions, potentially including variations to increase difficulty. Advanced individuals should consider weighted variations or more challenging progressions, performing 3–5 sets of 10–15 repetitions. 

Can I get visible abs from just doing these exercises?

Abdominal visibility depends primarily on body fat percentage (typically below 15% for men and 22% for women). No amount of ab exercises alone will reveal your abs if they're covered by a layer of fat. A comprehensive approach including proper nutrition and overall fat loss is necessary through a combination of resistance training, cardiovascular exercise, and caloric deficit. 

Are there any people who should avoid either leg raises or sit-ups?

Individuals with acute or chronic lower back pain, herniated discs, or recent abdominal surgery should generally avoid both exercises without medical clearance. Pregnant women, especially in the second and third trimesters, should modify or avoid traditional sit-ups due to potential diastasis recti concerns. Those with significant hip flexor tightness might find leg raises exacerbate existing postural issues and should address these imbalances before incorporating the exercise. 

How long will it take to see results from these ab exercises?

Strength improvements typically become noticeable within 2–4 weeks of consistent training, while visible changes in muscle development generally require 6–12 weeks of dedicated work combined with proper nutrition. Visual results depend heavily on reducing body fat percentage through a combination of exercise and nutrition.

How does SOLE equipment support comprehensive leg raise and sit-up training?

The Equipment Mat is crucial for floor-based ab exercises, offering superior cushioning that protects your lower back, tailbone, and hips during extended core training sessions. The professional-grade thickness absorbs pressure that would otherwise create discomfort on hard flooring, enabling the controlled eccentric phases necessary for maximum abdominal activation without the joint pain that limits training volume.