Holding In Your Stomach: Understanding Core Muscles, Hollowing vs. Bracing, and Building Abs

Does holding in your stomach work your abs?

Holding in your stomach, depending on the specific technique employed, primarily engages the deep core muscles, particularly the transversus abdominis, enhancing core stability and posture, but it is not sufficient for significant hypertrophy of the more superficial abdominal muscles like the rectus abdominis.

Understanding Your Core Muscles

To properly address the question, it's crucial to understand the anatomy and function of your core musculature. Your "abs" are more than just the visible six-pack. The core is a complex cylinder of muscles designed to stabilize your spine, transfer force, and facilitate movement.

• Rectus Abdominis: This is the most superficial abdominal muscle, running vertically from your ribs to your pelvis. Its primary role is spinal flexion (e.g., crunches) and contributing to trunk stability. This is the muscle associated with the "six-pack."
• External and Internal Obliques: Located on the sides of your trunk, these muscles are involved in rotation, lateral flexion (side bending), and trunk stability.
• Transversus Abdominis (TVA): This is the deepest abdominal muscle, wrapping horizontally around your torso like a natural corset. Its fibers run horizontally, and its primary function is to draw the abdominal wall inward, increasing intra-abdominal pressure (IAP) to stabilize the lumbar spine and pelvis before movement. It is often referred to as the "body's natural weight belt."
• Multifidus, Pelvic Floor, and Diaphragm: These muscles also play critical roles in core stability, working synergistically with the abdominal wall.

The "Holding In" Phenomenon: What Are We Really Doing?

The act of "holding in your stomach" can refer to two distinct, yet often confused, core engagement techniques: abdominal hollowing (often called the "stomach vacuum") and abdominal bracing. While both engage core muscles, they do so differently and for different purposes.

Abdominal Hollowing (Stomach Vacuum): The Transversus Abdominis Connection

What it is: Abdominal hollowing involves actively drawing your belly button in towards your spine, often performed on an exhale. This action specifically targets and contracts the transversus abdominis (TVA).

How it works: When you hollow, you are consciously activating the TVA to compress the abdominal contents and pull the abdominal wall inward. This action does not typically involve significant contraction of the rectus abdominis or obliques, which are more involved in spinal flexion or rotation.

Benefits of Hollowing:

• Enhanced Core Stability: By strengthening the TVA, hollowing improves the foundational stability of your lumbar spine, reducing stress on the lower back.
• Improved Posture: A strong TVA contributes to better postural alignment, helping to flatten the lower abdomen and support the spine.
• Reduced Back Pain: For individuals with certain types of lower back pain, strengthening the TVA can be a crucial component of rehabilitation.
• Visceral Compression: It helps to compress the internal organs, which can contribute to a flatter appearance of the midsection.

Limitations: While hollowing strengthens the TVA for stability and postural support, it is not an effective exercise for building visible "six-pack" abs (rectus abdominis hypertrophy) or for developing maximal strength in compound lifts.

Abdominal Bracing: The Global Core Activation

What it is: Abdominal bracing involves stiffening the entire abdominal wall, as if preparing for a punch to the stomach. It's a co-contraction of all the core muscles (TVA, rectus abdominis, obliques, multifidus, pelvic floor, and diaphragm) to create a rigid cylinder around the spine.

How it works: Unlike hollowing, which draws in, bracing focuses on creating stiffness and increasing intra-abdominal pressure outward against the abdominal wall. This technique is designed to maximize spinal stability and force transfer during heavy lifting or powerful movements.

Benefits of Bracing:

• Maximal Spinal Stability: Essential for protecting the spine during compound exercises like squats, deadlifts, and overhead presses.
• Increased Strength and Power: A rigid core allows for more efficient transfer of force from the lower body to the upper body, improving performance in strength and power sports.
• Injury Prevention: By stabilizing the spine, bracing helps prevent excessive movement that could lead to injury.

Does "Holding In" Build Abs (Rectus Abdominis Hypertrophy)?

The answer is generally no, not in the way traditional abdominal exercises like crunches, leg raises, or planks do.

• Hollowing (Stomach Vacuum): Primarily targets the TVA for stability and visceral compression. While a strong TVA contributes to a flatter stomach appearance by pulling the abdominal wall in, it does not directly cause hypertrophy of the rectus abdominis (the "six-pack" muscle). You won't get visible abs from hollowing alone.
• Bracing: While bracing engages the rectus abdominis as part of a global core contraction, its primary purpose is stability, not hypertrophy. The rectus abdominis needs to be worked through its full range of motion against resistance (e.g., spinal flexion) to stimulate significant muscle growth.

Therefore, if your goal is to develop visible, hypertrophied abdominal muscles, you need to incorporate exercises that specifically challenge the rectus abdominis and obliques through dynamic movements and progressive overload, in addition to managing body fat levels.

Practical Applications and Best Practices

• Integrate Hollowing: Practice the stomach vacuum regularly, especially if you're looking to improve posture, develop foundational core stability, or alleviate lower back discomfort. It can be done anywhere, anytime – while driving, sitting at a desk, or as part of your warm-up.
• Master Bracing for Lifts: For strength training, particularly compound lifts, mastering abdominal bracing is paramount for safety and performance. Learn to "brace for a punch" before initiating the movement.
• Combine for Comprehensive Core Health: The most effective approach to core training involves a combination of techniques:
  • Hollowing/TVA work: For deep core activation and foundational stability.
  • Bracing: For maximal stability during heavy lifting and athletic movements.
  • Dynamic Abdominal Exercises: For hypertrophy and strength of the rectus abdominis and obliques (e.g., crunches, planks, leg raises, Russian twists).

Conclusion

Holding in your stomach, specifically through the technique of abdominal hollowing, effectively works your deep core muscle, the transversus abdominis, leading to improved core stability, posture, and a potentially flatter midsection. However, it is not an effective method for building the visible, hypertrophied "six-pack" muscles of the rectus abdominis, which require dynamic, resisted movements. For a strong, functional, and aesthetically developed core, incorporate a balanced routine that includes both deep core activation (hollowing), global bracing for stability, and traditional abdominal exercises for strength and hypertrophy.