Bracing

Bracing is deliberately tightening the trunk muscles to support the spine and hips.^{1International Sports Sciences Association, Strength and Conditioning, p. 327.} When the diaphragm and deep trunk muscles contract, they pressurize the abdomen.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 54.} The mostly fluid abdomen acts as a “fluid ball” that supports the spine from inside, reducing the force the back muscles need and the compression on the discs.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 54.}

Most of that pressure comes from the oblique abdominal muscles and diaphragm rather than the rectus abdominis.^{3Zatsiorsky, Kraemer and Fry, Science and Practice of Strength Training, 3rd ed., p. 185.}

In practice

• Keep the core braced during heavy lifts.^{4International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 284.} General fitness clients should hold a neutral spine; athletes whose sport forces them out of neutral under load should still keep the core braced.^{4International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 284.}
• Bracing doesn’t require holding the breath.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 54.} Pressure can build with the airway open, which the NSCA treats as the safer option for most resistance training.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 54.}
• On compound lifts, Israetel and colleagues describe bracing as a slight arch in the lower back, a breath in and tight abs.^{5Israetel et al., Scientific Principles of Hypertrophy Training, p. 157.} The stable base lets more of the effort go to the target muscle.^{5Israetel et al., Scientific Principles of Hypertrophy Training, p. 157.}
• Train the obliques directly with exercises such as resisted trunk rotations and lateral sit-ups, since they generate much of the pressure.^{3Zatsiorsky, Kraemer and Fry, Science and Practice of Strength Training, 3rd ed., p. 185.}