Increasing intra-abdominal pressure during leg presses protects your back.
Those looking to build strength and size in their hips and legs will often incorporate leg presses into their lower body workouts. When lifting heavy loads with the leg press, your will naturally take the necessary steps to increase your intra-abdominal pressure by using the Valsalva maneuver, which is performed by forcefully exhaling with your airways closed. This increase in intra-abdominal pressure helps to protect your spine.
Understand The Valsalva Maneuver
The Valsalva maneuver is the result of a simultaneous tightening of the abdominal muscles, compression of the chest cavity and closing of the larynx to prevent air from escaping. Increasing intra-abdominal pressure via the Valsalva maneuever increases the stability of your spine. According to Dr. Daniel Hackett's 2013 study published in the Journal of Strength and Conditioning Research, a brief Valsalva maneuver is unavoidable when you're lifting heavy weights or performing lighter lifts to muscular failure.
Know the Leg Press Benefits
The leg press is a heavily used machine exercise because it effectively targets your glutes, quadriceps and calves. To perform the leg press, lie in the unit and place your feet up onto the platform hip-width apart with your toes pointed forward. Push the platform away from you slightly and release the weight lock so that the platform is free to move. Lower the platform to your chest by bending your knees, continuing until your knees are bent just beyond 90 degrees. Then straighten your legs to complete the rep. After you've completed the set, finish with your legs fully extended and set the weight lock again so that the platform is locked into place.
Combining the Two
The leg press places compressive forces on your spine, according to strength and conditioning professional Jason Ferruggia. This stress on the back is at its highest as your knees are lowering toward your chest. Therefore, you will initiate the Valsalva maneuver as you lower the platform toward your torso. Hold your breath and the tightness in your torso, and extend you legs. You will then forcefully exhale and release the abdominal contractions. Increasing the intra-abdominal pressure during the leg press helps protect the spine from the compressive forces. However, Ferruggia also recommends protecting your back by only bending your knees to about 90 degrees.
Consider Your Health
When you use the Valsalva maneuver for prolonged duration while performing straining exercises, you significantly reduce blood pressure and venous return, which is the rate at which blood returns to the heart. As a result, you deliver less blood to your brain, which can cause dizziness and sometimes even fainting. When you begin breathing again, your body tries to quickly recover by dramatically increasing blood pressure to unsafe levels. While using the Valsalva maneuver during leg press is safe for healthy young men, if you have blood pressure issues, visit your medical professional prior to using the Valsalva maneuver during your leg press workouts.