Leg Press and Abdominal Pressure

If you're looking for a way to train your legs in a more convenient way than working with free weights but need more of a challenge than simple bodyweight exercises, you may be drawn toward the leg press. Leg presses target your quads, along with the hamstrings, calves and glutes. While they're generally considered a safe exercise, trouble can arise if you start to experience excessive abdominal pressure.

  1. Under Pressure

    • Whenever you exert the force needed to lift a weight, you should tighten your abdominals and other core muscles. This is a process known as bracing. You don't need to squeeze the core as hard as possible, as doing so can effectively "turn off" the core, notes strength coach Jim Smith. Ideally, you should maintain an even amount of abdominal pressure throughout your whole set. Different exercises require a different amount of bracing, depending on the strain involved. A maximum barbell squat, for instance, might require a maximum brace, whereas a leg press would need less.

    Making the Maneuver

    • The Valsalva maneuver is another action that takes place when lifting weights. In essence, the Valsalva maneuver involves sucking air into your diaphragm and stomach, then attempting to force this air out with a closed glottis, meaning it doesn't escape. This can increase pressure on the walls of the blood vessels and heart, notes weightlifting coach Brandon Morrison. Performing the Valsalva maneuver can be dangerous, warns Michael Scott of Sports & Physical Therapy Associates. It can drastically increase your blood pressure and result in dizziness, sickness and fainting.

    Just Breathe

    • Scott adds that provided your abdominals are tight, pressure should be high enough without needing to implement the Valsalva maneuver. To stop yourself from doing it involuntarily, try counting out loud as you perform your leg presses.

    Still Safe?

    • Even if you don't use the Valsalva maneuver and maintain an acceptable degree of abdominal bracing, leg presses may still be a poor choice of exercise for you. This is especially true if you're at a high risk of pelvic floor problems or have had issues in the past. Heavy leg presses can place too much stress on the lower back, abs and pelvic floor muscles and should be avoided if this is the case. Opt instead for single-leg exercises such as lunges, step-ups and split squats, holding dumbbells if you need extra resistance.