It's a common belief that leg lifts strengthen the lower abdominal muscle. It might very well may feel that way, as the exercise does produce fatigue in the pelvis area, sometimes felt as a burning sensation, that can be mistaken for the lower portion of the lower abdomen.
However, the fact is that you are actually working the iliopsoas and rectus femoris, the two hip-flexing muscles that lie deep beneath the sheath of muscle known as the rectus abdominis.
The hip flexors play an important if complex role in core support, especially of the lumbar spine. Leg lifts can help stabilize your lower back, improving your posture and alignment that also improve your appearance. More importantly, it makes you more resistant to injury and lower back pain.
“Leg lifts are essential for a strong core and a strong lower belly,” says Los Angeles-based personal trainer David Knox, author of Body School: A New Guide to Improved Movement in Daily Life.
“If you just do crunches, you might get a six-pack, but you won’t have a strong core.” Leg lifts are great for lower abs because they engage the hip flexors, and the hip flexors engage the lower belly, says Knox. When done properly, they also engage the inner thighs and the butt muscles, which are key to core strength and stability, he adds.
Knox recommends starting leg lift exercises from the “up” position. After lowering the leg almost to the floor, let it spring back up before it touches the floor, which puts strain on the back. “And if you experience lower back pain, don’t lower the leg quite as much—find the range that doesn’t take you to the threshold of pain," he adds.
- “Many people will be too tight to put their leg up vertically,” says Knox. “Don’t force it. Just start where you can manage comfortably.”
- Keeping the lower back flat protects it from injury.
- The leg and foot should be fully engaged. Stretch the knee and work that muscle so you’re building strength throughout the apparatus. That will also work the abs harder and improve coordination.
- You can place your hands under your butt but not your lower back.
- How many reps? That of course depends on your condition. The American Council on Exercise recommends one to three sets of 10 to 25 repetitions for abdominal exercises.
Wouldn't it be nice if you could target the specific areas you'd most like to tighten? Unfortunately, just as there is no Santa Claus, there is no such thing as spot reduction.
It's the Holy Grail of sports medicine, and the most determined researchers have yet to prove that it's physiologically possible to target a body part for fat- or weight-loss. So all of the leg-lifts and crunches in the world won't give you “six pack” abs.
The American Council on Exercise recommends a eating a low-fat diet diet and following an exercise regime that includes cardiovascular and strength straining.
1. Single Leg Lift
HOW TO DO IT: Lie flat on your back, knees bent vertically to 90 degrees. The shoulders press down into the body. Forearms press flat against the ground, palms down, near the hips. Press your lower back into the floor.
Pressing your lower belly and lower back into the floor, curl your rising knee up and over your belly, toward the chest. With the knee as hovering over a flat, stable lower back, extend the lower leg upward and straighten it as much as possible.
Lower the leg at a smooth and even pace. Your leg only has to drop a few inches below the vertical line above your hips to work the muscles. If you’re just starting out, a few inches can be enough.
As you lower the leg, push it out and away from the body using the butt and back as it rises. This protects the lower spine from strain. Try for 10 reps on each leg. Rotate the leg open from the hip on the second set.
2. Double Leg Lift
These are performed exactly as Single-Leg Lifts with two exceptions: The feet and knees should be pressed completely together, forming one stable unit, and both feet leave the ground. Once your legs are vertical, try point your feet as you take your legs down and up.
Double leg lefts should be approached with particular care. Because they engage the hip flexors, which originate in the lumbar spine, there is a risk of hyperextending the lower back. Single-leg lifts with the opposite foot on the floor may be better for some.
- Body School: A New Guide to Improved Movement in Daily Life, by David Knox
- University of New Mexico: Contraindicated and High-Risk Exercises
- Ace Fitness: Should I Train My Abdominals Every Day? Also, What Ab Exercises Are Best?
- ACE Fitness: Shape Up for Summer the Healthy Way
- Journal of Physical Therapy Science: Comparison of Muscular Activities in the Abdomen and Lower Limbs While Performing Sit-up and Leg-raise
- ExRx.net: Lower Abdominal Myth