Touching your toes comes in handy during a yoga session, but research suggests that there's a tipping point to how much flexibility is actually beneficial. When your tendons and ligaments are too loose, the joints may not be fully protected, upping your risk of injury, says Mike Boyle, owner of Mike Boyle Strength and Conditioning in Boston. This test focuses on your hip flexors, a commonly stiff (yet frequently ignored) spot for women: Tightness here signals a host of muscular imbalances in the hips, glutes, and hamstrings that can lead to muscle strains and lower-back pain.
The Test: Thomas Test
Test each leg separately. Lie on a bench, knees at your chest (a). Hold one knee with both hands as you extend your other leg, relax your hip, and lower as far as possible while keeping the leg straight (b).
Excellent If your extended leg drops below your hips
Good If your extended leg is parallel to your hips
Below Average If your extended leg is above parallel to your hips
Flex Even Farther
Tight hip flexors? Blame weak glutes. Strengthen them by doing this move three times a week: Lie on your back with your knees bent and feet flat on the floor. Pull your right knee to your chest with both hands, then lift your hips by pushing down into your left heel. Hold for six seconds, then return to start. Do six, then repeat on the other side.
Just because you bang out 50 crunches a day doesn't mean your abs are as strong as they should be: "The role of the entire core is to stabilize the spine while your arms and legs move," says celebrity trainer Valerie Waters, who has sculpted the bodies of A-listers such as Jennifer Garner and Kate Beckinsale. "Crunches flex your spine instead." Here's a better way to measure core strength.
The Test: Walk Outs
Get onto your hands and knees, palms flat on the floor, knees bent 90 degrees, and back flat (a). Slowly walk your hands away from your body, keeping your arms straight and your core and glutes engaged (b). Extend as far as you can, hold for 20 seconds, then slowly walk your hands back to the starting position, maintaining proper form and control. If you fall, drop your hips, or lose form at any point, retry the test.
Excellent If your thighs are nearly parallel to the ground
Good If your thighs are less than 45 degrees to the ground
Below Average If your thighs are more than 45 degrees to the ground and/or you're unable to hold the position for 20 seconds
Make Over Your Middle
If you fall below average, focus on doing a plank until you can hold it for 30 seconds: Get into a modified pushup position with your forearms on the floor and your legs extended straight behind you. Your body should form a straight line from your shoulders to your feet. Engage your core and glutes and hold this pose. Or balance on something unstable—a stability ball, a BOSU trainer, a Valslide—during any exercise. Your core will have to work even harder to keep you steady.