These six muscles may never earn top billing, but they may rejuvenate your workouts and ignite new growth.
Know it: This muscle, located on the side of your chest along your ribs, attaches to and allows you to rotate your shoulder blade (a.k.a. scapula). It plays a vital role when you raise your shoulder to flex your arm and move it away from your body; that’s why it’s prominent in boxers but not your average guy. The reason? Blame the bench press. Because of the support provided by the bench, the serratus anterior doesn’t receive much direct challenge during this popular exercise.
Test it: Do a pushup without wearing a shirt and have someone look at your back during the move. If you have a winged scapula, your shoulder blade will stick out; this means your serratus is weak. A strong one suctions your scapula in during the movement, eliminating the winged look.
Improve it: Standard pushups strengthen the muscle, but doing pushup variations is the quickest way to correct a weakness. Use a power rack to perform incline pushups on a barbell. Start with your body at the lowest incline that doesn’t allow your shoulders to wing—which means placing the bar relatively high. Perform 3 sets of 8 to 12 repetitions. As you become stronger and learn to control your scapular motion, work your way down the rack until you’re doing regular pushups with perfect body alignment.
Know it: This muscle near your gluteal (butt) region helps with thigh rotation and tends to suffer from overuse. Why? Because weak hamstrings and glutes force the piriformis to take on some of the work those big muscles should be doing. This creates back and hip pain, and weaker lower-body performance.
Test it: Sit on a chair and cross one leg over the other, with the crossing ankle of one leg resting on the bent knee of the other. If you can’t get your top leg parallel to the ground, your piriformis is probably tight.
Improve it: Increase your mobility with windshield wipers. Lie on your back with your knees bent and your feet placed wider than shoulder-width apart on the ground. Press your knees together, and then return to the starting position. Do 2 sets of 10 to 15 repetitions. Now add some soft-tissue work: Sit on a foam roller with your weight shifted to your right butt, and place your right ankle on your left knee. Roll your right glutes from top to bottom, working any painful areas. Continue for 45 to 60 seconds, and switch sides. Do this daily.
Know it: The psoas (so-az) muscle runs through your hips to connect the lower portion of your back to the top of your thigh. It’s one of your body’s main back stabilizers and hip flexors (the muscles that line your hips and allow you to bring your knees toward your chest). If you sit all day, the psoas becomes rounded like a banana; then, when you stand up, the psoas pulls on your back, making you more prone to pain and lower-back injury. “A weak psoas also means you’ll end up with assorted knee issues, because other secondary hip flexors take over and cause pain,” Robertson says.
Test it: Lie on your back and pull one knee to your chest. Keep your other leg straight. If the psoas is of normal length, your straight leg will rest on the floor. If your leg sits above the floor, your psoas is either stiff or shortened.
Improve it: The only way to strengthen a weak psoas is by bringing your knee above 90 degrees. Sit with your knees bent on a low box or bench (6 to 10 inches high) (3). Maintaining good posture and keeping your abs tight, use your hips to raise one bent knee slightly higher than your hips. If you lean forward or backward, you’re not performing the exercise correctly. Hold for 5 seconds, and return to the starting position. Complete 3 sets of 5 repetitions per leg. Also, to help release some of the pressure you may feel, use your thumb to press on your hip flexor; it’ll be on your side and a little lower than your belly button.
Tensor Fasciae Latae
Know it: This muscle (also known as the TFL) starts along the outer edge of your hip and can affect lateral movement (abduction), which is movement away from your body. A tight TFL can mean you’re at increased risk for lateral knee pain, because it attaches directly to your ilio-tibial band–tissue that runs vertically along the outsides of your thighs to help stabilize your knees. Weak or tight abductors means you’re constantly getting beat off the dribble, or you’re late getting to the ball on the tennis court.
Test it: Try old-fashioned leg lifts. Lie on your side with your legs straight, and raise your top leg to about a 40-degree angle. Then lower it. You should be able to lift your leg in a straight line, without your hip or thigh moving forward. Make sure you’re using hip strength, though; many people substitute motion from their core and lower back to finish the movement.
Improve it: Stretching the TFL is the secret to improving your performance, say Robertson. To stretch your left TFL, stand with your left hip adjacent to a wall. Cross your right foot in front of your left foot. From this position, contract your core and left glute, and then push directly into your left hip. Don’t let your hips move backward, and instead make sure your left hip pushes to the side. Hold for 20 to 30 seconds, and then switch legs so your other side faces the wall. Perform 2 or 3 reps on each leg every day.
Supraspinatus and Subscapularis
Know them: The supraspinatus is one of the small muscles at the top of your shoulder that makes up the rotator cuff; the subscapularis is a large muscle on the front of your shoulder blade. Blame your desk job for weak shoulders: If your upper body is rounded, it’s most likely because your chest is tight, which means the opposing muscles in your shoulders are weak. Strengthen the stabilizing muscles, and you’ll see improvement on your bench press and in overhead sports like swimming or tennis, as well as in your overall upper-body power.
Test them: Bring your arms straight out in front of you at about a 45-degree angle, your thumbs pointed up—like you’re about to hug someone. Have a friend stand in front of you and push your arms downward with moderate pressure. (The friend’s hands should be positioned above your wrists on your forearms.) If you feel soreness in your shoulders or can’t resist the pressure, you probably need to strengthen your supraspinatus.
Improve them: Stand holding a light pair of dumbbells in front of your thighs, palms facing each other. Keeping your thumbs pointed up, raise your arms up at a 30-degree angle to your torso until just above shoulder height. Hold for 1 second, and lower to the starting position. Do 2 sets of 8 to 10 repetitions. The exercise will help you add pounds to your bench by improving the stability of your shoulders.