“We know that strength training reduces the signs and symptoms of many chronic diseases, including heart disease, diabetes, and obesity,” says Jennifer L. Kraschnewski, MD, MPH, an assistant professor of medicine and public health sciences at Penn State College of Medicine. Lean muscle burns more calories, helping you maintain a healthy weight, she explains.  All you need to get started? Just 15 minutes—and not even dumbbells. “Body-weight exercises can be just as effective at building muscles as traditional moves,” says Lara Hudson, a fitness expert and star of 10 Minute Solution: Tighten & Tone Pilates. Here, Hudson shares her total-body, Pilates-inspired strength workout. Do it at least twice a week for a stronger, longer future.  Reclining Leg Circles Start in a seated position and lean back onto your forearms. Press your legs together and extend them toward the ceiling. Inhale and tilt your legs to the right 45 degrees. Exhale as you circle them forward, left, and then back up to the ceiling. Reverse directions and circle to the other side. Repeat sequence 4 times. Front Plank Low Twist Begin in a forearm plank position, with your shoulders over your elbows and hands clasped together. Inhale as you rotate your pelvis to the right, rolling onto the edge of your right foot. Exhale as you return to center; roll to left side. Repeat 4 times. MORE: 6 Habits People With Healthy Weights Have In Common Side Plank Mermaid Begin in a forearm plank position, with your shoulders over your elbows and hands clasped together. Rotate to the left, rolling onto the edge of your left foot. Lift your right arm up to the ceiling. Exhale as you lower your left hip to the mat and right arm by your side. Inhale and press your right side up as high as possible, lifting your right arm overhead. Repeat 4 times; switch sides.  Butterfly Lie facedown with your hands behind the base of your skull and fingertips touching, chin tucked in, and forehead on the floor. With your legs slightly apart, bend your knees and touch the sides of your feet together. Inhale as you lift your thighs and elbows as high as possible toward the ceiling. Exhale as you slowly return back to the floor. Repeat 4 times.  MORE: Your Anti-Aging Walking Workout Reverse Tabletop with Knee Pull Begin in a reverse tabletop, with your shoulders directly over your wrists and knees over your ankles. As you exhale, lift your left knee toward the chest. Inhale and bring your left leg down, tapping the foot on the floor. Repeat 4 times. Then hold your left leg as you pulse your left hip up and down 8 times. Repeat sequence on the right side. Double-Lunge Twist Step your right foot forward. As you rotate your spine to the right, exhale and bend both knees until your left knee taps the ground. Inhale and press back up as your return to the starting position. Repeat 4 times; switch sides.