Squats

Illustration: mckibillo

To begin building muscle, you don't need a gym membership—or even a set of hand weights. Here are a few classic exercises you can do almost anywhere. With each, strive for three sets of eight to 12 repetitions, resting 30 to 60 seconds between sets; as the exercises become easier, mix up your routine to challenge your muscles in different ways. (For more moves, check out acefitness.org/exerciselibrary).

Squats

Squats activate all four muscles of the quadriceps, which are important for stability as you age. Make sure your knees don't go past your toes as you squat.
Planks

Illustration: mckibillo

Planks
These engage the entire core (including the lower back), while crunches primarily target the belly. Can you hold the pose for five seconds? Count that as one set. As you get stronger, hold it longer.
Bridges

Illustration: mckibillo

Bridges
This exercise tones your glutes and core, improving your balance. Lift your hips off the floor to make a diagonal line from your shoulders to your knees.
Lunges

Illustration: mckibillo

Lunges
Lunges work your quadriceps, thighs, and gluteals—some of the biggest muscles in your body. Building them up will help you shed calories all day long.
Push-ups

Illustration: mckibillo

Push-Ups
Push-ups, one of the oldest exercises (and probably one of the best), target the upper body and the core. At first do them against a wall (1) or on your knees (2), then try the standard way (3).

Keep Reading: Dr. Oz's 7 reasons to start building muscle today