When the muscles of the quadriceps -- the fronts of your thighs -- are significantly stronger than the hamstrings -- the backs of your thighs -- you are at risk for developing a muscle strain. You do not want the hamstrings and quads equal in strength, according to the book, "The Female Athlete: Train For Success" by Matt Brzycki. Rather, the hamstrings should be at least 65 percent of the quads, meaning that if your quads can lift 100 pounds, your hamstrings should be able to lift 65 pounds.
Warm up your legs with five minutes of full-body movements such as walking, jumping rope, climbing stairs or cycling before you strength train.
Include complete lower-body strengthening exercises in your workout routine. Do exercises such as squats, lunges and step-ups, or use a leg press machine. Perform a squat from a standing position with your feet hip-distance apart. Hold onto a dumbbell in each hand for added resistance. Bend your knees to 90-degree angles and lower your hips while keeping your weight balanced in your heels. Then, straighten your legs and return to the starting position. Complete one to three sets of eight to 12 repetitions of two or three lower-body exercises.
Incorporate quadriceps-specific exercises into your leg training routine. Perform leg extensions on a weight machine. Sit on the leg extension machine with the backs of your knees resting against the seat. Position the back support to touch your back. Adjust the rollers so they rest across the front of your lower leg slightly above your feet. Exhale and straighten your legs. Inhale and return to the starting position. Select a weight you can extend for one to three sets of eight to 12 repetitions.
Do hamstring-specific exercises such as a leg curl to strengthen the backs of your thighs. Select a weight that is approximately 65 percent of the weight you used for the leg extension. Perform the leg curls from a seated or lying position. While seated, rest the backs of your lower legs on the moveable pad and lower the stability bar to rest on your upper thighs. Flex your feet and as you exhale, pull your legs underneath your seat. Inhale and return to the starting position.
Complete balance-training exercises for overall leg stability. Do balance board squats or lunge onto a dome-based stability trainer. For example, place the dome side up on the floor approximately 2 feet in front of you. Stand tall and step forward with your right foot. Place your right foot in the middle of the dome. Push off with your right foot and return to the starting position. Repeat the lunge with your left leg. Complete up to three sets of eight to 12 repetitions, of up to three balance exercises.
Perform your leg-balancing routine two or three days a week with one or two days of rest in between sessions.