One of the most famous animals in the fictional Dr. Doolittle stories is the pushmi-pullyu -- a two-headed cross between a gazelle and a unicorn. Both heads of the creature are constantly trying to take control which leads to obvious difficulties. The muscles of your body are similarly paired. For instance, the quadriceps and hamstrings are called opposing muscles. In order for the quadricep to contract, the hamstrings have to relax and vice versa. If you don't exercise and stretch both muscles equally, your body will become imbalanced which may lead to gait or joint problems. Consult your health-care provider before you exercise your quads and hamstrings if you have a history of hip or knee injuries.
Aerobic exercises, including jumps and shuffles, will use both your hamstrings and quadriceps. You don't need any equipment for these exercises -- just a flat surface with plenty of room to move. Begin with a vertical jump. Stand upright with your feet together and your core engaged. Sink your butt toward the floor until your thighs are parallel to the ground. In an explosive movement, jump straight up and extend your legs. Land softly on the balls of your feet. The lateral jump is similar, except you move about a foot to the side with each jump. Shuffle runs are a traditional football exercise. Stand with your feet slightly wider than hip-width and sink down into a squat. Run in place while retaining the squat position.
Old school exercises like squats and lunges tone your upper legs. For a squat, stand with your feet slightly wider than hip-width apart. Keep your back flat and your core muscles engaged. Sink your butt toward the ground as if your were sitting down. Continue the downward motion until your thighs are parallel to the ground, then push through your heels to return to the start position. Lunges are slightly more complicated in that they require more attention to form. Stand with your feet together. Step forward with your right foot and slowly bring your pelvis down until your right thigh is parallel to the floor. Your right knee and ankle should be in line. Your left leg should be extended with the toes curled under. Keep your back straight. Push off your right foot to return to the start position and repeat on the opposite side.
Stretching will help to protect your muscles, joints, ligaments and tendons from injury. Traditional yoga poses such as the downward facing dog relax the quadricep and hamstring muscles. Begin in a plank position with your back flat, your wrists in line with your shoulders and your toes curled under. Your arms should be fully extended. Slowly push your pelvis up and back to bring your body into a V shape. Try to touch your heels to the floor, but stop when you feel tension.
While it is good to strengthen your legs, it is important to exercise your entire body to keep your anatomy balanced and to optimize your fitness performance. Plan to strength train all of the major muscle groups on three nonconsecutive days each week. Additionally, aim for at least 150 minutes per week of aerobic exercise such as running, walking or bicycling.
Carolyn Robbins began writing in 2006. Her work appears on various websites and covers various topics including neuroscience, physiology, nutrition and fitness. Robbins graduated with a bachelor of science degree in biology and theology from Saint Vincent College.