Your quadriceps are a group of powerful muscles in the front of your thighs that help you produce forceful movements, such as when you kick a soccer ball or bound up a flight of stairs. The best exercises to build up size and strength in your quadriceps would depend on your goal, fitness status and the sport or activity that you play. Some exercises will help you perform better, while some others may provide very little benefit if any at all.
Isolate the Quads
Isolation exercises usually target one muscle group or joint and are popular with bodybuilders. They are also used in physical therapy as part of a patient's rehabilitation process. The leg extension, for example, isolates the knee extension movement with your body in a seated position, allowing you to train your quadriceps under a lot of resistance. Although isolation exercises are easy to do, the strength you gain won't effectively carry over to athletic performance and daily activities.
Having bigger quadriceps doesn't mean they will necessarily be stronger and faster when you play your favorite sport or activity. For example, squatting with a barbell or a kettlebell requires your quadriceps to work with other leg and hip muscles to move and maintain balance, which isn't developed by doing leg extensions alone. According to the SAID principle, which stands for "specific adaptation to impose demands," doing full-body exercises that closely mimic the motion of a specific skill, such as a soccer kick or a linear sprint, will help you improve your athletic performance. Sample exercises include side lunges, stepups, double kettlebell swings, stair bounding and box jumps.
Focus on Lowering, Not Lifting
During exercise, your quadriceps contract concentrically and eccentrically, which is the shortening and lengthening of the muscle fibers while they're under tension, respectively. For example, when you lower your body into a deep squat position, your quadriceps undergo eccentric contraction. As you stand up, your quads contract concentrically. Since the tension applied to the quads is greater during eccentric contraction than concentric contraction, emphasize the eccentric phase of the exercise, recommends exercise physiologist Len Kravitz, PhD. Eccentric training can be applied to either isolation or full-body methods.
Refuel and Recover
After a workout, there is a window of time in which your body needs sufficient nutrients to repair muscle damage and replenish carbohydrate stores in your muscles. Dr. Kravitz recommends that you eat a meal that is rich in carbohydrates and has some protein -- with a ratio of three-to-one -- within 45 minutes after training. For example, if you eat 30 grams of carbohydrates, eat 10 grams of protein. Between one to three hours after your workout, eat another protein-rich meal with carbohydrates and very few saturated fats. The ratio of protein to carbohydrates should be five-to-one. Consult a sports dietitian to help you customize your meals to get the right amount of nutrients according to your lifestyle and health conditions, such as diabetes, anemia or lactose intolerance.