Although your upper thigh is wide, the muscles that combine to make up the quadriceps are small. The rectus femoris, vastus lateralis, vastus medialis and vastus intermedius work together to form the quadriceps. The main function is knee extension, with the rectus femoris being responsible for hip flexion. While you cannot contract only one muscle of the quadriceps group, you can change the focus of your exercises to target the inner quads, which are made up of the vastus medialis muscles.
Perform leg extensions with your toes turned out. Sit in the leg extension machine. Adjust the back support so you are seated upright with the backs of your knees resting against the seat. Position the roller just above your feet. Turn your toes slightly out, but not to the point you experience discomfort in your knees. Exhale and straighten your legs as you lift the weight. Inhale and slowly return to the starting position. Use a weight that you can lift for one to three sets, with eight to 12 repetitions in each set.
Target your inner quads by doing squats with your toes turned out. Stand with your feet slightly wider than hip-distance apart. Turn your toes outward on angles of approximately 45 degrees. Hold onto a dumbbell in each hand, or place a barbell across your upper back. Inhale, bend your knees and lower your hips into a squat. Keep your knees in line with your toes and aim to lower yourself until your thighs are parallel with the floor. Exhale, straighten your legs and return to a standing position. Use a weight with which you can squat for one to two sets, with eight to 12 repetitions in a set.
Use a static contraction to forcefully target the inner quads. Sit on the floor with your legs straight in front of you. Roll up a bath towel and place it underneath your left knee. Place your hands on the floor for support. Cross your right calf over your left shin. Straighten your left leg and lift your left foot off the floor. Hold this position for a count of 20. Slowly release and repeat 20 times. Reverse the leg positioning and repeat the exercise on your right leg.
Cycle for 20 to 30 minutes two or three times a week to target your inner quads. Use a road bike or a stationary bike set to a moderate resistance. Pedal at a moderate to fast pace after slowly pedaling for a five-minute warm-up.
Strengthen your inner quads one or two days a week with at least one day of rest in between resistance training.