Located on the back of your thigh, your semitendinosus muscle is one of your hamstring muscles, along with the rectus femoris and semimembranosus. Your semitendinosus works with the other hamstrings muscles to extend your hips and flex your knees. According to the American Council on Exercise, it is important to strengthen your hamstrings with exercises in weight-bearing positions. Isolated hamstring strength training exercises are also important.
Seated Leg Curl
Sit on the seated hamstring curl machine and place your ankles on top of the ankle pad. Adjust the thigh pad so it rests comfortably on your thighs and lock it into place. Keep your back pressed against the back support. Slowly bend your knees, bringing your heels under your body and toward your buttocks. Bring your feet back as far as you can without arching your back. Slowly return to the starting position and repeat for the desired number of repetitions.
Hold a dumbbell in each hand. Allow your arms to hang at your sides, with your palms facing each other and your feet parallel. Step forward with one leg, keeping your back straight. Bend the knee of your front leg to a 90-degree angle. Once your front knee is bent, your back leg should be about 2 to 3 inches off the floor. Return to the starting position by forcefully pushing with your front leg. Switch legs and repeat the movement. Continue alternating legs until you have completed the assigned number of repetitions. A longer stride forward places more emphasis on your semitendinosus and the rest of the hamstrings muscles group.
Lying Leg Curl
Lie face-down on the hamstring curl machine. Place your ankles under the ankle pad, with your knees at the edge of the bench. Hold the handles at the top of the machine to stabilize your body during the exercise. Lift your heels and bring them toward your buttocks by bending your knees. Once you reach the top of the movement, slowly lower your heels. Do not allow the weight plates to touch again at the bottom of the movement. Repeat until you have completed the designated number of repetitions.
Barbell Stiff Leg Deadlift
Stand with your feet flat beneath the barbell, about shoulder-width apart. Keeping your lower back straight, bend your knees and bend over from the hips, grasping the barbell with an overhand or mixed grip. Position your hands shoulder-width apart. Lift the weight to standing position. Bend at your hips, lowering the barbell to the top of your feet. Flex your knees slightly during descent and keep your waist straight, flexing slightly at the bottom of the movement. With your knees bent, extend your hips until you are standing upright. Pull your shoulders back to prevent your back from rounding during the lift. Repeat for the designated number of repetitions.