Yes, there is a yoga called Uttanasana. It is common for people to be unable to touch their toes when bending forward with their legs straight. Hamstrings are the set of three muscles that rest behind the thighs, running from your pelvis and hip area down to your knees. When you bend down to touch your toes, hamstrings do the most work. The range of motion of your hips is equally important. When you bend down to actually reach the ground, you have to be able to bend your hip joints forward. You also have to be able to flex your lumbar spine.