The partial stiff-legged deadlift is an effective hamstring builder.
In this exercise analysis (Quicktime ipod compatible, 6MB; Google streaming flash video), Bud Gibson, and I (Nancy) demonstrate the partial stiff-legged deadlift, a very effective hamstring exercise. The primary muscles worked are the biceps femoris, semi membranosus and the semitendinosis. These are the three muscles that make up the hamstring group. The gluteus maximus is also affected by this exercise.
We chose the partial deadlift because it takes stress off the lower back. When the exercise is performed properly the bar is only lowered 2-3 inches below the knee. This provides adequate stretching of the hamstrings and also allows the spine to remain straight throughout the exercise. If the back rounds the lumbar spine is put in a very vulnerable position which may lead to injury.
The first photo shows the starting position for the exercise. My torso is tall and spine straight, I have about a hip width grip on the bar and there is a slight bend in my knees. As I begin the exercise I focus on bending or "hinging" forward at the hips. If I bend properly at the hips it makes it easier to keep my spine straight. This also allows me to push my hips back slightly to allow a greater stretch through the hamstrings. I also focus on maintaining the slight bend in my knees. If my knees bend as I am lowering the bar I will lose the stretch in the hamstrings therefore making the exercise less effective.
The second photo shows the lowest part of the exercise. At this point the bar is about 2-3 inches below my knees and I am feeling a full stretch in the hamstrings. To raise the bar to the start position I contract my glutes and hamstrings and straighten my torso.
The third photo shows Bud in the start position. His torso is tall and he also has a hip width grip on the bar. His foot stance is a bit wider than mine (this is not significant enough to affect the exercise). The fourth photo shows Bud at the lowest point in the exercise. Note how well he maintains the slight bend in his knees. He is getting a good stretch in his hamstrings and glutes and he maintians a nice, flat back.