If your hamstring muscles tend to be tight, it will be difficult to assume good golf posture. You may end up rounding your back and tucking your pelvis in with too much knee flex, as you address the ball, instead of bending from your hip sockets and keeping spine straight. Rounding of the back and excessive knee flex prohibit the amount of turn you can do in your backswing leading to swing faults.
Lie on your back with your legs extended and arms at your side.
Raise one leg up straight up in the air towards your chest trying to keep both legs extended including the one on the floor.
Grab onto to your calf or around your knee to hold the raised leg straight.
Hold position the position for 8 to 10 counts.
Return to start position and repeat on opposite leg.
Do 8 to 10 repetitions on both legs.