Although this may be hard to pick-up off the written page I will explain what changes you may need to make to your current running style.  I tried this after having issues running on a variety of treadmills.  I just thought the belt was not working correctly, as it was constantly jerking and it wasn’t smooth.  Could it have been my weight?  The answers to both are a resounding no!  My technique was all wrong.  I was landing on my heel as I ran.  This landing basically stops forward motion, which causes the belt to slide, but more importantly, it caused extreme pressure to go up my leg, through my knees and hips and into my lower back.   

All accomplished and elite runners run on the balls of their feet.

The foot should strike the surface with the ball of the foot, in a dorsiflexed position (with toes pointing forward not downwards) otherwise this creates a “breaking” motion.  The heel doesn’t touch the ground.  The foot on landing on the surface should be “light” not heavy, it then “grips and scrapes” the surface.  The knee is slightly bent on contact with the surface and the foot lands below the centre of gravity – just below the hips.  Think of your leg working in a circular motion from the hip joint.

This brings the heel of the foot behind the body. The hamstrings and gluteus maximus (backside muscles) play a very big part in this movement.  The thigh moves forward with the action of the quads and hip-flexors, the leg is extended and the foot drops again, landing on the ball of the foot as above.  The back should be straight and relaxed, not bent at the waist.  The shoulders should be relaxed, the arms should be bent at approximately 90° and the motion should be from the shoulder not the forearms.  As the arm moves back it should continue to stay in 90° flexion.  The hands should be held with the palm facing inwards not down. If you prefer to hold your hands in a fist, the thumb should rest on the forefinger.  The head should be up with your eyes looking ahead not down.

You will know when you have got it right, you will be able you feel it.  It will feel weird at first, but it will feel more comfortable.