As you can see from the video this particular leg press is a relatively simple piece. There is only one adjutstment (the seat) and it's easy to load the weights. There are, however, a few aspects that you must be aware of before using the equipment. The first would be proper foot placement.
As you can see in the first photo my feet are placed near the top of the platform. This allows a safe knee angle (knees are not forward of the toes) when I am in the lowest part of the exercise. If you consistently allow your knee's to come forward of your toes you may irritate the joint or cause significant injury over time. In the third photo Bud shows a slightly different foot placement (his are a bit higher on the platform than mine) and a very safe knee angle. We both achieve the 90 degree bend in the knee that is desired and Bud is actually able to get a little more range.
The second point is to make sure you do not fully extend your knees at the top of the move. A very common mistake is to allow your knees to "snap" or "bounce" into that fully extended position. This may also cause injury. The second photo shows I may have a bit too much extension in the joint. Although I did not feel like I was extending completely (the video shows I'm not bouncing) I will have to reevaluate my extension. The fourth photo shows Bud at the top of the move. Note how there is still a slight bend in his knee. By keeping his knee slightly bent he maintains tension on the muscle. This is desirable because the more tension on the muscle the more effective the exercise.
- One last point would be to keep your feet flat on the platform for the duration of the exercise. When the feet remain flat the quads and gluts act more effectively. If the heel lifts away form the platform there will be more calf activation and an increase in pressure on the knee joint.