Questions
2) What are Clean pulls and Snatch pulls
3) What is Jerk from rack, is this similar to a push press?
Answers
This one is like a "straight leg deadlift". The difference is that you bend your knees slightly and keep them that way during the lift. Your back must remain straight throughout and all of the movement occurs at the hip joint. This exercise works lower back and hamstring muscles and is a good alternative to "good mornings" as a conditioning exercise.
Pulls (snatch or clean) are the first part of the lift - from the start position to the position of "full extension". Full extension is achieved when your legs are straight, heels are off the floor, torso is vertical, arms are straight and shoulders are shrugged. The bar should be around waist height in this position.
This is simply the jerk (split receiving position) performed from the starting position - bar on the shoulders - and returned to the shoulders after each repetition. "Rack" refers to the racks or stands from which the bar is lifted onto the shoulders to begin each set, so the exercise could just as well be called "jerk from shoulders" or just plain "jerk".
This one is a little harder to explain without demonstrating. Snatch balance is used to develop good technique when moving into the snatch receiving position (full squat). You begin with the bar on your shoulders behind your neck, holding it with a wide (snatch) grip. You bend your legs slightly (dip as in the jerk) and extend them quickly (drive as in the jerk) to get the bar moving upwards. Once you have fully extended you body you "drop" very quickly into a squat position while extending your arms overhead