There are several good ways to do a manual squat the following is one:
The manual squat is extremely effective. Like all manual resistance exercises the lifter and the spotter must work together. Of all the manual exercises it couldn’t be more true in manual squatting.
The lifter must get into and maintain the correct posture or the exercise becomes almost impossible to spot. The correct position is that the shin always remains perpendicular to the floor never moving from 90 degrees during the entire exercise. Every degree of lower leg movement from 90 degrees means the athlete is losing musculature tension and therefore, utilizing leverage to make the exercise easier.
The idea of the manual squat is to rotate around the knee joint and limit as much leverage as possible. Doing this enables the spotter to effectively apply resistance to an otherwise extremely powerful lifter and lever system.
In the picture to your left the exercise has already begun as the lifter started about 4-6 inches lower. The lifter is lightly holding on to the grooves in the cement pillar with his fingertips for balance.
The shin should be perpendicular to the floor. In the picture the athlete needs to sit back as his shin has drifted forward several inches from 90 degrees…. Not Good.
The spotter applies pressure at the hips. The athletes job is to rotate up and forward. Understand what we are talking about is 
rotation of the musculature around the knee. During the movement the femur or thigh bone will swing towards the post that the athlete is grasping, while the lower leg remains stationary. The athlete is instructed not to use his arms just the target muscles of the legs, hips and glutes.
In this picture the lifter needs to raise himself up and forward only about 4-6 more inches. He should never totally straighten his legs.
The shin in the photo is still to far forward.
You will find that an athlete is very weak in the lowest position of the squat and many do not like this unfamiliar position, which causes a high level of muscular pain during the movement. This is where the spotter makes sure the athlete does not move the shin forward or backwards for leverage and uses only their leg muscles to elevate themselves to develop great strength.
During the lowering phase lifters tend to try and relax near the bottom to release tension, but they must maintain the stress throughout the movement.
Lifters are allowed to make large lifting sounds …arrgghh… during this exercise while they release air…as long as they maintain their dignity….
The manual squat is a great exercise, especially right after a Pendulum Hip Press or Pendulum Pro Squat or Barbell Squat to GET STRONG.
