While there are no changes to the general program structure in week 4, there are a number of new things to hone in on while doing the exercises.
During the TRX Single Leg Squat be sure to keep the body weight over the foot. The goal is to use the TRX only to assist in the balance required to do this exercise. In an ideal state, this exercise could be performed with slack in the TRX the entire time. Use a light finger tip grip on the handle and go through a full range of motion with strength and control.
Try to lift the hips a little higher than before while doing the TRX Hamstring Curls and TRX Hip Press. This will raise the intensity of both exercises.
Be sure to raise the tailbone as high as possible when pulling the knees to the chest in the TRX Suspended Crunch to Body Saw. This added range of motion will enhance the quality of the movement and ensure that you truly engage the abdominals to perform the action.