The barbell jerk is not done by pressing the barbell up with the arms. It is performed by explosively driving the bar with the legs then immediately lowering the body beneath the bar by explosively rearranging the feet and bending the legs. The arms are used to accelerate the body under the bar as the feet and legs are repositioned and then to fix it (lock it out) overhead.
In order of popularity, here are video examples of the three methods currently used to accomplish lowering the body in the barbell jerk.
Split Jerk, Power Jerk and Squat Jerk.
My training day Friday 1/8, clean pulls from below knee to 140kg and Front Squat to 100kg + kettlebell 10 minute set; a free form H2H workout with 12kg.100 reps each arm 24kg swing to finish.