Do 12 reps then 10 reps then 8 reps then 6 reps all with a 1 minute rest between . Then back to 12 reps with a super set ( no rest ) 12 reps of sit - ups . As you get stronger just tilt the weight further back . Eventually you will be increasing the weight .

Question: What is it most likely that the person is trying to do ?
Answer: Annoy their trainerLose weight and get fitWaste their timeWin a world record