Perform two sets of as many situps as you can. Go through a full range of motion. If you can do 40, each week try to add five to your total. Follow this with two sets of leg raises performed with your hands under your hips. Do not bend your knees or let your feet touch the floor. Do as many repetitions of leg raises as you can.
Perform five sets of weighted situps. Hold a dumbbell high on your chest, and select a weight that allows you to complete half as many situps as you did for your first set on your previous training day. Follow this with side bends for your obliques. Hold a dumbbell in one hand while standing up with your back flat. Lean to one side lowering the dumbbell, then lean as far as you can in the other direction. Do two sets of 15 to 20 repetitions per side.
Perform four sets of situps completing 80 percent of the repetitions you performed per set on your first training day of the week. Rest as long as you need to in-between sets, but still keep your rest time to a minimum. Follow this with four sets of leg raises at 80 percent of the volume per set used on day one.
Train three days a week. Each day will require a variety of training methods. Each day will require additional exercises. Take a day off in-between each training session, two days after your last training day.Day one is where you work on your single-set endurance, day two you develop strength. Day three you build your tolerance for volume. If you can add five repetitions to your first set every week, in eight weeks you will go from 40 to 80 situps.