Doing situps helps build lean core muscles while also defining your waistline. To improve the number of situps you can do, focus on building strength in all of your stomach muscles. This includes performing a variety of exercises for your obliques, the rectus abdominis and the transverse abdominis.
Use a stopwatch to time how many situps you can do. Lie flat on your back, bend your knees, keep your feet on the floor and clasp your hands behind your head. Use your stomach muscles to lift your upper body to your knees and lower back down. Repeat as quickly as you can for one minute.
Start on your hands and toes to perform an abdominal plank. Keep your back in a straight line without letting your knees sag. Tighten your abdominal muscles and hold this position for as long as you can.
Lie flat on your back to perform reverse crunches. Start in the same position as a regular situp. Use your stomach muscles to lift your pelvis off the ground and draw your knees in to your chest. Repeat until you reach muscle failure.
Perform seated trunk rotations with a medicine ball or dumbbell. Sit on the floor with your legs bent while holding the weight at chest level. Lift your heels off the floor and slowly rotate from the right to the left. Repeat until your muscles fail.
Perform toe touches on your back. Lie down on your back, stretch your arms overhead and straighten your legs. Flex your core muscles and pull your straight legs toward your upper body as you reach for your toes with your hands. Slowly lower down until your arms and legs almost touch the floor and repeat as many times as you can.
Repeat this workout every other day to continue building stomach strength. Alternate the types of exercises you perform every three to five weeks to avoid hitting a plateau in your program.
Check how many situps you can do regularly. Choose one day every week to reassess how many situps you can do in one minute -- seeing progress will keep you motivated.
Ashley Farley has been a certified personal trainer since 2008. She is also a writer specializing in healthy living, fitness and nutrition topics. Farley has an Associate of Science in mental health services from the Community College of the Air Force and is pursuing her B.A. in English at Wright State University.