Jamie wants to improve her abdominal strength. Which change to her workout will help her to achieve this? Use a higher resistance or weight and fewer repetitions, eight to 10 repetitions per set. Use lower resistance or weight and a high number of repetitions, 12 to 18 repetitions per set. Use a lower resistance or weight and decrease the number of repetitions by two or three. Use a higher resistance or weight and increased repetitions, at least 20 per set.