• Sore abdominal muscles need rest in order to repair and rebuild themselves.Dustin image by mhiser from Fotolia.com
  
  

Abs Need Rest

• Your abdominal muscles are like any other muscle in your body; after intense workouts that make your abs sore the day after, they need rest to rebuild and repair themselves. Therefore, you should do exercises that specifically target the abs three days a week, and include a day of rest in between to allow for development.
  
  

Abs Rarely Become Fatigued

• The majority of ab workouts conducted rarely work the muscles to the point of soreness the day after. Furthermore, abdominal muscles are much thinner than other muscles, so you do not run the risk of growing your abdominal muscles too large. Ab workouts should therefore be done five days a week, and a rest day is not needed.
  
  

Bottom Line

• Abdominal workouts should not be done if your muscles are sore, as you increase the risk of injury. Therefore, start with three days per week, and, according to Len Kravitz, PhD, "if you rarely fatigue the abdominal muscles enough so that they need an additional day to recover," increase your days to five.