Are you ready for a tight mid-section and killer thighs? Take our 30-day abs and squat challenge to boost your core, leg and butt muscles in just one month!
Sit-ups exercise your abdominal muscles and reinforce your core.
Crunches also also target your abdominal muscles, but with less strain on your lower back.
Squats boost your core while also engaging your lower body, toning your legs and improving your flexibility.
Source : wwws.fitnessrepublic.com