There are many that will work, I guess it depends on how many you do but never push it too mucht, aching is fine, pain is NOT
Get someone to lightly hold your feet while you do sit ups
and another 2 that i've found that I think will work fairly quickly are these....
well then are there any exercises that will help tone up my stomach quickly. i feel like i tried a bunch of workouts for awhile and none of them got me the results i wanted....at all. so i'm kinda big on workouts that will show me results FAST...help!! aha
vivi_81 is spot on, your BMI is slap bang in the middle of normal. What you have to remember is that you are very young, you are still growing even if you can't see it and by dieting at your age without anything in the reserve tank you would be depleting your body of vital minerals and vitamins that could mean trouble in a few years. If youre feeling "flabby" research specific exercises for the areas you want to tone up
you probably don't want to hear this, but at 5'5 you should not loose any more weight... 129 is absolutely perfect. try to tone up instead. this will give your body a better contour, if that is what you have a problem with.