Strengthener #2: abs

 To have a good posture, the muscles all around our torso need to work as a team. The group that most of you know are the abs. You would see here one exercice for them for beginners and one that is more advanced:
 Starter: -"Crunch": Lay on the ground, lying on your back. Bend your knees so your feet are flat on the floor. Cross your arms on your torso. Contracting your abs, lift your torso off the floor until your scapulas(shoulder blades) are off the floor. Hold for 5 seconds. Do 3 set of 8 to start.

Avanced: - Plank :  Lay on the ground, on your belly. Put your fore-arms near your head, palms on the floor. Lift yourself, like on the picture below, being on your toes and holding yourself on your arms, contracting your abs. Hold for 30 seconds to start. Repeat 3 times.

 Don't forget, if you are feeling any pain, stop immediatly. It is really important to drink water, especialy if you are training.
N.B.Most people have a hard time with the plank, so be carefull while doing it. Personnaly, I can do 20 crunches no problem, but holding the plank for 30 seconds is real hard. So be sure to start with the crunches!