This week's exercise

10. Dynamic prone plank

Functionality: This dynamic exercise tones, lengthens and strengthens just about every muscle in your body. It is very challenging, and if you have back problems, please ask me for assistance before trying it on your own.  The extension (as shown below) can be very good for your spine, but you may have to modify, depending on your personal issues.

Exercise: Get on your hands and toes, facing the floor, keeping your head, back and legs in a straight line and your arms straight underneath your shoulders. Lift your rear to the ceiling, pulling your belly button into your spine, forming a pike or downward dog (yoga) position, lengthening your arms and legs. Return to plank position and bend your elbows against your sides, lowering your torso and legs to the floor. Keeping your lower body flat on the floor, use your arms to push your chest and head up towards the ceiling (similar to the cobra in yoga), stretching out the front of your body. Lower down and push your body back into plank position. Repeat 5 to 10 times. As you get stronger, increase the number of repetitions.

Progression:
Additionally, you can make this into a diving pushup, by diving down from the down dog position into the up dog position, and then return the way you came, reversing your dive.

Weakness is not a reason, it's an excuse.