Exercise is hard

I have been trying to get in the habit of going to my CrossFit workouts three times a week. I am enjoying it, but most workouts kick my butt. Here was today's, with some notes.

• 100 Double Unders (jump rope, spinning two revolutions per jump)
  
• 10 Burpee Box Jumps (stand, down to the floor in a plank at the bottom of a pushup, back to standing, jump up on a 24" box, jump down, repeat)
  
• 20 Ring Push ups (instead of hands on the floor, your hands are on gymnastic rings lowered down to a few inches off the floor)
  
• 30 Wall Ball (hold a 20 lb medicine ball at your chest, go into a deep squat, rise quickly and push the ball up against the wall, over a 10' line. Catch and repeat)
  
• 40 Power Cleans (take a barbell with 95 lbs, from the floor, lift it quickly up to your chest, as though you are about to do a press. Repeat)
  
• 30 Wall Ball
• 20 Ring Push ups
• 10 Burpee Box Jumps
• 100 Double Unders

This is how the workout is prescribed. If you have to back off things, that is allowed. The workout is timed, and you are trying to finish as quickly as possible.

I was able to do most things, but I used 75 pounds instead of 95 and I haven't mastered double unders, so I had to replace each with 300 normal jump ropes.

I can't tell you how tiring this is. Everything but the double unders uses your triceps. Mine were melting by the end. I just keep telling myself "whatever doesn't kill you makes you stronger."