I walk 12-minute miles and, on a forgiving surface, can still run an 8-minute mile -- the ankles and plantar fascia give out before the heart and lungs do.

I have never been able to do 10 pullups or 50 pushups -- I plateaued a bit under half that. Physical coordination and upper body strength are two attributes in which I have always been well below average.

I can probably handle the situps.

What I have is endurance, slow-twitch muscles, and a good cardiovascular sytem. What I lack are power, speed, fast-twitch muscles, raw strength, and coordination.