Physical education on the road

In case you ever need to know how to do pull-ups with no bar, you throw a towel over a tree and try to hold on. This way of doing pull-ups has many benefits. Studies indicate that grip strength is a better indicator of cardiovascular health than blood pressure. In the doctor's office, they have you hold a band while a steadily increasing force pulls it away.  The force of gravity was more than sufficient. 

Another benefit is that it improves judo hand strength. And the obvious benefit is abs like Troy's. But my real point with this picture ...

Is that your your hands form into claws that you can't open without help. But not to worry, that wears off quickly.