My first experience with the group was taking the burning springs hike with Tom Stevens and about six others.

We had a very nice hike with a visit to the burning springs which was unique with the natural gas that is emitted in the creek bed.  The additional walking we took was only mildly taxing until I offered piggyback ride to my son. He weighs about 63 lbs., and once on my shoulders, a brisk walk up a hill soon simulated either heart failure, or perhaps hiking at a very high altitude (I think).

Soo, I have two such units available, the other is of the 43 lbs., eight year old girlish variety.

My other form of similar exercise discovery is getting on my eliptical stepper with a backpack full of nine pints of water, which gets the heart going pretty well. 

Happy hiking to all.