My son, Zach, and I were discussing possible projects for the Instructables Fitness Challenge. As a baseball player, Zach does a lot of physical conditioning. A strenuous exercise that he does for baseball conditioning is pulling a weight attached behind him with a band of rubber while running. We decided to build a cart that a person can add weight to while running. The rubber tubing attached to the weighted "Chariot" allows the runner to get a more strenuous exercise than simply running. If the runner lets up in running, the weighted chariot gets slightly easier to pull briefly, before becoming much harder when you have to exert more force to build back the momentum. I believe that this helps muscle development via the process of muscle confusion. Muscle confusion workouts operate under the theory that by constantly changing movements, the body will be forced to respond. Muscle confusion workouts mix up the exercise routine so the muscles have a harder time adapting, which causes them to work harder and produce visible results.

Step 1: Materials

Materials
Inexpensive weights - (garage sale)
8 feet of 2 inch by 3 inch pine wood.
2 feet by 4 feet 3/4 inch thick plywood
1 - 12 inch long piece of 3/4 inch threaded iron water pipe
1 - 3/4 inch diameter iron flange.
1 - 5/8 inch threaded eye bolt and nut
8 feet of heavy duty rubber tubing
2 - clips for either end of the rubber tubing
3 - 3 inch diameter castor wheels with rubber wheels
1 1/4 inch long drywall screws
wood screws
6 - 5/8 diameter by 1.5 inch long bolts with nuts, washers, and lock washers
Paint

Tools
Saw, screwdriver, wrench, drill

Step 2: Chariot Base

The first step is to build a solid base for the chariot from 2 inch by 3 inch pine. Cut three pieces of 2 x 3 pine 24 inches long at a 60 degree angle on each side so you can form an equilateral triangle. Once the three pieces of pine are cut, lay them out on the floor and glue them together with wood glue. Then wait overnight for the glue to harden to nail two 8 D finishing nails into each of the three joints of the triangle. I like to use the wood glue first to make nailing them together easier.

Step 3: Plywood Base and Wheels

Cut two equilateral triangles with 24 inch sides and 60 degree angles from 3/4 inch thick plywood. Line up the castor wheels at each apex of one piece of the 3/4 inch plywood. Drill 5/16 "" holes through the plywood. Attach the 3 castor wheels with 5/16 inch bolts, washers, lock washers, and nuts to the bottom piece of the plywood. Attach the plywood bottom with the three castor wheels to the 2 x 3 base with 1.25 inch drywall screws.

Step 4: Attach Eye Bolt

Drill a 5/16 inch diameter hole on the top piece of 3/4 inch plywood near one of the apexes of the triangle. Attach the eye bolt to the 3/4 inch plywood using a washer, lock washer, and nut. Attach the top plywood to the 2 x 3 inch base using 1.25 inch drywall screws.

Step 5: Attach Vertical Pipe to Hold Weights

Use four wood screws to attach a 3/4 iron water pipe flange to the middle top of your chariot. Then screw in a 12 inch 3/4 inch diameter nipple or iron water pipe into the flange. You will stack your weights through the 3/4 inch pipe.

Step 6: Rubber Tubing Attachment

Cut 8 feet of heavy duty rubber tubing. On each end of the rubber tubing, slide about 4 inches of tubing through the handle part of your clip. At the four inch side of the rubber tubing, tie the tubing into a knot. You will now have a piece of 8 foot rubber tubing with clips on either end. Attach one end of the rubber tubing to the eye bolt on top of the chariot. Wrap the other end around the runner's waist and secure with the other clip.

Step 7: Get in Shape!

Load up the chariot with as many weights as you think that you can handle. We have about 80 pounds of weights on the chariot in our video. Get running and get those muscles confused and in shape!