While preparing for my sons' next track and field event, I felt we needed a edge; strength training. First I looked online for vests but found them to be either really expensive or not made for children.
The one's I did find for children were the Sensory Integration weighted vest for kids with D.I.S.(Dysfunction of Sensory Integration), they were expensive ($50-$125), didn't offer enough weight and were just not cute.
So I decided to try and figure out how to make a cheap weight vest whose weight could be adjusted depending on the exercise.

Step 1: First Attempt

My first attempt wasn't bad but the vest was too bulky, the sand shifted to the bottom of the vest and the weight wasn't adjustable.

Step 2: Materials

Supplies:
1. Duct Tape (The Stronger the Better) 60 yd $8.99 Ace Hardware
2. 2" Velcro sticky back (Industrial Grade) 15 ft $25.00-Amazon
3. 1 1/2" D Rings (4) $1.00 sewing supply store
4. 1 1/2" Nylon webbing $25.00 (50 yd roll) sewing supply store

Tools:
1. Yard stick
2. 18" ruler
3. (2) Scissors (1) for Duct tape (1) for Nylon webbing
4. Sewing machine (easier) or needle and thread (harder)

Step 3: Let's Begin

Measure the person who the vest is for.
First measure from collar bone to collar bone ( my sons were 11" and 8 3/4").
Second measure from the top of the sternum to right below the navel (12" and 9 3/4") or just add an inch to the original measurement.

Step 4: Let's Tape

Cut one strip of duct tape double the size of the second measurement ( you'll be making the front and the back of the Vest) . Continue cutting and slightly overlapping each new strip on top of the preceding until you have reached the width of the first measurement. Then clean up the edges.

Step 5: It Takes Two

Cut the duct tape fabric in half, now you have two pieces (front & back of vest). Next begin making the straps by cutting and measuring a piece of duct tape about 33". Cut another piece the same size and lay it on top of the first, you now have one strap (repeat for second strap).
Attach both straps to the front and back of the vest, make sure the person head can easily fit thru the opening of the vest.

Step 6: Sew

Measure out how much webbing you will need and cut one strip for the D-rings and one to secure the vest around the waist.
You can either use a machine (quicker) or if you don't have a machine hand sew (slower).
Take two D-rings feed one end of the webbing thru them and sew the webbing together, repeat on the other end.

Step 7: Add Straps

This Step is pretty simple. Measure about 3" from the bottom of the vest and duct tape nylon webbing to the outside of the vest. Melt edges of webbing to keep them from fraying.

Step 8: Velcro Up

Cut velcro to size and stick it to the vest. Put as many strips as you want (I placed 5 so that I could bring the weight up to ten pounds on each side for a twenty pound vest).
And that's it for the vest, but we are not yet done, let's make some weights.
I will next show you how to make two different sizes a 1 lb which I call a Burrito (because of it's shape) and a 1/2 lb Biscuit (small size). Which will attach to the vest adding weight that can be adjusted depending on need.

Step 9: How to Make a 1 Lb Burrito

Supplies:
1. Sand (50lb bag) $3.99 Ace Hardware
2. Gray duct tape 55 yd (Nashua) $2.70 Home Depot
3. Black duct tape 60 yd (Tuff Stuff) $8.99 Ace Hardware
4. 2" Velcro sticky back (Industrial Grade) 15 ft $25.00-Amazon
5. Ziplock Sandwich bags $3.99 grocery store

Hardware:
1. 1 cup measuring cup
2. Scissors
3. Scale (optional)

Step 10: How to Make a 1/2 Lb Biscuit

Step 11: Before and After

Since having made these vest our training sessions and and my sons' overall event times and distances have improved, There are some tweaks that I want to do to improve on the vest but given the results, I would say they were a success! This completes this Instructable, I hope you enjoyed it.