We have a 2 year old 70lb yellow lab that is full of energy and does well on the leash rather it is walking or go along with us on a bike ride.  My wife wanted to take him running with her but didn't feel like holding on to the leash because typcially your arms move a lot when you run.  She told me about this belted leash she saw online one day so of course I pulled up Amazon typed it in found about 5 different brands saw this was the cheapest and best reviews so I bought this one.  I bought it on Friday around 3pm and paid to have it shipped in 1 day for $3.99 because she wanted to use it on Saturday because of the nice weather we were getting.  She went for a good run with Scout or dog and said it was AWESOME and the cool thing is the loop can go from left to right depending on what side the dog likes the most.  I'm not a huge runner but I did take him out on it for a walk on Sunday and I have to say it was pretty nice to not hold on to the leash the whole time.  The good thing is you can grab it like a leash if you have to just in case the dog starts to pull away.  We highly recommend getting this esp. for the price.