If you get a bad brand they might start stinking really bad soon after wearing it.
The weighted vest is great for people who do not like doing workouts with free weights or machines (body weight exercises)
Those little 2 1/2 pound weights some people run around with is the one of the LEADING causes of Orthopedic surgery on the shoulder, however I am not sure how the vest could be harmful when running. Possibly on the back? i would not suggest you sprint in it though.
Stair running with the vest on would likely be the best thing you can do with it.
