They should develop some sort of conveyor belt machine that takes the weights up so you only have to lower them! Otherwise gym pulley style machines seem perfect for this.
There is a technique known as "cheat reps" in strength training. The idea is to recruit more/stronger muscles to cover the concentric motion and to isolate the muscle you are training in the eccentric. It is an excellent tool when used intelligently. I wouldn't recommend it for beginners because it can make it easy to injure yourself and is not really needed until your strength starts to plateau anyway.