Plyometrics have been around for a long time, although it is quite new to many cyclists. Sports that require a lot of explosiveness (basketball, football, most all sports…) have been using plyos to get more power for over 30 years. It is a less used workout in endurance sports. I am actually a big believer in these efforts. While plyos are not going to give you the endurance base for a 5 hour race, they will give you a better muscle balance, quick power pull and full body strength that is so important for sprinting and climbing.
The biggest drawback for cyclists is the injury potential. A good 70% of cyclists I know have started these workouts without the proper build up and ended up with an injury. There is a very specific build up I use with my athletes that involves running, weights and explosive work on the bike that lasts a while before I introduce plyos into their training. Even with this build up, we start very slow (less extension and bend) and work up to full go on these intense efforts.
As much as I love Lance Armstrong (feel the sarcasm), this video is a great start to applying these workouts.