High-tension training methods teach our bodies to exert more force. Plyometrics and the shock method are often used for lower-body power development (depth jumps, loaded jumps, and landing from various heights.) However, very few people use the same methods for the upper body.
Such drills can be very effective at improving bench-pressing strength. Example: the ballistic bench press.
This is the only exercise in which I consider using the Smith machine effective. The objective is to lower the bar to the chest, throw the load in the air, then catch it and start again.
The load you use should be light, because the goal is not to just be explosive, but to be ballistic. Use a weight that's about 20 percent of your maximum effort. If you bench 300 pounds you'd use 60 pounds for the bench throws.
Lower the weight under control, quickly reverse the motion, and toss the bar into the air as hard as you can. But be ready to catch it on the way down unless you want to get decapitated.
Note: This won't work well with Smith machines that use counterweights.