Not sure about Layne's version of speed work but the standard version is lighter weights lifted as explosively as possible. Multiple sets 6-8 of 3 reps or less with 50%-70% of your 1rm. The point is to apply as much force into a lighter weight as you would with an all out one rep max.
Very often accomodating resistance is used as well (bands and chains) to further encourage "accelerating" the weight on each rep.