Wave loading is a high intensity training protocol used to develop maximal strength, especially relative strength. It should be used with multi-joint exercises and performed during an intensification phase of training. Wave loading is based upon the concept of post-tetanic facilitation (PTT), which states that a more powerful muscular contraction can be achieved if that contraction is preceded by a strong muscular contraction.
With a wave loading workout, you work up to a maximal weight, then reduce the weight and work back up to a new maximum, as follows:
90 x 5, 95 x 3, 100 x 2
95 x 5, 100 x 3, 105 x 2
100 x 5, 105 x 3, 110 x 2
105 x 5, 110 x 3, 115 x 2
With this protocol, trainees should be able to use more weight during each successive “wave” as the nervous system adapts to the previous sets. Another variation, one that should be reserved for advanced trainees, calls for 12 sets of work in four waves.
Another Example here