It's "plyos". Plyometrics. Skipping rope, push-ups. Strenuous stuff.
Plyos was created in 1410.
Lev Borisov was born on December 8, 1933, in Plyos, Ivanovo Oblast, Russian SFSR, USSR [now Russia].
Plyometrics(also known as "plyos") is a type of exercise training designed to produce fast, powerful movements, and improve the functions of the nervous system, generally for the purpose of improving performance in sports.
You want to mix strength training, plyos, and sport specific movements into a combined regime. I'd check out The Jump MAnual, there are others available but this spoon feeds most of the basic vertical jumping concepts.