The core of John Wooden's Pyramid of Success includes CONDITION, SKILL, and TEAM SPIRIT.
Don't forget your warmup of your cardiovascular and neuromuscular systems. Dynamic stretching "elongates and coordinates" muscles. Simple exercises are here. Plus, players love exercises like karaoke.
How can we improve our athleticism? Maximal oxygen consumption (VO2max) is the best measure of overall fitness. Tabata Training is proven to increase VO2max. "The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.min-1, while the anaerobic capacity increased by 28%. An athlete could perform this with either a cycle ergometer or treadmill (under a physician's authorization).
Jumping rope is validated to improve many metrics in 10-12 year-old boys. "It was determined that weight, body fat ratio, 20m sprint, VO2 max and leg strength measurements were significantly different in favor of rope jump group (p<0.05). In 10-12 year old boys, rope-jump training program was the result of having a positive effect on strength, VO2 max and especially speed."
Here is their training program (3 days/week)
Jump rope. Practical jump rope workouts cycle varies. Some use 30 seconds on and 30 seconds off. Stack.com describes four useful exercises.
Hexagon Jump Training, developed by the US Tennis Association. Click link for details.
Lagniappe: Coaches Clipboard shares Alan Stein drills. I think Pete Carril argues that none of these exercises occurs in a game and therefore are limited. I see both sides.