Based on these skills, soccer players must develop joint stability, balance, and connective tissue strength through the ankle, knee, back and shoulders (to support and stabilize explosive jumping, sprinting, changing direction and decelerating),posterior chain strength and power (to develop strength through glutes, hips, and legs for jumping ability and speed), reactive ability, quickness, endurance, and lateral speed (for first-step quickness and defensive ability), and core strength (to stabilize lower lumber spine, and to aid in control of large motor movements) Although each position has its unique demands, all soccer players must improve these essential basic motor abilities. A soccer player’s ability to run is most often judged by his/her times on a 40 yard sprint. His/her ability to change directions quickly is most often judged by his/her time in a 20 yard shuttle.