A weak core will decrease your athletic performance on the field or court. You will also be headed for core-related injuries.
Core strength is no doubt the weakest link on most athlete's bodies (and people in general). Why? Because most spend too much time strengthening the limbs (arm and legs).
Strength training should be just the opposite....stabilize and strengthen the core first (where all movement begins) and the limbs last.....show me an athlete with a strong, explosive core and I'll show you an athlete who will excel over her or his opponent...... If you have trouble maintaining your speed during the late stages of a game, you probably have a "core weakness" problem. Core strength is important to help you remain strong and upright when you are running, especially when you are tired....adequate core strength helps your speed endurance, which is the ability to maintain maximum velocity or a percentage of maximum velocity for a prolonged period of time or in a fatigued state. The best players and teams have excellent overall body strength, core strength and speed endurance (and they win the most games).
Low back injuries and other injuries of the shoulder girdle and torso are usually related to "weak core muscles" or "postural problems."
One painful and slow-healing injury that many athletes suffer is the oblique muscle strain or pull. This type of injury is usually incurred when doing a twisting or rotating movement such as swinging a bat/racket, rotating explosively, etc. The obliques are part of your core and can be strengthened with exercises like planks and medicine ball exercises. Don't ignore the core!