Excessive fatigue and lack of strength, conditioning, concentration and control exposes one to severe injury in a contact sport such as rugby union. Strong muscles provide stronger, more stable joints, reduce the risk of injury and can tolerate more bumps and bruises.
This is especially important when it comes to the neck or cervical spine. Over the years, players have become fitter, bigger, stronger and faster, and if you are under-developed and not appropriately conditioned, you are at severe risk of getting injured.
A Mental game to Health and Fitness 