It is relatively easy to fight for sport and then step things up for the real thing. However, it is difficult and dangerous for a person to train for deadly effect, and then try to tone things down to fight for sport. Under the right conditions, a normally calm person can become angry enough to kill. However, a normally angry person finds it difficult to calm down under any circumstances. A sport fighter has to take purposeful actions to be deadly, so a sport fighter is usually not accidentally deadly. However, a deadly fighter has to be constantly vigilant when sport fighting so as to not harm the opponent. In the heat of an intense fight, a sport fighter is not tempted to be deadly, whereas, the deadly fighter has to be constantly vigilant or he or she may revert to training and harm the opponent.
Being a warrior is more of an attitude or state of mind than it is training to be a deadly fighter. Anyone can be deadly when they choose to be. To be a warrior and still live a normal life, one only has to maintain a warrior attitude. This is easier to accomplish for people who have been raised to believe there are worse things than death in life, such as disgrace or dishonor. For others, they have to train to achieve and maintain a warrior attitude.