Officers must learn about their psychological and physiological reactions to stress and anxiety and how they can control and minimize their negative effects. For example, adrenaline can have many physical effects including dilated pupils, sweating, tension in neck and upper back, and increased heart rate. Techniques can be learned to improve and control one's physical and psychological reactions, which are strongly linked. Physical fitness is essential for effective performance in high-risk law enforcement encounters. Use of force training should also focus on motor skill fitness and physiological control. The latter is comprised of relaxation and breathing training. Methods of training the mind include improving concentration, positive self-talk, and mental rehearsal. Additional general training considerations include adoption of a use of force continuum and dynamic, or simulation scenario, training under real life conditions. 13 references