A personal trainer is a fitness professional involved in exercise prescription and instruction on one on one basis. They motivate clients by setting goals and providing feedback to clients. Trainers also measure their client's strengths and weaknesses with fitness assessments. These fitness assessments may also be performed before and after an exercise program to measure their client's improvements in physical fitness. They may also educate their clients in many other aspects of wellness besides exercise, including general health and nutrition guidelines to reach their fitness goals. Qualified personal trainers recognize their own areas of expertise.