Science studies have identified several risk factors for muscle pain related to activities. They include repetition, force, posture, vibration, temperature, contact stress, and unaccustomed activities. These terms are often used for ergonomic reviews. Ergonomics is the study of people and activities. In general, activities should vary in their tasks and use multiple muscle groups to accomplish the job. Remember, exercise is good for your health. Work can be part of your daily exercise routine to keep your heart, lungs, and other body systems working at their best. However, too much of a good thing can cause muscle pain. For example, playing three softball games on a weekend without getting into shape is likely to result in some Monday morning muscle pain. The same process can occur at work so you need to stay in good physical condition to meet the demands of your job.