Law enforcement agents protect life and property, and uphold the law within a jurisdiction. Many of the job requirements are not based on education, but on one's physical and mental characteristics. To become a law enforcement agent, individuals need to complete agency training programs, such as police academy.
A muscle strain, also called a pulled muscle, occurs when a muscle is stretched too far, and microscopic tears occur within the muscle fibers. Common muscle strains include pulled hamstrings, groin strains, and calf strains. The usual symptoms of this type of injury include pain, spasm of the muscle, swelling, bruising, and limited mobility.
As you read (or will read) on the main Pulled Muscle Symptoms page, there are three levels of a pulled chest muscle. The most mild is a 'tweak' , where for a variety of reasons, the muscle is just in spasm, or otherwise temporarily unhappy due to insufficient nutrition, blood supply, etc.