For example, an Athlete who is sponsored by a protein bar company cannot go on social media and say that the protein bar tastes terrible and not to buy it. This term is usually used to only protect the company and not the athlete. 

Example Contract Language:

Non-Disparagement: The Athlete shall not (a) knowingly make any damaging or harmful statements—spoken, written, or online—about Company and Company’s products; or (b)  do anything which might reasonably be considered to be immoral, scandalous or obscene, or otherwise damage the reputation of the Company during the term of this agreement.