Tim S. Grover is an American athletics trainer, author, and motivational speaker. Born in London, England, Grover emigrated to the US at a young age. He graduated from the University of Illinois-Chicago with a bachelor’s degree in kinesiology, followed by a master’s degree in exercise science. While in college, he played on the school’s basketball team, and he later pursued a career as a trainer. He has over 35 years of experience training professional athletes across a variety of professional sports, most notably basketball players Kobe Bryant and Michael Jordan. Grover has built on his coaching work to become a motivational speaker, using his insights from the world of sports to offer advice and inspiration to people from all walks of life. In addition to Relentless, he is the author of Winning: The Unforgiving Race to Greatness.

Because Grover’s advice is based on his observations of athletic failures and successes, his coaching philosophy may be less useful—or even harmful—to people in different fields or with different professional goals. For instance, Grover recommends trusting one’s instincts rather than deliberating between options. This approach has worked well on the basketball court for some of his clients but may be less relevant in personal and professional situations where decisions have long-term consequences. In addition, his emphasis on frankness may not be equally accessible in all contexts; in particular, members of marginalized communities may find themselves penalized rather than rewarded for speaking candidly. Overall, the work will resonate most deeply with readers who have athletics-related goals and an interest in sports stories.