Jeff Cavaliere is a well-known fitness expert, physical therapist, and personal trainer. He gained popularity through his YouTube channel, where he shares workout routines, nutrition tips, and fitness advice. With a background in sports science, he emphasizes the importance of proper form and injury prevention in exercise. Before his online success, Jeff worked as the head physical therapist and assistant strength coach for the New York Mets. His experience in professional sports has helped him develop effective training programs that cater to various fitness levels. Jeff is also the co-founder of the fitness brand Athlean-X.