The disciplines primarily involved in describing and understanding human movement are biomechanics and kinesiology.
Fitness professionals teach clients how to perform exercise movements and how to use exercise or rehabilitation equipment.
Biomechanics is the study of the motion and causes of motion of living things, using a branch of physics known as mechanics (the study of forces). The study of biomechanics is essential for fitness professionals because it forms the basis for documenting human motion (kinematics) and understanding the causes of that motion (kinetics).
Kinesiology is the study of the mechanics of human movement and specifically evaluates muscles, joints, and skeletal structures and their involvement in movement. Kinesiology is primarily based on three fields of science: biomechanics; musculoskeletal anatomy; and neuromuscular physiology. Kinesiology includes the study of gait, posture and body alignment, ergonomics, sports and exercise movements, and activities of daily living and work.
A variety of health care practitioners, including fitness instructors, personal trainers, exercise physiologists, athletic trainers, medical doctors, physical educators, occupational therapists, physical therapists, chiropractors, and ergonomists, use biomechanical and kinesiological principles.