The primary difference between compound exercises and isolation exercises is the number of muscle groups they target. Compound exercises work multiple muscle groups and joints simultaneously, such as squats, deadlifts, and bench presses. These exercises improve overall strength and functionality, as they mimic real-life movements. Conversely, isolation exercises focus on a single muscle group, like bicep curls or leg extensions, allowing for targeted muscle development. While both types of exercises have their place in a fitness routine, compound movements are generally more effective for building strength and improving overall athletic performance.