Compound exercises are exercises that require several muscle groups and multiple joints to work together. In contrast, isolation exercises target a specific muscle and often only utilize one joint. For example a Barbell Squat is a compound exercise that requires the muscles in your glutes, thighs and core to work together and utilizes movement in your anke, knee and hip joints. The Seated Leg Extension is an isolation exercise as it focuses specifically on the quad muscle and only uses movement at the knee joint.

Since compound movements activate a larger area of your body and therefore allow you to use significantly greater amount of resistance, the best time to do them is at the beginning of your training session when your muscles are most fresh. You’ll be able to lift heavier weight more safely and do your sets at a higher intensity when you do your compound exercises as your 1^st to 3^rd exercise of the workout, before fatigue affects your performance. Your mental focus is likely to be better in the 1^st hour of your session too, which is important as compound movements often have more complex technique points than isolation exercises.