When it comes to working out muscle groups together, it's important to find a balance that promotes overall strength and avoids overtraining. One common combination is pairing chest with triceps as they often work together during pushing movements like bench press or push-ups. Similarly, back and biceps can be trained together as they are utilized in pulling exercises such as rows or pull-ups. Legs can be trained separately or combined with other muscle groups, depending on personal preference and fitness goals. Finally, incorporating core exercises into any workout routine is crucial for stability and overall strength development.