The resistance exercises you do in the gym can largely be divided into two different types: isolated and compound. Compound exercises are any movements that involve more than one joint, and use a large number of muscle groups, whereas isolated exercises only use one joint, and tend to focus on one muscle group.
Take training legs as an example, where a compound exercise would be a squat, as you are using your glutes and hips so you will be working your legs, as well as your calves.
An isolation leg exercise would be leg extensions, where the only joint that is changing angle is your knees, so it targets your legs without engaging your glutes. Both isolation and compound movements have their place in the gym, however there are some big advantages to making sure your workout contains compound exercises.
Burn more calories
Compound exercises will be using some of the largest and most powerful muscles in your body, and in order for these big muscle groups to keep working, they will need more energy than if you were using smaller isolated muscle groups. Compare a deadlift with a hamstring curl, both exercises are targeting your hamstrings, however a deadlift will also require activation from your glutes, back, biceps, shoulders, forearms and your core.
During your session all of these muscles will require blood flow to provide oxygen to the muscle fibres so your heart rate will increase more than if you were just working a single muscle group, and then after your session during recovery, they will still be demanding more energy, which your body can get from food and fat stores.
Improve Muscular Imbalance
Isolation exercises are very useful , but sometimes you can easily over-train some body parts in relation to others, and this can result in strength and aesthetic imbalances. With large compound movements, it helps ensure that large muscle groups are doing the hardest parts of the movement, and they are supported by secondary muscle groups.
Take a bench press for example, you are mainly using your pectoral muscles, however your triceps are also being trained during the movement, as is your anterior deltoid to some extent.
With every day movements like walking & climbing stairs, your muscles and joints need to work together, For this reason large movements are crucial for every day strength and balance, and minimising injury risk as you strengthen your muscles appropriately in relation to one another, also its crucial to craft an aesthetic balanced physique.
Improve Core Strength
With compound movements, it is the lifter’s responsibility to keep their body in a safe position, so your core gets worked during every rep. If you are only training with isolation exercises, often you are using machines and supports to keep your body locked in a fixed position. This helps to target the muscle in isolation, but your core often doesn’t need to work to keep your body steady.
Take for example a squat and a leg extension machine. With a squat, you must keep your chest up, back flat, heels down and distribute power evenly through your legs. With a leg extension however, the machine guides your movement path for you, so you don’t need to actively keep your balance, or tense your core.
Good core strength can help all of your other lifts improve too, and is much more likely to improve from compound lifts than isolation.
Stimulate Greater Hormone Release
As these movement will be recruiting more muscle fibres than isolation exercises, your body will consequently release greater levels of hormones, particularly growth hormones such as testosterone. These hormones are responsible for repairing your body to help you improve the way you can deal with similar stimuli next time they occur.
In this case, these hormones can help you to increase muscle mass and get stronger, than if you were training with isolation exercises alone. This is one of the reasons that training legs is so important, as they are huge muscles groups, the hormone release during leg sessions can help you to experience greater body changes all over.
When to use Compound Exercises
Compound exercises depend on several muscle groups working together, so for this reason I will normally start my workout and those of my clients with compound movements. This is because I want my large muscles to be doing the work, and not be limited by smaller muscle groups failing first.
Because compound exercises use so much effort and energy to complete with good safe form I also don’t like performing these at the end of a workout when the smaller muscles and more importantly the central nervous system is fried.
Take Home Message
Compound exercises are a great way of promoting strength balance in your body, as well as burning more calories, and requiring more core strength than isolation exercises.
Use compounds alongside isolation exercises during your workouts.
Proper form is always more important than the weight you’re lifting.