I want to clear this up once and for all because apparently this is yet another contentious issue that idiots like to argue about. You could say “just let idiots be idiots and argue as much as they like”, and actually that’s a good suggestion! However for new people who don’t know any better, it’s easy to get the wrong idea when you read these arguments and try to decide who you think is correct. Usually when two people are arguing, insisting that their way is the ONLY way, usually both of ’em are wrong.
First off I’ll do my best to explain the difference between compound and isolation exercises. Here goes!
Simply put, when we talk about a compound exercise we are talking about an exercise that utilises multiple muscle groups.
The deadlift is a good example of a compound exercise. If you consider the movements of a deadlift (or just watch the video) you can imagine the quadriceps muscles contracting to straighten (extension) the legs at the knees, at the same time the hamstrings, glutes and spinal erectors are recruited to straighten up at the hips. The core muscles (such as transverse abdominals) are engaged as we use strict form to maintain good spinal posture throughout the lift, and of course our arms and shoulders are involved in holding on to enormous amount of weight we are pulling up from the ground. That’s a LOT of muscles all working in the one lift.
Bench press and squats are the other “big two” compound exercises involved in competitive powerlifting. Olympic weightlifting is another obvious example of compound exercises.
As the name implies, isolation exercises are different to compound exercises in that they target one individual muscle or muscle group very specifically. Strictly speaking, this is not always a technically accurate term as other supporting muscles may be recruited during the exercise, but without being too pedantic we can describe any exercise where we specifically target an individual muscle as an isolation exercise.
Which is better, compound or isolation?
As with most “which is better” type questions in life, the answer is as follows: Neither. Or both. It depends.
It is generally agreed that heavy compound lifting is the best approach for gaining strength, and with increased strength usually comes increased muscle mass. So, I could imagine someone who’s ONLY goal is increased strength (such as a powerlifter or strong man competitor) might forego isolation exercises altogether and use compound movements exclusively. However, as multiple muscles are recruited in these lifts, you could also imagine the usefulness of a particular isolation exercise to target a muscle or muscle group that is a weak link in the chain, preventing the competitor from lifting to his true potential.
For those of us who are concerned more with aesthetics, isolation exercises become more important. We should still be performing our compound movements as heavy as possible to promote strength, muscle mass, good posture and functionality. However, lets consider some of the smaller muscles that really make or break a great physique in terms of symmetry and proportionality. To hit these smaller muscles, often we need to use very specific techniques.
A good example is the rear deltoid which is often neglected, resulting in asymmetrical shoulders or even the appearance of a rounded back & shoulder area. The front deltoid in particular will be worked while doing bench press and / or shoulder press, and may appear over developed or disproportionate to the rear of the shoulder. If you imagine a rowing exercise as the opposing movement to the bench press, there are massive muscles at work (lattisimus dorsi, rhomboids, trapezius etc) throughout the back, which greatly minimise the workload of the relatively tiny rear deltoid muscle. So, in my opinion it is usually necessary to incorporate an isolation exercise targeting the rear deltoid specifically in order to build symmetrical shoulders, although the same is not true for the front delt. This is just one example of the value of isolation exercises.
Isolation exercises for biceps and triceps.
This one is really down to the individual. The biceps will be worked while training the muscles in the back, and triceps will be worked while training bench press or shoulder press exercises for chest or shoulders. For many people, this is sufficient to achieve great arms… but for others, some specific bicep and tricep exercises may be required. Personally, I think training arms is FUN at the end of a workout, and that’s enough reason for me!
Remember, everyone is a little different and what works for you might not be right for someone else. It might not be enough, or it might be too much. Find what works best for you, and train as hard as possible as consistently as you can.