Everyone knows I am a Functional Fitness Fanatic. I believe in the principles of training the body for movements that are present in the daily realm and motion based exercises that provide not only muscular stability, but strength and development through a co-ordinated system. However, isolation exercises do have their place. Apart from being the 'bodybuilding' style development of physique and only having aesthetic value, I am now rethinking my standpoint and realising that the rehabilitative value of isolation serves a purpose as well.
Compound exercise involve multiple muscles and usually multiple muscle groups in an action. They require a co-ordination of muscles firing in sequence to be able to perform an action 'effectively'. The loading of a compound movement is attributed most directly to an increase in performance of an action. That is - you are able to transfer the strength or loading from the training into a movement based action in a real world application. It is one thing to be able to do 50kg bicep curls but can you lift yourself up a 20' rope climb? Maybe not. This is where compound training comes into its own. It works the co-ordination and multi directional aspect of a movement so that you have both concentric and eccentric strength, not only in the target muscle but in the supportive and complimentary muscles of a group action. This is vital if you are actually going to encounter movements that involved more than one direction and more than one muscular action.
But isometric exercises do serve a purpose. And, as I am being accepting of altering my ingrained opinions - they have a place in the training realm particularly when it comes to targeting specific muscular imbalances. We have heard the classic case that you find with leg extensions - where the gluteal group is not active enough in hip extension to maintain power and maintain stability of the pelvis in extension of the leg. After all, if you don't have a solid base to push against, a lot of your energy is wasted in stabilsing a non stable surface. Try doing a push up on a BOSU ball and you will get the idea. EVERYTHING works harder (refer to ??? Method)
So a gluteal that is not firing in co-ordination with the hamstring leaves the hamstring doing the bulk of the work whilst the 'butt muscles' take a little holiday. And thats a whole lot of work that the hamstring has to do - poor hamstrings. This leads to ineffective hip extension, and if you are a runner in a half marathon, a jumper in hurdles or a half back in football, your stride is going to fade and be less powerful because of the inefficiency of the muscular balance. That means - slower time!
So being able to target these small muscles that don't do as much of the work is beneficial if you are trying to improve your overall performance. Building up strength and/or power in the smaller and isolated muscles can bring about a greater improvement in your overall performance. But you have to be diligent as too much work in isolation can and will result in a power dominance in the other direction and then again, the overall performance will suffer from the result. Yes, an over powerful butt muscle! Damn that gene pool!
So does a combination of compound and isolation exercises work? The short answer is yes. Used together they both serve a purpose. But you don't want to be too reliant on one or the other to only achieve the benefits of increased performance. It's a constant to and fro of balancing both types of exercises in a training regime. Ideally, isometric exercises should be done secondary to the primary movement. If you are working rope climbs and then doing bicep curls on top of them (though we all know big biceps doesn't transfer to arm flexion strength,don't we Mr Brachialis) you are working the isolated muscle group secondary to the primary movement. Think of it as exhausting the big group first and then targeting the smaller ones.
As a trainer once exclaimed to me when working with sequence of training - 'strength first, then power, then endurance, and after - glamour' Translated this means that you want to work your strength movement first. The big kahuna of the chain where the most muscle groups are being utilised in powerful concentrated and co-ordinated movements such as the squat, the deadlift, the overhead press. Then comes power. Where you are relying on a ballistic nature of movement to move a load across an arc of movement in a fast motion. PURE POWER. Think Push-Jerk, Thruster, Ball Throw or chin up. Then comes endurance, where you want to work the fibres that are meant to last the long haul. This is high rep range of a single motion. Repeatedly performing the action so that the muscles learn not to give up after 5 reps. Then comes glamour. Fatigue a muscle so that it grows back bigger. SIMPLES.
So I'm learning to embrace my isolation exercises and build them into my own sense of routine so that I can manipulate my performance to best serve my purpose. If your purpose is to look ripped at Bondi then 'Isolation all the way' is your game plan. Hit those muscles and make them fatigue. But if you actually want to move with load, perform in a movement based action - then you want to target the most effective use of movement with power and strength. If that strength action isn't as effective as what it could be because of a muscular imbalance then isolation is the way to move forward. Target the ineffective muscle and work it considerately and with formulaic function (ie - working to activate and increase ability - not to make it bigger). This will lead to overall improvement in performance and a better result for the action you are trying to achieve.