If you have ever heard someone mention the words ‘Compound’ or ‘Isolation’ but not really known what they were talking about I am going to explain in this post.
Compound refers to any movement that cross multiple joints and engage more than one major muscle group. They will always have a primary muscle that is the target area you want to develop, but the movement will also activate secondary muscles.
As a rule of thumb compound exercises can be categorised by pulling, pushing or deadlifting. They will all activate more than one muscle group across more than one joint. As an example you could look at the squat, the primary muscle group being targeted is the Quadriceps (Vastus Lateralis, Vastus Medialis, Rectus Femoris & Vastus Intermedius) but it actually activates your Abdominis Rectus, Erector Spinae, Obligues, transversus abdominis (aka core muscles) to stabilise your spine. In addition to the core muscles and Quads the squat also engages the Gluteus Maximus (Butt muscles).
If you are training to gain muscle mass, your programme should include compound exercises if it is going to be successful. It has been proven that compound exercises create a hormone response releasing more Growth Hormone (GH) and Testosterone, both of which are connected with hypertrophy (muscle growth).
COMPOUND IS SO GREAT, WHY TRAIN ISOLATION?
To answer this you first need to understand what Isolation exercises are. They target one muscle group across a single joint. This means only the targeted muscle carries out the work and supports the load.
An example would be tricep extension, the bicep acts as an antagonist relaxing so that the agonist (tricep) can contract. As a result the tricep is supporting the load and controlling the extension of the arm at the elbow joint.
Isolation exercises should be performed to prevent any imbalances and improve strength within weaker muscles.
In summary: there is a place for both Isolation and Compound exercises within your workout, but if you want to increase size you will need to incorporate compound movements. Using Isolation movements to get symmetry and improve overall functional strength.