When it comes to building muscle mass through the use of weight and strength training, it’s important to understand the different approaches one can take. The body is comprised of 6 major muscle groups (chest, back, shoulders, arms, abdomen and legs). Each of these major regions can be broken down into subcomponents in which we can perform exercises to target specific muscles in that muscle group. Each region has many exercises that we refer to as either compound or isolation. Compound movements are exercises that target multiple muscles/joints while isolation movements focus on one to two muscles/joints.
What’s The Difference?
To make this simple, let’s break down the difference between compound and isolation by looking at the chest. The chest is a giant muscle that is made up of several smaller fibers packed into one section. Although most people will associate the chest fibers in regards to upper and lower chest, the chest actually has around 8 different segments of fibers that create the pectoralis major and minor. The largest fibers would be those in the upper and middle chest while the lower chest contains the smallest of them.
In order to best target the fibers as a whole, it’s important to focus your routine primarily on compound movements. Compound movements are ones that occur when you are pressing/pushing a barbell, dumbbell and even some machines. These movements can be performed in 3 different ways (incline, decline and horizontal/flat). Most people will associate horizontal pressing with flat bench press as this is one of the most common exercises for the chest muscles.
However, it’s important to understand that due to the way the chest fibers are stimulated, performing a flat bench exercises via bench press, machine press, and even dumbbell press will all yield the exact same results on muscle growth so long as the stimulus applied remains the same/constant with each variation. What makes compound movements so important for muscle growth is that these forms of exercises target a large group or region of muscles on the body for maximum muscle stimulation and growth so long the stimulus remains stable and constant.
Isolation movements are another form of movements with many exercises. Isolation movements focus primarily in targeting one joint on the body that places the tension on one muscle group and not multiple. A great example for this in regards to isolation training for the chest would be when we perform flies. Chest fly’s performed with either dumbbells, cables or machine are all considered to be isolation movements. Performing chest fly’s requires you use significantly less weight compared to presses, however, fly’s provide a greater emphasis on the chest fibers due to the movement so a lighter weight load will be just as effective as compared to a heavyweight load on presses. The results will be identical.
It’s important to understand that these isolation movements are designed to be performed in ways that avoid pressing in all forms. A proper way to perform isolation chest flies is to make sure you’re performing a hugging motion with arms and not pressing like in the bench press. With isolation movements its best to use a lightweight for a high rep range (15-30+ reps) with multiple sets (6+ per isolation exercise) with a very short rest time. Rest time for these movements should be under a minute or so while with heavy compound movements like presses I recommend keeping rest time around 1-3 minutes depending on your conditioning.
With compound movements, you are able to perform exercises at a much greater weight capacity. Because of this, I recommend using a faster tempo with your movements with around 1-2 seconds on both the concentric and eccentric movements with about a 1-second pause on the full contraction of the movement. With Isolation exercises, a slower movement will be best to utilize a greater muscle stimulation. For isolation exercise, its best to increase your concentric and eccentric motions to about 3-10 seconds depending on the exercise and your conditioning.
It’s important to note that performing 3 reps of bench press with a 10 second movement on the 4-1-4-1 (4 sec negative – 1 sec pause on bottom – 4 second press – 1 sec pause at top) is equivalent in regards to stimulus as if you perform as many reps of bench press as possible for 30 seconds with proper muscle engagement. The reason for this, although one method will involve 3 slow 10 sec reps vs say 10 fast 3 sec reps is that the tension applied is the same 30 seconds. If you are someone who usually performs fast movements but is lacking results, slowing your speeds can be a great way to break a plateau in strength and conditioning.
Take Home Message
Incorporating both heavy compound exercises, as well as moderate-to-lightweight isolation exercises, are perfect for all workout routines for every muscle region in order to ensure adequate and maximal growth. Just because you can push a heavy amount of weight in one direction for a few reps multiple times does not mean you are actively engaging your muscles fully. Understand how muscles are broken down into fast and slow twitch fibers.
Fast twitch fibers should be trained with heavy movements at about 70-80% of your 1RM while Slow Twitch fibers should be trained with about lighter movements around 30-60% your 1RM. Although each muscle groups fast and slow twitch fibers will vary, fast twitch fibers should be performed at in a low rep range while slow twitch is performed in a moderate to high rep range. If you want your muscles t to achieve maximal growth, engage the fibers fully by performing a mix of heavy compound movements with light-moderate weight isolation exercises. (Although I discussed the Chest/Pectoral muscles in this article is was to provide you with a visual example as an explanation).