I’m a fan of utilising isolation work strategically to maximise muscle mass. However, you do not have to do it to build muscle. You can gain mass only using compound lifts. In fact, as a beginner I would say this is the best way to train.
Several studies support this approach. Sadly, this has led some people to complete poo-poo the use of isolation exercises. I think this is a silly decision.
Long-term, however, I think a program based on only compound lifts will limit your overall muscle mass. There are two main reasons:
- For advanced trainees, they will find their overall training volume limited if they only ever do compound work
- For naturally skinny guys, compound lifts are essential for developing a base, but they will probably do more to develop the torso than the arms
Once you have reached advanced status in the gym you will carry a lot of muscle mass and be very strong. To continue to gain both muscle mass and strength you will need to gradually do more. This is the known as the principle of progressive overload.
Progressive overload requires that you…
…Lift heavier weights, do more sets, and/or get more reps at a given weight.
At the advanced stage increasing your training workload through only compound, multi-joint lifts can be extremely demanding. The amount of fatigue generated by heavy sets of squats, deadlifts, presses, rows, pull-ups etc. takes its toll. Often this toll is so taxing on the body that recovery is compromised.
At this advanced stage, it would be wise to strategically use isolation work to increase overall training volume. Isolation exercises tend to be much less taxing on your recovery capabilities. Thus, you can do more total work and still recover.
By doing this you can optimise the stimulus:fatigue ratio of your training.
- Only ever doing compound lift creates a big stimulus but a hug fatigue ratio.
- An all isolation lift program has a small stimulus and small fatigue ratio.
- A combination of both, especially when advanced, creates a strong stimulus and keeps fatigue manageable.
Given the progress equation can be simplified to:
Training (Stimulus) + Recovery (Fatigue management) = Progress/Adaptation
It is pretty clear that the combination of both compound and isolation lifts is preferable.
Most hardgainers are tall and skinny with long arms and legs. For the typical hardgainer, relying on the compound lifts early in their training career is a good decision as it is the most time efficient way to stimulate a large area of muscle mass. It is also very effective at packing on a good chunk of weight. Your first 15, 20, even 25 pounds of gains might well be achieved only though compound lifts.
Persisting with a compound only routine will likely enter diminishing returns territory after a couple of years max.
The problem is that the typical hardgainer will have stubborn muscle groups that do not respond so well to compound exercises. Often these will be the arms. Lots of sets of presses, chins, and rows will thicken up the hardgainers torso and put some size on their arms. After the newbie gains stage, however, they will most likely find that their arms look disproportionately small. As a result, some isolation work for arms makes sense to help develop a symmetrically developed physique.
So, when it comes to isolation exercises I would summarise my thoughts as follows:
- Not required as a beginner
- Not essential if you just want to add some muscle to your frame
- Generally, more important for long-limbed lifters
- A good idea to create a stimulus but manage fatigue as you advance
- Required to completely develop your physique and reach your genetic potential