You probably already know that there are two different types of weight-training exercises: compound moves and isolation moves. Compound moves are exercises where more than one joint moves at the same time. When you do a compound exercise, you also work multiple muscle groups with a single exercise
In contrast, isolation moves are ones where there’s movement of a single joint and the focus is on a single muscle group. A classic example of a compound exercise is the squat or deadlift. When you do this exercise, you FEEL the many muscle groups you’re working. An isolation movement of the lower body would be leg extension and triceps extensions and biceps curls are isolation exercises that work the upper body.
You may have heard that compound exercises are better than isolation moves for muscle development and that these exercises should make up the bulk of your workout. The reason? When you do compound exercises you stress lots of muscle fibers simultaneously. This makes your workout more efficient and time expedient. Working more muscles at the same time also burns more calories, especially when you do moves like squats and deadlifts that work the big muscles in the lower body.
With compound moves, you heat up your body more and force it to work harder, so you get more of a metabolic effect and that favors fat loss. Plus, compound exercises train muscle groups to work better together for greater functionality. For example, leg curls or leg presses do little to improve functional strength but squats train your muscles and nervous system to work more efficiently as a team.
With all of the benefits compound movements offer, you might wonder whether you even need to do isolation exercises. The reality is you do. Although isolation exercises shouldn’t make up the bulk of your workout, they still have their place in a well-balanced training program. Here’s why you still need them.
Isolation Exercises Have Their Own Unique Benefits
You might think, based on the fact that compound movements are so strongly favored, that isolation exercises aren’t very effective. Not so! In a study published in the Asian Journal of Sports Medicine, compound and isolation exercises promoted hypertrophy and strength gains equally well in a group of untrained men. Isolation exercises hone in on a specific muscle group so you can hit It hard. They also add extra punch to your workout. For example, you can work your triceps doing push-ups and follow up with triceps kickbacks to further target the muscle. That’s a powerful stimulus for triceps growth!
Correct Lagging Muscle Groups
Even if you use good technique when doing compound exercises, you sometimes have a lagging muscle group that doesn’t develop as quickly as other muscles. A lagging muscle group that’s weak can limit your performance when you do compound exercises, like squats and deadlifts. Once you identify a laggard, use isolation to give that muscle focused attention. By bringing that muscle up to speed, you’ll get more out of your compound movements and reduce the risk of injury.
When you have a stubborn, lagging muscle, the extra, focused stimulation that an isolation exercise offers can help you thoroughly fatigue that muscle to stimulate growth. If the growth of a particular muscle has slowed over time, add a few sets of isolation exercises to hit the muscle hard while continuing to do compound exercises. Isolation movements are ideal for bringing “lazy” muscles up to speed.
Some Muscles Benefit from Isolation Exercises
If you’re trying to develop your glutes, compound exercises, like squats and lunges are helpful, but EMG studies show that isolation exercises work the glutes in a more targeted manner, unlike lunges and squats that hit the quadriceps harder. If your goal is more prominent glutes but you don’t want larger thighs, isolation exercises like hip thrusts, glute kickbacks, and single-leg glute bridges can help you build your glutes without adding more mass to your thighs.
Tips for Making the Most of Isolation Exercises
Stick mainly to compound exercises when you first begin training. As a beginner, learn how to do basic, multi-joint exercises correctly before adding isolation exercises.
Do isolation exercises at the end of your workout. Keep the focus on compound movements that work the most muscles while your muscles are still “fresh” and fatigue is less of a factor. These are the workhorse exercises of your training and should be a priority since they offer the greatest return. Also, compound exercises, like squats and deadlifts, carry a greater risk of injury. So, you don’t want fatigue to be a factor when you do them.
Think about how much training time you have. If you have limited time to work out, the ratio of compound to isolation exercises should be even higher since these exercises work multiple muscle groups at the same time. If you have limited time, you need to blast as many muscle groups in the shortest time possible. If you have more training minutes, add isolation exercises for the muscles that need more attention at the end.
Use isolation exercises to correct imbalances. Is the biceps muscle on one side larger or stronger than the other? Use isolation exercises on that side to even things out.
The Bottom Line
Keep the ratio of compound exercises to isolation exercises high, around three compound exercises for every one isolation movement. Compound exercises give you the most bang for your training buck and they should make up the majority of the exercises you do. They’re also important if you play a sport and want to improve your performance as they teach muscle groups to work together. But, don’t underestimate the benefits that isolation exercises offer. You need them to bring up lagging or weak muscles and, sometimes, to break through a plateau when a muscle group has stopped growing. For certain muscle groups, like the glutes, isolation exercises target the glutes without adding additional size to the quads. Don’t make them the bulk of your workout but make sure they’re part of your routine.
Asian J Sports Med. 2015 Jun; 6(2): e24057.Published online 2015 Jun 22. doi: 10.5812/asjsm.24057.