Compound versus isolation exercises: what are the benefits and drawbacks?

Resistance exercise is an excellent way to increase muscle strength and size. In addition, it is often used to improve sports performance. An ongoing debate among fitness professionals, coaches and fitness enthusiasts is about which sort of exercises are most effective, compound or isolation exercises.

Compound exercises

Compound exercises, also known as multi-joint exercises, consist of movements in several joints and exercise multiple muscle groups. Well known examples include the bench press, seated row, leg press and the squat. Multi-joint exercises target a large number of muscles at a time, and they tend to place larger demands on muscle coordination. Therefore they are more difficult to perform correctly. However, because they target a large number of muscles, the weakest link is exercised most, making it very effective in increasing strength. They are often more suited for athletes who use resistance training to increase their performance in their respective sports, since most movements in real life, involve multiple joints and a large number of muscles. The large number of muscles trained also means that the heart rate increases significantly and more energy is used than during isolation exercises, making them more suitable for losing body fat. Additionally multi-joint exercises can help improve joint stability because often all muscles around a joint are trained during a compound exercise.

Isolation exercises

Isolation exercises, also known as single joint exercises, consist of movements in only one joint and a limited number of muscle groups, generally those sharing the same function. Examples include the leg extension, biceps curl and the side raise. These exercises are easier to perform correctly since only a limited number of muscles is activated and only one simple movement is performed. The main advantage of this is that the targeted muscle can be trained more effectively. The reason for this is that the exercise is not limited by other weaker muscles, which might give up before the main muscle is properly exercised. Single joint exercises are therefore very effective in increasing strength in one muscle group. This strength however does not translate very well to multi-joint exercises, limiting its’ use for athletes interested in increasing their sports performance. It is however very useful for people who seek to increase the size of specific muscles, such as bodybuilders. Since they are easier to perform as well, they are often better suited for beginners who have trouble performing multi-joint exercises correctly.

Exercise order

Most resistance exercise programs however, consist of both multi-joint and single joint exercises. The order of exercises is very important if one wants to maximise effects in muscle strength, muscle size, coordination and sports performance. It is generally recommended to perform more difficult multi-joint exercises before single joint exercises which exercise the same muscle. This way, the multi-joint exercise can be performed optimally without getting hindered by an already fatigued muscle. The single joint exercise can then be performed to further exercise and exhaust single muscle groups, which is more beneficial for muscle growth. This way the single joint exercises do not get in the way of the multi-joint exercises. The other way round does decrease strength gains in multi-joint exercises and can in some cases even increase the risk of injury because the body has more difficulty stabilising movements when muscles are already fatigued.

Overview

The table below depicts the properties of single and multi-joint exercises.

References:

-Bushman, B. (2011) Resistance Exercise. In: American College of Sports Medicine Complete Guide to Fitness & Health. USA Human Kinetics.

-Kraemer WJ, et al. American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2002 Feb;34(2):364-80.

Zatsiorsky VM, Kraemer WJ. (2006). Strength Exercises. In: Science and Practice of Strength Training Second Edition. USA Human Kinetics.