Isolated exercises focus on one muscle group at a time. They are useful for developing that particular muscle group in isolation, especially if it is deficient.
Compound exercises recruit more than one muscle group and use multiple joints at one time. They increase strength faster than isolated exercises and make the most of your workout time. This advantage is due to the engagement of more motor units during the given workout time commitment. If done correctly, they also develop body composition proportionately and build total-body strength.
Due to the more significant neuromuscular stimulus of compound exercises, they have more transfer of specificity to functional movements. The squat, deadlift, lunge, bench press, row, overhead press, and pull-up are good examples of compound exercises. Anyone serious about building strength will have these exercises as the basis of their training.
The squat is considered one of the best exercises for improving quality of life. It recruits so many muscles in a single movement and increases strength relevant to activities of daily living from youth through to old age.
1. A review of the acute effects and long-term adaptations of single- and multi-joint exercises during resistance training. Gentil P, Fisher J, Steele J. Sports Med. 2016 Sep 27. www.ncbi.nlm.nih.gov/pubmed/27677913
2. Single vs. multi-joint resistance exercises: effects on muscle strength and hypertrophy. Gentil P, Soares S, Bottaro M. Asian J Sports Med. 2015 Jun; 6(2): e24057. www.ncbi.nlm.nih.gov/pmc/articles/PMC…