Isolation exercises refer to specific movements or exercises that target and work on just one muscle or muscle group at a time, rather than multiple muscles working together. Full definition
If you're one of those people that rely on doing only isolation exercises for developing your biceps you've probably noticed that they are not as efficient in delivering the results. (fitnessandpower.com)
Thus, there's a big difference between cheating on the last rep or two of isolation exercises like the dumbbell curl and lateral raise versus a barbell pull or press. (legionathletics.com)
Not that you shouldn't do isolation exercises, but around 75 % of your training should consist of compound exercises. (cathe.com)