You might've already considered this, but I thought I'd point it out just incase. If you spread the workload out over more muscle groups, your body will have to work harder to pump blood from one muscle group to the next, and then back again. So hitting multiple muscle groups in one circuit would give you a better workout in terms of endurance training. Not trying to be like "ur doin' it wrong", just givin' some food for thought.
I think if the goal was cardiovascular endurance then that would be ideal, and after you're done bulking that's how I'll reallign it.
However, the goal is muscular endurance. Which is to say, developing the muscles to take longer to fatigue, and enable them to work at a higher level when fatigued. In that way, a single muscle group specific workout (at least to me) makes more sense.
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