Body Parts Focused Routines Or Full Body Workout - Ask Common Strong

"Why and when it's best to target your muscle groups versus blasting everything"

Body parts focused benefits:

Specific upper and lower body focused routines are excellent for guys looking to gain muscle mass in particular areas of their body or sustain a training program for the long haul. These are commonly less exhausting and are ideal for major bulk-ups

More focused strength gains: 
Body part-specific training sessions such as (chest day, back day etc) while less time efficient can definitely dial in the specificity of the goals of your training program."Getting in your major lifts and accessory work catered to that muscle group will. Just be careful you don't over emphasize one muscle group over the others that's when muscle imbalances and may lead to certain injuries"

Full Body Benefits: 
Total-body routines benefit guys who are just targeting strength and aren't really preoccupied with mass, as well as those who are really trying to shred body fat. When you're engaged in a total-body strength and conditioning routine that's either focused on lifting heavy or quick, interval-like metabolic moves.
Greater Hormonal Response, Better for weight loss/fat loss, 

"Hitting your full body all the time from a conditioning aspect is great; it’s the model CrossFit follows," Arent notes"