How exactly is he holding you up? Is he constantly talking to you wasting away time? Or does he take longer than you to recover between sets? If it's too much idle chatting, then just explain to him your expectations for each workout and that you guys need to get the work done. If he's taking too long to rest between sets, then see if you can do 2 sets for every 1 set he does. You may still only get 3 exercises done since you have to wait for him, but you'll be able to do more work at each exercise which will still be beneficial. Also, you can try getting away from the machines and working with DBs. That way you can have your own set of dumbbells and bench to do exercises at your own pace and he can have his set.
"Strength is the product of struggle, you must do what others don't to achieve what others won't."
Squat: 463 Bench: 275 Deadlift: 529 Total: 1262
"Technique is always the first place to begin when striving to improve at a specific skill."
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