There's nothing wrong with a good "bro rep" a bit of swinging at the end of a set until you feel like your arms are going to explode from the pump. But at the start of a workout be a bit more sensible, focusing on:

• Controlled movement
• Full range of motion
• Core stability
• Time under tension

Try this complex for biceps, shoulders, and triceps:

The magic is in the tempo. Make each rep take a minimum of 30 seconds. Start off with two dumbbells, holding one dumbbell by your side while the other arm works:

1. Bicep curl until full contraction.
2. Rotate the dumbbell to a neutral shoulder press position.
3. Shoulder press to full extension.
4. Rotate to a palms-facing-forward grip (keep reaching up while pulling the ribs down).
5. Rotate back to a neutral grip.
6. Perform an overhead triceps extension aiming for full range of motion with no change in elbow position on the way back up.
7. Do a slow negative shoulder press.
8. When you reach the racked position, rotate to a palm facing up grip.
9. Do a slow negative bicep curl.
10. Repeat on the other side.

Not challenging enough? Increase the weight. Now shake your arms off for 20-30 seconds and do the full set another 6 times for 7 total sets.

By the way, as soon as you start speeding up or swinging, the weight is too heavy – save your bro reps for later. Remember, the slower you move and the more you're shaking the better!

Look out for one arm struggling more than the other. Until you balance that out, use the weight that your weaker arm can do, and use that weaker arm to begin the sets when you're most fresh.

Another variation you could do is both arms at the same time:

You'll have to decrease the weight slightly when doing both arms.