Weak Side First
With unilateral exercises (one side at a time), it’s common to discover that your left and right sides are not perfectly symmetrical. While strength deficits like these are common, they’re still worth remedying. You can do just that with the right approach: Start with the weaker side.
Starting with the weaker of the two sides allows for the weaker side to set the pace for the stronger side and keep the two even. If you’re targeting 8-10 repetitions, and your weaker side gets stuck at 9, you should stop at 9 on the other side, even if you could keep going. Over time, the extra effort on the weaker side will help to bridge the gap between the two.
If you were to do the opposite and begin on the strong side, you would get 10 on one side and then only 9 on the other, which can exacerbate the asymmetry between right and left.
If you can’t tell that one side is noticeably weaker, starting with your non-dominant side is a good rule of thumb. If you’re right-handed, start with the left. If you kick a soccer ball with your left foot, begin with your right leg.

