There's a case for training your weakest muscles first in any workout. After all, they're holding you back, right? But on the other hand, there are some times when training them first will only make everything that comes afterward less effective.
I'm not talking about doing flyes before presses on chest day. Sure, you may be able to press less after that, but it's a classic pre-exhaust technique that has helped lifters add upper-body muscle for decades.
There are relatively few exercises on my no-fly list, but they're important ones. So pay attention and get this right!
1. Lower Back Before Deads, Squats, Bent Rows
The lower-back musculature, primarily the erector spinae, is isometrically engaged when doing a wide range of multijoint movements for back, legs, or even standing overheard presses. Because you’re going heavy with these exercises, you want your erectors strong to support your torso. Positioning lower-back movements like good mornings, back extensions (aka hyperextensions), or stiff-legged deadlifts in front of these heavy movements could be a big mistake!
If your lower back is highly fatigued, good luck keeping it in ideal position when you're attempting to do heavy bent-over rows, deadlifts, or even squats. What was already a weak link may become a weaker one, compromising both the weight you can use and the number of reps you complete, not to mention the increased risk of rounding your back.
A better choice: Do your lower-back movements at the end of your workout after all your heavy standing exercises are completed.
2. Grip Before...Pretty Much Anything
Grip and forearm strength are the great X-factors for many trainees. If they're weak, you're weak. Get them stronger, and you get stronger.
The flipside, however, is that if your grip is cooked, you're cooked. Exercises like wrist extensions, hammer curls, and reverse curls all affect your grip and forearms, which can adversely affect your ability to hold on to a heavy weight. Shrugging movements also require a strong grip as well. Here, the consequences mean compromising the weight or the number of repetitions you can achieve.
A better choice: Do forearm-specific training last to finish your arms off. If you struggle to hold a shaker bottle, you're doing it right!
3. Bis Before Back, Tris Before Chest
Doing chest flyes before bench presses, as mentioned earlier, is a legitimate pre-exhaust technique. But the same thinking doesn't apply to other muscle groups like training triceps before chest. If you work your triceps—a small muscle group—first, your presses won't do much for your chest. The same goes for doing biceps before lat-intensive work.
A better way: A good rule is to train larger muscle groups first, then smaller ones. The only time to ignore this is when you're training completely different muscle groups that don't affect the other, such as lower back and chest.