First off, for those that may be new to weight training. Your 1RPM (one rep max) isn't going to be very important. You need to be hitting the gym for a few months, building a strong foundation before you start thinking about getting into some more advanced techniques. And knowing your 1RM for the purposes of training. Just isn't that important unless you reaching a particularly advanced level or you're competing in powerlifting.
What is a 1RM?
It's really not that complicated. Simply put, your one-rep max is going to the absolute highest amount of weight you can move for one full rep for a given exercise. It's important to note that 1RM's are only really considered for the 4 major weightlifting exercises.
- Bench Press
- Shoulder Press
There really isn't any sense if trying to figure out your 1RM for bicep curl as it just doesn't help you in any way.
How do I find my 1RM?
You can theoretically find your 1RM using calculations based on the weight you can do 4-6 reps of. A formula provided by MensHealth can help: (4-6RM x 1.09703) + 14.2546
However, if you really want to figure out your one-rep max we'll explain it to you. The concepts are more or less universal across any of the big 4 exercises. The idea is that you gradually build up the weight without fatiguing your muscles. So that when you reach that max weight. You can use all your strength to move it. To get an accurate reading of your 1RM.
You might think that if you're gradually working up to it, you're going to get fatigued before you even reach it, here's how you're going to do it step by step so that your muscles don't give up before you do.
1. Warm-up: Start off with a lightweight, one you can do many reps out. However, it's important that you don't do more than 3-5 reps with this weight, even if you can do 30. The point is to warm up and get your body used to the movement before we start packing on the weights. It's important to start off relatively light
2. Rest (2-3min): Even if this initial weight was nothing for you and you feel like you can jump right into the next set it's important to rest to ensure your muscles are not being tired out.
3. A slight increase in weight: Bring the weight up slightly and do another 3-5 reps, again, even stop there even if you can do more. Then repeat the rest period.
4. Test your 1RPM: Once you've completed 2-3 warm-up sets of 3-5 reps, it's time to start moving closer to your 1RM weight. You're going to estimate what a good starting point would be for you would be based on how your warm-up went. This testing sets are going to be a max of 1 rep with 3-4 minute breaks in between to maintain your energy and muscle strength. You don't want to take to many sets to find your 1RM so start challenging yourself fast at this point. Increase the weight gradually based on how easy your last set was. Until you reach the weight you're just making it on. Now you've reached your 1RM. It's can be good to get an estimate on your 1RM before testing it in reality. You can find a calculator here.
IMPORTANT: 1RM testing should only be attempted by experienced lifters who know what they're doing. It is also always important to have a partner or safety bars in place in case you overload yourself and are unable to complete the rep.