Note to Mods: I put this in IMHO because there may not be a General Answer. Feel free to move.
I’ve decided to start hitting the weights, in addition to karate and the exercise bike. I want to avoid just pushing weights at random and thus minimizing the benefit. However, I don’t know where to begin.
Is there a formula for determining how much weight you should lift and how often? Something like: lift as much as your muscles can possibly lift; divide that by 3, and that’s how much you should lift. Do 15 reps, rest, then repeat.
I appreceiate any and all advice.
Yes, there are many different formulas/programs. I recommend the “Dummies’ Guide to Weight Lifting” or another good book on the subject. If you’ve joined a gym, then hire a trainer for an hour. Generally speaking, fewer reps of more weight = bulk and strength-training, more reps of less weight = muscle definition and endurance. A good compromise program is lift whatever you can for ten reps/three sets (the last reps in the set should be difficult). There are an infinite number of theories out there, though. And don’t train more than three times a week (unless you alternate working out diff. parts of your body).
Jill
There are different guidelines for different specific goals in strength training. A good general guideline is to select a weight which will allow you to perform 8-12 repetitions WHILE USING GOOD FORM. (If you have to rely on momentum or fling the weight around, you’re lifting too much, and could hurt yourself.) A good starting point to guess this weight is around 80% of the max you can lift.
It’s probably a good idea to start out just a little bit lighter weight than that for the first few times you use the machine (or use free weights) until you get very accustomed to the movements required. When you’re totally comfortable with the motion, then start adding on weight.
When I find that I’ve been able to knock out 13-14 reps for 2 or 3 workouts in a row, I know it’s time to add the next increment of weight. I am a “one-set wonder” — by choosing the heavier weights, I’m OK doing just one set per exercise. If you plan to do multiple sets, you will probably need to drop back a bit on the weight.
JillGat’s recommendation to hire a trainer just to get you started is a very good one. They can observe your form to make sure you’re doing things correctly. And even though I’m certified to teach strength training, every time we get in a new piece of equipment at our Y, I ask a staff person to demonstrate it, and help me find the correct settings for me. It’s always easier for a person standing off to the side to see if you’re properly placed on the equipment than it is for you to guess at it.
I use the guideline that, if I can do 12 reps in good form at a weight, then I should add more weight. Start conservatively–there’s always room to move up, and you don’t want to hurt yourself early on. But remember, good form is much more important than a lot of weight.
Look at this document on weight-training myths so you can avoid some common pitfalls. Contrary to what Jill said earlier, high reps at low weight don’t help with definition, unless you’re doing circuit-training.
Also, I forgot to mention that authorities disagree on the ideal number of sets you should do. See this page for a discussion about low-volume training. FWIW, I’ve been using a two-set workout–one warmup set of 12 reps at 50% the weight I’m working on, and one full set of at most 12 reps at 100% the weight–and it’s definitely worked just fine for me.