Basics: How to set your warmup weights

How do I warmup for heavy strength work? What about assistance exercises?

We're going to address this today.

But first, two quick definitions to keep in mind - a work set is the weight you intend to work out at in order to meet your goals; a warmup set is a set below your work set weight levels used to get ready for the work sets.

Do I need to warmup before my specific lifts? This depends on what you're doing.

For repeated effort (say, you intend to do 3 x 10 or 4 x 15), if you are already warmup up from previous exercises, you may just choose to forgo the warmup. If you've benched 3 x 5 x 135 pounds or deadlifted 3 x 225, your body is probably ready to go for a set of 3 x 10 lat pulldowns or 3 x 5 pullups or some pushups. You don't need to get ready for every exercise.

For maximumal strength attempts, you absolutely need to warm up. If you're attempting to deadlift 3 x 225 pounds, even if you did 3 x 225 the week before, skipping right to the maximal weight is foolish. You haven't practiced the pattern of the lift yet today, you haven't ensured your body is warm, you haven't tested your strength at a lower level to see if you are up to that weight today or not. If your form is anything less than perfect, you're asking to get hurt. Even if it is perfect, you may be hurt anyway, and you'll be missing out on the benefits of practicing the lift a few more times each workout.

If you know the weight you're going to attempt:

1) Subtract the bar weight from your working weight. For example: working weight is 135 pounds, bar is 45 pounds, so 135 - 45 = 90.

2) Divide the resulting number by 3 (for two warmup sets) or 4 (for three). Round off to the nearest 5 or 10 to make it easier to set the weights - few gyms have fractional weight plates. Ex: 90/3 = 30, or 90/4 = 22.5 rounded to 20 or 25.

3) Add that number to the bar weight and then to each successive warmup set until you get to your working weight. Ex: 45, 45+30= 75, 75+30=105, 105+30=135, so you'd warmup at 45, 75, and 105 pounds before working at 135 pounds. Or for four sets, 45, 45+20=65, 65+20=85, 85+25=110, 85+25=135. You warmup at 45, 65, 85, 110, and then work at 135. Weights rounded up as the overall bar weight went higher.

Programs that use this method or something extremely close to it include Starting Strength and Stronglifts 5 x 5

If you don't know your goal weight, you can try working up.

Since you don't know where you intend to end up, you can't pre-calculate your warmup sets. You add weight to the bar as you go, and your warmup sets and your working sets sort of blend together.

Simply start with the bar-only and lift that for the desired number of reps (see below). Then add a little weight, and complete another set. Repeat, until you either reach a new maximum weight for the day or until the lift is too heavy to complete with good form, whichever comes sooner. You can keep setting PRs (personal records) if you're feeling very strong, but if form breaks down, or the bar slows down to a crawl, or you miss a lift...stop.

Prorgams that use this method include Westside for Skinny Bastards. This method is also used in programs like Starting Strength on your first workout day, to set the initial weights. From there, however, the program uses the first method because you already know the goal weight for the day.

How Many Reps?

This is a big question. I'm of the school where you do the same number as your working sets all the way through, but slightly higher (5+ reps) on the lowest weights.

Just some guidelines:

For repeated effort, a set of about 10 reps at a light weight, but one you that is somewhat challenging (say, 50-60% of your working weight), is usually sufficient. You don't want to go too heavy or too light, or for too many reps. This isn't work, it's warmup. If you go too heavy, it's just a work set!

For maximum effort, you can use the same number of reps as your working sets for each warmup set or decrease the number of warmup reps as you go.

If you use the same number of reps, it's simple - for work sets of 5, do warmup sets of 5. For work sets of 8, do warmup sets of 8.

Some programs prefer you use less reps on the warmups. You start with the same number of reps as your working weight or even higher (as many as 10+ reps bar-only, for example). As your warmup goes on, you drop below your working reps to avoid tiring yourself out as your get warmed up. Example: You are warming up to 3 x 5 x 135 pounds with 4 sets, as above. You might do 10 x 45 pounds, 5 x 65 pounds, 3 x 85 pounds, 1 x 110 pounds, 3 x 5 x 135 pounds.

If you are working up, warmup is less of an issue. It's all warmup until it slowly blends into work sets, and the dividing point is not clearly set. If 5 x 135 pounds is heavy for you, then a "warmup" set of 5 x 115 or 5 x 125 might be partly warmup and partly lower-weight work.

The way I've learned to "work up" is to start at 5 reps on the bar, and then move up in weight. As you close in on the working weights, you steadily drop the reps to the rep count of the working sets. If you're doing sets of 5, you keep doing 5 the whole time. Sets of 3, you do 5s for the very light sets, then move to 3s as it gets heavier. Singles and doubles follow the same arc, but drop off to 2 or 1 reps.
For example: I'm aiming for a new maximum single in a lift; my previous max single was 175 pounds and I aim to meet or break that record. I start out bar-only and slowly work my weight up. My work-up ends up looking like this:
5 x 45 pounds
5 x 95 pounds
3 x 135 pounds
1 x 155 pounds
1 x 175 pounds
1 x 185 pounds

An advanced warmup method worth considering is supramaximal warmups, detailed here by the late John Christy.