Rapid-Fire Sets: A Strength Training Workout For Endurance and Strength

The Rapid Fire Set workout can be done on a Smith Machine rack or on strength machines at the gym

The following strength training workout is an excellent way to test your strength while still developing your muscular endurance.

It requires that you can quickly adjust the weight: Gym machines, a Smith rack, or at home with quickly adjustable dumbbells. I wouldn’t recommend doing this workout with conventional barbells or dumbbells unless you have the entire training area to yourself, such as at a home gym. Definitely don’t do this with barbells and dumbbells at a regular gym.

You basically do a lot of light, gradually increasing reps for each exercise in rapid-fire sets of just 4 reps per set. Eventually, you hit a max weight, then take the weight down and repeat the rapid-fire cycle one more time.

This can build muscular endurance while still building muscular strength, and gets your heart rate going enough to generate better mitochondrial development than your typical strength endurance weight training.

First, pick a muscle group:

Chest
Shoulders
Back
Arms
Lower Body

Pick two exercises for that group that can be done on a machine, on a Smith rack, with adjustables, where you don’t have to move or change locations to change the weight.

For example, let’s say you’re doing chest:

Good: Chest Press Gym Machine, Chest Fly Machine, Smith Rack Bench Press
Bad: Dumbbell Chest Press in the gym with shared dumbbells, Barbell Bench Press where the weights are shared with others

Once you are set up at your apparatus of choice for the first exercise: Set the weight really low, at least half your 1RM or less. You can even start at the lightest weight possible if it’s not comically easy to lift.

Start with 4 careful, deliberate reps at this weight. Don’t rush. Focus on maintaining your proper form and range of motion, since obviously lifting the weight itself isn’t a huge challenge.

After you finish, without a break, add 5 pounds to the weight. (If you track your workouts on paper or a fitness watch, you may log the last set of 4 easy reps first.)

Once the new weight is set, once again do 4 careful, deliberate reps. Again, stop and immediately add 5 pounds. Repeat.

Continue doing these rapid-fire sets until you finally get to a weight where 4 reps are challenging. Once you finish that set, rest 30 seconds while you quickly make a decision:

If you could lift 4 more reps at that weight again, then add 5 pounds and do 4 more reps. Then rest 30 more seconds while you once again decide if you can continue or not.

If you can’t finish 4 reps, or you know you can’t currently go any higher with the weight, then take the number of the current weight and divide it in half. Set your new weight to that number, or slightly lower if you need to round down to the nearest 5-10 lb increment.

For example: You max the exercise out at 65 pounds. So you divide 65 by 2, which is 32.5, and then you round down to 30 lbs and set the weight to that amount. If math is hard, make it easy for yourself.

  • If using a machine where the weights are stacked, you can also find a point halfway between the high weight and zero and set the pin there. Make it easy for yourself.
  • You could also just pick the lightest weight that you started with, or one a few pounds heavier if you found those first rapid-fire sets way too easy.

Once you’ve re-set the weight lower, then resume the original 4 rep pattern, immediately increasing the weight 5 lbs if you’re good to go, or resting 30 seconds before increasing weight and resuming if not.

Do your best this time around to build back up to the max weight from the last sequence, and if possible try to go 5 lbs higher for 4 reps.

However, if you do end up at failure at any point before that, then that can be your last set of 4 reps and you can stop for this exercise.

In any case, once you max out this time around, you can stop for this exercise and take a longer break (1-3 minutes).

During that break, find your next exercise, set up the weight at a light amount, and then repeat the above sequence for that new exercise.


For one muscle group, this workout should take about 12-20 minutes, depending on when during each sequence the weight becomes challenging.

You could do one muscle group each workout, cap every workout with some core exercises, and call it a day after about 20-30 minutes. Training this way you could strength train 5 days a week, or even every day if you’re not too sore (given the muscles you just worked will need to do a bit of work during workouts for the other muscle groups).

(This is the best approach for endurance athletes, as they need their legs for their aerobic workouts. One strength workout for legs each week is probably enough.)

Or you could do two muscle groups each day, again cap the workout with core exercises, and do a solid 30-45 minutes. A good approach for two-per-workout would be to do two upper body muscle groups one workout, then for the next workout do one upper body group and then legs… then do two upper body groups the next, one upper body and also legs the next, and so on.

(If you’re primarily strength training and you don’t do a ton of cardio, this is probably the best approach, as you can work out legs several days a week without compromising any other training goals.)

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4 thoughts on “Rapid-Fire Sets: A Strength Training Workout For Endurance and Strength

  1. Samuel says:

    Awesome!

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  4. […] since introducing the Rapid Fire Sets I’ve modified the approach in a way that suits my training and has benefitted me quite a bit. […]

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