Most well-designed resistance training programs prescribe weights as a percentage of a rep max (RM)—the heaviest weight you’re able to lift for a specified number of repetitions. Usually this is your 1–3RM for programs focused on strength and your 6–12RM for programs focused on building muscle. Volume (reps) and intensity (percentages) are assigned to sessions in a way that aims to provide progressive challenge over the course of the program while not taxing your body beyond its ability to recover between sessions.
But there are two main challenges with the approach. First, people are unique (surprise!) and adapt at different rates. Second, the max those percentages are based on is often an estimate. (And even a tested max is just a snapshot of your ability on a single day—likely completed with the help of a little adrenaline.)
All of this means that at some point, even with a well-designed program, the weight-rep combo that’s on paper might be more than what you’re able to handle.
When that happens, most people do one of two things. They force the reps—often missing a few, creating excess fatigue, and grooving bad technique in the process. Or they abandon the program and start picking weights based on how they feel, which can mean too little stimulus to keep progressing. But there’s a better option in between: back off on purpose, in a way that keeps you following the program (and keeps you practicing good reps).
Decide from your last set, not your mood
How you feel walking into the gym is usually a poor guide for what to expect from the day’s session. For various reasons, you can feel stiff and sluggish but still have a good training day—or feel like you’re going to crush it but have a rough time once the weight is in your hands. So definitely don’t make a decision to adjust prior to doing your movement prep.
A better guide is the set right before your heavy work, along with how the same sets went last session (if you’re later on in the program). Watch for a few signs:
- Your movement slowed down noticeably when lifting the weight.
- Your technique changed (hips shot up early, back started to round, elbows flared).
- You had to grind more than you’d expect for that weight and number of reps.
- You missed a rep (on a prescribed set from a prior session).
If one (or more) tells you that you’re unlikely to be able to complete what’s written, it’s time to adjust. How you do so depends on where you are in the program and how frequently the signs occur.
One off day, anytime
If there’s an obvious cause—you’re battling a bug, sleep-deprived, or abnormally stressed—that’s a circumstance, not a mood, and it doesn’t mean there’s anything wrong with the program. Treat it as a bad training day, and return to the program as written on your next session.
When the signs keep showing up
If the signs show up session after session, you and the program are out of sync—and the best fix depends mostly on where you are in the program. Adjusting a program this way is often called re-casting.
Early in the program—the first week or two—prompts the biggest change. Struggling this early usually means the starting max was too high. Lower it, recalculate every weight from the new number, and either restart from the beginning or continue from where you left off (using the recalculated numbers).
In the middle, repeat a week or two and climb again from there. In this case, you’ve been progressing, but the program just got a little ahead of you. Repeating weeks obviously extends the program, but it enables you to build some momentum leading into the heaviest weeks at the end.
Near the end, you have options.
If you’re training to get stronger over time and you haven’t yet repeated weeks, doing so here is still an option. If you’ve already repeated weeks, you’re ready to move on to other things, or the prescribed reps at this point in the program are low, slightly reducing the weight on sets you doubt you’ll be able to complete will do the job. In this case, slightly means just enough to complete the reps as written, but little more than that. A heavy set (85–95% of 1RM) trimmed by a few percent is still heavy, so it still promotes adaptation.
If you’re peaking for a specific test or event, the priority is staying accustomed to heavy loads as you near testing day. So long as prescribed reps are not in the 1–2 range, keep using the specified weight but cut the reps, stopping a rep shy of either failure or your technique falling apart. If the reps are in the 1–2 range, reducing the weight as specified above or reducing the number of sets (depending on your ability to lift the weight at all) is the way to go. (A few years ago, I reduced the sets at the end of a group training get-up program, and numerous PRs were still set on the final week.)
A note on kettlebells: Since the variation between typical kettlebell sizes ranges from about 20% at smaller sizes to about 8% at larger sizes, it’s usually impossible to reduce weight by a few percent. An effective strategy in this case is spreading the total reps across more sets—5×3 (sets x reps) instead of 3×5, for example.
Putting it into practice
Optimally, your adaptations will stay aligned with those expected by your training program. Still, it’s helpful to have a strategy for re-casting the program when a misalignment occurs. (If you’d rather not bother figuring out the optimal way to re-cast a misaligned program, that’s what a coach is for.)
And if you’re worried that adjusting means you won’t reach your goal, remember three things: First, that it’s better to miss the goal and save the injury than the reverse. Second, that the goal (or the estimate behind it) may have been too high anyway if you find that you’re in need of re-casting. And finally, that the point of re-casting is realigning your ability to adapt with the program—which often leads to better final results than you might expect.