This morning I was reading a review article of some training-related research (here’s the original research abstract), and I was struck by a subtle yet profound realization about a common weight-training recommendation and the fitness industry, in general.
Before I get to the realization and how understanding it can improve your training results, let’s briefly review the research and the common recommendation.
The research compared last-rep velocity (LRV) and reps in reserve (RIR) in terms of accurately predicting an individual’s proximity to failure on any given rep.
LRV is an objective measurement of the speed at which any single repetition is performed within a set of any size. It can be used to estimate proximity to failure because a muscle’s contraction speed slows as failure approaches.
RIR, on the other hand, is a subjective assessment made by the lifter (based on how a weight feels, perceived fatigue, and whatever other criteria the lifter deems important) as to the number of reps s/he believes are left in the tank before reaching failure.
The research indicated that LRV was a more accurate predictor of proximity to failure than RIR in earlier sets and with lighter weights, while the review article suggested that both criteria could be useful for training.
(In recent years, RIR has become a popular fitness industry recommendation for deciding when to stop a set. For example, a program’s guidelines might suggest performing 8-10 reps leaving 1-2 reps in reserve. In other words, choose a weight at which you think you could complete between nine and twelve reps and stop each set one or two reps shy of failure.)
While RIR is less accurate with lighter weights and in earlier sets, it can be fairly accurate in later sets because you have the experience from the sets performed earlier in the session to make better assessments. According to the review article:
In a typical training session, you expect those later sets to be more productive than the earlier ones. RIR helps you accomplish that.
In terms of LRV, the review article suggested (and I completely agree) that we probably don’t need to use any fancy equipment to measure rep speed like the original researchers did. Simply paying attention to each rep’s speed is close enough for practical purposes. They then go on to suggest:
If your goal is to get clients to push themselves a little harder, tell them to continue each set until they complete a rep that’s noticeably slower than the previous one.
And this brings me back to my realization: The mainstream fitness industry is obsessed with failure or, at least, near failure.
Now don’t get me wrong; I’m not criticizing the research, the use of RIR in all cases, or paying attention to LRV. In terms of research, initially discovering and then either confirming or refuting information is the definition of progress. Applying the idea of reps in reserve is useful at times, particularly for developing body awareness or approximating effort with intermediate or advanced lifters. And paying attention to rep speed, particularly with explosive lifts, is highly effective for a variety of outcomes.
But the ideas of “expecting those later sets to be more productive” and “continuing each set until they complete a rep that’s noticeably slower” are effectively saying that almost, but not quite failure is what produces the best results.
And that’s just not true.
The amount of quality time spent under tension is what produces results from strength to endurance to improved body composition. Quality work happens when we’re fresh, not fatigued. And we stay fresher throughout a training session when we stop our sets far from failure, not when we get as close as we can without actually reaching it.
This means that stopping a set just before rep speed slows is a better recommendation. As is emphasizing that every quality set is productive, not just the last (because every quality rep of every quality set contributes to the total amount of time spent under tension).
Putting it into practice
In practical terms, aiming to stay “mostly fresh” throughout each set instead of reaching “almost failure” will equate to a difference of only a few reps per set, if that. Of course, that doesn’t mean those reps need to be completely skipped…
Particularly if you are used to training to failure or almost failure, try the following strategy for the next few weeks:
- Stop each set just before your rep speed slows down. (If you have to re-grip the weight, briefly pause, or take an extra breath before a specific rep, that’s also a decent indicator to stop.)
- After finishing your planned number of sets, add up all the reps that you skipped compared to what you had planned or usually do.
- Do another set (or two or three or four) until you complete the total number of reps that you had skipped in your earlier sets.
Then expect to feel less fatigued and see your results improve.