If you’re unfamiliar with the term, it is short for “As Many Reps as Possible. And it refers to performing as many reps during a set as you possibly can only once your body “fails” and you can no longer squeeze out another rep is the set is complete.
In theory, training to failure seems like it’d guarantee serious gains. You’re pushing your body to the brink with this type of training, and the significant muscle damage it creates should leave you with an optimum chance for gains as long as you rest and recover appropriately.
However, recent research has found that training to failure consistently may not be as beneficial as you might believe. We did a study too and here are the takeaways.
Fifteen well-trained males participated in the study. They were divided into two groups: a Repetition Maximum (RM) group and a Relative Intensity Using Sets and Repetitions (RISR) group.
- The RM group used a program based on repetition maximums and trained to failure with at least their last set of each exercise. They consistently trained at 100% relative intensity.
- The RISR group used a program based on percentages and avoided training to failure. This group trained at around 80% relative intensity on average throughout the study.
Both groups lifted three times per week for 10 weeks (weeks 9 and 10 consisted of a taper). At five points throughout the study, they were tested for:
- Power (Unweighted Squat Jumps, 20kg Squat Jumps, and countermovement jumps)
- Strength and Rate of Force Development (Isometric mid-thigh pulls)
Weekly volume load (which is defined as the number of repetitions times the weight of the load) was similar between groups, but weekly strain (based on Rating of Perceived Exertion scores) was significantly greater for the RM group. So while both groups ended up performing similar amounts of work, the group that trained to failure more often experienced more strain.
As for measures of power and strength and rate of force development, the RISR group had the edge in all five categories.
Standing Jump and Countermovement Jump: Moderate between-group effect sizes supported RISR
Isometric Peak Force: Small between-group effect sizes supported RISR Rate of Force Development from 0-50ms and 0-100 ms Large and moderate between-group effect sizes supported RISR
The researchers concluded that “this study demonstrated that RISR training yielded greater improvements in the vertical jump, rate of force development, and maximal strength compared to RM training, which may partly be explained by differences in the imposed training stress and the use of failure/non-failure training in a well-trained population.
This study is not the first to find that extensive training to failure during your routine may do more harm than good.
In conclusion, “it appears that similar increases in muscular strength can be achieved with failure and non-failure training.” Going all-out all the time won’t result in greater strength gains than stopping the majority of your sets with “reps in reserve” (meaning you feel you could perform a few more reps at the conclusion of the set, but you stop anyways).
For power and speed development, stopping your sets further from failure allows you to consistently train at a higher velocity. Along with the higher levels of strain in the RM group, this is probably why the RISR subjects had better jump and rate of force development results at the end of the study.
Leaving a few reps in the tank rather than consistently training to failure is easier, yet leads to better results. While training to fail every now and then can have benefited, it should be used only on occasion as opposed to being your default approach.