Get more powerful and improve athletic performance by training smart with inter-repetition rest periods. Using inter-repetition rest (IRRs) is an advanced technique for getting more work done and producing more power, while minimizing fatigue. It works like this: You introduce a rest interval after every repetition or after a certain number of repetitions within a set in order to get more out of your training.
IRRs can allow you to increase volume and metabolic intensity by being able to bang out extra reps that you wouldn’t be able to do otherwise because of muscular fatigue. They can also be used to maintain power as you progress through a workout because with the short recovery periods, you avoid the slowing of movement speed as fatigue increases.
For example, if you can normally power clean 200 pounds for one rep and 180 pounds for three reps, try resting fifteen seconds between single reps by pausing with the barbell on the floor. You may be able to clean 185 pounds for three single reps, maybe even 190 pounds. The result is you are performing the same number of reps with a greater power and intensity.
A new study in the Journal of Strength and Conditioning Research shows that using IRRs can “feel” easier too. The study looked at rating of perceived exertion (RPE) and power output in the power clean with no inter-repetition rest, or with either 20 or 40 seconds of rest. Participants were trained college-aged men, and they performed 3 sets of 6 reps of the power clean at 80 percent of the 1RM.
Results showed that fatigue was much greater in the no rest condition than the 20- and 40-second rest conditions.RPE was inversely associated with power output in each condition. Greater fatigue and a higher RPE meant that power dropped as the set progressed, whereas with the increasing IRR, RPE was lower and power output was much higher. For example, below you will see how fatigue increased and power decreased with less rest. A 10-point RPE scale was used with 1 being no effort and 10 being maximal effort:
The no rest condition produced a 9 percent drop in peak power for all 18 reps. There was an average 16 percent drop in peak power as each set progressed from the first to the sixth rep. The average RPE for all sets was 7.43.
The 20-second rest condition produced a 3 percent drop in peak power for all 18 reps. There was an average 5.5 percent drop in peak power as each set progressed from the first to the sixth rep. The average RPE for all sets was 6.46.
The 40-second rest condition produced a 2 percent drop in peak power for all 18 reps. There was an average 3 percent drop in peak power as each set progressed from the first to the sixth rep. The average RPE for all sets was 5.3.
Researchers suggest that the short recovery between reps in the two IRR models allowed for recovery of short-term energy substrates such as phosphocreatine. The results of this study confirm previous evidence that creatine is resynthesized in about 22 seconds.
The benefit of IRR training is obvious in that it will allow you to produce maximal power within each repetition to get the greatest power adaptations for your effort. Using IRR is a smart way to train because it may feel easier but you will be more powerful, faster, and produce more force. Using IRRs can also allow you to lift a greater volume and get more reps at a higher weight when doing a body composition or hypertrophy protocol.
Another use of IRRs is to rest or “pause” during slower exercises such as squats or bench presses to target the high-threshold motor units. To do this, pause in the “up” of these extension exercises, or for flexion exercises like biceps or hamstring curls, pause in the “down” position.
Of course, you can pause in the disadvantageous position as well to increase intramuscular tension. The disadvantageous position for flexion exercises is the “up” position, and for extension exercises it is the “down” position. You can imagine that holding the bottom position of a squat for 1 or 2 seconds would provide a valuable training stimulus!
Hardee, J., Lawrence, M., et al. Effect of Inter-Repetition Rest on Ratings of Perceived Exertion during Multiple Set of the Power Clean. European Journal of Applied Physiology. 2012. 112, 3141-3147.