Rest-Pause Training Increases Muscle Mass and Reduces Bodyfat
There are several reports that weight training may require more energy and a longer duration of recovery compared to endurance training but despite this, there are surprisingly few studies published on the particular influence of high-intensity resistance training on metabolism. Rest-pause is a training method that involves taking a short rest within a set. It has been shown to increase muscle strength, as well as muscle growth. Rest-Pause training may be not only good for increasing muscle mass but also useful for reducing bodyfat as well.
In one study, researchers had two groups of well-trained lifters. One group performed four sets of 8-12 reps of 8 different exercises (machine row, bench press, military press, leg curl, leg press, triceps extensions, biceps curls, and sit-ups.) They performed all sets to failure for each exercise while resting for 2 minutes between each set of the compound exercises, and 1 minute after the isolation exercises. In the other group, they used the rest-pause method, but they only performed three exercises, the bench press, machine row and leg press. For each exercise they used their six rep max and performed six reps, rested for 20 seconds and did as many as they could, repeating the 20-second rests and lifting as long as they could, which was usually 2 or 3 more. That was considered one set. They rested for 2.5 minutes between each set, doing three total sets of the leg press and two of the bench press and machine row. The researchers said this method made it comparable to high-intensity endurance training.
At the end of the study, the rest-pause group showed a greater increase in fat burning post-exercise at 22 hours compared to traditional training. The increase fat metabolism after traditional training was about 5% while after rest-pause training it was 23% and these data suggest a significant effect on metabolism corresponding to 452 Kcal per day. The interesting finding was that with the rest-pause program protocol with less volume and the same load was accomplished in nearly half the time of a traditional resistance training program. However, the post-workout resting energy expenditure was much greater with the rest-pause group. In other words, the group that trained rest-pause style were burning more calories at rest than those training in a traditional style, in this study, for a full day after their final rep. Rest-Pause training allows subjects to improve metabolism and, at the same time, muscle mass and strength all of which are promoted as beneficial by many guidelines.
Another benefit to rest-pause training is that it can improve muscle mass as well. One of the biggest challenges to doing cross-fit is the short rest periods between sets which can leave a person completely exhausted. Short rest periods such as rest-pause training can lead to increases in strength according to research. Researchers had ten male weightlifters perform three sets of power cleans for six reps per set using 80% of their one-rep max, and resting three minutes between sets. In one trial, they completed all six reps in succession without any rest pause between reps. In the second trial, they did a 20-second rest-pause between each rep. And in the third trial, they did a 40-second rest-pause between every rep. Each protocol (no rest, 20 second rest periods, 40 second rest periods) was performed in a randomized order on different days each separated by at least 72 hours. Peak power, force, and velocity were obtained for each repetition and set. At the end of the study, as expected power decreased by 15% from rep number one to rep number six when the subjects did not use rest-pause between reps. With the 20-second rest-pause between sets, power decreased by only 6% from rep number one to rep number six. And with the 40-second rest-pause between reps, power declined by just 4% from rep number one to rep number six. The results of the study show that when the subjects used rest-pause between reps they were better able to maintain power from rep number one to rep number six. The results demonstrate that rest-pause periods allow for the maintenance of power in the power clean during a multiple set exercise protocol and that this may have implications for improved training adaptations. This is necessary for maximizing gains in power.
If you select the bench press as your exercise, a rest-pause series with an emphasis on hypertrophy might look something like this:
Set 1: 250 x 8 reps
Rest 20 seconds
Set 2: 250 x 3 reps
Rest 20 seconds
Set 3: 250 x 2 reps
Hardee JP, Triplett NT, Utter AC, Zwetsloot KA, Mcbride JM. Effect of interrepetition rest on power output in the power clean. J Strength Cond Res. 2012 Apr;26(4):883-9.
Paoli A, Moro T, Marcolin G, Neri M, Bianco A, Palma A, Grimaldi K. High-Intensity Interval Resistance Training (HIRT) influences resting energy expenditure and respiratory ratio in non-dieting individuals. J Transl Med. 2012 Nov 24;10:237.