A just-published study from sport scientists out of Appalachian State University bring to light the importance of the amount of rest between repetitions and how it can impact your ability to maintain strength and power through a typical set of heavy resistance training. Several variables are critically important that all must come together for positive changes in strength and muscle mass to occur. Variables such as intensity, choice of exercise and frequency are common considerations. Of these, intensity is easily the most important as a foundational variable. If you aren't using enough intensity to overload your body the other variables simply take a backseat. Volume and the order in which you complete the exercises are also key considerations. Volume and frequency come together oftentimes as practical considerations due to the time constraints often associated with working a 9 to 5 job each week, but optimal volume is also important to ensure adequate overload is applied which ultimately will help drive improvements in strength and power. Rest between sets is another key variable and it's commonly prescribed that for optimal growth or hypertrophy, high volume and low rest (30 to 60 seconds) is needed between sets and for greater improvements in strength and power much longer rest periods are needed. In this recent study, however, young, healthy college aged males who had previously been resistance training were asked to complete three workouts. Each workout used the power clean exercise, one of the best exercises to develop whole-body strength and power and an exercise that carries over extremely well into athletic performance. Each workout had the athletes complete three sets of six repetitions at 80% of their one-repetition maximum. The key difference was that for one workout no rest was given between sets, another workout 20 seconds of rest was given between every repetition and in the final workout 40 seconds of rest was given between each repetition. All workouts were performed in a random order with at least three days of rest before each workout. As expected, when greater rest was given, the athletes were better able to maintain strength and power throughout the set of repetitions. For example, power decreased by nearly 16% from the first rep to the last rep when no rest was given, but power only decreased by 5.5% when 20 seconds of rest was given and 3.3% when 40 seconds of rest was given. Similarly, peak force decreased by 7.3% with no rest between repetitions but only decreased by 2.7% and 0.4% when 20 and 40 seconds of rest, respectively, were given between each repetition. Finally, peak velocity values decreased by 10.2% with no rest but only decreased by 3.8% and 1.7% when 20 and 40 seconds of rest, respectively, were given. All in all, these results highlight the important of taking enough rest between each repetition.
How Do You Use This Information?
In some instances causing greater amounts of fatigue, which commonly occurs with lower rest levels, is a desired training outcome and can help to stimulate more muscle growth. On the other hand and particularly when attempting to develop peak levels of strength and power, adjusting your workout program to achieve a greater quality of a workout becomes critically important. In this instance allowing for increased amounts of rest allows for better maintenance of strength and power through a set of repetitions. When greater force and power can be produced across an entire set the overall level of load and stimulus placed on the body may go up which over time could result in improved performance outcomes. Additionally, taking a little more rest may also allow for greater mental focus and potentially could also allow a person to use a slightly higher amount of weight than if they were not allowing any rest between repetitions. In conclusion, for athletes who train to maximize strength and power, manipulating the amount of rest you take between each repetition may be an important factor.
Hardee, JP, Triplett TN, Utter AC, Zwetsloot KA, Mcbride JM. Effect of Interrepetition Rest on Power Output in the Power Clean. J Strength Cond Res. 26(4):883-889, April 2012.