Getting enough rest after weight training is essential for optimal muscle growth and performance. Unfortunately, many get insufficient rest because they simply disregard the fact that weightlifting breaks down muscle tissue, creating the requirement for adequate rest to fully recuperate. In addition, insufficient rest may occur when alterations in training are implemented to boost training stimulus without sufficiently addressing the increased requirements for greater rest. As a result of inadequate rest from either of the aforementioned reasons, complete muscle recovery may not occur and performance in the weight room can eventually decline and even deteriorate into the state of overtraining. In fact, inadequate rest between workouts can raise the chance for injury.
Beginners Need More Rest
The necessary amount of rest required between workouts for full recovery is heavily influenced by many different factors, with one of the more pertinent influences being the subject’s level of conditioning or training experience. In fact, less-experienced lifters require more days off between workouts and should progressively decrease the amount of rest days between workouts as they become more fit. To start, novice weightlifters should begin a program with only two to three strength-training sessions per week, with at least one rest day between training days, as there are numerous resistance-training studies that have shown that this training frequency was initially effective for strength gains in untrained individuals.1,2 However, it has also been shown that untrained subjects did not fully recover all of their strength two days after a lower-body workout consisting of five sets of 10 repetitions on the leg press3, suggesting that lesser-trained individuals may actually need recovery periods greater than one day, depending on the type of exercise performed. Taken together, the best approach for beginners entails lifting sessions completed on nonconsecutive days while providing one to two days of exercise-free rest days between workouts. Yet keep in mind that some individuals might require additional rest days, and may want to begin with only two workouts per week on nonconsecutive days.
More Advanced Lifters Require Less Rest
For the more experienced weightlifter, promoting continued muscle growth requires a gradual increase in exercise stimuli. While there are many parameters that can be altered to boost the training effect for advanced lifters, an increase in exercise frequency exemplifies a powerful way to accomplish this objective. This is primarily because increased training frequency encourages the use of split workout routines that maximize exercise volume without dangerously depleting recuperation time. For instance, although more advanced lifters usually exercise at a higher frequency of four to six days per week, split training protocols target different muscle groups on various days providing adequate rest of one to two days for each specific muscle group. In fact, studies have shown that training four to five days per week using a split protocol achieved better results than those who split-trained three days per week.4
Sore Muscles Increase Rest Requirement
Exercise-induced muscle damage primarily occurs when performing a lift that your body is unaccustomed to, or when you crank up the training intensity by increasing the amount of weight lifted or the total number sets performed.5 In addition, more intense workouts incorporating weightlifting movements that focus on the negative contraction or eccentric component of the lift induce even greater muscle damage. This is primarily because the negative or eccentric phase of muscle contraction forcibly lengthens the muscle cell, generating more destructive forces on the muscle fiber and causing greater damage.
Greater muscle damage stimulates many different cellular and molecular mechanisms that cause the muscle cell to grow and become more powerful6, while also requiring longer rest periods between workouts for full recovery. The increased necessity for rest is due to the fact that lifting weights with sore muscles limits your ability perform in the weight room, and may lead to further anatomic and biochemical deficiencies within the muscle tissue that may ultimately cause overtraining and injury. In order to reduce extensive muscle soreness and avoid lengthy rest periods, slowly increase exercise intensity and utilize eccentric training techniques periodically for relatively short durations. This methodical approach should provide acceptable amounts of muscle soreness that will not require too much time out of the gym, while simultaneously supporting optimal muscle growth and strength.
Extensive Rest Periods Increase Fast-Twitch Fiber Content
There are essentially three major types of muscle fiber that are generally segregated as follows: slow-twitch (type I), moderately fast-twitch (type IIA) and very fast-twitch (type IIX). The fibers are called “slow” and “fast” due to the relative rate at which they contract, with fast-twitch fibers contracting roughly four times faster than slow-twitch fibers7, giving the fast-twitch fiber a greater force-producing capacity as well. As a result, slow fibers are important for endurance activities such as long-distance running, whereas fast fibers are essential for power-based sports such as weightlifting, bodybuilding and football.
Interestingly, a study by Andersen et al.8 has shown that resistance training combined with substantial rest between workouts can shift one type of fast-twitch fiber to the other. In this study, the researchers demonstrate that muscle fibers exposed to extensive weight training initially decrease the number of very fast-twitch fibers from nine percent to two percent, converting them to the other fast-twitch fiber type. However, when the same subjects were exposed to long periods of rest, they surprisingly showed a relative increase in very fast-twitch fibers— increasing the amount of very fast-twitch fibers from nine percent to an average value of 18 percent at the end of the rest period, which also correlated to overall strength gains.
Although the mechanism underlying the increase in very fast-muscle fibers from long rest periods is unclear, some useful applications can still be drawn. For starters, in order to boost the relative amount of very fast fibers for improved muscle force production and muscle growth, the best training strategy appears to be heavy resistance training followed by an ample rest period leading up to the day of the contest or competition.
For most of Michael Rudolph’s career he has been engrossed in the exercise world as either an athlete (he played college football at Hofstra University), personal trainer or as a Research Scientist (he earned a B.Sc. in Exercise Science at Hofstra University and a Ph.D. in Biochemistry and Molecular Biology from Stony Brook University). After earning his Ph.D., Michael investigated the molecular biology of exercise as a fellow at Harvard Medical School and Columbia University for over eight years. That research contributed seminally to understanding the function of the incredibly important cellular energy sensor AMPK— leading to numerous publications in peer-reviewed journals including the journal Nature. Michael is currently a scientist working at the New York Structural Biology Center doing contract work for the Department of Defense on a project involving national security.