By: Barbell Logic Team
Fatigue initiates the adaptive response to training. We want to induce fatigue as a consequence of training. But fatigue may be the result of many possible factors, not all of which reflect a training stress where force production is the primary stressor. Fatigue that results from energy depletion, for example, may be the result of high-intensity interval training instead of strength training. When it comes to fatigue, not all sources are created equal. We want to induce fatigue as a training stress resulting from our efforts under the bar while avoiding intra-workout fatigue from other sources that is going to affect your form. One of the ways we manage intra-workout fatigue is with our rest between sets.
Rest Between Sets is Good for Your Form
Productive training causes fatigue in a variety of ways. Peripheral fatigue may come from depleted energy stores or muscle damage. When you lift, you drain your glycogen, phosphocreatine, and ATP stores. A reduction in available energy means that your muscles cannot perform at the same pre-workout levels—depleted energy results in the reduced function of your skeletal muscles. Peripheral fatigue may also be a muscular response to accumulated byproducts from muscle activities, impairment of the muscle contractile mechanism due to exercise-induced muscle damage or immunological or genetic responses to the training stress.
Central fatigue—or tiredness as a result of the down-regulation of your motor function by your CNS—is like a governor on a car engine. Your CNS limits muscle contraction and force production in response to sensory input as a way to prevent excessive damage to your muscle cells. You experience a decrease in performance in the same way you would if as a result of depleted energy stores.
Fatigue initiates the adaptive response to training. We want to induce fatigue as a consequence of training. But fatigue may be the result of many possible factors, not all of which reflect a training stress where force production is the primary stressor. Fatigue that results from energy depletion, for example, may be the result of high-intensity interval training instead of strength training. When it comes to fatigue, not all sources are created equal.
We want to induce fatigue as a training stress resulting from our efforts under the bar. But, unless you are intentionally incorporating a conditioning component into your lifting, we want to avoid intra-workout fatigue from other sources that is going to affect your form. Because no matter the source, fatigue “means the inability to maintain a given exercise intensity.” (Brooks, Fahey “Exercise Physiology” (4th ed 2005)). Fatigue within your workout can hinder your ability to lift a given weight for a given number of reps.
This does not mean we should avoid fatigue at all costs, but rather we should manage it to meet our training goal for any giving session. One of the ways we manage intra-workout fatigue is with our rest between sets.
There are several reasons why rest between sets is an important consideration for your programming and your progress, particularly during the Novice Linear Progress. These have been discussed at length in the following sources:
- “Rest Between Sets” by Michael Wolf, SSC (November 07, 2018)
- “The First Three Questions,” by Mark Rippetoe (December 30, 2015)
- “Practical Programming For Strength Training,” by Mark Rippetoe and Andy Baker (3rd Ed 2013) Ch. 5
Another reason to manage your rest between sets is for the sake of your lifting form.
“Form is as much a part of your program as the sets and reps you are supposed to do that day. And it must be as much of a priority, not just because your PRs don’t count if you cut your depth, not just because correct lifting is safe lifting, but because consistency of form directs the training stress, making the hours you spend in the gym more valuable, leading more directly to your goal.” From “The Importance of Form and Consistency,” Barbell Logic.
The inability to continue lifting at a given intensity leads to form creep within a workout. Unchecked this can become a long-term problem. All lifters have “default” form issues. For really great lifters, their default form is very close to their practiced, perfect form. For most of us, however, as fatigue sets in and we mentally shift from the cues that dictate how we should lift and start just trying to survive the lift, we open the door for bad habits creep in. Unchecked, constant fatigue and constant form-related problems can lead to major form issues, requiring a deload and lost progress.
A long term goal for any lifter should be to change your default habits to good lifting habits, giving fatigue and form creep less to work with. This means that you need to practice good form. If you don’t manage your recovery within the workout, you will return to your default habits instead of building new habits through continued and constant requiring of your motor patterns.
How much rest is too much? (Or too little?)
There is no hard answer. How much rest you need between sets will depend on your own programming and your present goals. As with every training variable, your rest should support the goals of the training session. If you are just starting out, a good rule of thumb is to set your rests between three to five minutes. Keep in mind that your goal is going to be to complete each set with as close to perfect form as possible—this is one of the main goals for a new lifter—so use rest as a tool to help you do so.
Artificially shortened rests to build fatigue or cause particular stress are normal, but not arbitrary. You should understand the goals of your program and how rest between sets will affect your goals.
The upper limit to your rest is likely going to be determined by the amount of time you can spend in the gym. This is where you need to determine whether shortened rest is the answer to your time issues, whether you need to tighten up your gym time or implement a structural change to your program. Tracking your rest between sets and making small changes in response to your lifting can also provide useful data for your training log.
Be efficient with your time, but don’t rush your rest between sets. You are already working hard to maintain your lifting form, don’t complicate the process by adding unnecessary fatigue to your workouts.