How Long Rest Intervals Should Be For Building Muscle And Strength
Weightlifting is about variables. The chosen exercise, number of sets, the number of reps, amount of time you spend lifting, what type of warm up, which playlist you’ll nod your head to, and what’ll be highlighted today - how long you “rest” between sets.
This last variable tends to shy away from the spotlight. Doesn’t get much mention, but has its fingerprints all over your results whether you’re aware or oblivious. Let’s put those paws in the right place by learning what works best for you.
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How Do We Make Energy
To understand rest protocol you should first understand how you’re able to produce in the first place. We won’t go too far in the weeds, but the way we move, and live for that matter, is based on a combination of 3 energy systems. These systems allow you to continuously turnover adenosine triphosphate (ATP).
If you were to stop turning over ATP.. You’d stop turning over.
You’d die.. The end.. Night night.. Close the curtains.
Your 3 ATP-turnover mechanisms are:
ATP/Creatine Phosphate (CP)
Glycolysis
Aerobic Oxidation
Creatine Phosphate and glycolysis do their jobs anaerobically, signifying that they don’t require oxygen.
Aerobic Oxidation doesn’t, because it’s aerobic. Aerobic means requiring oxygen.
You have these three distinct systems and at different levels of intensity/duration of intensity one system takes over as head coach, yet the others don’t leave the field.. They assist. Although one mechanism may dominate at a particular moment they all contribute, to a degree, at all times.
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ATP/Creatine Phosphate
A ready-to-go pure form of ATP is stored in your muscles and at maximal or near-maximal intensity kicks-in for up to about 4 seconds. With larger muscles you’ll have more room for potential ATP storage, yet how long you can fuel yourself with uncut ATP remains unchanged.
ATP hastily depletes by losing a phosphate. Once ATP is short a phosphate it goes from tri to di - adenosine diphosphate (ADP).
If you're a hardcharger, still going all out, creatine phosphate takes control of the energy wheel and adds a phosphate to ADP, recreating usable ATP.
Creatine phosphate can continue replenishing ATP for 8-10 seconds, so after about 10 seconds creatine phosphate has to prepare its vacation of the driver’s seat and allow glycolysis to take over.
Upon exhaustion, to fully restore your baseline level of ATP in a particular muscle you’d need to rest for 3-5 minutes.
Regardless, 70% of ATP is reformed after 45-60 seconds.
To fully restore creatine phosphate stores you’ll need 8 minutes.
This is why creatine supplementation is popular.
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Glycolysis
Glycolysis grabs the reigns after creatine phosphate loses some of its grasp.
It comes in at 10 seconds, sharing a great deal of the load, then becomes dominant from approximately 45-120 seconds.
Glycolysis converts ADP back to ATP by using glycogen stored in the muscles and glucose in the blood.
As you continue repping out those sets a byproduct of this pathway, lactic acid, accumulates in the working muscle. It’s that all-too-familiar burning sensation that shows its face as you approach your anaerobic threshold, which occurs once your ability to flush lactic acid is overpowered by its accrual.. Then muscular failure sets in and you have no choice, but to end the set or greatly decrease intensity.
As lactic acid is flushed it morphs into a beneficial form: lactate. Lactate can be converted to glucose or used as an energy substrate.. The saga continues.
Glycolysis takes up to 8 minutes to fully recover once you’ve gone over the 80-120 second mark of high intensity. What limits this pathway is your tolerance of lactic acid rather than complete depletion.
Note: glycolysis is anaerobic, but bolsters oxidation when pyruvate, another byproduct of glycolysis, is sent to mitochondria for aerobic glycolysis. In aerobic glycolysis no oxygen is used, but pyruvate enters the Krebs Cycle assisting the process of converting ADP to ATP before it’s ultimately oxidized.
Another note: pain tolerance is a strong factor with prolonging glycolysis, along with your body’s ability to swiftly flush lactic acid; this can improve with training experience.
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Aerobic Oxidation
Finally.. Last, but functionally not least: Aerobic Oxidation.
As the most dominant energy system most of the time, it handles business during low intensity scenarios from walking to the mailbox to running a marathon.
Your aerobic capacity has been shown to fuel greater than basic, yet less than high intensity activities for days [2].
When putting in work, aerobic oxidation significantly steps forward after around 75 seconds, but puts its name on the building after roughly 120 seconds.
It’s the only system that’ll use fat as a supporter for converting ADP to ATP through a process called beta oxidation.
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How Long Should I Rest Between Sets
Alriiight that’s how the action takes place, but how long should you go between bouts of doing the work? That depends on your main goal.
Strength/Power And Sustained Power
If your first priority is to add weight to the bar, if you want to build your bench, squat, deadlift, vertical leap, or pinky curls - this is your que.
This que also applies to developing sustained power.. That applies to sprints, as well as near-maximal lifts lasting 4-10 seconds.
With this goal upfront you need to give it the long-haul between sets.
Take the powerlifter route and rest 3-5 minutes after a set.
When lifting for strength you’re usually in the low rep range of 1-6, so the sets won’t take too long, leaving you relying heavily on your ATP-CP system for fuel.
Pros:
More energy for heavy lifts with each set
Time to refocus
ATP-CP will be ready to roll at or near full capacity
Can still gain muscle
Cons:
You’ll burn less calories per minute compared to shorter rest periods or those completed with supersets
Won’t pack on muscle as quickly as other routes
Takes longer to finish a workout or you won’t be able to do as many exercises
May experience boredom between sets
Could lose some momentum if you’re not moving around
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Hypertrophy
You all about the muscles? Want to swell up like my knee when I was trying this ab challenge out?
30-90 seconds between sets is for you.
Will your anaerobic energy systems fully recover? No, but they’ll give you some juice and this strategy leads to an increase of metabolic stress. A healthy level of metabolic stress allows you to step into an even more hormonally beneficial realm for hypertrophy [4]. With a hypertrophy focus you’ll spend much time in the 6-12 rep range.
Pros:
Chance to gain muscle quickly
Can get more work in during any allotted time frame
Still provides an opportunity to boost stronger
Cons:
Not as much energy for each lift
Less than the most efficient way to gain strength
Probably will need new clothes once you burst out of the sleeves 😏
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Stamina
Want to enhance your ability to last? Improve muscular stamina?
Keep your rest periods short.. <30 seconds. Here you’re usually enforcing higher reps in the 15+ range.
Pros:
Improves endurance
You’ll get a faster pump
More calories are burned per minute due to the extra work
Cons:
Could compromise some potential strength gains
Can’t hit as heavy with such short rest
Will fatigue faster, for systems not recovering fully
When rest periods are too short hypertrophy is undercut, since the level of resistance is nowhere near what it could be to elicit substantial growth
Note: if your main goal is fat loss go with a hypertrophy rest period or abide by the superset protocol I mention in My Thoughts, for the more muscle you carry the more fat you burn even at rest.
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What To Do Between Sets
Whatever period of rest you lean on; don’t waste it.
Don’t just sit, make it productive. If you’re not doing supersets prep equipment, get your next few songs ready, keep the blood flowing with a little walking around, hydrate, visualize your next set, write how the previous lift went in your journal, get your flex on.. Practice those contractions, work on your breathing technique. Whatever you do make it count, rest doesn’t mean wait.
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My Thoughts
There’s a PubMed study [6] making the rounds that suggests 3 minute rest periods tend to not only work better for strength, but for hypertrophy when compared to 1 minute rest periods.
I disagree, or at minimum put an incomplete on this study, reason is although the 3 minute group and 1 minute group followed the same lifts.. The 3 minute group spent more time in the gym.
Up until around 75 minutes of testosterone-inducing lifts you set a potentially anabolic stage. If the 1-minute group is out the door sooner, of course their results won’t match. Also the study doesn’t account for extra work a 1 minute rest period would allow you to do if the same amount of time in the weight room was spent.
A way to marry your strength and hypertrophy pursuits is to go with supersets for opposing muscle groups i.e. bench press followed by bent row [7] followed by a hypertrophy rest period. This way you allow each worked muscle time to recoup, yet still get surplus work in. However this isn’t apples to apples.. You won’t get 100% of the strength benefits from 3 minutes rest or 100% of the hypertrophy 30-90 seconds rest benefit, but you’ll get a high percentage of each.
This should go without saying, but if you neglect your nutritional needs.. No workout plan will make you the gain’s favorite.
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So, It’s About That Time
Details.. It’s always about the details. I say it all the time, the further you go on this fitness journey the more they come into play. Keep learning, keep growing, and rest appropriately for your goals. If you do that, as well as abide by the other factors you’ll put those muscles to use and you’ll Be Great.
Sources:
[1] Pubmed.Ncbi.Nlm.Nih.Gov/19691365/
[2] Dietitiansaustralia.Org.Au/Wp-content/Uploads/2016/12/58-1-supplement-the-fuels....Pdf
[3] Nesta Fitness Training Manual
[4] Ncbi.Nlm.Nih.Gov/Pmc/Articles/Pmc5489423/
[5] Issa Fitness Training Manual