One thing that causes a lot of confusion amongst trainees – especially beginner trainees – is how much time they should take off between workouts.
And the internet certainly hasn't helped. There are fitness programs with a high frequency of training (near-daily) and fitness programs where you only stimulate a muscle group once a week and everything in between.
Which one is right and which approach is wrong? I know you're dying to know.
It's really not that hard and the majority of you shouldn't complicate it further than this:
- ~48-72 hours for any muscle stimulated as it should be for hypertrophy (muscle mass), power or strength-oriented goals via neuromuscular training
- ~48-72 hours for high-intensity interval training (AKA HIIT) or sprint interval training (AKA SIT) – Anything above ~85% max heart rate
- ~24 hours for any moderate-intensity aerobic cardiovascular work – anything between ~60-85% of max heart rate
- Low-intensity training like walking requires basically no recovery interval unless you're doing a large volume of it – like walking 6+ hours a day for example
"~" is a symbol meaning approximately. And I use that liberally here because for the average person, a few hours north or south of these numbers won't make a significant difference, just try to be close.
For beginners (in particular) and typical intermediate trainees, this is an excellent approach and I wouldn't blame you if you stopped reading there. That's the tl;dr.
The majority of trainees are intermediates and fall under this umbrella anyway. So unless you're actively training for high performance in sport, the above probably applies to you. With rare exceptions.
But ... But ...
Yes, I know perfectly well that there are professional athletes who train more than this and survive. I've trained some myself. And arguably was one for several years in my late teens/early twenties.
You are not a professional athlete. Probably not even a semi-professional athlete or serious amateur athlete. Or you wouldn't be reading this. The above works 98% of the time and it's very simple to follow:
- If you lift, take a day or two off before you repeat exercises that train what you trained (i.e. same/similar movements and/or same/similar muscle groups)
- Sprint or do high-intensity interval training and you should still take a day or two off before attempting it again
- If you do "cardio" wait until tomorrow to do it again and you'll be fine
- Walking shouldn't require much in the way of 'recovery'
That people who defy these simple rules can exist does not invalidate the guidelines.
It's not that you can never train more than this. It's that training more than this adds a thick layer of complexity the average person will get lost in. I'm going to explain as much of that complexity as I can below. In particular, the concepts of recovery and the beautiful balancing act it plays with fatigue.
What Is Recovery?
This one is pretty simple:
Recovery is the ability to repeat (or ideally slightly exceed) a previous performance.
In other words, you'll know you've rested enough if you can repeat or ideally exceed a previous workout performance. This is why repeating workouts is important.
If you do exercise Y for 5 sets of 5 reps with 120 kg as part of a workout, the next time you repeat that workout we expect to see you match that at a minimum. If we don't then we can probably conclude that you failed to "recover." But in an ideal world, we see progressive overload applied for a subsequent workout in one of two main ways:
- A slightly higher resistance = 5 sets of 5 reps with 122 kg or 125 kg as examples
- More reps = 5 sets of 6 reps with 120 kg, or the first few sets are to 6 or 6 and the final set is only 5 would also be indicative of slight improvement
Or a combination of both.
Now there are other ways to apply progressive overload without changing the number of reps or weight but these methods are harder to quantify cleanly.
These do some other things like manipulating the muscles involved and the training outcomes in terms of coordination and neural adaptations though.
- Manipulating the range of motion makes exercises progressively harder – going from a quarter squat to a half squat to a full squat for example.
- Manipulating the mechanical leverage makes some exercises progressively harder – going from a short lever to a longer lever, for example, bent-arm Scap raises to straight arm Scap raises.
- Manipulating positioning so more bodyweight is moved by working muscles – elevating the feet makes a push-up harder and elevating the hands makes them easier.
- Manipulating the position of the load – a Zercher squat or overhead squat will feel much harder than a barbell front or back squat, but limit the load and change the training outcome too
- Manipulating the starting position of the exercise – an Anderson Squat will feel harder than a normal squat because you're not used to starting from a dead stop on the squat traditionally
- Manipulating the equipment involved – a belt squat will feel a lot easier than a barbell squat and probably permit more overall load because it's attached much closer to your centre of mass but has a different strength curve.
- Manipulating the stability of the action – a single leg squat instead of a two-legged squat; less stable positions are harder but not necessarily "more valuable"
- Combinations of the above.
- And probably some others that escape my brain at the moment ...
No matter what you do to apply progressive overload, you've recovered if you can repeat the same workload again. And preferably you've improved a bit and can handle something a bit harder.
This is important to understand for two reasons:
- If you can't repeat performance, you likely didn't rest long enough between sets or performance attempts – or external factors like nutrition, sleep, stress are impacting the recovery process and thus your performance acutely
- Fatigue is accumulative, so if performance starts to suffer chronically despite resting a similar length of time to what previously worked, then this might be indicative of the need for a longer recovery period (usually called a deload) to counterbalance the accumulation of fatigue.
What is Fatigue?
This is more complicated and we still understand very little about fatigue in the big picture. But when we exercise, we often experience a temporary reversible reduction in strength or speed, which is broadly referred to as “fatigue.”
There are two main types of fatigue:
- Central Fatigue (AKA Central Nervous System Fatigue or CNS Fatigue for short) → fatiguing mechanisms occur in the brain/spinal cord
- Peripheral Fatigue (AKA PNS Fatigue) → fatiguing mechanisms localized to the muscles involved
Central Fatigue Primer
Central fatigue impacts the motor cortex, and by extension, the magnitude of the electrical signal sent to the working muscles from the brain and through the spinal cord. The size of this signal determines the magnitude of the motor unit recruitment of the muscles. Larger signals = more muscle recruitment. Smaller signals = less muscle recruitment.
Central fatigue means less muscle recruitment leading to slower, less powerful contractions. Despite your best intentions to move as powerfully or as quickly as possible, the signalling pattern just won't allow it.
Central fatigue is a lot like suddenly being in an area with poorer cell phone coverage.
And contrary to popular opinions online central fatigue is greatest during aerobic forms of exercise or when strength training is done closer to failure, using light loads and lots of training volume. i.e. when exercise durations are longer, metabolites accumulate to a greater degree, and inflammation responses are higher.
The irony is that CNS fatigue has a much more dramatic effect on explosiveness, power outputs and strength than it does on the types of training that cause it. The specific problem it creates is limiting the recruitment of the highest threshold motor units of the muscle. It's like a governer chip that limits the speed of your car.
Most high-rep, endurance and aerobic styles of training are done at relatively low speeds and low power outputs that do not require large amounts of neural excitation or the largest motor units. So it's not unusual for people participating in these activities to not realize how fatigued they are with this type of fatigue until it's too late.
Peripheral Fatigue Primer
Peripheral fatigue is localized to the muscle and has a lot more factors involved.
There are 4 dominant mechanisms of peripheral fatigue that I'm aware of but am not going to go into much detail explaining them all because you probably don't care how this all happens, only that it does:
- Loss of sarcolemmal excitability* → The electrical signal from the central nervous system is distributed along the surface of the muscle fibre cell membrane (sarcolemma). Fatigue disrupts this distribution and lowers excitability because the action potentials reaching the T-tubules are lowered.
- Loss of excitation-contraction coupling → T-tubules are basically voltage sensors. When they detect action potentials they release calcium ions into the sarcoplasm of the muscle fibre, converting the electrical signal into a proportionate chemical signal. It's believed that fatigue disrupts this with an abundance of phosphate ions that bind with the calcium ions, lowering their availability. And/or disruptions to minor protein availability at the triad junctions.
- Loss of myofibrillar sensitivity → Once the calcium ions are released, they are detected by a protein (troponin) allowing another protein (tropomyosin) to move, revealing myosin-binding sites on actin so that the sliding filaments can do their thing. If troponin fails to detect the calcium ions, then nothing happens. It's thought that hydrogen or phosphate ions (metabolites) are mostly to blame for this too, but this mechanism is currently the least clear.
- Disrupted cross-bridge cycle → It requires ATP for the filaments to slide, and that basic energy supply is either impaired by the accumulation of metabolites (phosphates that reduce ATP availability) or excess accumulation of the calcium ions that damage the myofilaments.
Well, that was certainly more science than you probably needed but briefly reveals how complicated fatigue is above and beyond my initial recommendations.
A lot of this explains why eccentric contractions take so much longer to recover from than concentric and isometric contractions. And that will lead me to how and why some people can train more often than my recommendations above.
Hint: They manage fatigue better via training manipulation.
I think what's interesting about all of these peripheral mechanisms, is that theoretically, the fatigue caused by any one of them is either relatively quick to resolve because metabolite accumulation tends to dissipate relatively quickly – probably accounts for more of the recovery between sets. Or slow to resolve because something is damaged (the muscle cell membrane, the triad junctions, or the myofilaments) and accounts more for the recovery required between training sessions.
In any case, when central fatigue is minimized, and peripheral fatigue is the stronger of the two types; Then the muscle fibres of the highest-threshold motor units can be trained most effectively.
Central fatigue has a much more negative effect on our ability to stimulate strength, power and hypertrophy than peripheral fatigue. Meaning if you're going to manage a type of fatigue in the long-term, peripheral fatigue is the more desirable of the two to address.
*Sarcolemmal excitability is the signal Electromyography (EMG) measure for anyone that cares.
Recovering Fast vs Slow
Recovery is all the rage currently and warrants a separate article. Vibration massagers, vibration training, ice massagers, foam rollers, old-school massage, cold showers, electrostimulation, ice baths, all that stuff!
Paradoxically people are dropping hundreds of dollars a year on recovery equipment without fully understanding what recovery is or what it means.
Can you speed it up? Sure.
Can you speed it up enough to matter? Debatable.
In athletes, sure, what else do they have to do but train, eat and recover, this is literally their job. A 0.1% improvement matters at elite levels of sports performance.
Everyone else? It's hard for me to see most of the research as anything but a wash.
There might be other reasons to do some of this stuff. For instance, some of it might lower subjective feelings of 'perceived fatigue' and 'delay onset muscle soreness' (AKA DOMS) in some people, some of the time, but the data is really inconsistent and highly variable.
Take it with a grain of salt. Or at least try things, see how they work for you, and continue to use them only if you feel they work. Which is very different from objective quantitative data on their usefulness.
At the very least, most modalities won't hurt performance, even if they don't enhance it.
More objectively speaking, a meta-analysis in 2018 found that massage was really the only modality that led to significant decreases in various known markers of fatigue – Creatine Kinase, Interleukin-6 and C-Reactive Protein.
Cold Water Immersion (kind of a broad term for cold showers, ice bathes, and the like) and the use of compression had an effect but a much smaller one. Basically, everything else was a mixed bag of usefulness. If it worked at all.
Most research on this topic looks at things that are thought to be proxies for recovery and has failed to look at actual performance from training session to training session. Some look at performance as a whole.
According to an even more recent meta-analysis in 2020 looking at the effects of massage on actual performance we see basically no effect on performance. It's not detrimental, but it doesn't improve it either.
Well, so what gives?
Remember I said recovery is simple: recovery has occurred when you can repeat a performance.
If you can repeat your performance at the 46-hour mark, instead of the 48-hour mark, you have technically 'sped up recovery.' But is that benefit practical?
Probably not. A beneficial improvement would be 24 hours instead of 48, or 48 hours instead of 72 hours because days of recovery are how most exercise is programmed and executed.
Is anyone going to shorten the frequency they train at by 2 or 4 or 6 hours and try to lift every 46, 44 or 42 hours instead of every 48? No, that would be impractical.
It just doesn't make any sense to try and implement. Eventually, you'd end up waking yourself up in the middle of the night to train, which would disrupt sleep, and lower any advantage you were getting by training at a slightly higher frequency.
It's far more practical to think of training in daily cycles, not exact hours. And my recommendations have always already accounted for this by using approximately 48-72 hours, not exactly 48 hours, or exactly 72 hours. It's more like wait until tomorrow, wait a day, or wait 2 days before you repeat a workout.
If you train at 6 pm on Monday and have to get your lift in again at noon on Wednesday that's not a deal breaker. You won't need to skip that lift because it's happening 42 hours later, and not exactly 48. There is no magic switch that happens exactly at 48 hours, other than it's a nice easy number for researchers to work with.
Remember fatigue is complicated and accumulative (especially CNS fatigue).
In other words, if you can repeat a training performance you can safely assume you've recovered. No special modalities are necessarily required. At least until you're unable to do that for about 2-3 workouts in a row. What a lot of people would call a plateau or a stall.
When that happens, CNS fatigue has likely accumulated to a point where resting that standard ~48-72 hours isn't enough to allow the accumulative fatigue to dissipate to a point where performance can continue to improve.
And typically this warrants an even longer recovery period than usual. Most often called a deload period. A deload is a one to two-week period of time where training is altered to reduce its fatiguing effects. The easiest way to do this is to lower training volume (duration or # of sets) but maintain intensity.
The other solution (that I'm much more fond of with the average trainee) is simply to cycle the training to something new and ramp up the training volume as I would for any training cycle – for example, 2 sets of everything, then 3 sets, then 4 depending on the new intensity.
This lowered initial volume of a new training cycle can act as a deloading period, allowing the accumulative fatigue to dissipate. And it doesn't or won't feel like you're just doing less of the same stuff.
Why Might Recovery Modalities Be Useful?
If doing something like massage, or cold water immersion, or wearing compression garments between training sessions doesn't speed up recovery by a meaningful degree then what might the benefit be?
Well, the research looking at this is still very limited. Most of it looks at acute repeat sprint ability or time to exhaustion measures. But lowering perceived fatigue and any sensations of DOMS does generally appear to lead to better training quality. At the very least psychologically.
And that might matter. It makes the training a bit more enjoyable at least. And higher training quality theoretically improves performance better.
But again, research into chronic performance measures generally indicates little to no improvements (nor detriments!) over the long haul with any recovery modality.
At least any of the research I've managed to find. So take that as you will.
Given that (especially CNS) fatigue is accumulative and eventually interferes with progress. It's possible that using recovery modalities extends how long it takes for each stall or plateau to occur.
Now that's highly speculative on my part, but not completely outside the realm of possibility. If you can delay a stall or a plateau by even a week or two, then theoretically you're getting more progressive training into a similar time frame.
This might lead to better outcomes that most studies are powered to observe (the longest typically only lasts 16 weeks). If you can delay the need to deload or cycle, while still making progress, then it's possible some recovery modalities are more useful than they seem.
Only research and time will tell.
There are some clinicians and researchers who believe deloading at all is an indication you're doing too much. Either you're training too close to failure, training with too much intensity, training eccentrically too much, doing too much volume or you're not recovering long enough at all. Or some combination of those.
They worry that deloading leads to some detraining, which might be true if you're an elite athlete simply trying to maintain your training status. I sincerely doubt that's the case if the intensity remains high. But how does this apply to the average person? Maintenance is not the same as progression.
I, however, feel that's a very hard line to walk and that continued indefinite progress without an eventual need for deloading (or variety) is a pipedream. Until we discover a reliable and practical way to monitor all the different types of fatigue it's simply too difficult for the average person to accurately walk that line.
Velocity-based training (VBT) is promising, but still fairly inaccessible at the moment. Although the cost of this equipment has come down significantly in recent years. I'm not sure it's yet worth the investment for anyone who isn't a serious amateur athlete.
Minimizing Fatigue, Not Speeding Up Recovery
So how do athletes seemingly train so hard every day?
Well, they don't ...
I know it sure looks a lot like they do, but fatigability is relative. It's true that they train much harder than the average person, but they are not average.
Fatigue is relative. If you build up a tolerance to fatigue by training a lot, you reduce the impact of fatigue on recovery. The majority of their training is much easier than it appears to the average eye. It's easy for them.
A lot of training allows you to tolerate higher frequencies, intensities, and more training volume. Training like it's your job helps a lot more than you realize.
But the other things these superheroes who train so frequently do is they:
- Cycle intensity → the highest intensity training is usually only done 2-3 times a week
- Manipulate and alter exercises → Changing exercises slightly alters the recovery demands
- Manage rest differently → more often than not, much longer rest intervals are used between sets to maintain quality
- Manage and cycle proximity to failure → training further from failure reduces fatigue, but still maintains a lot of power/strength
- Ramp up the volume, contraction types, and frequency of training → You build up a tolerance to all of these things by slowly increasing it over time. Athletic training is a multi-year process.
- Choose productive exercises that minimize fatigue → training at longer muscle lengths for eccentric actions increases fatigue
- Manage and cycle contraction types → sled work is predominantly concentric and much easier to recover from than full dynamic contractions. Isometric/static training is also much easier to recover from.
- Diligently plan the entirety of the training approach and modify as recovery and results dictate on the fly
And that's really just the tip of the iceberg. If all that seems like jibberish to you, that's why I recommend the much simpler framework at the very beginning of this article.
In a nutshell, it's a lot of little things that the average person is probably not willing to manage just so they can train 6x a week when 4x a week will do for the average goal. Improving less than 1% matters in elite performance scenarios.
It matters substantially less if you just want to recomposition 10 lbs of fat mass for 10 lbs of lean mass.
Frequency, rest, intensity, volume, exercise selection, contraction type and proximity to failure all impact recovery to one degree or another.
So what athletes do is cycle all of these things to one degree or another in order to minimize and manage fatigue. This by extension manages recovery.
Some Broad Examples
Let's say you're an endurance athlete. You can basically slog out long-slow steady-state distance work daily. You'll build up a tolerance to a daily slow practice, mostly to maintain aerobic capacity. But you probably only have a couple of very hard training days in the mix. Hill training, interval training or tempo training is spaced out and more often done only 2-3x a week maximum.
The type here influences this greatly. Being in a pool is a lot less taxing on the body than being on a bike, which is less taxing than rowing and finally running (which has impact).
So volumes and intensities can be adjusted accordingly. Michael Phelps can spend 5 hours in the pool daily because he's in a pool and therefore buoyant. Cyclists are more apt to train maybe 2-5 hours a day. Whereas Marathoners by comparison might only train 1-2 hours a day.
If you throw resistance training in the mix, it's probably only twice a week in-season and probably only after you practice your sport in an effort to maintain strength levels as best you possibly can and reduce injury probability. Off-season you might lift more, but you'll probably also reduce the higher intensity training to manage that new fatigue.
Now let's consider the other end of the spectrum and talk about strength-sport athletes (powerlifters, Olympic lifters, or strongmen).
Here very little cardio is going to be done. When it is, it's going to be pretty short bursts of aerobic intensities for 20-30 minutes using non-weight bearing modalities like the stationary bike for maybe 1-3x a week. The bike is concentric action only and has low technical demands but is also in most gyms already. Very often sled work and other concentric training modalities are done instead.
They'll lift about 4x a week typically but very often cycle intensity, exercises and ramp volumes up over time. They'll have one or two really hard days, followed by more moderate training. They usually avoid grinding reps, training further from failure which aids in recovery.
This is contrary to bodybuilding, whereby you need certain proximity to failure to grow in moderate rep ranges with shorter rest intervals. This translates as only being able to train muscle groups every 48-72 hours, which has led to some crazy split designs over the years in an effort to increase frequency. But to be honest, all the evidence points to simple 2-day splits done twice a week, or full-body training done 2-3x a week for beginners as ideal in non-drug users. This amounts to 2-4 hours of lifting per week or so. Not very much.
And then somewhere in the middle, you have power (or mixed sport) athletes. You're going to do a lot of technical training for your sport daily but a lot of it will be much lower intensity than you might think. Easy shooting, throwing, catching or passing drills, easy skates will make up the bulk of technical training. As technical training is best done when fresh. Lifting in season is usually low volume, high intensity, maybe 2-4x a week, far from failure (strength/power maintenance is the priority).
Gameplay varies widely. Baseball players play near-daily, but use low-weight tools at high speeds which is less fatiguing generally speaking. Any running/sprinting is fairly minimal when compared to other sports.
While American Football players will play only weekly and generally leave everything out on the field, followed by a day off (or very light day) or two. Leaving a lot of room for tape review and lower intensity training throughout the week. Soccer players typically twice a week. Basketball/Hockey every other day.
All professional teams now use HRV, GPS and a bunch of other tools to help track fatigue and manage recovery. Arguably some athletes are probably doing to much and this has increased injury prevalence and injury time is a lot more problematic than resting players periodically. You're starting to see the latter happen a lot more in an effort to improve athlete longevity and maximize player value.
Yes, there are deviations from those generalizations. Genetics plays a role. The player's mental state plays a role. The training history of the athlete plays a role. The injury history plays a role. The organizations play a role.
Having worked as a head strength and conditioning coach for Football (the American kind) it's a whole different culture from any other sport I had personally played a lot of (Volleyball, Soccer, Basketball and Track mostly). Very much a sink or swim environment at lower levels.
Whereas my track experience was that the coaches were always very concerned with recovery and doing too much. And the rest of that varied in the other sports I played depending on the coach. Some coaches would grind us with distance work (lots of laps or suicides) because they felt conditioning was really important. Others would spend far more time on technical training at moderate intensities.
The Point Is ...
The framework at the beginning of this article is very easy to follow and implement.
When people deviate from this, they are monitoring recovery very closely most typically for sport. It gets very complicated very quickly and only in a good way if training frequently is required.
For most goals, it isn't.
The approaches used for elite sport are generally complex, highly nuanced and hard for the average working individual to implement.
Just because such and such famous athlete (or actor or bodybuilder or fitness model) trains like XYZ, does not mean that you should train XYZ.
You are not them. Whenever possible keep it simple, so you don't have to worry about all the scientific jargon I just spewed.