Certainly it is accepted sports medicine and fitness program dogma. I’ve learned it and repeat it myself to others:
Avoid weight training the same body parts two days in a row; if primarily aerobic training alternate hard days with easy recovery days; take a day off per week lest you risk overtraining.
And it makes sense. But is it true? Is there any actual basis for this advice or is it just someone’s belief that has been repeated so much that it has become accepted as truth?
What evidence is there that it takes more than 24 hours to recover?
I exercise everyday, but I do light to moderate cardio + pilates. I just don’t believe you can overdo light cardio: too many people --the vast, vast majority of people off all times and places–have walked 5-10 miles a day every day of their life. Running and weight lifting are different: I only do weight lifting every other day.
No such thing as a rest day when you’re on crutches, going to college five days a week and live alone on a second floor apartment with no elevator. That was me in January 1999. When I first broke my leg I was a good 45lb overweight with no tone whatsoever. It was all I could do to get down to my car, drive to school and go home again and flop into bed. To get better with the crutches I added in swimming at the college gym and as many pushups as I could do at home, every day without fail. By that Easter, random strangers were complimenting my physique.
Of course I’m not advocating that anyone get in shape using this method, just saying that I had no rest days and got fit, no problems. Of course, as soon as I was all healed and found drinking buddies the weight came back on and I joked about busting a leg again so I could do the crutches fitness program. =)
Joe Friel’s “The Cyclist’s Training Bible” spends a fair amount of time emphasizing that measured training will give better results than daily hard training. He references a fair amount of science behind it and it wasn’t specific to Cycling. IIRC, a lot of the studies initially came from the East German Olympic teams.
Personal stories and individual humble opinions are well and good, but what I am asking for is whether or not there is basis that is a bit more methodical than that.
I’ve kept digging on my own and I can come up with a little, but mostly it applies to elite athletes.
For instance, there is this study of well trained cyclists. They measured them at their baseline training (unfortunately only defined as “All subjects had competed for at least 2 yr and were training a minimum of 3 days/wk”) and then again after increasing their training, in 2 week “programs that doubled normal training volumes. The majority of the increase in training volume was in the form of high-intensity training, i.e., above the lactate threshold”. Finally they retested them after a 2w of recovery. The findings were
It was unclear why that occurred however.
And the question remains unclear where the drop off from benefit to decrease in performance occurs, or what feature caused it. And as noted below, what they induced may not really be overtraining at all, albeit it seems like something to avoid anyway.
This review unfortunately only confirms to me how little of what is advised dogmatically is actually based on real data. Overreaching and overtraining can occur, but there is no magical amount of time needed for recovery between exercise sessions or critical max loads of intensity. They clarify the difference between “overreaching” (OR) and overtraining syndrome (OTR)
The review concludes realistically that the way to avoid overtraining is to monitor for it and to rest if it occurs.
Which honestly isn’t much help.
Thing is I believe, on the basis of common sense and anecdotal experiences, that rest days and/or alternating with easy days are very important. I’d just like to know that there is a more definitive basis for that belief than that: common sense often leads one to conclusions that should be true but are not.
The findings state clearly that ITP resulted in a decrease in performance. The findings did not identify the root cause or the threshold of ITP, but that doesn’t invalidate the effects.
This surprises me. Your first cite had over 30 references, the second over 80. The Friel book I mentioned has 30 references per chapter. This is a highly-studied area – and not casually, but scientifically studied. The fact that we don’t have the answers to all of the questions doesn’t imply a lack of rigor, but instead reflects on the complexity of the topic. Keep in mind also that the science of training wasn’t studied until the 1960’s with breakthroughs only in the 1980’s.
When muscles grow what’s really going on is your breaking them down. In a sense you’re injuring the muscle. The body then says, OK if this guy is gonna break apart his muscle, we’ll make it a bit thicker. Then the muscle gets bigger.
If you don’t rest, your muscle will not get a chance to grow. Now that said, the key to muscle growth is variation. If you work out everyday, fine, as long as you don’t do it all the time. If you work out 7 days, stop one, then start up. Don’t work out 7 days straight the next week. Work out every other day. Then the next week work out 4 days in a row off one, on two…
Always vary your routine. If you were to consistantly work out every other day, you’d also run across the same problem. You’re muscle would adapt and stop growing. So whatever you do is fine. Really, as long as you don’t overdo it to the point of injury and allow some time for muscles to repair themselves and grow.
The point I failed to clearly make is that the level of decrease they saw may better fit what the following review called overreaching (“short-term decrement in performance capacity … in which restoration of performance capacity may take from several days to several weeks”, and which may be “a relatively normal and harmless stage of the training process”), not overtraining (recovery from which is much more prolonged).
Highly studied still does not mean that the data to make dogmatic statements exists. Can you point me to any specific references that provide the data that a program that avoids working the same specific muscle groups two days in a row at the level of exercise c.w. the usual home or fitness club exerciser, does better than one that does? Or that the risk of either overtraining or even overreaching is significantly reduced by taking an off day once or twice a week in the absence of signs of fatigue or excessive soreness? These are the mantras that most experts repeat as established fact and that I am asking about. And while they make some sense they also do not. Let’s face it, throughout most of history humans have worked hard physically most every day. The stevedore, the furniture mover, the blacksmith, the farmer working the plow day in and out - they didn’t alternate easy and hard days, every day was full of lifting heavy objects all day - and maybe they took the Sabbath off and maybe not. Compared to the scale of exercise our species has engaged in for most of its history 45 - 60 minutes of weight training and/or aerobic exercise a day, every day, is hardly coming up to evolutionary activity norms. Part of me, that unavoidable skeptical part, must question a statement that our bodies can’t handle that on a regular daily basis.
I am not saying that a program is better without breaks mind you. Even if there is no evidence that it increases the risk of either overreaching or overtraining, there is real benefit psychologically for most of us (certainly for me) of taking a day off here and there, and for not feeling guilty about it. But that still does not justify experts stating as fact that which may be merely humble opinion.
There’s a big difference between heavy traditional work, or evolutionary activity, and modern-style strength training. Sure, blacksmithing, or shoveling, or tanning ox hides, or pulling a primitive plow, or walking 20 miles is hard work, but the work done per unit of time is still way below an average free weights workout.
I have done all of the above. I can’t pick a 250 lbs. barbell off the floor for more than about 30 seconds before I feel my muscles burn and lungs exploding, yet I can bang on heavy pieces of iron, or shovel wet sand, for an hour straight before taking a short break. There isn’t any real work approaching the intensity of strength training, and can’t be. Recouperation correlates to this, no?
Also, it’s simply not true that there were no easy days in traditional societies. A subsistence farmer’s year has it’s leisurely periods, as does the forager’s. When it’s time to chill, those guys do just that.
In Olympic-style weight lifting workouts, you’re expected to squat almost every day, sometimes 6 consecutive days a week, with two squat sessions a day on two or three of those days. You cycle in intensity, but you’re going at least 80% for each workout. Those workouts gave me plenty of leg strength and I never felt overtrained. Bodybuilders never squat that much, so maybe you should train less frequently if your goal is size rather than strength (although my thighs got plenty big).
You’ve got the primary scientific basis for rest days, as it applies to building muscle tissue. The OP wasn’t specific about the way in which rest days matter, but you’ve covered that in the remark about injuries, unless someone is working out in order to get injured. There may be other reasons for rest days, and specific schedules that help in the development of particular abilities, but preventing injury means it always matters.
Not quite. He’s got a standard response down, but in the absence of any actual evidence to support the claim that standard answer is not “scientific”; it is an “IMHO”, perhaps even a myth, despite its wide acceptance by various “experts”. Could be true. Could not be true. Having studied physiology some I do not believe that there is any evidence that muscle injury is required for muscle growth, even though it is sometimes stated that myogenic satellite cells respond to trauma and help muscles regenerate. It is also however stated that trauma is only one of the possible triggers for satellite cells to activate, others including exercise directly itself, and soluble growth factors triggered by exercise. The various growth factors, induced locally by exercise, may be the major contributor. In fact, the only actual study I have been able to find failed to show that inflammation and/or injury was required for muscle growth.
And even if muscle damage is a requisite part of muscle growth, there is no reason to believe that the repair is not complete enough by 24 hours to tolerate another bout or that another bout in that time frame would always interfere with additional gains. The fact that Olympic weight lifters (as referenced above) do train consecutive days, six days a week, sometimes two sessions a day, without any particularly high rate of injuries, or of overtraining syndrome, that I am aware of anyway, argues against accepting the dogmatic statement as proven fact.
Tracking down the origin of the mantra I can only find this, which states that aerobic exercise more than three days a week increases the risk of injury, basing that conclusion on two studies from 1987 and 1977. Old, but I can accept that as evidence that activities likely to damage tendons and connective tissue (like running, pitching, and many other highly repetitive activities) may benefit from rest intervals greater than 24 hours.
Well this is all very interesting. I guess this is another one for the skeptical pile. I’ve seen the mantra expressed for at least 40 years now. So is there any factual basis for muscle growth through regeneration of broken fibers, aside from the side effect you mentioned above? I’m not surprised that another ‘scientific fact’ turns out to never have been verified. It is surprising that this one hasn’t been used to make headlines with the ever increasing popularity of physical fitness. I guess I didn’t categorize this in the medical/biology field which produces so much half-baked science.
Well there is nothing in those articles that proves that injury plays no role, just no evidence that it does and strong evidence that injury is not required to have muscle growth.
Medicine/biology is not much different that anything else: sometimes beliefs and opinions get passed down as if they are fact. There is role for those who question what the Emperor is actually wearing, who actually ask (one dogma at a time): “Uh, and what exactly is the evidence for this thing that we all have been taught and have passed on to the next generation of students?” Sometimes the evidenciary basis of these things we all “know” is solid, but sometimes … not.
I will note that not all programs follow the alternating easy/hard day program. Olympic weightlifting has already been discussed. Crossfit, for another example, typically does three hard days in a row, and then a day off - not to avoid injury or overtraining I think, so much as on the belief that going all out needs a break to keep up the degree of intensity during the three in a row “on” days. They claim they have found that formula through trial and error experience. Swimmers often do at least three or four hard days in a row as well.
And don’t get me wrong - I am not saying that rest is not important; it is just that is seems that it isn’t really a proven fact (barring highly repetitive connective tissue damaging activities like running or pitching) that it is for all who exercise (and probably especially at the level of the average Joe just trying to keep the weight off and get some basic health benfits of fitness). Given a lack of proof either way I’d personally err on the side of caution and take my days off here and there, and certainly not do two or more hard running days in a row. But that’s opinion, not evidence based fact.
I’m not trying to criticize all of medicine/biology as a science, but there seem to be more cases of faulty reasoning there. It is harder to get solid answers since the cellular functioning is extremely complex and we still have to make guesses about a lot of things. But there have been many cases where Emperor was naked. A perfect case is peptic ulcers. Medical research went on for years based on a ‘common sense’ theory that bacteria could not survive in the harsh environment of the stomach. Even when observations of ulcers responding to antibiotics were made, they were ignored. Medicine is required to take best guesses when peoples lives are at stake, so some of it is understandable. Funding of medical research through grants may also contribute to the problem by giving researchers a financial motivation to overstate results. But as you state, no field of study is immune to the problem.