Plenty of mystery still remains about the science of recovery: why some methods are supposed to work but don’t; why others feel like they work but have no scientific evidence to support them. And in today’s day and age, there’s no shortage of recovery methods. Just take a two-minute stroll through Instagram: For every shot of an NBA player giving a thumbs-up from an ice bath, you’ll see a soccer megastar with his legs in an oxygen chamber, an elite cycling team wired up to machines between mountain stages, or Dwayne Johnson fueling up after a gym session with enough food to feed an entire Little League team. In fact, you could make the case that Instagram is basically the world’s biggest advertisement forum for elixirs, magical garments, oxygen tents, acupuncture needles, weird bruises, powders, and all manner of wizardry aimed at one singular purpose: recovery.

To better understand recovery—the process by which your body rebuilds itself, your muscles reenergize, your hormones return to balance, and your central nervous system repairs—it’s important to distinguish between its two forms: passive and active.

Passive recovery, of course, occurs when your body is at rest— this includes sleep, diet, and applying compression. Active recovery, meanwhile, happens when your body is in motion: walking, light lifting, having a light go on a stationary bike.

Both forms are equally important for optimizing returns on your workout because they target different aspects of muscle regeneration. The easiest way to think of it is this: Passive recovery helps repair, while active recovery helps deliver the tools necessary to repair—or, as author and personal trainer Harley Pasternak describes it, active recovery “flushes out all the metabolic by-products and brings in nutrient-rich blood that helps heal muscles damaged in the gym.” Active recovery is the crucial step guys skip. If you’ve just hit the weights hard or rowed for an hour, you can’t just hit the showers, call it a day, and expect your body to magically bounce back in peak form.

“The most effective form of recovery after intense or resistance exercise is active recovery,” Pasternak says. Aside from speeding nutrients and oxygen to damaged muscles, it also helps reduce muscle soreness, which is a good thing.

“Muscle soreness isn’t some badge of honor after an effective session,” says London-based trainer David Kingsbury, the man responsible for getting most of the movie X-Men, including Hugh Jackman, ripped. “Although it can and will be a by-product of training, that’s not what people should be shooting for.”

Of course, before you plan your recovery, you have to decide how often to work out and how to space out those sessions.

“If you come back to train too soon, your body will still be in the recovery phase, and the result will be poor performance in training,” says Keith Baar, professor of molecular exercise physiology at the University of California, Davis. And if you continue to train too frequently, ultimately you’ll experience diminishing returns. “In extreme cases,” he says, “you can even upset your hormonal balance.”

Former U.S. marathon runner Ryan Hall is an example of this. He believes that extreme training—he’d sprint seven miles down a 9,000-foot mountain, then run back up—led to the low testosterone levels that forced him to retire at 33.

So should you go hard three days a week? Five? Seven? What about heavy lifting and cardio?

Generally speaking, when it comes to strength training: “For most people who push themselves hard, two full-body workouts a week are enough, with two days of recovery in between,” Baar says. If you do split-body sessions, it’s two workouts per body part per week.

As for cardio, this type of exercise is crucial. Body-weight exercises—cycling, rowing, swimming—can be done more often than high-impact exercises like running, which cause significant mechanical, not just muscular, fatigue, Baar says. So for those, you’ll need a lower volume of work and even more days off in between to aid recovery.

For guys who want to work out every day, Baar says it’s perfectly all right. After all, elite athletes do it. The trick is to trade out hardcore lift days for occasional days of light cardio.

Finally, some good rules of thumb for endurance training: If you feel like crap—slightly sick or “off ”—or if your resting heart rate first thing in the morning is overly high, you’re not fully recovered. (For this reason we highly recommend using a fitness tracker.)

Bottom line: Find out what works for you. If you find you’re not seeing gains in the gym or on your runs, try adding another day of rest. That way you’ll be sure you’re training at the peak of your adaptation zone, when your body is repaired and ready for physiological gains, rather than when it’s in a recovery phase and still in need of repair.

PART ONE: The Recovery Methods You Should Absolutely Use

1. Hit the Bike for a Light Ride Right After Doing Anything

Any trainer worth his or her salt will tell you that light cardio is the best form of active recovery for pretty much any workout. Whether you’re coming off strength training, a HIIT session, or a soul-crushing bike ride, a bit of easy cardio will help loosen muscles and limit lactic acid buildup.

“Spinning for 10, 15 minutes on a bike is a really good tool,” Kingsbury says. “Especially after heavy leg sessions, I always try to get my clients to Spin with very low resistance.” Whether it’s on a Spin bike at the gym or a real bike outdoors, the trick is just to make sure the resistance is low. This isn’t a workout; it’s a way to get motion into your body and your heart rate up. And if a bike isn’t accessible, walking is a perfectly acceptable alternative. Just make sure to move at a decent clip.

Kingsbury also recommends lower-volume, high-frequency workouts between big lifting days. “Things like muscle soreness will be reduced because the volume is reduced, but you’re still getting a great training stimulus.”

Just crushed your workout? Don't hit the showers—hit the Spinning bike and pedal lightly for 20 minutes.

2. Splay Out on a Massage Table (If You Can Afford It)

One of the most effective active-recovery methods for professional athletes is massage. The reasons have never been fully understood, but new research is shedding light on the matter.

“There’s a lot written about massage and how it may work, like by reducing inflammation and swelling,” says Thomas Best, M.D., Ph.D., a professor of orthopedics and sports medicine at University of Miami Miller School of Medicine and one of the leading experts on massage. “What we’ve been doing with our research is trying to prove or disprove that.”

What have they found?

“Turns out that most of the time, what’s purported to be occurring, is,” Best says. “Our studies support the idea that postexercise massage reduces inflammation and improves the ability of the muscle to contract and rotate in the joint. We also showed that massage looks to be able to provide some stimulus for muscle regeneration.”

One point of interest that Best stresses is that while massage appears to be effective anytime after a workout, its greatest benefits come immediately post-workout. “Our study showed across the board that when massage was done immediately after the exercise, the results were even better,” he says.

The amount of massage performed turns out to be important too. In Best’s study, he found that a 15-minute massage did just as well as, if not better than, a 30-minute massage.

3. Hit the Perfect Balance of Protein and Carbs Exactly One Hour After Exercising

Just as an engine needs fuel to run, muscles need fuel to grow. But the question is, what type of food? And when do you eat it?

The simplest answer to the first question is: protein, carbohydrates, and vitamin-rich fiber. But as to when those foods are best consumed, there’s a lot more to it than most of us have been led to believe.

The long-held belief that protein is better for long-term recovery and carbs are better for quick bursts of energy is, Pasternak says, “an oversimplification of a very complex metabolic process.”

A 2007 study tested the effects of protein and amino acid consumption on muscle anabolism, mass, and strength, and found that 20 grams of protein ingested one hour before and one hour after intense resistance training increased muscle-protein synthesis over those who took a carbohydrate placebo. And a 2001 study published in the American Journal of Physiology found that carbohydrate and amino acid consumption immediately before resistance training increased muscle gains over those who consumed it after.

Protein consumption is still the key to muscle regeneration, but carbs shouldn’t be ignored.

“Carbohydrates are really useful,” Kingsbury says. “They’re anticatabolic, and they reduce cortisol levels and things like that. Having carbs as part of your recovery is really important.”

4. Power Down Your Phone, Booze Less, and Hit the Freaking Sack

You’ve probably seen that old weightlifter’s maxim: Lift, eat, sleep, repeat. Needless to say, those dudes are on to something.

“Sleep is important for almost all biological functions, and given the increased physical recovery needs of athletes, it’s likely even more important for them,” says Shona Halson, the head of recovery at the Australian Institute of Sport.

According to Halson, sleep deprivation likely has the greatest effect on medium- to high-intensity prolonged activity, particularly the kinds that involve a high cognitive function, like hitting a 90 mph fast- ball or sinking a three-pointer. Which means that, for weightlifting, which requires slightly less brain power, it might be possible to get away with a day or two of sleep deprivation, but over the long term your body will begin to break down and open you to injury as you lose focus.

“Accidents in the gym from tiredness are really common,” says Kingsbury, who often has to tailor his Hollywood megastars’ workouts to demanding shooting schedules. “Often they’re on very little sleep, and we have to manage that. Some days we won’t train because they haven’t slept enough.”

For the record: You should get at least seven hours of sleep a night and eight or even nine if you’re in the middle of hardcore training.

PART TWO: The Recovery Methods You're Free to Use (If You Like Them)

1. Rock Your Favorite Yoga Poses Immediately After a Session

Like romance, there’s one thing you can say for sure about stretching: It’s complicated.

For one thing, there are two types of stretching, dynamic and static, and each has different effects on the body. Dynamic stretching involves constant movement, like arm swings or trunk rotations. Static stretching means reaching into a position, then holding it, like a bent-over hamstring stretch. For years the consensus was that you should do dynamic stretches before a workout, to increase blood flow and prime your muscles for exercise, and static stretching after a workout, to rid your muscles of lactic acid buildup, stave off soreness, and increase flexibility. (Also, studies showed that static stretching before a workout is a big no-no because it will impair your strength.)

It turns out that’s not exactly correct because not all of your muscles are created equal. The more elastic parts of your skeletal system, like the calf and Achilles tendon, can recover quicker from a static stretch since that’s partly what they were built for. Larger muscles, however, like the rest of the lower body, which was examined in the 2014 study, are made much weaker because they are not meant to be stretched.

Bottom line: Do dynamic stretching before a workout, but only after your warmup, like a round of jumping jacks to get blood and oxygen flowing into the muscles. In the case of static stretching, the latest research says it reduces strength in your muscles for up to 24 hours afterward, so do it only if you’re not hitting the gym again the next day. Otherwise, keep it dynamic and pre-workout.

2. Don the Coolest New Tights

Compression is the biggest new trend in fitness, specifically compression sleeves and tights. Amazingly, there’s still limited data on what, exactly, it does.

But a study published in the Journal of Strength and Conditioning Research showed that delayed-onset muscle soreness was substantially lower in rugby players who used compression garments over those who didn’t. Of course, a lack of soreness isn’t definitive proof that it aids in recovery, but it’s certainly a positive sign. And given that there appear to be no negative side effects, it’s worth trying.

3. Dabble in Acupuncture, or Pull a Michael Phelps and Try “Cupping”

Anecdotally, athletes and fitness trainers claim that a whole host of methods can aid in recovery. Two of the most popular are cupping and acupuncture.

Cupping, which was all the rage at this summer’s Olympic Games in Rio de Janeiro, involves a special cup being placed on the skin, with heat or an air pump used to create suction. The idea is that suction draws blood to sore muscle areas, which helps to promote healing.

Acupuncture, sometimes called dry needling, is a much older technique, in which small needles are inserted into various trigger points on the surface of the body, the theory being that the needles unblock energy flow (or chi) and help the muscles to relax and recover. Unfortunately, there’s very little in the way of definitive proof on either technique. As Pasternak says, “There are a number of things you can do that have little evidence to support them. As long as they don’t hurt you, and you personally feel that it helps, then by all means do whatever you want.”

PART THREE: The Recovery Method You Probably Shouldn't Use

1. Hang Out in a Giant Tub of Ice

Ice baths have been a mainstay of post-workout recovery for quite some time—which is a problem, for two main reasons.

First, a study last year at the English Institute of Sport measured various markers of physiological stress before and up to 72 hours after cold-water immersion and found no positive improvement over those who didn’t use an ice bath—meaning they didn’t promote recovery at all.

More troubling, that same study showed that ice baths may actually hinder recovery. Ice blunts inflammation—great for treating an injury. But certain types of inflammation are important for recovery’s repair and adaptation processes; and in terms of decreasing inflammation, ice is indiscriminate. While massage may blunt only the right types of inflammation, ice hits them all.

Remember, recovery is all about your muscles repairing themselves. Because of this, the study’s author, Jonathan Leeder, Ph.D., recommends using an ice bath only in a competition scenario, when the feel-good factor is more important than any training gains. During training, however, ice baths should be avoided.

2. Apply Tons of Heat​

So if ice-cold water isn’t a cure, what about heat?

Sorry, but there is exactly zero research that suggests that heat is good for recovery, either. While heat can help relax muscles, relaxation alone hasn’t proved to be a route to recovery. On the other hand, heat hasn’t been shown to impede muscle recovery—at least not yet. So if a dip in the spa feels good a few hours after a hard workout—no harm, no foul.

But if an injury is involved, heat can actually be a detriment—at least while the injury is in its acute early phase. If that’s the case, absolutely lay off.

Ultimately, recovery is like Gestalt psychology, which says one must look at the whole rather than the sum of its parts. Some recovery methods may help a lot, some may help a little, some may simply work as psychological placebos.

But all of it can work together to give you the best possible chance at realizing your goals, so failing to come up with proper recovery protocols is putting yourself at a severe disadvantage.

“I’ve got friends, people I know who train six, seven days a week,” Kingsbury says. “When you lift weights on a day that used to be a rest day, it’s not the most effective way of making progress.”

The simple fact is: If you want to get bigger and fitter, what you do outside the gym is just as important as what you do in it.