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The Science of Performance |
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Power Runningsm Part 8: Recovery By now you have come to understand that muscles are the primary limiting factor in your running and that the best way to improve your running is by conducting intense training. This brings us to another aspect of training that is so misunderstood, so ignored, and so debated that we must devote part 8 of this series to it. That aspect is the rate at which the body recovers and grows from a workout. No other factor is more important to your longevity than this one. And no other factor is more debated either. Training is a stress on the body You probably already know that training stresses the body. The question to ask is what happens to your body when you impose a stress on it, say a maximum set of bicep curls, a hard 400 meter sprint, or a marathon? The answer to this question is crucial because it determines how frequently you will train and ultimately how much you improve. As I outlined in part 5, your muscles undergo considerable stress from hard or long training. The harder and longer you train, the more stress the muscles endure. Stress results in micro-trauma, with symptoms such as ruptured and inflamed muscle cells and muscle soreness that can last for multiple days. Micro-trauma results in decreased performance and increased chance of injury. Why is micro-trauma important? It is important because you will not improve until the muscles recover from that trauma. How Long Does it Take to Recover? Muscles do not recover from micro-trauma in a single day. Think about it this way; if you cut yourself how long would it take for the cut to heal? Of course it depends on the depth of the cut; the deeper the cut the longer the healing time. But even a minor cut won’t heal in one day. Cells don’t regenerate in a single day. It takes longer than that. The same thing applies to your muscles. The longer and harder you train, the more stress you put on the body, the more micro-trauma you experience, and the longer it will take you to recover. You have to train hard in order to improve, but each increase in intensity necessitates an increase in recovery time. Intensity and recovery are inextricably intertwined. So, just how long does it take to recover from a workout? Obviously there are a lot of different factors that have an effect on recovery rate, but I can tell you this - it takes a LOT longer than you may have ever suspected. For example, a study conducted by Taiwanese researchers investigated recovery levels after a hard bout of bicep curls (1). The researchers recorded starting strength levels and then had the subjects perform a maximum set of eccentric bicep curls. The researches then tested the subjects’ bicep strength levels every day for the next week. They observed that even after 7 days the subjects had not fully recovered to their starting level of strength. Imagine that; still not recovered after a full week of rest. Does this apply to runners too? Absolutely! Studies on runners have observed damaged muscle and decreased performance from hard training and racing. Hikida et al performed muscle biopsies on a group of marathon runners the day before, immediately after, and three, five, and seven days after the marathon. Muscle cell damage was still evident after seven days (2). Warhol et al also conducted muscle biopsies on marathon runners, saw the same evidence of muscle cell damage, but continued to take samples for up to 12 weeks. He concluded that it took up to 10 – 12 weeks for the muscle damage to be fully repaired (3)! This phenomenon doesn’t apply to just marathon runners though; other studies have observed the muscle damage in non-marathon runners and other athletes. Any athlete, endurance or otherwise, is subject to the micro-trauma we are discussing. As bad as micro-trauma may be, there is something even worse - chronic muscle fatigue. “…research in swimmers and runners has shown that even daily training can produce chronic muscle fatigue that only recovers after a prolonged period of reduced training or rest...” (4) Did you note that part about daily training causing chronic muscle fatigue? The bottom line is that it takes much longer to recover from training than many believe and that the longer and harder you train the more recovery time you need. If you don’t take the time to recover, you will, at best, suffer sub-par performance, and, at worst, become injured or chronically fatigued. There is one more thing we have to cover and that is the concept of “easy runs”. Just about every volume training program on the planet advocates “easy runs” as a method for speeding recovery from hard training or racing. Make note of this – there is NO evidence that running easily causes a runner to recover faster. Easy runs don’t “flush out lactic acid” or “stimulate blood flow and hence recovery” or “keep the oxygen delivery system tuned up” or anything else like that. Easy runs do, however, add additional stress to the body and may increase the chances of injury and overtraining. Indeed, research examining the recovery rate of marathon runners found that easy runs following a marathon actually reduced the rate of recovery (5). What About the Elites? For many runners, our discussion of rate of recovery may seem inaccurate. After all, elites run upwards of 100 miles per week and they couldn’t do that without adequate recovery – apparently contradicting my recommendation of 2-3 days per week of training for those of average abilities. The simple answer to this dilemma is found in inborn genetic ability and the normal distribution curve. Have you ever had a teacher that “graded on a curve”? If so, do you remember what that means? Are you familiar with “the bell curve”? Both of these are referring to the normal distribution curve. Basically, a distribution curve is a measure of the distribution of something across a population. The distribution curve in humans creates a shape called the normal distribution curve. For example, if we measured the height of a large, random sample of males we would find a few very short guys and a few very tall guys, while the vast majority would be in the middle. The normal distribution curve looks somewhat like an inverted letter u or a bell, such as the examples shown below.
Notice that they differ in how they are spread out. The area under the curve is the same in all cases, but the height varies. Without going into all the details for measuring the curve, just know that every physical variable falls into a distribution curve. We discussed height already. Other examples would be intelligence, sprinting speed, strength, endurance, and, of course, rate of recovery. Some people will recover very quickly. Some will recover very slowly. Most will recover at a moderate and average rate of recovery. I recall a study conducted by Arthur Jones, the inventor of Nautilus weight training machines. Arthur studied the recovery rate of strength trainees. In his study, one man recovered in less than one day (I recall it taking this fellow an amazing 4 hours or so to recover). A few took a week to recover. Most took 2-3 days to recover. This is a great example of a distribution curve at work. If you took a large group of runners, had them conduct a hard workout and then measured their rate of recovery, it would form a normal distribution curve. In either case, how smart would it be for the few who took a week to recover to train every day? Conversely, would you advise those who recovered in less than a day to train once every three days? Wouldn’t it make sense for each to train at a frequency determined by their personal recovery rate? Injury and Recovery How does this apply to runners? It applies in exactly the same way. The average runner will not recover in 1 day. Research on recovery indicates that it can take days to recover from a workout or race. Several research studies have examined the amount of time it takes to recover from various workouts and have confirmed that 1) different runners recover at different rates and 2) that it can take days to recover from a workout or race. For example, one study examined recovery following a 10 km run and revealed that the runners had not recovered 48 hours after the run (6). Even more telling is research on injury. Injury indicates that a person has exceeded their rate of recovery; that the load on the body is greater than the body can handle or recover from. Research shows that the rate of injury amongst runners soars at 4 days per week of running and beyond. At just 40 miles per week, a little more than half of all runners will become injured. That gives us a fairly accurate picture of mid-point of the bell curve as it applies to runners. That’s why I recommend 2- 3 days running for the average runner – or said more accurately, for runners with an average rate of recovery. Elites are at the far right of the bell curve. They recover faster than the average runner and, consequently, benefit from more frequent and higher volume training. If you have an average rate of recovery and you try to train at the same frequency as someone who has an above average rate of recovery, I can assure you that you are setting yourself up for overtraining and/or injury. The Bottom Line Okay, enough with all the science; where does all this leave us? To sum up, it can take days to recover from a hard workout. Long runs and races (half marathon and above) can take weeks to recover from; this explains why most marathon training programs recommend 2 to 3 weeks between long runs – it simply takes that long for your body to recover. Training hard, before you have recovered, will likely delay or impede the recovery process, resulting in sub-par performance and an increased chance of injury. There is no evidence that easy runs cause a runner to recover faster. There is evidence, however, that easy runs can slow down the recovery process. Here are my recommendations. Do not run every day. Run 2 – 3 days per week, but those days should be hard, fast, or long. If you are one of the lucky runners who recover faster, set up your training frequency and volume to match your recovery rate. Training frequency must be determined by recovery rates. If you recover faster than average, then you can train with greater frequency, volume, and intensity. If you recover slower than average, they you must decrease your training frequency, volume, and/or intensity. Next, do not run easy runs. Eliminate them from your program. They won’t make you run faster, and they do not make you recover faster. Instead, they set you up for injury. Till next time, keep on running. Reference:
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