27 January 2013

An attempt to run a marathon using SCIENCE: part IV (Cross training)

(I was going to cover muscle recovery in this post, until I realised this would mean getting to grips with ice baths. There's been so much ice outside the house this week, that I couldn't quite contemplate sitting in a bath of it inside. So that's postponed for warmer weather...)  

In the last week and a half, I have been forced to try OTHER sports besides running. This has led me to two conclusions:
  • I am ill-equipped to do other sports.
  • Swimming pool timetables are worse than third-year-of-a-biology-degree revision timetables.
Some people refer to training in other sports besides your "primary" sport as "cross-training". I refer to it as a pain in the bloody backside. It all began with the snow - when it hit a week ago on Thursday, I decided I could probably take a day or two off from running to rest various niggles. By Sunday, the roads were still skating rinks. There was to be no traditional Sunday long run and I had been reduced to pacing around the house like a caged animal. It was time to hit the pool.

The first problem was that I didn't have a swimming costume, which meant swimming in a mismatched bikini that I had to tie on so tightly it hurt. The second problem only became apparent after about four lengths - the stretchy rubber strap on my 15-year-old pair of goggles had stopped being stretchy and pretty much disintegrated as soon as I tried to tighten it. Mr Hayley, who had been cajoled into joining me for a swim, was made to share his pair, which meant stopping to hand them over every four lengths or so.

The ice continued to hang around, leaving me no choice but to persevere with the cross-training regime. I found myself at a 7.00am "group cycling" class, cycling to tracks from Big Willy Style... oh yes. And then back at the pool again on a Saturday morning, only to be told that adults aren't permitted to swim on Saturday mornings. After driving to three different swimming pools, all with similar anti-adult policies, we decided we'd emitted enough carbon for one day and went for a big, fatty-fat-fat breakfast to make up for our disappointment. At least we now have two pairs of goggles and a timetable for every swimming pool within a five-mile radius.



Anyway, this post is primarily about the scientific basis for cross-training, so I'll get on with it. Actually, there seems to be very little to support the idea that cross-training in other sports complements endurance running - at least in terms of performance. This New York Times article summarises the current state of research on cross-training, which is based on a few small studies from the nineties, most of which didn't last longer than a few weeks. The general consensus seems to be that although you can maintain a decent level of fitness by substituting runs for cycling or swimming sessions, the only thing that is going to make you really good at running is doing a lot of running.

In one 1994 review, a researcher at the University of Tennessee concluded that athletes (and ordinary folks) never see any greater benefits from cross-training than they do from their main sports. There may be some transfer of aerobic capacity between running and cycling, but less with swimming. Boo. Another study took the interesting approach of comparing physiological adaptations between runners and cyclists. Intriguingly, an athlete's ability to use oxygen, measured as VO2max (based largely on heart and muscle adaptations, see posts II and III), was specific to their individual sport. So a runner would be able to achieve a higher VO2max on a treadmill, whereas a cyclist would be able to achieve a higher VO2max on a bike. This hints at just how well our bodies are able adapt to different sports. BUT, it turns out triathletes have pretty similar measurements on both treadmill and bike, reflecting the fact that they train regularly on both.

So my cross-training probably hasn't made me any better at running. On the other hand, that wasn't really my expectation. I was trying to ensure that I didn't lose any fitness during my marathon training regime, and to protect a dodgy ankle from pounding on hard ground. My best guess based on limited literature is that my running fitness would take a few weeks to drop off, and that swimming, and certainly cycling, would go some way towards slowing that drop-off. But what about protecting my dodgy ankle? According to the Tennessee guy:
"...cross-training may be an appropriate supplement during rehabilitation periods from physical injury and during periods of overtraining or psychological fatigue"
Okay. Good. But note the "may" in this sentence. It seems common sense to me that if you're reducing your weekly mileage on the roads, you're less likely to get injured (this study on injuries in high school runners and this one on risk factors for running injuries come to tentatively similar conclusions) but I can't find any evidence to suggest that adding cross-training to an already demanding running schedule will stop you doing yourself a mischief. And perhaps surprisingly, this very small study appears to suggest that running and cycling take an equal toll on your feet, thus throwing my early morning Big Willy cycling sessions into jeopardy...

All this contradicts a lot of what I have been reading in marathon training plans, which seem to suggest that cross-training should form a big part of your weekly routine. I'm not convinced it does that much good, besides giving your body a bit of a break from punishing work outs on hard pavements. I think I will continue with one swim a week (not on Saturdays) just to see what happens. But otherwise, how about a leisurely stroll, a lie down on the sofa or a big fatty-fat-fat breakfast?

20 January 2013

An attempt to run a marathon using SCIENCE: part III (Fuel)

Hello lovelies. Well, the weather here in Bristol has thrown a spanner in the works as far as marathon training is concerned.

Friday - definitely a rest day
Perhaps fortunately, the snow has made time for resting a niggly knee/ankle/lower back and exploring "cross-training", which I now intend to cover in a future post. (Cross-training is not, apparently, using one of those boring, horrible machines in the gym - it involves doing OTHER THINGS besides running, an idea I hadn't given much thought to until this week...) I have refused to feel guilty at the sight of the odd runner bouncing down the road, mostly on account of the fact that they might easily slip over on the ice and DIE, a fate which, I think we've established, it would be best to avoid. Anyway, onwards with today's post, which is about fuel.

A couple of weeks ago, I headed out for my Sunday long run, intent on breaking the half-marathon barrier for the first time. I'm a fairly early riser and do most of my running in the mornings before breakfast, but for long runs I tend to wait until about 11am, so I can get some porridge at a reasonable hour and have time to digest it. Clearly, though, a bowl of porridge wasn't sufficient to fuel my 25km attempt, because suddenly, at just over half marathon distance - about 22km - my legs became so heavy that I couldn't carry on. I had heard about "hitting the wall" and "the bear on the back", and this felt very much like both of those things. At once.

Being about 3km from home at this point, it took me over half an hour to walk back on unsteady legs. My head was swimming and I was on the point of falling over by the time I stumbled up the stairs to our flat. It was my own stupid fault and in retrospect, I should have at least carried a phone and some extra water in case of emergency. But having run six half-marathons (more if you count those run in training) including two in the last three months, I must have got a bit complacent and thought 25km was an easily achievable target. I was also skeptical about whether "the wall" actually existed.

If I had really done my homework though, I probably could have avoided any of this happening by taking on extra fuel during my run. I spent my evenings the following week researching carbo-loading and doing cost comparisons between energy gels (I am THAT cool...). One of my prime concerns was finding something that I could take without feeling sick, which is what happened after I knocked back one of the energy gels being handed out by the stewards in the Bristol half-marathon last year. I finally plumped for SiS's GO Isotonic Gel (60ml) and, on the potentially spurious advice of a triathlete I met in Moti, some Jelly Belly sport beans.


Now, before we get into how all of this worked out the following Sunday, let me share some of the results of my research with you. I want to recommend one particular paper for those who, like me, are a) interested in the science of endurance running, and b) fans of pretty graphs. Because this one has a RAINBOW EFFECT graph in it that I really enjoyed...

The paper is published in PLOS Computational Biology and it's open access. Although it's theoretical, it provides a really decent and not-too-complicated background on metabolic needs, i.e. fuel, for endurance runners; the key thing being that it's focused on marathon running and in particular avoiding hitting the dreaded wall. While there seems to have been some debate about whether the wall exists or not, and whether it's necessary to take on carbohydrate in the form of energy gels etc, this paper takes a more nuanced approach, suggesting that the wall exists for some runners but not for others. Perhaps unsurprisingly, it depends on how fit you are and how fast you run. So while a highly trained, elite athlete may be able to maintain a quick pace for 26 miles and finish without taking on extra carbohydrate, mere mortals will have to hit the sports gels.

"Runners with large aerobic capacities and relatively large leg muscles can store enough liver and muscle glycogen to fuel marathon runs at elite-athlete paces (paces approaching those required to challenge the current world records of 2:03:59 for men and 2:15:25 for women) without exhausting physiologic carbohydrate stores; runners with smaller aerobic capacities or relatively small leg muscles must run at slower paces or refuel during the race in order to avoid ‘hitting the wall.’"
As the author indicates, it all boils down to how much fuel you can store in your liver and leg muscles, and how efficient you are at using oxygen to get energy out of it. (Tying nicely into our discussion of VO2 max in the last post). So Paula Radcliffe can presumably do both of these things pretty well. Me: not so much. I can "carbo-load" my muscles before a race by eating lots of pasta, but I won't be able to take on enough to see me to the end of a marathon - my body is just not well enough adapted. The upshot is that at some point between about 1.5 and 4.5 hours I am likely to hit "the wall" unless I consume extra carbohydrate. At least according to the rainbow coloured graph...


This basically shows that runners of varying abilities and fitness will hit the wall anywhere between 9-26 miles. So given that I hadn't made any particular effort to carbo-load that Sunday and was carrying dilute squash only, it's probably safe to say that about 13-14 miles, I hit the wall. Incidentally, if you're interested in carbo-loading, there are references in the paper to some further studies on optimal strategies.

What of the next Sunday's long run then? Well, I had myself pretty well prepped by then. I bought what I've since referred to as a "utlity belt" for the beans and strapped on a little-used arm band/pouch to carry the gel. (Actually the utility belt also has special elasticated gel holders for easy access, but on the first run out with it I was worried about the packets slipping through).

All fuelled up

Going on advice from t'internets and the packet instructions, I took the gel at about 1 hour 30 and carefully chewed on sports beans (to avoid choking... another unforeseen way to DIE during a marathon) throughout my run. Whaddya know? I got to 25km at a nice, steady 5:30/km pace and, still flying, I decided to see how far I could go - 30km (~19 miles) total! Which brings me to almost three quarter distance. I can't put this all down to the gel/beans, of course - perhaps I had eaten extra pasta the night before, I can't remember - but I'll wager they helped. I guess there were also some psychological aspects involved too - once I got to 25km I suddenly felt awesome!

But back to the science. It doesn't seem to matter too much when you take these things, as long as it's before your existing stores runs out.
"The timing and distribution of midrace fuelings evidently have little impact on their effectiveness, provided the required total amount of carbohydrate is consumed sufficiently far (typically approximately 30 minutes) in advance of the anticipated onset of fatigue."
I'm still skeptical about using these types of energy drinks and gels too frequently. I don't recognise half of the ingredients on the back of those Go gel packets, so who knows what mischief some of the them might be causing. Doug at Rock Creek Runner has experimented with natural alternatives to energy gels. Fine if you fancy chomping on almonds or thinly sliced, baked sweet potatoes during your run, but I'm not sure how well such dry foods will go down. And I'm worried about the choking... Still, if you're braver than me, you can also salt the sweet potatoes to account for the electrolytes in energy gels. (Disclaimer: I haven't done any in depth research on electrolytes, but they do include salts. Probably more useful in weather warmer than SNOW, when you're really sweating).

Whatever you use, I'd definitely recommend trying it out before a race. During the Bristol half, I was silly enough to take an energy gel I hadn't tried out beforehand, but I'll never do it again. Plenty of websites advise testing different brands to find something that works for you, especially as it seems gulping down pure carbohydrate can upset your stomach. I personally chose isotonic as opposed to hypertonic (concentrated, take with water) because I guessed that a lower concentration would be less likely to make me sick. However, this does mean having to carry a slightly larger gel packet. I also avoided those with caffeine in them - watch out as it's not always listed explicitly. There's a fairly succinct review of five of the most popular here.

That about wraps up this post. Do have a gander at that paper, and others, and let me know what you find. I might have a go at tackling muscle recovery next week, as I seem to have got it all wrong so far...

14 January 2013

An attempt to run a marathon using SCIENCE - part II (Interval training)

Long run, week 1/13 of the countdown. A very decent start!
PART II: Interval training

On the first Friday after Christmas 2012, I drove out to a soggy field in north Bristol, parked my car and trudged across the grass to a pavilion in search of a bunch of wiry, lycra-clad people. I located them immediately, tried to look as if I knew what I was doing and went for quick bound around to assess the mud situation. It was a bog and I didn't have any spikes, but I couldn't possibly be seen to be backing out. I went back to the pavilion and watched in trepidation as Bristol & West AC coaches trudged back and forth positioning small red cones around the perimeter, blocking off areas where the ground had gone to mush. Ten minutes later I was sliding my way around the mile-long, makeshift running track in a pair of completely grip-less trainers, doing my best to hang onto the back of the "slow" group. This insanity was repeated three times, allowing only a couple of minutes for recovery between miles, at a rapidly deteriorating pace (on my part, anyway).

This particular brand of torture is called high intensity interval training or HIIT for short. Actually, most of the training sessions I've been to so far have taken place in far less slidy surroundings - at an athletics track - but all of them have been variations on the same theme: pain. I jest! Well, not really. Other variations include: sets of 400m and 800m separated by single slow laps; pyramids of 300m, 400m, 500m, 600m, 500m, 400m, 300m; and a 5k "steady" (actually quite fast) run followed by 200m repetitions. Oh, you get to enjoy it, honest.

I was lured into HIIT by the suggestion that it would improve my endurance running over longer distances and since, as discussed, I have 26 miles to cover in April, it seemed like a good idea. Well, I have to report that it seems to be working. Just since the start of December I've taken around a minute off my 5k time and yesterday I ran to half marathon distance a minute quicker than I ever have before... and carried on running for another 9k! (See pace graph above, more on data geekery to come in another post). Get in! But of course, plenty of other factors could be contributing to these gains. So I've been doing a bit of background research on HIIT to see what SCIENCE says about all this.

It turns out the benefits are actually fairly well documented. There are an awful lot of papers out there on this subject and I won't pretend to have read them all, but there are two things I've tried to find out. First, what changes is HIIT making to the way my body works when I run? And secondly, will HIIT actually help me run faster over longer distances?

I'll start by answering the second question, because it's fairly easy to say whether or not something is having an effect, whereas it can be a little bit more difficult to say why. Most of the papers I looked at focused on elite athletes and they showed that, yes, HIIT can help them improve their performance. One small study, for example, focused on endurance runners who were asked to swap their 45km a week training schedule for HIIT sessions involving repetitions of 30-second sprints. After four weeks, they had maintained their 10k times, without regularly running that far. The effect seems to extend to other endurance sports as well, including cycling - a couple of HIIT sessions involving 8 x 5min a week actually improved performance over 40km time trials. While many of these studies are small, there are scores of them, all using different HIIT schedules and trying to work out the optimal combination of high and lower intensity training for improving performance.

With most of these studies we're talking Olympic level athletes. One review suggested elite athletes could expect to see improvements of between 2-4% in intense exercise performance. I haven't found as many studies to tell me whether I, as a lowly recreational/club runner, can expect to make the same gains.  But I think it's fair to say that HIIT could help me run faster, with one possible caveat: I can't just do a few fast laps of a track two or three times a week. Although it may be possible to maintain performance over a few weeks by replacing all of my 5-30k runs with HIIT, the general feeling seems to be that to get the best result, I have to do both.

To deal with the first question and why this works, I found a paper entitled 'Endurance exercise performance: the physiology of champions'. So again we're looking at elite athletes, but assuming we're all built in a similar way, there are a few things you want to improve to get better at long distance running. I'll just look at a couple that seem to crop up constantly in the literature. The first is the amount of oxygen your body can use in a given time, known as VO2 max. This depends on processes in your mucles and (or including) your heart - most importantly, perhaps, how much blood your heart can pump with each beat, or what's known as stroke volume. The second thing you want to improve is your lactate threshold: the point at which your body stops operating under normal aerobic metabolism and turns to anaerobic metabolism. Essentially, it stops using oxygen to send energy or ATP to your muscles and starts makes ATP without it, producing hydrogen and lactic acid and causing you enough pain to stop you in your tracks. (Interestingly, it may actually be the hydrogen and not the lactic acid that causes the "burn").

So the crucial question is: does HIIT increase your body's ability to do these two things? Well, here's one study that suggests that it does. What's particularly encouraging is that the people involved in this study weren't elite athletes; they were "recreationally active" types, people who maybe jogged or cycled two or three times a week - normal people! (What's surprising is that as part of their study, the researchers seem to have taken muscle biospies from their victi... er, participants' legs and then asked them to cycle to exhaustion. Presumably this didn't all take place in as quick succession as the paper suggests?) The main result was that these people improved their metabolic capabilities over a six weeking training programme - their abilities to use sugar and fat as fuel. Another study does the crucial comparison between HIIT and moderate exercise and comes up in favour of HIIT for the first factor we looked at, VO2 max.

Again, these studies were small, but given the wider breadth of research in this field in general, I'm pretty confident I should be seeing some benefit. The other interesting aspect is it seems that experts are now starting to look at HIIT training for people with underlying health problems such as heart disease. These sessions are pretty hard going, so I'd be surprised if a doctor was to prescribe a course of HIIT with the local athletics club for someone with heart problems, but I can see why the idea appeals - it appears to be less work for greater benefit. For healthy, slightly more serious runners though, reviews on the subject seem to suggest that incorporating some HIIT into your training schedule can help you improve your times while cutting down on some of those long distances. But importantly, I wouldn't presume to go into a 26 mile race without having run at least 23-24 miles in training.

So that was part II. It gives me some idea why my times may have improved over 5-10k in the last few weeks. But I think my surprise half-marathon PB yesterday during a 30k run was down to something else: finally conquering 'The Wall'. It's taken me longer than it should have to realise that my body simply stops functioning after about two hours of hard exercise. So when I went for my Sunday long run yesterday, I took what was basically a utility belt full of fuel in the form of energy gels and beans, and carried a bottle full of sticky, sugary squash. Part III is going to be all about fuel.

10 January 2013

An attempt to run a marathon using SCIENCE - part I

Like the idiot I am, I've signed up to a marathon. I now have until 14th April to figure out a way to run 26 miles and I need all the help I can get. So I'm going to be harnessing the power of SCIENCE to try to do what Pheidippides did (before collapsing and dying, remember) all those years ago.

Sunday is traditionally "long run" day for endurance runners and there are 13 Sundays left before my attempt to run the Worcester Marathon, so each Sunday after pounding the streets of Bristol, I will be reporting on my progress. In particular, I'll be reporting on different bits of SCIENCE that I have been, and will be, employing to make my way around the marathon course without meeting the same fate as Pheidippides.

(At this point, if I was on the telly, I would probably have to say something like "Do make sure you consult your doctor before embarking on any strenuous exercise regime." Thankfully, I'm not on the telly. So it'll be fiiiiiine.)

(And of course, I'm doing all this at the same time as trying to write a book, which has to be completed at vaguely the same time as my training regime... It'll be fiiiiiine...)

Hopefully, this may be of some genuine benefit to other runners - many will be training for the London Marathon on 21st April. If it is of no genuine benefit, then it may at least be vaguely amusing (see bullet point number nine in the list below). I'll be covering bits of SCIENCE related to:
  • High intensity interval training (running as fast as you can and then jogging for a bit before running really fast again, otherwise known as pain)
  • Eating to run (most importantly, is it okay to eat cake?)
  • "The wall"
  • Drinking (not that sort - hyper/hypo/isotonic and all that jazz) and energy gels
  • Muscle recovery
  • Kit, including the mythical "right shoes"
  • Stretching (eek, I'm very bad at this, must do better)
  • Yoga / pilates / core strength
  • Ice baths (no no no no no no no no no no no no no no)
  • Niggles and injuries (I am a complete hypochondriac - Mr Hayley will attest to many phantom Achilles injuries and broken toes)
  • Other things that will undoubtedly crop up along the way (unlike the niggles and injuries, hopefully)
I will be citing actual scientific research and using myself as a test case. Which means you can probably trust most of what I say about other people's research and forget all of what I say about my own research, since n=1 is a pretty poor scientific study.

I should also say that I'm not starting from zero here. I've been running for about ten years at varying levels of fitness. I can run a decent 5k, 10k and half marathon no trouble. Yes, I have a Garmin sports watch. No, I don't have one of those weird feeder tube things to drink from when I'm running. I run about 30-40k a week depending on the time of year/weather/number of weeks till very infrequent races. I've even recently joined Bristol & West AC... although training with them makes you feel like a complete amateur again. But I've never run a marathon. I am also no expert in sports science. I am simply a science writer who likes to run, trying to find a way to do it for several hours without dying. So let's see what happens...