Finally this weekend the cold snap broke. I don’t think it got above 22F until Friday, and the nightly lows at our house were in the 8-11F range. Even if I’d been willing to brave the temps, there was too much snow & ice around for biking, but frustratingly, not enough for decent skiing either*. It was the kind of Northern Utah week I typically can’t stand. And yet oddly, I was in a great mood all week. Thursday afternoon I finally realized why this was- I was having a great running week.
*Though there is now.
I hate exercising indoors. Like most cyclists I put in some foul-weather time on an indoor trainer, but it’s not something I enjoy. I loathe the monotony, the sweat and the endless searching for something watchable on TV. I enjoy skiing- XC or backcountry- but time doesn’t allow me to do it daily. So I run.
I started running at my first job after college, when I was an electrical engineer at a large computer company. The facility we worked in had a big shower/locker facility, and there was a group of guys who regularly ran at lunch. I didn’t pay them much mind for the first several months I worked there.
As a single guy my cooking repertoire was limited. The only 2 meals I knew how to cook were taco salad and tortellini in alfredo sauce, which didn’t bother me, since I enjoyed both, especially the latter. There was a scale outside the locker room at work, and one day I stopped on a lark to check my weight. 194 lbs. In 6 months I’d gained 14 pounds. I was 23 years old, and did some quick math; by age 30 things were going to get scary. I started running the next week.
Running was my main form of exercise for the next 4 years, until I started biking. And after biking, it was my primary exercise in winter, and later, after I’d switched careers to sales, while traveling. (Business travel, with its tight schedules and restaurant meals, can be tough on the waistline, and over 2 decades of selling and traveling I’ve run all over the US, Canada and Western Europe.) After that first job, at several succeeding jobs in Massachusetts and Colorado I worked at offices with similar facilities, and was able to run regularly.
In 1995 I moved to Utah. The first company I worked for, in downtown Provo, was run by a cranky former Mormon bishop* who thought that the only 2 worthwhile ways to spend one’s time were at work or church. Early on I asked him about the possibility of getting a shower at the office. “Shower? Exercise? Big waste of time!” he snarled. “All that changing, and then showering and changing back- huge waste of productivity…” He wasn’t putting in a shower.
*To clarify, he was a former bishop, not a former Mormon. I mean he was a current Mormon. Oh never mind, you know what I mean…
So, at age 31, I was faced with one of those fundamental, fork-in-the-road life choices. I could forgo running during weekdays, resign myself to the gradual weight gain toward middle age, and be well-groomed and sweet-smelling, if a bit chubby. Or I could be fit & stinky. I chose fit & stinky, and I’ve never looked back.
Tangent: Provo in 1995 was even… oh, forgive me, I just don’t have a better word- “dorkier” than it is today. On several of my winter runs, people actually laughed and pointed at my black lycra running tights. That’s right, like they’d never seen a man in running tights… Really, it was like someplace out the 1950’s. In particular there was a building by the BYU campus where school-age children would sometimes be filing in or out. One week, on 2 different days, the kids- probably about Bird Whisperer’s age now (10)- pointed and hooted and hollered at me and my tights. After the second day, I thought, “This is ridiculous…”
Note: I’ve told this story- which is true- several times. Anytime I’ve told it to a man, they’ve loved it. Anytime I told it to a woman, they thought I was a jerk. You’ve been warned.
So the next day I made sure to run by the building again at the same exact time. Sure enough, the boys saw me and started pointing, hooting, hollering right away. But this time I broke into a smile, turned and jogged straight up to them. As I did so, I reached into the pockets of my running jacket and pulled out a dollar bill in one hand, and a small envelope in the other. “Who wants a dollar?” I called out, holding the bill high above my head. Several boys shouted, clambered and reached for it. The loudest and most obnoxious jostled his way to the front. I looked down at him. “You want this dollar?” I asked.
Obnoxious Provo Boy: Yeah!
Me: OK, but you have to do something for it.
Me: Give this note to your mother.
OPB: Uh… OK…
I handed him the dollar, the note and jogged off. The note read, “You shouldn’t have married your brother.”
It’s hard to get exact figures, but only something like 10% or so of the adult US population runs regularly. Which is funny when you really think about it, because there’s a fair amount of evidence that one of the most important selection pressures over the last couple of million years in shaping the form of the modern human body has been endurance running capability.
This may sound silly on the face of it, because compared to other running animals we’re familiar with- dogs, cats, horses, deer, squirrels- we seem pathetically slow, and certainly many, many animals can outsprint us. But when it comes to long distance endurance running- especially in high temperatures- it turns out we’re not half-bad. And when compared to other primates, we’re marathon-superstars.
Compared to chimpanzees, the human body is chock-full of enhanced running features. Some are obvious, like our feet. Our big toe is no longer opposable (like a thumb) but is adducted, or in-line with the plane of the foot along with the other 4 toes. This wasn’t a minor change; it necessitated the evolution of a new muscle- the Adductor hallucis- from the existing contrahens muscles in the feet of primates. With its adducted big toe, our foot can no longer grasp but is better suited for propulsion through the “toe-off” we take with each running step.
This lengthening of the foot and strengthening/enlargement of a single toe is interesting because it parallels running evolution in other animals. Horses run on a single enlarged toe (the hoof is a toenail) and the foot of an ostrich features one powerful giant toe, with a couple of atrophied minor toes on either side. Deer and antelope run on 2 toes, but the metatarsal bones in those 2 toes have fused, making them an effective single toe.
Side Note: Our metatarsals are of course not fused, and metatarsal stress fracture is a common overtraining injury among human runners, one that I have experienced twice.
Moving up from the feet, our legs are composed of a set of long spring-like tendons- such as the Achilles and the iliotibial (IT) band- connected to short muscle fascicles. This system of springs- which are largely absent in other apes (chimpanzees don’t have a real Achilles tendon)- captures a portion of the strain energy from each foot impact and releases it into the next toe-off.
What’s interesting about these tendon-springs is that they aren’t that important for walking, which is a very different gait from running. In walking, your center of gravity is lowest mid-stride, and highest when your legs are alongside one another. When running, it’s just the opposite; your center of gravity is highest mid-stride, when you’re actually airborne. The long-tendon-spring system in our legs doesn’t do much for walking, but it reduces the energy spent running by as much as half.
Side Note: It should be noted that our “running” is, from the perspective of a quadruped, a trot. We don’t have any equivalent gait of a canter or gallop (below), like horses or dogs do. Like a trot, our running is a bouncy up & down gate in which each forelimb swings in tandem with the hind limb.
What’s interesting about horses (and other running quadrupeds) is that there’s a speed range for which each of their 3 gaits is the most energy-efficient, and it will voluntarily switch from one gait to the next when changing “speed zones.” A horse will switch from walking to trotting at around 2 meters/second, and then from trot to gallop at ~ 4.5 m/s. We do the same thing, only with 2 gaits; most humans voluntarily switch from walking to running at ~2.5 m/s because it’s actually more tiring to walk at that speed than to jog.
Our long tendons allow the powering muscles to be located farther from the end of the leg, which means we don’t have to move as much weight back and forth with each stride. Although our legs are much heavier (due to length and muscle) than a chimpanzee’s, only 9% of our leg mass is contained within our feet, vs. 14% for chimpanzees.
Endurance running also provides an explanation for our most obvious unique feature among apes- our hairlessness, which combined with our increased number of sweat glands and our cranial circulation network- which uses sweat-cooled veinous blood to cool brain-bound arterial blood- makes our cooling system much more effective. But less obvious changes are also important. Unlike apes, the musculature of our shoulders is largely decoupled from that of our head and neck, allowing the head to aim straight ahead while the torso rotates side-to-side. And our “muzzles” are shorter, making our heads easier to support upright in a lean-forward position. We have a strong ligament- the atlanto-occipital membrane, also absent in apes- connecting the back of the head to the top of the spine, acting as a shock-absorber, and allowing our arms and shoulders to counterbalance our head while running.
Side Note: I’m guessing the price we pay for this decoupling is decreased upper body strength, which is why most of us can’t hang from a tree limb like a chimpanzee.
Tangent: Speaking of sweating, the “fit & stinky” thing works because a) I run in Utah, where it’s so dry that sweating isn’t as much of an issue, b) I run mainly in the winter, and so don’t get very hot and c) I do a Howie-shower. A Howie-shower- named for a friend of a friend’s former boyfriend- consists of a “tactical” sink-washing of armpits, face and neck. It ain’t perfect, but like I said- fit & stinky.
Nested Tangent: And of course I generally change in/out of my running gear in one of the restroom stalls. I’m the only guy in my office who ever changes in a stall, since no one else ever runs with me- or not for long, anyway*- so most coworkers know who it is when they see a man dropping his pants and changing shoes in the adjacent stall. Every once in a while though, someone still asks. Last week, “Lance”, asked, “Alex, is that you in there?” to which I replied, “No, it’s Senator Larry Craig.”
*Which will be the subject of another, future, running-related post, entitled “How All My Coworkers Keep Breaking Up With Me.”
The most dangerous part of my lunchtime run BTW is the start and finish, when I cross the giant parking lot of the Wal-Mart/”Family Center” shopping plaza in Midvale. That lot is like a magnet for spaced-out cell-phone-chatting minivan drivers from all over the valley…
Our knee, ankle and hip joints are all larger relative to our body mass than in the apes, and even our spinal vertebrae and disks- as problematic as they often are- are larger in diameter relative to body mass.
We have another partial-muscle-decoupling- also absent in apes- between our hips and our thoracic musculature, evident in our narrow* waists. And this brings me to one of the most fascinating differences between us and the apes, and a question that has most likely plagued all of us at some point in our lives: Why is my butt so big?
*Yes, all of my examples assume an “in-shape” human… There are many disagreements within paleoanthropology, but nobody postulates that 300 lb hominids were running down gazelles a million years ago…
OK, so you may say that’s a dumb question- people get big butts from eating too much, right? Well, yes, but I’m talking about the muscles. If you look at the gluteus maximus of a fit human, such as a runner or cyclist, our glutes are way bigger than those of a chimpanzee, gorilla or orangutan. Essentially, apes have no asses.
Our glutes connect our femurs to our trunk, and though they’re hardly used at all while walking, they flex every stride during running, keeping us balanced and preventing us from pitching forward. In short, wherever you look, the human body is packed with stabilization and thermoregulation-related enhancements to optimize endurance running. We are the running apes.
So when and why did this endurance running capability come about?
A Really Short Version of Human Evolution
Lots of questions in human evolution are still unanswered, but this much is certain*: Humans and chimpanzees last shared a common ancestor somewhere between 5 and 7 million years ago. Between 3 and 5 million years ago our ancestors were one or more of the various forms of Australopithecus that lived in Africa over that time. (“Lucy” and the recently-famous “Ardi” were both Australopithecines, albeit about a million years apart, though of course we don’t know whether or not their particular species were our ancestors.) About 2.5 million years ago, the genus Homo- our genus- appeared, which produced a series of more and more modern-appearing (and bigger-brained) hominids, some group of which eventually led to us.
*Yes, it’s certain. Don’t get all bible-y on me or what-not. You can believe in both God and evolution and it’s just fine. You won’t turn into a newt or a lungfish or a democrat or anything.
Australopithecines seem not to have had most of these running-specific features*, yet we know, from things like Lucy’s footprints, that they were regularly- if not exclusively- bipedal. So presumably Australopithecus was bipedal, but not an endurance runner. Most of the cool running features don’t appear until Homo habilis (2.5 million years ago) or even Homo erectus (1.8 MYA)
*To be fair, there’s a lot of inference from fossils in making these judgments. For example, tendons don’t fossilize. But the size of the groove in the heel bone into which the Achilles tendon fits is much smaller in Australopithecus than in later hominids.
For hominids to have evolved for endurance running ~2 MYA, there must have been some selective benefit. In general there are 2 reasons to run: to evade something, or to catch something. Evasion seems to be a weak explanation; pretty much any predator of the African savannah can outrun a hominid*. So that leaves pursuit. On the face of it, it’s hard to think of people running fast enough to catch game, but there are modern-day examples- the Tarahumara of Mexico, the Khoisian peoples of Southern Africa- of people running down deer and antelope. They do so not by outsprinting the animal, but by overheating it to the point of collapse, leveraging the efficient human cooling system over the long haul.
*With the obvious- and perhaps not insignificant- exception of fellow hominids.
Endurance running might have also helped early hominids just to get within projectile range (The head-shoulder muscle-decoupling may also have made us better throwers) or it may have aided a scavenger lifestyle. Being the first scavenger to a recent kill might have had a significant benefit, especially if groups of hominids were able to drive off predators or other competing scavengers.
So all this is interesting, but it begs the question: why are the vast majority of modern humans such sucky runners? The obvious answer is that we’re fat and out-of-shape, and certainly that’s the case for many (most?) of us. But here’s a little not-so-secret: the ranks of amateur bike-racing are filled with 40-something former runners. So many bike racers turned to the sport after repeated stress-related injuries from running, and this suggests 2 other possible explanations for our general running suckiness.
First, we’re bigger. Not just fatter, but bigger, and bigger bodies mean more impact-stress when running. I and many of my friends are over 6 feet tall, and human height through much of the world has increased in recent decades, largely through better nutrition. But more importantly, we live longer. I’m guessing not too many H. erectus made it past 35 or 40 and so they probably didn’t often face many of the debilitating wear-and-tear-related injuries that we middle-agers struggle with. In tuning our ape-bodies for endurance running, evolution did the best it could with the materials at hand. But our spines, knees and sacral joints were originally evolved for quadrupeds, not bipeds, and ultimately you can only do so good a job with the wrong tool.
I’ve had my share of running-induced injuries, which peaked 5+ years ago during a spate of marathon-related training. I’ve smartened up a bit since then, and this year have gradually worked up to a pleasant 5 miles a day without any soreness or discomfort. I ran every day last week in the cold, felt great, and weighed in Friday morning at 171, only a pound above summer “race weight.”
Note about sources: My main source for this post was the very layman-friendly paper Endurance Running and the Evolution of Homo, Dennis M. Bramble & Daniel E. Lieberman. Another helpful source was Bernd Heinrich’s interesting and entertaining book, Why We Run. Special thanks to Bird Whisperer for videotaping his dad running back and forth in a snowstorm.