Friday, August 16, 2013

Weekly mileage and other statistical myths

In the sport of cross country and distance running, “weekly mileage” is the one metric that is quoted early and often. What’s your mileage at? What are you hittin’ a week? Oh man, he’s crankin’ 90-mile weeks like it’s his JOB! How many 70-mile weeks have you hit this summer? On and on and on. It’s such a common topic of conversation that we don’t even notice it anymore.


In baseball nowadays, there is a tug-of-war between old-school fans/players/executives who eschew the sabermetrics: Old statistics vs. new statistics. The newer, advanced metrics tell a much deeper and nuanced story of the sport. The traditional hitting stats are batting average, home runs and RBIs. But now, there is also on-base percentage, OPS and WAR. For pitchers, the traditional stats are wins, losses and ERA. Now, there is ERA-plus, FIP and BABIP. Marist Running Alum C-Fred sent me a long article about this very topic, and it jibes well with this running-related topic.

Weekly mileage is an excellent statistic, or metric, by which to gauge our fitness. But, much like the old-fashioned baseball statistics that we still quote and use extensively to judge players, it is not all it’s cracked up to be. It is one statistic that is often misunderstood, and far too frequently given more significance than it really requires.

Why do I say this? The weekly mileage statistic gauges the amount of miles an athlete covers in a 7-day period. Think about that statement for a second. A 7-day period can be Monday to Sunday, which is what most athletes use to calculate their total. A smaller but still significant subset of runners uses the Sunday to Saturday paradigm to calculate weekly mileage. No problem. All good. OK. Here’s where things get interesting.

Let’s say an athlete was planning on getting a 15-mile run at the end of their training week, Sunday. But alas, Sunday features severe storms all day. Or, an unplanned and unexpected stomach bug hits. Or, there is a family outing that we forgot about. Life intervenes with training at times. So, you don’t get that long run in. Perhaps you only have time for a quick, short run. Perhaps you take the day off entirely. Then, the e-mail comes from the distraught runner: “Coach, I didn’t get my long run in; my mileage this week’s gonna be really low!” Oh. For shame, for shame.

Then, a funny thing happens. Monday’s a nice day. No problems. Long run of 15 miles. The rest of the week proceeds swimmingly, and the runner caps the week with their usual, Sunday long run of 15 miles. Whoa. Wait a minute. Now, tally up that Monday-to-Sunday period – with the bookend long runs – and all of a sudden that anemic weekly mileage from last week is trumped by a monstrous week of training. Is that first week a waste? Is that second week overtraining?

Instead of answering that question, I will relate to you a story from my old newspaper days. Because of the vagaries of the industry and of staffing, when I first started working at Dutchess County’s Finest DailyNewspaper, my days off each week varied. I was low man on the totem pole, so I often drew the short end of the stick and had to get the least desirable days off. Some weeks, I’d be off on a Monday and Tuesday. Oh joy. Other weeks, I’d get split days off – Monday and Thursday. Swell. There was one period, during the heavy summer vacation weeks, where I had Monday and Tuesday off one week, and then Saturday and Sunday off the following week. Wow! A weekend off. Great, right? Well, look closely there. Yeah, I got my two days off each week, and yeah, I got a rare weekend off … but I also worked 10 days in a row. NOT FUN.

Similarly, if a runner needs to take a day off from training each week, the least effective way to do this would be to take a Monday off one week and a Sunday off the following week – thus effectively stringing together the better part of two weeks (12 days) without an off day. Yes, technically, it was one day off per week. But again, your body knows sequences of days. It does not know a calendar. Thus, weekly mileage as a metric is a moving target. There are always seven days in a row to add up. Just because you choose to add up the same days each week, does not mean you need to go out for those extra few miles late on a Sunday night to get to some elusive total, so it looks neat and tidy in your running log.

Listen. I am not smart enough or creative enough to create new statistical metrics for our sport – the running equivalent of Batting Average for Balls In Play (BABIP) or Wins Above Replacement (WAR). Despite this, I cannot help but try to think up some potential solutions, or other ways of looking at this topic:

--Keep track of monthly mileage. This takes a lot of patience and probably will not go over well with most runners, but it is actually a pretty good metric to judge long-term training consistency.
--Try to keep weekly mileage consistent by doing similar workouts on similar days, week-to-week – all the while not fretting over minor differences in week-to-week totals based on days off and any other of life’s vagaries that might crop up.
--Or, how about my favorite solution: Each week, map out your training by making sure you hit your key quality days – long run, workouts, doubles, days off if needed, etc. – and have them spaced out appropriately. And then fill in the blanks according to how you feel, the weather, and any of the myriad other factors that play into excelling in our sport. Give yourself a goal range for weekly mileage, as opposed to a single, concrete number total. Aim to be somewhere in that loose range you have created for yourself. And at the end of the week, your total is what it is. Leave it at that.

Preseason starts in about 48 hours. Guaranteed, the big topic of conversation will be weekly mileage. It is certainly possible that I will be the biggest culprit in fostering this talking point. But remember: Weekly mileage is important, but it may not be as vitally crucial as you think. See you soon …

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