Coaching Letter #227

On bottlenecks

Hi there! Thank you so much for subscribing to the Coaching Letter—you rock. I can’t help myself: I just have to mention that we’ve had a blizzard here in the northeast (37 inches in Providence!), and today is the third snow day in a row for our local school district, which is most unusual. But unlike many of my reflections on the weather, this one has a direct connection to the topic of this CL, which is bottlenecks. And it is next in the series of Coaching Letters on shifting from improving individual practice to designing systems that reliably support improved practice.

I’ve done a lot of snow shoveling over the past few days, which has given me a lot of time to think. It occurred to me while I was doing all this shoveling that I was actually enjoying it, because I’m trained for it. I have all the right muscles for snow shoveling—back, legs, shoulders—because I row. Not on water any more—who has the time?—but on the rowing machine (AKA erg) at the gym. I learned to row in college and was pretty good at it, and it has become my go-to cardio exercise since my Achilles tendons object if I run much any more.

Since I spend a lot of time on the erg, I see a lot of people try it out. OK, I’m going to make a couple of gross generalizations here; forgive me. The people on the erg tend to fall into a couple of categories. There are the young guys who come in after school, sit down, don’t strap their feet in, and then just yank very hard for a couple of minutes and then walk away, totally out of breath, never to be seen again. Then there are the women of a certain age who move slowly up and down the slide, not putting in much effort, and therefore able to keep going for a long time, but they would get more cardio-vascular benefits from simply walking around the track. And then there are the regular guys, mostly older, mostly pretty fit, but I can still outrow them. Why? Because their technique sucks. (I have also learned that they are not terribly receptive when I try to give them feedback, but that’s for another time…)

I read somewhere that rowing is an uncommonly honest sport, because it rewards efficiency. In other words, you need three things to row well—strength, particularly in your legs and back; cardio-vascular endurance, because even a sprint in rowing is 2km, which takes me the better part of 10 minutes; and technique which, as this quick tutorial on rowing shows, is a lot harder than it looks. And what tends to hold people back in their rowing is their technique, because that is the variable that affects whether power is applied smoothly and continuously throughout the stroke cycle (catch→drive→return). In other words, even if you are strong and fit, you are going to find rowing exhausting and frustrating if you don’t have good technique.

Here are the biggest misconceptions people have—talking about the erg here, it’s different on the water. People think it’s about arm strength, but your arms are straight for most of the stroke, and mostly just finish the stroke and push away again as fast as possible. People think that if you lean further back you’ll get a longer stroke, but there’s not much power in leaning back another couple of degrees, so that’s wasted effort. People pause at the catch, when you’re furthest forward at the beginning of the stroke cycle, but that’s exactly the wrong time to pause, as that’s where most of the energy is needed, and so you need to engage your quads when there is most resistance. People think you’ll go faster if you move up the slide more quickly, but that’s wasted energy—you need to let the chain pull you back and concentrate on getting ready for pushing with your legs and bracing with your back. OK, I could go on, but you get the picture.

Here is the translation to systems. Rowing looks simple, but is actually pretty complicated (although not complex—see CL #214. If you think of the ability to row as a stock (see CL #215) then there are three inputs: cardio-vascular fitness, strength, and technique. You need all three. And the one that is holding you back—the place in the system that is constraining the system output—is called the bottleneck. And as with rowing, the bottleneck is not always immediately obvious. But:

An improvement that does not relieve a bottleneck won’t improve the performance of the system as a whole. You can improve your cardiovascular fitness, and that’s a worthy goal in itself. You should feel good about that. But it won’t necessarily make you a better rower, if your technique is what’s holding you back. If you want to improve the effectiveness of the system, you must find a way to relieve the bottleneck. In fact, in rowing, increasing power without improving sequencing through the stroke actually creates more drag. You can see this in an inexperienced crew—they get towards the end of the race, they are giving it everything they’ve got, but they lose focus on their technique and they just fall apart as a result. They are losing speed just when they are applying most effort—that is probably the best metaphor for why school improvement efforts that rely on putting in more effort are actually counterproductive. It’s one of the reasons why I hate the phrase: “How do we increase people’s sense of urgency?” Urgency is the last thing I want people to feel. If you up the pace without holding your technical discipline, you put strain on the system, you increase inefficiency, and you risk the system collapsing in on itself.

Bottlenecks are nested. Even once you have diagnosed that technique is your bottleneck, you have to get inside that bottleneck and figure out exactly what part of your technique is holding you back—is it your stroke sequencing (you should never have to raise your hands to get over your knees), your connection at the catch, or something else? Similarly, once we decide that “instruction” is the bottleneck, the real work is to get inside it. Is the constraint the task itself — low cognitive demand that invites compliance rather than thinking? Is it the launch, where directions turn into examples and scaffolds so that students aren’t being asked to actually figure anything out? Is it the absence of formative feedback, so misconceptions are left unaddressed instead of being surfaced and refined? At the leadership level, naming “teacher collaboration” as the bottleneck is equally insufficient. Is the constraint lack of protected time, protocols that don’t focus attention on equitable practices, norms that discourage intellectual risk-taking, or a system that treats meetings as reporting sessions rather than places where professional learning happens? Until we locate the precise choke point, effort increases but movement does not.

Some things can’t be fixed. But that doesn’t make them the bottleneck you might think. For example, you can think of rowing performance as being stroke length × force per stroke × stroke rate × technical efficiency. You’d think that I can’t do much about my stroke length, since I can’t make my arms any longer. However, it turns out that arm length is not the only thing that matters for stroke length—it’s also hip flexion, ankle dorsiflexion, how level you keep your hands through the stroke cycle, and probably other things that I don’t know about. And I just had a bit of a breakthrough with my ankle flexion, funnily enough. I like this example because it speaks to the assumptions we make about what matters most. This, you’ll remember from CL #223, was Ron Edmonds’ whole point: We can’t do anything about students’ home circumstances, so it’s too easy to throw up our hands and say, “But we can’t do anything about that!”, and fail to notice that other factors—like strong leadership, high expectations, and feedback loops—are more salient.

Bottlenecks shift when capacity improves. You can probably always be improving your rowing technique. But at some point, it’s going to plateau, and other factors become the limits on your performance. At that point, the bottleneck is going to be either the power you can generate (which is a function of an impressive collection of muscles, which is what makes rowing such great exercise), or the ability of your cardiovascular system to sustain effort over time. Similarly, with teaching and learning, the quality of the tasks teachers can access is often the bottleneck—as Instructional Rounds has it, task predicts performance. But if you improve the stock of tasks, teaching becomes the constraint—ensuring that all students are asked to think and make their thinking visible and get a response from the teacher that moves their understanding forward.

You should probably work on only one bottleneck at a time. If you watch videos of elite crews training, what will probably strike you is how slowly they are moving. This isn’t because they lack fitness — every rower in that boat is in fantastic physical condition — but because fitness is not the constraint. They are spending time working on their timing, technique, and coordination because the payoff is much greater if they invest in increasing the efficiency of the boat moving through the water, and the way to do that is to make each rower hyper-aware of their own technique, the balance of the boat, and the movement of the rower in front of them. They slow the stroke because they can sustain the slower speed for longer periods of time, giving them more time to work on the non-physical factors. Instructional improvement often requires a similar deceleration. When the constraint lies in the quality of tasks, in how lessons are launched, or in how teachers respond to student thinking, adding more initiatives or increasing pace does not produce better learning. Slowing down to examine student work, rehearse task launches, script questions, or practice responding to misconceptions can feel inefficient in the moment. But the return on investment is big.

And sometimes the weather is the bottleneck—can’t do anything if teachers and students are snowed in at home.

I also need to point out that everything I know about bottlenecks I learned from reading Goldratt’s The Goal. It is well worth your time to read it.

Finally, if you ever get the chance to see the Boat Race—the annual rowing competition between Oxford and Cambridge universities held every year on the Thames between Putney and Mortlake, I highly recommend it. Best, Isobel