What two runners taught me about the real cost of dependent mobility
I’ve been training with Achilles International in San Francisco as part of my research into assistive technology for visually impaired runners. Every other Sunday morning, I show up as a guide — and every time, I leave having learned more than I contributed. Recently, I sat down with two runners from the Achilles community whose experiences crystallized something I’d been circling in my research: the problem we’re trying to solve isn’t navigation. It’s freedom.
Angela: “I Was Supposed to Be the Guide”
Angela is a marathoner. Chicago. New York. Berlin. London is this month. She runs ultras. She once completed a 50-mile race around Lake Merced. She is, by any measure, an extraordinary athlete.
She also has retinitis pigmentosa.
The diagnosis came just weeks after she finished the Chicago Marathon in 2018. An eye infection led to a specialist, which led to a visual field test, which led to the words no runner wants to hear. Her central vision remains, but her peripheral field is compromised — people appear suddenly from her left and right, and when she’s looking at someone’s face, she can’t see the ground.
Here’s the detail that stopped me: when Angela was diagnosed, she had already signed up to be a guide. She was going to volunteer at the Lighthouse for the Blind in San Francisco, helping other runners. She’d been paired with someone. Then the tables turned, and she found herself on the other side of the tether.
That transition wasn’t easy. When she entered the New York City Marathon — 50,000 runners, bodies appearing from every direction — the anxiety was real. But she resisted asking for help. “I can still see centrally, so I don’t really need a guide,” she told herself. “I don’t want to take that resource away from someone who has worse vision than I do.” And then, more quietly: “Part of it was pride. I didn’t want to admit that I needed help because I wanted to be the one giving help.”
A friend finally convinced her. Not for her own safety alone, but for the safety of the runners around her. Angela connected with a guide named Mariel through Achilles in New York, who brought a tether to the race. Angela didn’t want it. She didn’t want people staring, didn’t want to be seen as someone who needed help.
She never let go of that tether for the entire 26.2 miles.
“She would count down to speed bumps. She would tell me when the next aid station was coming. And I just felt this huge relief — because all I had to worry about was: can I get through to the end of the race? That’s all I had to think about.”
That sentence is, in a nutshell, the thesis of my entire research project. When the cognitive burden of navigation and hazard monitoring is lifted, the runner can finally just run. The Stress Wall — the theoretical threshold I described in my first white paper where cumulative perceptual workload exceeds sustainable capacity — doesn’t disappear. But a good guide pushes it back far enough that the run becomes about running again, not survival.
Angela still runs alone on weekdays. She treasures that independence, knowing it may not last forever. “There will probably be a time where I’m not able to,” she told me, “and I would have to rely on people. So if that technology came up — if you created something I could use — I would definitely use it. 100%.”
But she was specific about what that technology can’t be: clunky. Heavy. Conspicuous. She wants the option of both sound and vibration — sound for verbal countdowns in quiet environments, vibration for crowded or loud ones. She wants to choose, not be chosen for.
And then she said something that has stayed with me since the interview. She told me about the 50-mile ultra, and the guide who ran every step beside her. “I felt really bad,” she said. “If I could do this on my own — if there was some sort of technology — I wouldn’t have to bother anybody or ask anybody for help.”
That guilt. That’s something I hadn’t fully accounted for in my models. The Stress Wall isn’t just perceptual. It’s emotional. Every time Angela asks someone to give up their Saturday, their race, their 50 miles, she’s making a calculation that has nothing to do with obstacle density or velocity — and everything to do with the psychological cost of dependence.
Lucas: “Life Goes On — You Find a Way”
Lucas didn’t consider himself an athlete growing up. Sports weren’t for him, he thought. He’s blind, works at Google, and until about a year ago, he’d never run more than a few minutes at a stretch. Then some friends kept inviting him to the annual Google 5K, and he finally said yes. He started training on a treadmill in February, a blind friend pointed him toward Achilles, and by mid-March he was running outside for the first time.
Now he runs two or three times a week and hits the gym twice more. He’s hooked. But here’s the part that matters for this research: when Lucas isn’t running with Achilles on Saturdays, his primary option is the treadmill. And the treadmill, for a blind runner, is a different beast than it is for a sighted one.
“We’re not holding the front bar,” he explained, “but we have to keep a light touch. There’s no way to keep running straight without that. And if you step one tiny bit to the side, you could fall.”
That light touch means one arm can’t swing naturally. Over distance, the asymmetry builds. “Sometimes I stop running on the treadmill not because I’m tired or my legs are hurting,” he told me, “but because my shoulder is so stiff from keeping my arm in that position.”
Think about that. A runner who wants to train, who has the cardiovascular capacity and the will to go further, is forced to stop — not by fitness, but by the biomechanical cost of a compensatory behavior imposed by the absence of spatial feedback. That’s the Stress Wall operating at the physical level, not just the cognitive one.
Lucas has developed a clever system for getting outdoor runs: he maintains a rotating roster of six to ten different guides, asking each one to run with him just once every six weeks. “This way I can get more training outside,” he said, “and the person doesn’t need to make a huge commitment.” It’s an elegant social hack, but it’s also a system that requires constant coordination — another form of cognitive overhead that sighted runners simply never think about.
Lucas also brought a technologist’s perspective to our conversation. He’s familiar with Google’s Project Guideline — the painted-line tracking system that enabled a blind runner to complete a half marathon in Stockholm — and he offered two pieces of advice that have shaped my thinking.
First: scope the problem. “Solving the open problem of any type of navigation is an immense task,” he said. “I think you have to scope the problem you’re trying to solve and do things much smaller first, then increase in steps of complexity.” Project Guideline succeeded precisely because it didn’t try to solve open-world navigation. It solved line-following. That’s it. And that was enough to change someone’s life.
Second: be aware of the legal landscape early. Not as a reason to stop, but as a terrain feature to navigate. “Build first,” he said, “and then figure out later.”
When I asked Lucas if he’d tried Project Guideline himself, the answer was telling: no. He’d wanted to, but it wasn’t available in California at the time. A technology that exists but can’t be accessed is, for the individual runner, functionally identical to a technology that doesn’t exist at all.
What This Means for the Research
These two conversations reinforced three things I’d suspected but hadn’t heard articulated so clearly by the people living it:
The dependency cost is emotional, not just logistical. Angela’s guilt about her 50-mile guide and Lucas’s careful rationing of guide relationships reveal a dimension of the participation gap that goes beyond scheduling. Every assisted run carries a psychological tax. Technology that enables even partial independent training would reduce this tax significantly — not by replacing guides entirely, but by making guides optional rather than mandatory.
The treadmill is not an adequate substitute. Lucas’s shoulder pain from compensatory bar-holding is a vivid illustration of how indoor workarounds impose their own physical costs. Outdoor running isn’t a luxury for visually impaired athletes — it’s a biomechanical necessity for healthy training. Any assistive system we build needs to work outdoors, in real environments, under real conditions.
The form factor matters as much as the function. Angela was specific: not clunky. Not conspicuous. The option to choose between modalities. This aligns with the biomimetic principles in our companion white paper — biological navigation systems are lightweight, distributed, and metabolically efficient. Our technology should be too.
Both Angela and Lucas said yes when I asked if they’d be willing to stay involved in the project and eventually test prototypes. I’m building a network of runners and advisors whose lived experience will shape every design decision. Because the worst thing I could do is build something in isolation and assume I know what people need.
I don’t. They do.
Angela and Lucas — thank you for your time, your honesty, and your willingness to be part of this. See you on the next Sunday run.
This post is part of an ongoing research series at runlikeafish.blog exploring biomimetic approaches to assistive technology for visually impaired runners. If you’re a visually impaired runner, a guide, or a researcher working in this space, I’d love to hear from you. You can reach me at brooke@runlikeafish.blog