Outdoor Running on Winnipeg's Spring Streets: Surface, Footwear, Tendons

If you spent the long Manitoba winter running on a treadmill or — for the disciplined among us — at the indoor track at the Max Bell, the move outdoors in late April and May is a sneaky load change. The pace looks the same on the watch. The mileage looks the same in the log. But the demand on the body, particularly on the tendons of the lower leg, is different enough that we see a recurring spring spike of overuse injuries every year.

This post is about what actually changes when you take your running outdoors in Winnipeg, and how to manage the transition so you finish May running, not rehabbing.

Surface — what your tendons notice

A treadmill provides a slightly compliant, perfectly flat, and predictable surface. The belt assists toe-off marginally — you're effectively being pulled rather than fully propelling — and the impact profile is consistent stride after stride. Your Achilles, plantar fascia, and posterior tibial tendon do less eccentric work per kilometer than they will outdoors.

Concrete sidewalks and asphalt streets — most of Winnipeg's running surfaces in early spring before the trails fully dry — provide a much stiffer, less compliant surface. Impact peaks are higher, and the lower leg has to do more of its own work to propel the body forward¹. Add the small surface variations that come with cracked pavement, frost heaves, and the city's annual pothole reveal, and the demands on the foot, ankle, and lower leg climb meaningfully.

Tendons adapt to load — but they adapt slowly. Stiffening of the Achilles in response to a new load takes weeks, sometimes longer². A 30 km outdoor running week in the first week of May, after a winter of exclusively treadmill running, often exceeds what the lower-leg tendons are currently prepared for. The result is the same set of presentations we see every spring: medial tibial stress syndrome, Achilles tendinopathy, plantar fasciitis, and posterior tibial tendon irritation.

Footwear — what changes when the surface changes

The shoe that worked perfectly on a treadmill in February may not be the right shoe for outdoor running in May. There are two practical considerations:

Wear pattern. Most running shoes lose meaningful midsole compliance somewhere between 500 and 800 kilometres of use, depending on the shoe and the runner³. If you've been logging treadmill miles all winter, the shoe is now ageing into outdoor running on stiffer surfaces with less help from underneath.

Stack height changes. If you're considering a new shoe — and spring is when most runners do — be aware that swapping between very different stack heights or drops mid-block produces a tendon-load change. The same kinetic chain that's adapted to a 10 mm drop will see a different demand profile on a 4 mm drop, and the change isn't always benign⁴.

Practical translation: don't introduce both a new outdoor surface and a new shoe in the same week. Stagger the changes by at least two to three weeks if possible.

Volume — the real driver

The single best predictor of running-related overuse injury, in study after study, is a sharp change in weekly mileage. Nielsen and colleagues found that runners who increased weekly distance by more than 30% over a two-week window had a substantially higher rate of running-related injury than those who progressed more conservatively⁵. The acute-to-chronic load principle — the same thinking we apply to all sport-related overuse injury — works particularly cleanly for runners.

For most recreational runners coming back outdoors in late April or early May, a build of 7–10% per week is well-tolerated. A build of 25–30% per week, even if you "felt fine" in the first week, is the recipe for a tendon problem in the third or fourth week.

Specifically, what we see in May

The case mix at our clinic in May is fairly consistent year over year:

• Anterior shin pain in newer runners who jumped to outdoor mileage too fast.
• Mid-portion Achilles tendinopathy in experienced runners who switched shoes or routes recently.
• Plantar fascia symptoms in runners who'd been doing zero outdoor walking before launching into spring runs.
• Patellofemoral irritation in runners doing a lot of the new outdoor mileage on cambered Winnipeg streets, which the knee notices quickly.

Most of these respond well to load management plus targeted rehab, particularly when caught early. The patients who do worst are the ones who push through three weeks of escalating tendon symptoms before getting them looked at — by then, the tissue has been overloaded long enough to need a longer down-grade in volume.

The takeaway

Outdoor running in Winnipeg is one of the better things about May. The transition is also where most of the spring's preventable overuse injuries come from. There are no bad outdoor miles, only too many too soon — and the runners who finish the spring with their training intact are the ones who treat the surface change as a meaningful variable, build mileage progressively, and listen to early tendon signals before they become full overuse problems.

If something is already creeping in, the earlier we see it at Boreal Spine & Sport, the cleaner the rehab tends to be.

References

1. Tessutti V, Trombini-Souza F, Ribeiro AP, Nunes AL, Sacco IC. In-shoe plantar pressure distribution during running on natural grass and asphalt in recreational runners. J Sci Med Sport. 2010;13(1):151–155.
2. Magnusson SP, Langberg H, Kjaer M. The pathogenesis of tendinopathy: balancing the response to loading. Nat Rev Rheumatol. 2010;6(5):262–268.
3. Cook SD, Kester MA, Brunet ME. Shock absorption characteristics of running shoes. Am J Sports Med. 1985;13(4):248–253.
4. Malisoux L, Chambon N, Delattre N, Gueguen N, Urhausen A, Theisen D. Injury risk in runners using standard or motion control shoes: a randomised controlled trial with participant and assessor blinding. Br J Sports Med. 2016;50(8):481–487.
5. Nielsen RØ, Parner ET, Nohr EA, Sørensen H, Lind M, Rasmussen S. Excessive progression in weekly running distance and risk of running-related injuries: an association which varies according to type of injury. J Orthop Sports Phys Ther. 2014;44(10):739–747.

Author: Dr. Michael Minenna D.C., B.Sc., SFMA, FMS — Boreal Spine & Sport, Winnipeg, Manitoba.