There is a patient every physiotherapist recognizes. They present with runner's knee, or IT band syndrome, or Achilles tendinopathy. They respond well to treatment. They are discharged with a return-to-run plan and clear advice. And then, somewhere between six weeks and six months later, they are back.
This is not a clinical failure. The treatment was correct. The rehabilitation was appropriate. The advice was sound. And yet the injury returned, because the thing that caused it in the first place was never addressed. Not the tissue. The load.
For investors watching the preventive health space, this cycle represents something specific: a large, repeat-access patient population, a well-understood root cause, and a gap in the tools ecosystem that nobody has closed for the recreational runner. That gap is the opportunity.
The re-injury problem by the numbers
Up to 85% of recreational runners sustain an injury in any given year (Kluitenberg et al., 2015). The most common presentations: runner's knee, IT band syndrome, plantar fasciitis, shin splints, and Achilles tendinopathy (Kakouris et al., 2021) are overwhelmingly overuse injuries. Not trauma. Not accidents. Load accumulation that outpaced the body's ability to adapt.
What makes the re-injury rate particularly striking is that prior injury is one of the strongest independent predictors of future injury across all sports. A runner who has been injured once is meaningfully more likely to be injured again, not because their tissue is permanently compromised, but because the behaviour that caused the first injury is almost never changed by the clinical episode alone.
Kluitenberg et al. (2022) found that injured runners had commonly increased their weekly mileage by 30–50% in the four weeks prior to injury. A 140,000+ session dataset from Nielsen et al. (2025, Garmin RUNSAFE) found that sessions just 10% above a runner's recent load were associated with a 64% elevated injury hazard. Not a dramatic spike. Not a training camp gone wrong. A 10% increase above what the body was used to.
The mechanism is precise. The data is large-scale. And the behaviour it describes, unmonitored, unsupervised load accumulation, is exactly what recreational runners do every time they return to training after a clinical discharge.
Why the clinical episode doesn't break the cycle
Physiotherapy treats the injury. It does not, and cannot, supervise what happens next.
The patient leaves the clinic in a better state than they arrived. They have been educated. They have a return-to-run plan. They have been told to build gradually. And then they are on their own, with a Garmin on their wrist recording everything, and no tool to tell them what any of it means for how hard they should train tomorrow.
This is the structural problem. The data exists. The wearable infrastructure exists. The sports science methodology to interpret that data, Exponentially Weighted Moving Average (EWMA) load monitoring, validated in peer-reviewed literature by Williams et al. (2017, BJSM) and Impellizzeri et al. (2020, BJSM) exists and has been used in elite sport for over a decade.
What does not exist, for the recreational runner, is a product that connects those three things into a tool they can actually use between clinical appointments.
Elite athletes have performance coaches, sports scientists, and load monitoring infrastructure that flags dangerous trends before they become injuries. The recreational runner has a training plan that does not know what they did last week, does not know they were sick, does not know they took three weeks off and came back to week five of a programme designed for someone who never stopped.
The plan moves forward regardless. The body pays the price.
The market signal hiding in the re-injury rate
From an investor perspective, the re-injury cycle is not just a clinical problem. It is a market signal.
It tells you the current tools are not solving the problem. It tells you the patient group is large, motivated, already instrumented, and returning to the same point of failure repeatedly. It tells you the methodology to address the root cause is validated and available, it just hasn't been productized for this population.
Running is one of the most widely practised forms of exercise globally. The addressable market is not a niche. It’s tens of millions of recreational runners who own GPS watches, pay for training plans, hire coaches, and register for races, and who, at a rate of up to 85% per year, get injured doing it.
The economic cost of that injury rate is significant. Physiotherapy appointments, reduced activity, lost race entries, lapsed fitness subscriptions. But the more important signal for investors is behavioural: these runners come back. They do not stop running because they got injured. They recover, return, and without better tools, repeat the cycle.
That is a retention story as much as it is a health story. A product that breaks the cycle does not just improve outcomes. It earns lasting engagement from a user who finally has a reason to stay.
What breaking the cycle actually requires
The intervention required is not complex in concept. It is just precise in execution.
A recreational runner returning from injury needs a tool that knows their actual training history, not a template, not a plan designed for an average runner at a generic fitness level. Their real acute load. Their real chronic load. The trend between the two, and where that trend is heading.
LODE does this by connecting to Garmin wearables and applying EWMA to calculate both simultaneously. Rather than comparing a ratio to a fixed threshold, an approach the research has largely moved away from (Impellizzeri et al., 2020) LODE monitors the direction and rate of change of the relationship between acute and chronic load, classifying each runner's current phase and building a personalised weekly plan around it.
If the runner deviates, misses sessions, runs harder than planned, has a week that looks different from what was prescribed, the plan adapts to what actually happened. It does not move blindly to the next week. It recalculates from where the runner actually is.
It also accounts for the difference between external load (distance, pace) and internal load (heart rate response) recognizing that two runs at the same pace carry different physiological stress depending on sleep, fatigue, hydration, and recovery status. This is the distinction that separates a load monitoring tool from a basic activity tracker, and it is the distinction that matters for a runner returning from injury.
The gap is structural, not clinical
The recreational runner who keeps coming back to the physio is not doing anything wrong. They are doing exactly what they were told, building gradually, listening to their body, following the plan. The problem is that the plan is static and they are not. Their body changes week to week. Their load history is unique. And the tools available to them treat them as an average runner in an average week, every single time.
Closing that gap does not require new science. The research is settled. It does not require new hardware. The wearables are already there. It requires a product built specifically for the recreational runner, grounded in validated methodology, and designed to function as the intelligent layer between the data that already exists and the behaviour change that prevents re-injury.
That product did not exist for this population until now. The patient who keeps coming back, the 85%, the repeat presentations, the frustrated physios and the defeated runners, represents both the clearest evidence that the current tools aren't working, and the most compelling case for what comes next.
LODE is a training load management and injury prevention app for recreational runners, built on peer-reviewed sports science. Learn more at lodefitness.com.
References: Kluitenberg et al. (2015); Kluitenberg et al. (2022); Kakouris et al. (2021); Williams et al. (2017, BJSM); Impellizzeri et al. (2020, BJSM); Nielsen et al. (2025, Garmin RUNSAFE).
