Red Light Therapy (RLT) for Runners

Carlos Barrera
2026-03-31T11:49:41-04:00

Most runners assume progress happens during the run itself, in the miles logged and the effort sustained. In practice, it happens later, in the narrow window when the body is absorbing stress and rebuilding above baseline. That process is called supercompensation, and it helps explain why some runners adapt while others stay sore, stall, or slide into shin pain and knee trouble. Red and near-infrared light therapy is now being studied as a way to influence that recovery window, but its value depends on when it enters the cycle

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Running Is a Cycle, Not a Session

What makes running deceptive is that the work is visible while the adaptation is not. You can feel the long run, the hill repeats, the late-race fatigue in a tempo session, but the part that determines whether any of that work becomes fitness unfolds later, quietly, while you are back at your desk, asleep, or lacing up again before the previous effort has fully cleared.

That hidden sequence is what coaches and physiologists usually mean by supercompensation. A run imposes stress, performance drops for a time, recovery restores what was spent, and if the process is allowed to finish, the body rises slightly above its old baseline before settling again. The principle is simple enough. The difficulty is that running, especially at meaningful mileage, compresses the timeline. The next stimulus often arrives before the last one has been fully absorbed. (Kenttä & Hassmén, 1998; Hristovski et al., 2023)

For runners, that is where the real training story lives, not in whether a workout was hard enough, but in whether the body had enough room to turn that workout into adaptation rather than residue.

What Supercompensation Actually Means on the Road

In theory, supercompensation sounds tidy. Stress the system, recover, improve, repeat. In practice, it feels messier because runners experience the process not as a neat graph but as soreness, heaviness, freshness, or a lack thereof.

After a demanding run, muscle function declines for both mechanical and metabolic reasons. There is local tissue disruption, altered calcium handling, inflammatory signaling, glycogen depletion, and fatigue across the systems that support stride after stride. DOMS, when it appears, is part of that picture, usually peaking somewhere between 24 and 72 hours after an unfamiliar or especially demanding effort. It is common, often temporary, and not automatically a sign that anything is wrong. (Cheung, Hume, & Maxwell, 2003; Hotfiel et al., 2018)

The problem begins when runners confuse all soreness with useful soreness. The body can tolerate a surprising amount of discomfort and still move forward. It can also tolerate a surprising amount of accumulation before it finally starts charging interest.

Where Runners Break the Cycle

The runners who plateau are not always the ones who undertrain. Often they are the ones who stay trapped in the wrong part of the curve, returning to work while still submerged in fatigue and calling that consistency.

This is why high-mileage blocks can feel productive right up until they do not. The legs never become acutely injured, just persistently reluctant. A long run that once resolved by Tuesday lingers into Thursday. A workout pace that once felt controlled begins to feel negotiated. The body keeps showing up, but the rebound is incomplete. What should have been a repeating rhythm of stress and adaptation turns into overlapping layers of unfinished recovery.

That shift matters because overuse injuries in runners rarely behave like dramatic accidents. Medial tibial stress syndrome, the condition most runners simply call shin splints, is classically an overuse problem, associated with repeated loading and a failure of tissues to tolerate the training demands. Patellofemoral pain behaves similarly, often emerging not from one catastrophic session but from a cumulative mismatch between load and capacity. (Menéndez & Rueda, 2020; Esculier et al., 2020)

Seen through that lens, shin pain and runner’s knee are not separate from the supercompensation conversation. They are what the conversation becomes when the window keeps getting missed.

The Soreness Question: DOMS or Something Deeper?

DOMS tends to have a rhythm. It arrives late, peaks, and then recedes. It is often diffuse, often symmetrical, and often linked to a workout you can identify without much detective work. Chronic soreness is less polite. It hangs around past the point when it should have resolved, returns before the previous fatigue has cleared, or starts narrowing into specific structures that are being loaded more than they can recover. (Cheung, Hume, & Maxwell, 2003; Hotfiel et al., 2018)

That distinction matters for runners because the sport rewards routine. The same discipline that builds aerobic capacity can also hide a problem in plain sight. A runner may still be training, still hitting miles, still convincing themselves the body is adapting, while in reality, the recovery window has narrowed enough that every session is landing a little too early.

Once that happens, soreness stops being a simple aftereffect and starts to act more like a signal that the system's timing has changed.

What Happens at the Cellular Level

Recovery is often talked about as if it were passive, as though the body simply rests its way back to readiness. In reality, it is a highly active biological process, shaped by energy production, inflammatory control, blood flow, and tissue remodeling.

This is where photobiomodulation enters the discussion. PBM, commonly delivered as red and near-infrared light, appears to act in part through mitochondrial pathways, especially through the absorption of light by cytochrome c oxidase, with downstream effects on ATP production, nitric oxide signaling, oxidative stress, and cellular repair. That is why the field has attracted attention not only in general wellness but in sports performance and exercise recovery. (Hamblin, 2017; de Freitas & Hamblin, 2016)

The important point is not that light replaces recovery. It does not. The more interesting claim, and the one the literature supports with greater restraint, is that it may help the body recover more efficiently when the parameters are right. (Ferraresi et al., 2016; De Marchi et al., 2022)

Where RLT Fits in the Cycle

For runners, the appeal of PBM is not hard to understand. Running produces repeated eccentric load, high cumulative volume, and frequent contact stress across muscles, tendons, bone, and joint structures. A modality that may support mitochondrial efficiency, reduce exercise-induced muscle damage, and improve recovery markers speaks directly to the part of training that runners cannot simply grit their way through forever. (Ferraresi et al., 2016)

The literature is especially interesting because PBM does not seem to behave as a one-note recovery tool. In reviews of sports performance research, pre-exercise use has been associated with improvements in performance-related outcomes and lower biochemical markers of muscle damage, while post-exercise use has been linked to better recovery in some protocols. (Ailioaie & Litscher, 2021; Vanin et al., 2018)

That matters for endurance athletes because it maps neatly onto the supercompensation model. Before a run, PBM may help shift the fatigue curve by preparing tissue for the work ahead. After a run, it may help shorten or smooth the recovery phase. The run still creates the stimulus. PBM, in the best-case version of the argument, helps the body absorb it more effectively. (Ailioaie & Litscher, 2021; Vanin et al., 2018)

The Timing Problem Most Runners Miss

Most recovery discussions ask whether a tool works. The better question is when it works, and for what.

A runner heading into a long run, a hard interval day, or a race-pace session is not solving the same problem as a runner trying to recover from that effort two hours later. The first is trying to improve readiness. The second is trying to accelerate the repair. Those are related goals, but they are not identical, which is one reason timing keeps reappearing in PBM research. (Ailioaie & Litscher, 2021; Vanin et al., 2018)

This is also why a casual approach can flatten the benefits. If PBM is treated as a general wellness ritual rather than a training variable, it may still feel useful, but it ceases to be strategically useful. The conversation changes when it is placed inside the rhythm of the week: before the hardest sessions, after the highest-damage sessions, and more selectively when load is climbing, and the margin for error is shrinking.

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The Runner’s Supercompensation Protocol

A runner does not need an elaborate biohacking stack for the concept to be useful. What matters is matching the intervention to the role it is meant to play.

Before key sessions, the logic of PBM is performance-facing. The goal is not passive relaxation but readiness, especially on days when output matters more than mileage. Before long runs and speed sessions, that means using PBM as a pre-conditioning tool, not because it magically creates fitness, but because the evidence suggests it may reduce fatigue and support better performance under stress. (Ailioaie & Litscher, 2021; Aguirra et al., 2025)

After demanding sessions, the logic shifts. Now the question is no longer how to get through the workout, but how quickly the body can start the work that comes next. This is where post-run PBM fits best, particularly after long runs, race simulations, or blocks where soreness begins to spill across days rather than staying contained within them. (Ferraresi et al., 2016; Vanin et al., 2018)

In practical terms, easy days usually do not need the same intervention as quality days. A runner who is accumulating mileage without major soreness may use PBM selectively. A runner in a marathon build, or one who has started noticing the first signs of shin tightness or anterior knee pain, has a stronger case for treating recovery as part of the plan rather than as an afterthought.

Managing High Mileage, Shin Splints, and Knee Pain

One of the more seductive mistakes in distance running is to assume that all roadblocks are muscular. They are not. Shin splints and patellofemoral pain are reminders that running stress is distributed across the whole chain, and that tissue tolerance matters as much as aerobic fitness. MTSS is common in runners and sits on the continuum of tibial stress injury, while patellofemoral pain remains one of the most prevalent running-related complaints. (Menéndez & Rueda, 2020; Esculier et al., 2020)

That is why the recovery question is larger than DOMS. A runner may feel muscularly fine while the connective tissue quietly falls behind. This is also why modality choice matters. PBM may be appealing not because it substitutes for strength work, gait changes, or load management, but because it addresses a layer of recovery that ice, stretching, and massage do not fully reach, namely cellular energy and tissue response under repeated stress. (Ferraresi et al., 2016; De Marchi et al., 2022)

Why Coverage Matters for Runners

Coverage is not a glamorous variable, but for runners, it is a practical one. Running soreness rarely stays politely confined to one spot. Quads, calves, shins, hips, and knees all participate in the same training load, which means a recovery strategy built around one small patch of tissue can become cumbersome very quickly.

That does not mean localized PBM has no value. It does mean that for endurance athletes, the appeal of broader coverage is not abstract. It is a time and workflow issue, especially in periods when recovery needs are systemic rather than local. This is one reason full-body systems have become part of the conversation, even though the evidence base for whole-body PBM in sports remains more limited and less settled than that for localized applications. A 2025 systematic review, for example, found insufficient evidence that whole-body PBM improves exercise recovery or performance, which is a useful reminder not to overclaim the current science. (Álvarez-Martínez & Borden, 2025)

That nuance actually helps clarify the decision. The strongest case today is not that full-body PBM has already solved every recovery question in endurance sport. It is that runners, more than many athletes, have a workflow problem that broader coverage is trying to address.

What Changes When PBM Becomes Full-Body

When PBM moves from local treatment to full-body delivery, the argument changes from isolated symptom management to training logistics. The issue is no longer whether one calf or one knee can be treated. It is whether a runner with broad fatigue or multiple hot spots can use the modality consistently enough for timing to matter.

That is where format starts to matter almost as much as mechanism. A modality can be biologically plausible and still be operationally inconvenient. For runners, especially during heavy blocks, convenience is not a luxury feature. It is often the difference between a protocol that becomes a reality and one that remains theoretical.

Progress Happens Between Runs

The enduring myth in running is that progress belongs to the person willing to suffer the most. The physiology is less romantic and more exacting. Progress belongs to the athlete who creates the stimulus and then gives the body enough support, enough timing, and enough room to turn that stimulus into adaptation.

That is what supercompensation really describes. Not a mystical rebound, but a narrow biological opportunity. DOMS after a long run may still be normal. Persistent shin soreness and creeping knee pain may not be. PBM belongs in this conversation not as a miracle fix, but as a timing-sensitive tool that may help runners stay closer to the right side of the curve. (Cheung, Hume, & Maxwell, 2003; Kenttä & Hassmén, 1998)

The run is only the first half of the story. The second half is what the body manages to do with it.

References

Kenttä G, Hassmén P. Overtraining and recovery. A conceptual model. Sports Medicine. 1998.

Hristovski R, Balagué N, Vázquez P, Almolda-Tomás A. Long-term exercise adaptation. Physical aging phenomena in nonlinear adaptive systems. Frontiers in Network Physiology. 2023.

Cheung K, Hume P, Maxwell L. Delayed onset muscle soreness. Sports Medicine. 2003.

Hotfiel T, Freiwald J, Hoppe MW, et al. Advances in delayed-onset muscle soreness (DOMS): Part I. Pathogenesis and diagnostics. Sportverletzung Sportschaden. 2018.

Menéndez C, Rueda FM. Medial Tibial Stress Syndrome in Novice and Recreational Runners: A Systematic Review. International Journal of Environmental Research and Public Health. 2020.

Esculier JF, Bouyer LJ, Dubois B, et al. A Contemporary Approach to Patellofemoral Pain in Runners. Current Reviews in Musculoskeletal Medicine. 2020.

Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics. 2017.

de Freitas LF, Hamblin MR. Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy. IEEE Journal of Selected Topics in Quantum Electronics. 2016.

Ferraresi C, Hamblin MR, Parizotto NA. Photobiomodulation in human muscle tissue: an advantage in sports performance? Journal of Biophotonics. 2016.

De Marchi T, Schmitt VM, Danúbia da Silva Fabro C, et al. Can Photobiomodulation Therapy Minimize Exercise-Induced Oxidative Stress? A Systematic Review and Meta-Analysis. Antioxidants. 2022.

Ailioaie LM, Litscher G. Photobiomodulation and Sports: Results of a Narrative Review. Medicina. 2021.

Vanin AA, Verhagen E, Barboza SD, Costa LOP, Leal-Junior ECP. Photobiomodulation therapy for the improvement of muscular performance and reduction of muscular fatigue associated with exercise in healthy people: a systematic review and meta-analysis. Lasers in Medical Science. 2018.

Aguirra P, Sandoval-Matus I, Caniuqueo A, et al. A systematic review and meta-analysis of the acute effects of photobiomodulation therapy on muscle endurance in healthy individuals. Lasers in Medical Science. 2025.

Álvarez-Martínez M, Borden G. A systematic review on whole-body photobiomodulation for exercise performance and recovery. Lasers in Medical Science. 2025.

Frequently Asked Questions

What is supercompensation in running?

Supercompensation is the period after training when the body recovers from stress and briefly rises above its previous baseline, creating the opportunity for adaptation and improved performance.

How long does DOMS usually last after a run?

DOMS usually peaks between 24 and 72 hours after an unfamiliar or especially demanding effort, then gradually resolves as recovery progresses.

Can red light therapy help runners recover faster?

Research suggests photobiomodulation may support recovery by influencing mitochondrial function, oxidative stress, and muscle-damage markers when the timing and dose are appropriate.

Should runners use PBM before or after a run?

Before a key session, PBM is generally framed as a readiness or pre-conditioning tool. After a demanding run, it is more often used to support recovery and reduce the carryover of fatigue into the next session.

Is full-body PBM proven to improve running performance?

Not yet. Current evidence for whole-body PBM in exercise recovery and performance is still limited, which is why broader coverage should be discussed as a workflow advantage rather than as a settled performance claim.