Making Decisions On Run Intensity

When and why you should move away from pace-based training and toward effort-based training, especially in the middle of a race-heavy season with environmental stressors like heat.

1. Environmental factors – Heat, direct sun, and humidity can make prescribed paces misleading because the same pace that feels “manageable” in cool conditions can push an athlete into overreaching when it’s hot.

2. Season timing – You’re in what you called “the meat of race season” with frequent competition. The goal here is maintenance of sharpness without accumulating fatigue. Over-prescription (especially with rigid pace targets) risks tipping athletes into a hole they can’t climb out of before the next race.

3. Athlete education –A teachable moment with an athlete, particularly the older ones racing at a high level. Explaining why effort is prioritized over pace not only helps compliance for that session, it also builds their long-term racing intelligence—because race day often demands in-the-moment effort management.

4. Session design shift – Moving from distance + pace to time + effort (via a fartlek format) allows you to keep the intended physiological stimulus without tying performance to an external metric that would be skewed by conditions.

The Decision Point — Why Pace vs. Why Effort

This is the first fork in the road

• Environment → heat, humidity, wind, altitude all skew pace as a measure of intensity.

• Season timing → mid-season or race-heavy periods need careful load control.

• Athlete type → seasoned athletes may self-regulate better by effort; greener athletes often overcook “fast” segments unless given guardrails.

• Training goal → is the intent physiological (e.g., VO₂max stimulus, aerobic maintenance) or skill-based (e.g., change of pace, surging, feel for rhythm)?

In hot conditions especially, pace becomes a trap — it turns a controlled aerobic or tempo run into an unintentional threshold or higher session. Regulate by RPE (rate of perceived exertion) instead of stopwatch.

Athlete Education — Teaching the “How” of Effort

Some risk or pitfalls to remember with fartlek:

• Easy not easy enough → “easy” needs to be conversational pace, not “slightly less hard.”

• Fast too fast → “fast” is often interpreted as “sprint until my form falls apart,” which destroys the purpose.

Good communication tools here:

• Define fast as comfortably hard — form stays intact, breathing is heavy but controlled, you could hold it for ~5–6 minutes if you had to.

• Define easy as truly aerobic — you should feel your HR come down, breathing relax, and stride loosen.

• Analogies — e.g., “Think of the fast as a gear change, not flooring the gas pedal.”

For younger or inexperienced athletes, you can blend effort language with pace ranges:

“Fast should feel like 10K effort, but it’ll probably show up 20–40 seconds slower per mile than your cool-weather 10K pace today.”

Session Design — Matching Structure to Control

More control (specific pace/distance)

• When injury risk is high, load needs tight control, or the athlete can’t yet self-regulate.

• When you want precise energy system targeting.

Less control (time + effort fartlek)

• When environmental factors distort pace targets.

• When you want to work on adaptability, rhythm change, or mental freshness.

• When racing is frequent and the goal is maintaining sharpness without adding cumulative fatigue.

And within fartlek, you can scale the freedom:

• Prescribed times (e.g., 1:00 fast / 1:30 easy) but adjustable mid-set.

• Effort anchors (“fast” at 8/10 RPE, “easy” at 4/10).

• Optional downsizing (“If you lose form, shorten the next fast rep by 15–30 seconds”).

It’s not just about choosing pace vs. effort for a session — it’s about knowing your tendencies, limitations, and learning stage, then designing the workout and your communication so you can execute and grow from it without derailing the season.

Athletes live on a spectrum — from “too conservative” to “too aggressive”

• Conservative learners → Need exposure to “fast” sensations without panic, injury fear, or shutting down. They need reassurance that discomfort, danger. You’re often giving them permission to push.

• Over-aggressive chargers → Need pacing governors to avoid blowing up or hurting themselves. This is where pace targets and firm rest periods are a safety net.

• The sweet spot is an athlete who has the emotional control and sensory vocabulary to know what each zone feels like and when to hold back or push. That takes reps and mistakes — but those mistakes have to be non-catastrophic.

The “sensations timeline” is part of the lesson

Using specific distance such as 200s holding :40 leaving on :60:

• Early reps might feel “too easy” — but that’s by design, to save capacity for later.

• Mid-set is where pacing discipline starts to matter.

• Late reps teach athletes how to press while tired without overreaching.

That’s something experienced athletes anticipate, but newer ones only learn through guided repetition. Even if they understand intellectually, they haven’t internalized it until they’ve felt it.

The season context changes the teaching strategy

• Early season / low-stakes phase → More freedom to let athletes explore, make micro-mistakes, and learn what sensations mean.

• Peak season / tight turnaround between races → Safety, recovery, and availability for race day trump learning risk. Pace prescriptions tighten up here, especially in heat or with athletes prone to going too hard.

In a heavy race block, you can’t afford to let a “learning mistake” become an injury or a multi-day recovery hole.

To boil all this into a practical  decision map, it would be:

1. Assess athlete tendency → conservative, aggressive, or balanced.

2. Consider season context → early vs. race block.

3. Factor environment → conditions that skew pace (heat, altitude, wind).

4. Choose control level:

• High control (pace + distance) → aggressive athletes, hot/race week conditions, injury risk.

• Medium control (time + effort ranges) → balanced athletes, moderate learning risk, early-mid season.

• Low control (pure fartlek) → experienced, self-regulating athletes, low-risk part of season.

5. Educate every time → “Here’s why we’re doing it this way today,” so they build transferable racing skills.

Group Training Dynamics in Effort vs. Pace Sessions

If you’re one of the faster athletes

• Upside → You can dial things back, control the rhythm, and maybe even use the group as a chance for active recovery or sharpening with less load.

• Risk → The “control” can turn into complacency — you never hit your true session goals because you’re holding back for the group. Or you subconsciously still creep the pace up to prove you’re “leading” without realizing it.

If you’re one of the slower athletes

• Upside → Chasing faster runners can bring you into new speed sensations and build confidence.

• Risk → This is the big one: trying to match the group’s pace when it’s beyond your current capacity, especially in repeated reps, can lead to form breakdown, fatigue spikes, or injury. In fartlek or effort-based sessions, this is extra risky because you don’t have a clear metric telling you, “Whoa, I’m way over my target.”

Emotional maturity is the filter

It takes a self-aware, emotionally mature athlete to:

• Let the group go when the effort is too high.

• Not sabotage the workout’s intent just to “win” training.

• Avoid hiding in the pack when they should be pushing themselves.

Strategies in Group Settings

To manage this:

• Break the group into pace/effort pods so athletes match with those closer to their range.

• Assign leader rotations so faster athletes sometimes pace the group at the prescribed effort, not at “what feels comfortable for them” — keeps it honest and educational.

• Use time-based intervals so everyone works within their own capacity (e.g., “1:00 fast / 1:30 easy” rather than “200m fast / 200m easy”).

• Remind athletes pre-session → “Run your workout, not the group’s workout.”

This is why group fartlek is actually one of the trickier formats — the freedom of pace means athletes who are over-competitive or overly compliant are both at risk of missing the mark.

One of the most important (and often overlooked) layers:

The athlete’s durability profile and how it shapes not just the structure of the workout, but the risk tolerance behind the whole training approach.

The Bomb-Proof Workhorse

• Traits → High biomechanical resilience, years of consistent training, recovers quickly, tolerates both volume and frequency of intensity.

• Approach → You can prescribe aggressive sessions, higher frequency of hard running, and push into race-simulation intensities more often. Still, the risk here is overconfidence — these athletes will happily bury themselves unless you cap the load.

The Injury-Prone or Biomechanically Fragile

• Traits → May have a great aerobic base and training history, but has recurring soft tissue, joint, or structural issues if run volume/intensity spikes too quickly.

• Approach →Keep the running intensity and mileage within their tolerance ceiling.

• Use cross-training (bike, swim, elliptical, water running, ski erg, ski touring) to build the same aerobic capacity and strength without the same impact cost.

• When prescribing faster running, dose it sparingly and be very precise with recovery windows.

• Effort-based work is often safer in heat or fatigue phases to avoid forcing them into unsafe paces.

The Developing Athlete (New or Conservative)

• Traits → May not yet understand the sensations of high-speed running, may be hesitant to push, or hasn’t developed the resilience to handle frequent high-intensity running.

• Approach →Gradual, progressive exposure to fast running — start with shorter bouts, lower frequency.

• Heavy emphasis on education: “This is what controlled discomfort feels like” and “Here’s how you’ll know it’s too much.”

• Often benefit from some pace targets early on to give them guardrails until their RPE compass is calibrated.

Why This Matters in Pace vs. Effort Prescription

• Bomb-proof → Can tolerate race-simulation pace sessions and even over-distance or over-intensity stimulus when strategically placed.

• Injury-prone → Pace-based sessions may still be fine, but only if the pace is conservative and the volume is low — otherwise effort-based is safer, especially in hot conditions or when fatigue is high.

• Developing → Start with pace for clarity, gradually introduce effort-based so they learn to self-regulate.

In triathlon we have the luxury of building intensity in swim and bike so that run load can be controlled without losing total fitness.

Pure runners don’t have this — they have to either cross-train or risk being in a constant boom-bust cycle. That’s why, for the injury-prone, even elite-level running programs lean heavily on gym work, cross-country skiing, cycling, or deep-water running.

Some thoughts on how to look at quantifying the run intensity:

1. The main unit of measure

• You’re not counting “speed sessions per year” — you’re thinking total minutes of faster running per 7-day cycle (and then zooming out to see it in 30-, 60-, 90-day patterns).

• For injury-prone athletes → total time at threshold or faster is very limited, and often replaced with low-impact high-intensity work (bike, swim, uphill run).

2. Relationship to race demands

• Ironman / long-course → very little pure “fast” running, because you can get most of the race-day benefit through strength-based work, turnover drills, and consistency.

• Short-course / 5K–10K → more pace-specific running is needed, but still scaled to durability.

3. Risk management rules of thumb for the fragile runner

• Hard run sessions once per 7-day cycle, with 48–72 hrs before/after easy or non-run days.

• Fast work on safe terrain or in controlled environments (hills, treadmill) to limit eccentric damage and form breakdown.

• Hill work as the go-to for threshold/strength because it’s lower impact and more biomechanically forgiving.

Spiraling Over a Career

• For injury-prone runners, the “spiral” isn’t about stacking more and more volume or speed each year — it’s about slowly raising the ceiling of what they can handle without setbacks.

• Maybe in Year 1, they tolerate 6 minutes of faster running in a week without niggles.

• Year 2, you can get away with 8–10 minutes.

• Year 3, maybe 12–15 minutes.

• The spiral is capacity for safe intensity, not just intensity for its own sake.

Using hills as threshold work and treadmill for turnover is how to I protect the fragile runner while still giving them race-day tools.Log not just minutes of fast running, but also impact risk category (low: uphill, treadmill, strides / high: flat hard efforts, downhill running). That way, the season plan shows both volume and risk exposure.

One of the key dials a coach can turn: rep length as a progression tool, not just pace or total volume.

An example of a durability-based progression:

• More durable athletes (or those with years of consistent load) can often handle longer continuous reps at threshold or faster paces — e.g., 1500 m–2 km repeats, long cruise intervals, or sustained blocks.

• Less durable or injury-prone athletes benefit from breaking that same total time at pace into shorter segments with more frequent resets — so form, mechanics, and tissue load never cross the tipping point.

For some athletes, the “max effective rep length” might never extend beyond 800 m (or even 400 m for faster-than-threshold work), so progression happens by:

Increasing total reps (e.g., 12×400 → 16×400)

Shortening recoveries between reps

Layering higher-end sessions over months and years while keeping each rep under their form breakdown threshold.

That way, you’re controlling both the mechanical strain (per rep) and the metabolic load (total session) without forcing them into the danger zone where the cost outweighs the adaptation.

Reminder that availability beats ambition when it comes to running progression.

• Consistency is king — the best predictor of long-term success is avoiding long layoffs, especially from running.

• Risk–reward filter — before deciding on a workout, ask: “Does this choice increase my injury risk enough to derail weeks or months of training?”

• Race goals don’t override durability — wanting to run fast doesn’t justify gambling with a session that could set you back.

• Coach–athlete dialogue is key — conversations about rep length, effort, and pace need to happen in the context of sustainability, not just peak performance.

“Get to the start line healthy”. In practice, that means:

• For injury-prone athletes, shorter, sharper reps to maintain quality without mechanical breakdown.

• For durable athletes, longer continuous reps once they’ve earned that capacity.

• Always viewing training through the lens of how it impacts next week, next month, and next season.

Your number one job as a runner is to stay healthy and consistent. Every decision about pace, rep length, or total volume should pass the “Will this keep me training next week?” test. Running fast only matters if you make it to the start line, so choose the safest path that still moves you toward your goal.