Power-Based Race Execution

Coggan's algorithm smooths power with a 30-second rolling average before weighting it.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Raising to the fourth power emphasises hard efforts, reflecting their disproportionate physiological cost.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Many physiological responses, such as oxygen uptake, adjust with a half-life of around 30 seconds.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Averaging values raised to the fourth power can only equal or exceed the plain average.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

The algorithm was designed for efforts of roughly 20 minutes or more.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

IF expresses how hard a ride was relative to threshold.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

TSS is scaled so that one hour at IF 1.0 equals 100.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

TSS = hours x IF squared x 100 = 2 x 0.64 x 100 = 128.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

TSS scales with IF squared but only linearly with time.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

5 x 0.72 squared x 100 = 5 x 0.518 x 100 = about 259.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Coaching guidance places full-distance bike legs at roughly 68-78% of FTP, an intensity factor of 0.68-0.78, depending on ability.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Half-distance bike legs typically sit around 80-85% of FTP.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Around an hour of riding allows a higher share of threshold, while still leaving a run to come.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Fatigue and fuel limits reduce the fraction of FTP that can be held as duration grows.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

A VI near 1.0 means steady power; larger values signal surges that cost energy for the run.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Bike TSS well above about 300 is often associated with a poor marathon, though it varies with fitness.

Source: Friel, The Power Meter Handbook (2012) · recall

0.72 x 250 = 180 W.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Two athletes with the same FTP can differ greatly in how much power they keep after several hours.

Source: Maunder et al., Sports Med 2021 · applied

Freewheeling downhill lowers average power, while normalised power accounts for the harder climbing.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

The same normalised power ridden unevenly means more hard efforts, which cost more for the run.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

CP is the power that could in theory be sustained for a long time without exhausting W prime.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Monod and Scherrer proposed the hyperbolic relationship between power and time to exhaustion.

Source: Monod & Scherrer, Ergonomics 1965 · recall

W prime is a finite energy reserve, in kilojoules, that is used whenever power exceeds CP.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Typical values range from around 10 to 25 kJ.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Time = W prime / (P - CP) = 20,000 / 100 = 200 s.

Source: Jones et al., Med Sci Sports Exerc 2010 · applied

Above CP, oxygen uptake and lactate keep rising to maximum; below it, a steady state is possible.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Both sit near the boundary of sustainable effort, but CP comes from a model and FTP from a field test.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Maximal efforts of roughly 3 to 20 minutes are fitted to the power-duration model.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Any power above CP uses W prime; at a small margin it simply lasts longer before exhaustion.

Source: Jones et al., Med Sci Sports Exerc 2010 · applied

Below CP, W prime is not being used and is reconstituted over time.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

It subtracts work done above CP and adds back recovery below CP, second by second.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

The recovery time constant shortens the further power drops below CP.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

Surges above CP draw on W prime; with short recoveries, it can run low before the decisive moment.

Source: Skiba et al., Med Sci Sports Exerc 2012 · applied

Recovery is modelled as exponential, fast at first and slower as W prime refills.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

At W'bal zero, power must drop to CP or below; the model predicts exhaustion.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

At long-course intensities W prime is barely used; fuel and durability matter more.

Source: Skiba et al., Med Sci Sports Exerc 2012 · applied

60 W x 120 s = 7,200 J, about 7 kJ.

Source: Skiba et al., Med Sci Sports Exerc 2012 · applied

Later studies found the original recovery constants do not fit all athletes or all interval patterns.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

Large efforts far above CP spend W prime quickly, leaving little for later.

Source: Skiba et al., Med Sci Sports Exerc 2012 · applied

A larger or faster-recovering W prime lets a rider answer more surges.

Source: Skiba et al., Med Sci Sports Exerc 2012 · recall

It plots the highest average power achieved over every duration, from seconds to hours.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Maunder described durability as the time and extent of deterioration in physiological profiling characteristics during prolonged exercise.

Source: Maunder et al., Sports Med 2021 · recall

Thresholds measured fresh can shift after several hours, so fresh values may mislead long-course pacing.

Source: Maunder et al., Sports Med 2021 · recall

Profiles repeated after, for example, 2,000-3,000 kJ of work show how much each athlete's power declines.

Source: Maunder et al., Sports Med 2021 · recall

Prolonged exercise can shift thresholds and power outputs downward, with large individual variation.

Source: Maunder et al., Sports Med 2021 · recall

Comparing 5-second, 1-minute, 5-minute and 60-minute bests reveals sprinter or time-trial tendencies.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Short-duration power reflects VO2max and W prime more than long-duration capacity.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Placing quality efforts after long durations trains the ability to hold power when fatigued.

Source: Maunder et al., Sports Med 2021 · recall

Simple two-parameter models overpredict power over hours because they omit glycogen depletion and durability.

Source: Jones et al., Med Sci Sports Exerc 2010 · recall

Same fresh capacity, different fatigue resistance: a durability difference that matters in long races.

Source: Maunder et al., Sports Med 2021 · applied

Raising power slightly on climbs and into headwinds and easing where fast gave predicted time savings.

Source: Atkinson et al., J Sports Sci 2007 · recall

Small variations gave the time savings; larger swings cost more physiologically than they saved.

Source: Atkinson et al., J Sports Sci 2007 · recall

Time saved per extra watt is greatest where speed is lowest.

Source: Atkinson et al., J Sports Sci 2007 · recall

At high speed, aero drag dominates so strongly that holding a tuck saves more than pedalling adds.

Source: Atkinson et al., J Sports Sci 2007 · recall

Big efforts cost disproportionately in glycogen and fatigue compared with the seconds gained.

Source: Abbiss & Laursen, Sports Med 2008 · applied

Even pacing refers to effort, not constant speed or rigidly fixed watts.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Accelerating over the crest regains speed when it is lowest, where extra power is worth most.

Source: Atkinson et al., J Sports Sci 2007 · recall

Extra power helps most on the slow climbing section.

Source: Atkinson et al., J Sports Sci 2007 · applied

The physiological cost of hard efforts carries into the run, even if bike time barely changes.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Limiting spikes keeps variability low and saves energy for later, with little time lost.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Reviews conclude even pacing is generally optimal for longer efforts on uniform courses.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Early excessive effort drains W prime and glycogen and raises fatigue that slows the later stages.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Athletes' power fell over the bike leg, reflecting fatigue and pacing decisions.

Source: Abbiss et al., Int J Sports Med 2006 · recall

Knowing the remaining distance or duration helps the brain regulate effort to finish without collapse.

Source: Abbiss & Laursen, Sports Med 2008 · recall

An end spurt suggests pacing kept a reserve that is released as the finish nears.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Optimal pacing minimises total time, so the bike effort must leave a strong run.

Source: Abbiss & Laursen, Sports Med 2008 · applied

Athletes use perceived effort, which grows over the race, to judge whether pace is sustainable.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Heat raises cardiovascular strain, so the usual power target may be unsustainable.

Source: Abbiss & Laursen, Sports Med 2008 · applied

Positive pacing means speed decreases over the event; negative pacing means it increases.

Source: Abbiss & Laursen, Sports Med 2008 · recall

Early overpacing accelerates fatigue, typically costing more time later than it gained.

Source: Abbiss & Laursen, Sports Med 2008 · applied

Manufacturers commonly quote accuracies of plus or minus 1-2%.

Source: Maier et al., Int J Sports Physiol Perform 2017 · recall

Most devices were within a few percent, yet individual units and brands showed meaningful errors.

Source: Maier et al., Int J Sports Physiol Perform 2017 · recall

Zeroing sets the unloaded baseline so small drifts do not bias all readings.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Strain gauges drift with temperature; many meters compensate, but zeroing after a change helps.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

A static torque check with a known weight at a known crank length verifies the slope.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Chain and sprocket losses of a few percent sit between the two measurement points.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Different measurement points and calibrations mean a few percent difference is common.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

A 3% offset between devices can shift race targets by several watts.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

A meter can be precise (consistent) but inaccurate (offset), which is fine for trends but not for comparisons.

Source: Maier et al., Int J Sports Physiol Perform 2017 · recall

Zones should match the device being used; retesting avoids training or racing at the wrong intensity.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

VO2max declined about 6-7% per 1,000 m from near sea level, and performance fell with it.

Source: Wehrlin & Hallen, Eur J Appl Physiol 2006 · recall

Aerobic power drops with altitude, so sea-level targets overestimate what can be held.

Source: Wehrlin & Hallen, Eur J Appl Physiol 2006 · applied

Lower torso angles close the hip, which can reduce power output and raise metabolic cost.

Source: Fintelman et al., J Biomech 2014 · recall

Beyond some point, lowering the torso cost more power than it saved in drag, varying with speed.

Source: Fintelman et al., J Biomech 2014 · recall

Setting race targets from upright testing may overestimate what can be held in the race position.

Source: Fintelman et al., J Biomech 2014 · applied

Poor airflow raises body temperature and effort at a given power; fans reduce the gap.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

A closed hip angle pushes the abdominal contents up, which can limit ventilation at high efforts.

Source: Fintelman et al., J Biomech 2014 · recall

Technical sections interrupt steady power and add surges, raising cost at a given average.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

At around 6% per 1,000 m, 1,800 m suggests roughly a 10% drop in aerobic power.

Source: Wehrlin & Hallen, Eur J Appl Physiol 2006 · applied

Thermal strain lowers sustainable power, so the power-drag trade-off shifts.

Source: Abbiss & Laursen, Sports Med 2008 · recall

With about 20-25% efficiency, kilojoules of work roughly equal kilocalories of energy expended.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Energy expenditure helps estimate how much carbohydrate is being burned, although intake is limited by absorption.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

Software solves the power equation along the course to predict speed and time for a given power plan.

Source: Martin et al., J Appl Biomech 1998 · recall

Allocating a little more power where speed is low reduces predicted time for the same overall cost.

Source: Atkinson et al., J Sports Sci 2007 · recall

Decoupling of heart rate from power suggests rising physiological strain that may affect the run.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · recall

A slightly lower bike effort can produce a much better run and a faster total time.

Source: Abbiss & Laursen, Sports Med 2008 · recall

A controlled run with limited fade suggests the bike effort was sustainable.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Easing slightly and spinning a little faster helps the transition to running without losing much time.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied

Two rides at the same IF can leave very different fatigue depending on variability, heat and fuel.

Source: Abbiss & Laursen, Sports Med 2008 · recall

A TSS well above typical guidance points to overcooking the bike relative to their fitness.

Source: Allen, Coggan & McGregor, Training and Racing with a Power Meter (3rd ed., 2019) · applied