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Module 3 of 5

Performance Optimization

  • about 25 min
  • 5 reading sections, 5 min
  • 4 activities, 20 min
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Overview

Integrating wearable data into periodization and recovery management.

Listen to this moduleabout 11 min

Download the audio (4.9 MB)

What you will learn

  • Establish an individualised athlete baseline and define personalised reference ranges.
  • Integrate wearable-derived metrics into linear, block, and undulating periodisation at micro-, meso-, and macrocycle levels.
  • Interpret recovery indicators (HRV, sleep, perceived wellness, CMJ) and synthesise them into a recovery judgment.
  • Design a wearable-informed tapering plan for a competition peak.
  • Evaluate the marginal value of adding a new metric against the cost of measurement burden.

Video tutorial: Compared to themselves

How to build an athlete's own baseline, read today's value against it, and decide what a flag asks of you.

3 min 27 s

The video comes from Vimeo, and only after you press the button. What Vimeo then receives

Read the words of this video

A baseline is a distribution

This athlete’s resting HRV is 70 milliseconds. Is that good? You cannot tell. A baseline is not a single number. It is a distribution. Now try this: this athlete’s resting HRV averages 70 milliseconds, with a standard deviation of 6, over the past four weeks. That is the start of a useful reference.

How to build it

A usable baseline needs four things. Collect data for at least 4 to 6 weeks before you draw any conclusion. Keep the conditions the same every day. For HRV, that means first thing in the morning, lying down, with controlled breathing, before caffeine. Compute the athlete’s own mean and standard deviation for each metric. And define the athlete’s own reference range: within one standard deviation of the mean is the normal range. Beyond two is an anomaly worth investigating.

Reading today’s value

Now a morning reading comes in: 62. That is 8 milliseconds below this athlete’s mean, and the standard deviation is 6. So today sits more than one standard deviation below the mean, but less than two. That is a yellow flag. Sleep and wellness are unchanged. What does a yellow flag on one input ask of you? Monitor, and ask the athlete how they feel. Not a modified session, and certainly not a cancelled one.

Four flags

The flags work like this. Green: within the normal range, train as planned. Yellow: one standard deviation below, monitor and ask. Orange: two standard deviations below, modify the session by an amount you decided in advance. Red: three standard deviations below, substitute the session and escalate for review.

Never one metric alone

And never act on one metric alone. HRV down, sleep fine, wellness fine: monitor. It may be a single stressful day. HRV down, sleep declining, wellness declining: intervene. Wellness is a simple morning questionnaire: five items, rated from 1 to 5, on sleep quality, fatigue, soreness, mood and stress. It costs nothing, and it is often the most informative signal you have.

Not against the squad

One rule runs through all of this: compare athletes to themselves, not to the squad. Differences between athletes are far larger than one athlete’s day-to-day changes, so a squad average will mislead you.

Your turn

Before you add another metric, ask what decision it will change. If the answer is none, leave it out. A small set of well-used metrics outperforms a large set of unused ones. Now build a one-page profile for one athlete: the mean, the standard deviation, today’s value and a flag for each metric. The baseline builder in this module does the arithmetic.

Key ideas

A baseline is a distribution, not a number

“This athlete's resting HRV is 70 ms” is uninformative. “70 ms with a standard deviation of 6 ms over four weeks” is the start of a usable reference.

  • Collect 4-6 weeks first

    Before drawing any inference at all. A baseline built on five days is noise with a decimal point.

  • Standardise the conditions

    HRV on waking, supine, controlled breathing, before caffeine. Sleep: the same wearable every night. An unstandardised baseline measures your protocol, not your athlete.

  • Compare athletes to themselves

    Plews et al. (2013): between-athlete variability dwarfs within-athlete day-to-day variability. Population norms mislead.

  • Triangulate

    HRV down with sleep and wellness fine = monitor. HRV down with sleep and wellness also declining = intervene. Never act on one metric alone.

  • Taper: confirm, don't redesign

    Volume down 41-60% over 8-14 days, intensity preserved (Bosquet et al., 2007). Wearable data tells you whether it is working.

  • Measurement burden is real

    Five minutes per athlete per day, plus staff analysis time, plus the risk of number anxiety. Before adding a metric, ask what decision it will change.

The organising idea. Data does not write the plan. Data tells you whether the plan you wrote is doing what you intended.

Read

3.1 Building an athlete baseline that is actually meaningful

Listen to this section, about 2 min

A baseline is not a single number. It is a distribution. To say “this athlete’s resting HRV is 70 ms” is uninformative; to say “this athlete’s resting HRV averages 70 ms with a standard deviation of 6 ms over the past four weeks” is the start of a useful reference.

The protocol that delivers usable baselines:

  • Collect data for at least 4-6 weeks before drawing inferences.
  • Standardise measurement conditions (HRV: first thing in the morning, supine, controlled breathing, before caffeine; sleep: same wearable each night).
  • Compute the individual mean and standard deviation for each metric.
  • Define personalised reference ranges, typically ±1 SD from the individual mean for “within normal range”, and ±2 SD for “anomaly worth investigating”.

Research evidence. Plews, Laursen, Stanley, Kilding, and Buchheit (2013) demonstrated that HRV interpretation must be rooted in the individual: population norms are misleading because between-athlete variability dwarfs within-athlete day-to-day variability for the athletes whose training adaptation matters most. The principle generalises across metrics: compared to themselves, not to the squad.

Practical tip. A useful structure is a one-page “individual athlete profile” (Template A3) that displays the mean, SD, and current value for each tracked metric, with a traffic-light indicator. This document is the coach’s morning-meeting reference.

Practise: Builder

Baseline and reference-range builder

Ten morning HRV readings, then today's value. The tool computes the individual mean, the standard deviation and the flag your early-warning system should raise.

Readings, ms

Results

Individual mean
69.0 ms
Standard deviation
4.2 ms
Normal range, mean ± 1 SD
64.8 to 73.2 ms
Today vs mean
-2.61 SD

Orange: two SD below. Modify the session by a predetermined amount

Change one of the ten inputs to an extreme value and watch the SD widen: a noisy baseline makes every flag less sensitive. That is why standardised measurement conditions matter more than the device you use.

Read

3.2 Wearable data inside periodisation frameworks

Listen to this section, about 2 min

Classic periodisation models (linear, block, undulating, conjugate) were designed before continuous monitoring. They are not replaced by wearables; they are augmented.

Microcycle (one week). Wearables enter the microcycle through daily readiness. Each morning, the coach reads HRV, sleep, and wellness; categorises the athlete as green, amber, or red; and adjusts the day’s session accordingly. The decision rules are pre-defined (see Template A8) so the call is not improvised under pressure.

Mesocycle (3-6 weeks). Wearables enter the mesocycle through progressive overload management. The coach plans week-by-week increases in load (typically 5-10% per week within a block). Weekly load reports compare planned versus actual external load and observed internal-load response, allowing the coach to see whether the planned progression is being tolerated.

Macrocycle (one season). Wearables enter the macrocycle through long-arc adaptation tracking: for example, declining resting HR at the same training load suggests cardiorespiratory adaptation; stable CMJ height across a heavy block suggests neuromuscular preservation under load.

The principle: data does not write the plan. Data tells you whether the plan you wrote is doing what you intended.

Read

3.3 Recovery metrics: what they show and what they do not

Listen to this section, about 3 min

Three recovery domains, none sufficient on its own.

Heart rate variability (HRV). HRV reflects autonomic nervous system status: broadly, the balance between sympathetic (mobilisation) and parasympathetic (recovery) input to the heart. Higher resting HRV, in general and over time, indicates parasympathetic dominance consistent with recovered status. Lower HRV, particularly a sustained downward trend, indicates accumulated stress. Caveats: HRV is sensitive to alcohol, illness, life stress, and the measurement protocol; a single day’s reading should never trigger action: the trend over 5-7 days is what matters.

Sleep. Total sleep time, sleep efficiency (time asleep divided by time in bed), and time in each sleep stage are reported by most consumer wearables. Total sleep time and sleep efficiency are reasonably reliable in research validation against polysomnography (PSG); stage classification (deep, REM, light) is less accurate from consumer devices, and coaches should be cautious about acting on stage-level data. The actionable rule: track total sleep time and efficiency; treat stage data as suggestive, not definitive.

Research evidence. Walsh, Halson, Sargent, Roach, and colleagues’ 2021 expert consensus on sleep and the athlete provides the most current and authoritative practitioner reference. Coaches should be familiar with its core recommendations: pursue 7-9 hours nightly as a baseline; protect sleep on competition eve; treat persistent sleep disturbance as a wellbeing issue requiring intervention.

Subjective wellness. A simple morning questionnaire (five items rated 1-5: sleep quality, fatigue, soreness, mood, stress) costs nothing and adds the athlete’s own experience to the picture. Saw, Main, and Gastin (2016) showed that subjective measures often outperform objective ones for tracking acute training response. Coaches who rely only on devices and never ask the athlete are missing the most informative signal.

The discipline of triangulation: never act on one metric alone. HRV down, sleep fine, wellness fine = monitor, perhaps a single life-stress event. HRV down, sleep declining, wellness declining = intervene.

Practise: Case

The triathlete in week 11

A national-level age-group triathlete, 16-week build, peak race at week 16. Decide as the coach; each choice is answered with what actually followed.

  1. Stage 1 of 2

    Week 11: the data

    Across weeks 9-11: sleep efficiency has fallen from 91% to 82%, HRV from a 56 ms baseline to 47 ms, subjective wellness from 4.0 to 3.2. sRPE for the prescribed sessions is drifting upward: the same session now feels harder. The athlete reports no illness and no pain.

Read

3.4 Tapering with wearable confirmation

Listen to this section, about 2 min

Tapering reduces accumulated fatigue while preserving fitness, allowing peak performance at a competition. Mujika and Padilla’s (2003) reviews remain the foundational reference; a later meta-analysis (Bosquet, Montpetit, Arvisais, & Mujika, 2007) supplies the figures: optimal taper typically reduces training volume by 41-60% over 8-14 days, while maintaining or even slightly increasing intensity, and reducing frequency only modestly.

Wearable data adds confirmation, not redesign. During a well-executed taper, expect:

  • HRV to rise as parasympathetic recovery exceeds training-induced sympathetic load.
  • Subjective wellness to improve (mood up, fatigue down, soreness down).
  • CMJ height to rise modestly as neuromuscular freshness returns.
  • Resting HR to drift down slightly.

If the data shows the opposite (HRV declining, wellness worsening) during the taper, the plan is not working. The coach should investigate: is residual fatigue greater than expected? Is the athlete sleeping poorly? Is life stress confounding the picture? The intervention is not “ignore the plan”; it is “diagnose and adjust”.

Worked example. A 14-day taper for an 800-metre runner: volume reduced from 60 km/week (baseline block) to 30 km/week at day −14, then 22 km/week at day −7, then 12 km/week in the final week. Intensity preserved: race-pace work continued at full effort, reduced in volume. Through the taper, the athlete’s HRV moved from 65 ms (baseline mean) to 71 ms by day −5; CMJ height rose from 38 cm to 40 cm; subjective wellness composite rose from 3.6/5 to 4.2/5. The data confirmed the taper was working. On race day, the athlete ran a personal best.

Read

3.5 The measurement-burden trade-off

Listen to this section, about 1 min

The most-ignored design question in monitoring is: what is the cost of measuring this?

  • Athlete time (morning HRV measurement adds 5 minutes per day per athlete).
  • Equipment cost and maintenance.
  • Staff analysis time.
  • Risk of number anxiety: athletes becoming preoccupied with their own metrics in unhelpful ways. This risk is non-trivial, particularly among adolescents and athletes prone to perfectionism.

Before adding any metric, ask honestly: what decision will this change? If the answer is “none”, the metric should not be in the system. A small set of well-used metrics outperforms a large set of unused ones.

Quiz

Module quiz

  1. Question 1: An athlete's HRV is 8 ms below their individual mean. Their SD is 6 ms. Sleep and wellness are unchanged. What do you do?

  2. Question 2: How long should you collect data before drawing inferences from a baseline?

  3. Question 3: During a taper, HRV falls and wellness worsens. The correct response is:

  4. Question 4: You are considering adding a fourth daily metric. What is the first question to ask?

Reflection

Reflective prompt

These three answers become the “metric selection” section of your 90-day plan in Module 5.

Take it further

References in this module

All references
Co-funded by the European Union

WEARCOACH: Leading the Way in Wearable Technologies for Sports Coaching. Project reference: 101229603. https://wearcoach.sports4.eu/learn/performance/

Co-funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.