Measurable & Repeatable

You can’t get better at something you can’t measure.

Sounds obvious. But most athletes train without any real measurement. They do “hard workouts,” they feel sore, they “feel stronger,” and they hope it’s working.

That’s guessing. And guessing is fine when you’re starting out — but it’s not how you improve fastest.

Measurable & Repeatable is the foundation of everything in this book. It means:

• Measurable: you can put a number on it. Weight, reps, time, distance, RPE, how you felt.
• Repeatable: you can do the same thing again under the same conditions and get a comparable number.

If something is measurable and repeatable, you have data. If it’s not, you have stories.

The conversation with your body:

Here’s what most athletes miss. Every warm-up, every movement prep, every set — these are conversations with your body. Your body is telling you something every session. The question is whether you’re listening.

At first, you’re guessing. “How do I feel today?” is hard to answer honestly. Your brain lies. Your ego lies. Your mood lies.

But over months and years of the same warm-up, done the same way, in the same conditions, at the same time of day — the guessing gets better. You start to notice patterns. You learn what your body is telling you.

The rule from day 1: do it the same way. Same warm-up. Same conditions. Same movements. Write it down. This is how you learn to hear your body.

Standardization is the ritual that makes measurement possible.

The warm-up is your check-in.

Same movements. Same order. Same duration. Every session. Why?

• Your warm-up becomes a diagnostic tool
• You feel the same things every day — so you notice when something is different
• By the end of your warm-up, you know what kind of day you’re having

How to standardize:

Element	Standard	Why
Time of day	Same window daily	Body rhythms affect performance
Warm-up	Same sequence	Diagnostic check-in
Order of movements	Same order	Comparable conditions
Rest between sets	Same rest	Comparable stimulus
Bar setup	Same rack, same plates	Reduce random variation
Equipment	Same shoes, same belt	Reduce variables

What to measure every session:

• Load: weight on the bar, or bodyweight movement
• Volume: sets x reps
• RPE: how hard it felt (1-10)
• Notes: anything different about today

The signal vs. noise question:

Your numbers will fluctuate. Weight fluctuates. RPE fluctuates. Mood fluctuates. This is noise — the random variation that has nothing to do with progress.

Signal is what emerges over weeks. A new PR. A trending RPE. A pattern of fatigue. You can’t see signal in one session. You can only see it across many sessions under similar conditions.

The rule: measure the same way, every time. Then look for the signal.

“Don’t want to” vs. “can’t right now”:

These two things feel similar. They’re completely different.

• “Don’t want to”: mental. The gremlin. Your body is fine; your head is not. Push through — carefully.
• “Can’t right now”: physical. Your body is telling you something. Respect it.

Learning to tell the difference is one of the most important skills in training. The standard warm-up is how you learn it.

Measurement is not just about the bar. It’s about learning to read yourself with increasing accuracy.

Calibration is the process of aligning your perception with reality.

• You think you’re at RPE 7. Are you?
• You think you slept well. Did you?
• You think you’re recovered. Are you?

At first, you’re wrong a lot. Your RPE 7 is really an RPE 5. Your “good night’s sleep” was actually fragmented. Your “ready to train” was actually under-recovered.

But calibration is trainable. Here’s how:

1. Predict before, verify after. Before a set, guess your RPE. After, note your actual RPE. Over time, the gap shrinks.
2. Track subjective and objective markers together. Your mood + your HRV. Your readiness + your actual performance. See where they line up and where they don’t.
3. Reflect weekly. Did your perception match reality this week? Where was the gap?
4. Repeat for months. Calibration doesn’t happen in weeks.

What accurate calibration gives you:

• You know when to push and when to back off
• You trust your own signals
• You can autoregulate intelligently
• You can spot a real problem before it becomes an injury
• You can spot an opportunity before it’s gone

The signal vs. noise problem:

Your body sends signals constantly. So does your mind. But most of the noise is not signal.

• Signal: an injury warning, a fatigue flag, a readiness cue
• Noise: mood swings, bad dreams, mild aches that pass

The athlete who can tell them apart gets the most out of training — and the least injured.

This is the art. The science is the log. The art is reading the log.

The role of measurement:

Without standardized measurement, you can’t distinguish signal from noise. You can’t calibrate. You can’t learn what your body is telling you. Every session becomes a one-off, and every feeling becomes a guess.

Standardization + reflection over time = calibration. Calibration = self-knowledge.

At the research level, measurement is a science of validity, reliability, and error margins. Knowing this changes how you interpret your own data.

Three properties of a good measurement:

1. Validity: does the measurement actually reflect what you think it does?

• A vertical jump test measures lower body power. Good.
• A scale measures weight — but not body composition. Imperfect.
• RPE measures perceived effort. Valid for autoregulation if the athlete is calibrated.

2. Reliability: does the measurement give the same answer under the same conditions?

• A calibrated bar and plates: highly reliable.
• A tired athlete’s RPE: less reliable.
• A morning HRV reading: reliable if taken under standard conditions.

3. Sensitivity: can the measurement detect a real change?

• A scale can’t detect a 0.5 kg muscle gain if you also lost 0.5 kg of fat.
• A 1RM test can detect strength changes of 2-5%, not smaller.
• HRV can detect subtle autonomic shifts if conditions are standardized.

Standard Error of Measurement (SEM):

Every measurement has error. The SEM tells you how much.

Example: If your vertical jump has an SEM of 2 cm, then a change of 1 cm is meaningless (within error), a change of 3 cm is probably real, and a change of 5 cm is definitely real.

Minimum Detectable Change (MDC):

The smallest change you can be confident is real, not noise. Roughly 1.96 x SEM x sqrt(2).

Practical use:

• Squat 1RM: MDC is about 2-3%. Anything smaller is noise.
• Vertical jump: MDC is about 2-3 cm. Anything smaller is noise.
• RPE: MDC is about 1 point. Anything smaller is noise.
• HRV: MDC varies; usually a 5-10% shift from baseline is meaningful.

Coefficient of Variation (CV):

How much a measurement varies session to session. Low CV = reliable. High CV = noisy.

Examples:

• Squat 1RM: CV 2-3%
• Vertical jump: CV 3-4%
• HRV (standardized): CV 5-10%
• Self-reported readiness: CV 15-25%

Athlete monitoring systems:

Elite programs track:

• HRV (heart rate variability): autonomic recovery
• RHR (resting heart rate): aerobic fitness and recovery
• Sleep duration and quality: the biggest recovery lever
• Subjective wellness: mood, soreness, stress
• Training load: volume x intensity
• Performance metrics: velocity at fixed load, jump height, sprint time

The research on monitoring:

• HRV-guided training produces equivalent or better outcomes than fixed programming in trained athletes (Kiviniemi et al., 2007).
• Subjective wellness often predicts performance better than objective markers.
• Combining objective + subjective markers is more powerful than either alone.
• Standard error of measurement means athletes and coaches should not overreact to small changes.

Programming takeaways for advanced athletes:

• Standardize conditions: same warm-up, same time, same equipment.
• Track both objective (HRV, HR) and subjective (readiness, mood).
• Look for trends over weeks, not days.
• Know the MDC for your key tests — don’t chase noise.
• Trust the process: measurement over months reveals patterns that measurement over days cannot.
• Calibration is a long game. The athlete who measures carefully for years knows their body better than any wearable.
• The goal is not the data. The goal is the self-knowledge the data provides.