Guide · Training with Moxy

Stop training blind.
Look inside the muscle.

The Moxy (a NIRS sensor) shows you, live, how much oxygen the working muscle consumes and recovers. Instead of going by heart rate or feel alone, you train against what is actually happening inside.

Start training with real data

SmO₂ (TSI%)

Muscle oxygen saturation. The main curve.

tHb

Total haemoglobin: how much blood is in the area, flow and vasodilation.

O₂Hb / HHb

Oxygenated vs deoxygenated haemoglobin: delivery vs extraction.

The core idea

A reference + two limits

All Moxy training rests on three concepts. Understand these first.

Baseline: your reference

Before starting you measure your resting SmO₂. Everything else is read relative to that number, not in absolute terms. Two people with the same curve can be in different physiological zones: each trains against their own reference.

Desaturation limit: the floor

How far you let SmO₂ drop during the effort. A deep floor = you stress the anaerobic pathways. A controlled floor = aerobic work. If it barely drops, the stimulus is insufficient. Each coach sets where it starts to count.

Resaturation limit: the ceiling

How much you let SmO₂ climb back during recovery before the next effort. Recovering almost everything = fast-recovery profile. Recovering little = accumulation, you are draining the tank.

SmO₂ · one set with its limits% relative to baseline

effortresteffortresteffortrest

The mental rule

Floor = how much stress you put in. Ceiling = how much you clear before repeating.
By playing with those two limits and the duration of the effort, you choose which system you train.

Reading the curve

The 4 patterns

The app classifies every set into one of these patterns.

Flat / high

What you see: it barely drops. What it means: intensity too low for the goal, or you are well on top of that effort.

Deep drop + fast recovery

What you see: it drops hard and comes back to nearly 100% during the rest. What it means: good aerobic and vascular machinery, you extract a lot and refill fast.

Deep drop + slow recovery

What you see: it drops hard and barely climbs between sets. What it means: you are leaning on anaerobic pathways and/or lack clearing capacity.

Oscillating (sawtooth)

What you see: it rises and falls within the effort itself. What it means: irregular pacing or technique, gripping and releasing, choppy pedalling or stride.

The signal map

Which capacity you are training

The 7 systems Fishlimpia scores in every session, with their signals on the curve and how to trigger them.

CapacityWhat it isSignals on the curveHow to trigger it

Aerobic base (slow OX)What it is: Mitochondria in slow-twitch fibreSignals on the curve: Long efforts, moderate drop, good sustained recoveryHow to trigger it: Long sets, medium floor, high ceiling

Fast OXWhat it is: Mitochondria in fast-twitch fibre + fast resaturation between short effortsSignals on the curve: Short efforts with strong recovery and quick semi-recoveryHow to trigger it: Short intervals, rests that allow near-full recovery

Glycolytic (lactic)What it is: Anaerobic pathway with lactateSignals on the curve: Fast, deep drop on medium-duration efforts, slow recovery, HHb risesHow to trigger it: Hard efforts with incomplete rest

Phosphagen (alactic)What it is: Pure power, no lactateSignals on the curve: Very short blocks, shallow drops, supercompensationHow to trigger it: Max efforts of a few seconds, generous rest

VascularWhat it is: O₂ delivery and vasodilationSignals on the curve: tHb rises, supercompensation above baselineHow to trigger it: Moderate continuous work, progressive warm-up

Metabolite toleranceWhat it is: Clearing lactate / H+Signals on the curve: Recovery degrading set after set, no recovery, metabolic overheatingHow to trigger it: High density, deliberately short rests

Technique / economyWhat it is: Efficiency and pacingSignals on the curve: Sawtooth within the effortHow to trigger it: Constant cadence, real-time feedback

Several capacities in one session?

General rule: one leading capacity per session. Each goal's floor and ceiling limits are different and sometimes opposite. The aerobic base wants to recover; metabolite tolerance wants exactly the opposite. Mixing everything dilutes the adaptation.

What works: sequencing in order

From most neuromuscular to most metabolic, using your freshness early:

1Phosphagen / power (fresh)

2Glycolytic / tolerance (body of the session)

3Easy aerobic base (final flush)

Pair well

Fast OX + vascular. Glycolytic + metabolite tolerance.

Clash

A hard glycolytic session + quality aerobic base on the same day. Better on separate days.

The Moxy ends the argument: if the curve stops behaving the way the goal demanded (under-recovering, no longer dropping), that capacity is already fatigued and it is time to stop or switch blocks.

Protocols by sport

Running

CALF / QUAD

Star goal: aerobic threshold and base. You want a moderate, stable drop that does not keep falling within the block. The breaking point (when SmO₂ plunges and will not stabilise) marks your true threshold pace, often better than a heart-rate test.

Typical session: long blocks at a controlled pace, checking that SmO₂ stabilises. If it collapses, you are past threshold.

Cycling

VASTUS LATERALIS

The cleanest scenario for NIRS: stable leg, no impact, very readable signal. Ideal for threshold tests and intervals: you see live whether you resaturate during the rest or not, and adjust power set by set.

Typical session: intervals aiming for the same drop and the same recovery in each one. When recovery starts slipping, you have found your density limit.

Climbing

FOREARM × 2

This is where Fishlimpia shines: it supports two sensors, one per forearm, and compares which arm recovers worse. The finger flexor is small and highly vascular: recovery between attempts is where the gold is. Usual goal: metabolite tolerance and fast reoxygenation between routes.

Typical session: repeaters on an edge aiming for a target drop and measuring how much you resaturate during the rest. When you stop recovering to the set ceiling, the quality is gone.

How it looks in Fishlimpia

Clip on the sensor (Moxy or Train.Red) and the curve is logged alongside your set, automatically.

Live audio cues (deox low, recovered, stop) so you can train without looking at the screen.

When you finish: each set's pattern, the alerts and a score for the 7 systems with a one-line tip for each.

Connect your Moxy and start training with data

Stop training blind.Look inside the muscle.