Afitpilot®

Insights for peak performance

Training breakdowns, adaptation case studies, and honest lessons from real athletes using Afitpilot.

RPE (Rate of Perceived Exertion)A 1-10 self-reported scale measuring how hard a set felt. In strength training, RPE is anchored to "reps in reserve" (RIR): RPE 10 means you couldn't do another rep, RPE 8 means you had roughly 2 reps left, RPE 6 means about 4 reps in reserve.
Tonnage (Load)The total weight moved in a session — the simplest measure of mechanical stress placed on the body. Tonnage captures "how heavy was today?" in a single number.
Estimated 1-Rep Max (e1RM)A mathematical estimate of your true 1RM (one-rep max) — the heaviest weight you could lift for a single repetition — derived from a submaximal set. It lets us track strength progress without you ever needing to actually max out.
Volume (Total Reps)The total number of repetitions performed in a session, aggregated across all exercises. Volume is the most fundamental "how much work did you do?" metric.
HypertrophyAn increase in muscle cross-sectional area driven by training. Hypertrophy is the structural adaptation behind 'getting bigger' — muscle fibres add contractile proteins (myofibrillar) and fluid/glycogen storage (sarcoplasmic) in response to mechanical tension, repeated to a sufficient proximity to failure, with adequate protein and recovery.
SupercompensationThe principle that, after a training stimulus disrupts homeostasis, the body rebuilds slightly above its previous baseline during recovery — provided the next stimulus arrives in the right window. Supercompensation is the mechanism behind every progress curve: stress, recover, end up stronger than you started.
Progressive OverloadThe principle that for training to continue producing adaptation, the demands placed on the body must gradually increase over time. Progressive overload is the engine of long-term progress — every periodisation model, every program, every coaching framework is ultimately a way to manage progressive overload sustainably.
Zone 2A low-intensity aerobic training zone where you train just below the first lactate threshold — fully aerobic, conversational, sustainable for hours. Zone 2 is the workhorse of endurance development: it builds mitochondrial density, capillarisation, and fat-oxidation capacity without generating meaningful fatigue.
Polarized TrainingAn endurance training distribution where ~80% of sessions are easy (below first lactate threshold / Zone 2) and ~20% are very hard (above second lactate threshold / VO2max intervals), with minimal time in the middle 'threshold' zone. Polarized training is the dominant pattern in elite endurance sport across cycling, running, and Nordic skiing.

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