July 12, 2026 · 6 min read

The 4DP Test (Power Profile) — How to Identify Your Weaknesses Mathematically

The 4DP test (Four-Dimensional Power) describes you with four numbers instead of one: NM — 5 s sprint power, AC — 1 min anaerobic capacity, MAP — 5 min maximal aerobic power, and FTP — 20 min threshold power. FTP alone only says how you ride at a steady pace; it's the ratios between these four values that show mathematically whether you're a sprinter, a climber or a "diesel" — and which quality is your brake. Your weakness is the value that falls furthest below the rest of the profile.

The logic of 4DP: different effort durations load different energy systems. 5 seconds is phosphocreatine and neuromuscular recruitment, 1 minute anaerobic glycolysis, 5 minutes VO2max, 20+ minutes the lactate threshold. A single number (FTP) flattens that picture: two riders with a 260 W FTP can have an NM of 700 W and 1,100 W — and win and lose races completely differently. The continuous version of the same analysis is your power curve — 4DP simply reduces it to four checkpoints.

What the test looks like and the numbers you get

• NM (5 s) — a sprint from full freshness. Amateurs: typically 8–14 W/kg.
• AC (1 min) — a maximal one-minute effort, done partly on tired legs. Typically 5–8 W/kg. Closely related to FRC.
• MAP (5 min) — maximal aerobic power. Typically 3.5–5.5 W/kg; a healthy ratio is MAP ≈ 115–125% of FTP.
• FTP (20 min) — classic threshold power. If you prefer a shorter protocol you can also get FTP from a Ramp Test, but then you're missing the other three dimensions.

How do you read your weakness out of four numbers?

Convert everything to W/kg and compare the ratios against the typical ones: if FTP is >90% of MAP, your aerobic ceiling is blocking further threshold growth — train VO2max; if MAP is high but FTP ≤80% of MAP — you lack base and threshold work; low NM/AC with a strong FTP is the "diesel" profile that loses every surge. The value that sags below the rest points at the energy system to train in your next block.

The profiles and what they mean for training

• Sprinter (high NM/AC, average FTP) — wins finishes, gets dropped on long climbs. Train: sweet spot, threshold, aerobic volume.
• Climber/TT (high FTP/MAP, low NM) — strong at steady pace, helpless against attacks. Train: sprints, 30/15 micro-intervals, over-unders.
• Attacker (high AC/MAP, average FTP) — shines in 1–5-minute moves, lacks the "diesel." Train: longer threshold intervals, tempo.
• Balanced — no obvious hole; then you train for the demands of your target event, not the profile.

How often should you repeat a power-profile test?

Every 8–12 weeks, at the end of a training block — more often makes no sense, because adaptations take weeks and a full 4DP test is brutally taxing (it's effectively four tests in one session). Between tests, track progress passively: your 5 s / 1 min / 5 min / 20 min records from normal training and racing update the profile without a separate test — the same windows you watch on the power curve after VO2max interval blocks.

Summary

4DP is math instead of intuition: four points on the power curve, converted to W/kg and compared as ratios, tell you outright which energy system limits you. Do the full test once per block, find the sagging value and build the next 8 weeks around it — instead of endlessly training what you're already good at. Between tests, let the power curve do the work: if records in your weak time window are rising, the plan works; if they're flat, the stimulus is mis-aimed, not too small.

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