apps / 6499464775
Norwegian 4x4 Protocol
BEST VO2 & HR MAX TRAINING APP
Nikita Yampolski · Health & Fitness · $5.99 · US storefront
- rating
- 4.3 ★
- ratings
- 55
- updated
- Jun 10, 2026
- released
- May 1, 2024
v2.5
visible word pool · 9 words
title 22/30 chars · subtitle 30/30 chars
App Store search indexes the title and subtitle together with the hidden 100-character keyword field as one combined pool: any phrase assembled from those words can rank. These are the words of Norwegian 4x4 Protocol's pool that are public — the keyword field is not exposed by any API.
from the listing
Norwegian 4x4 HIIT Timer — Interval Training & VO2 Max BOOST VO2 MAX WITH NORWEGIAN 4X4 PROTOCOL WORKOUTS Train smarter with the Norwegian 4x4 protocol, one of the most studied HIIT methods for improving cardiovascular performance and endurance. A precise, distraction-free timer guides every interval so you can focus on the effort. KEY FEATURES: - Norwegian 4x4 Timer - Precision 4min work / 3min rest cycles - Heart Rate Training - Track 90-95% max HR zones - VO2 Max…
latest US reviews
★★★★★
Needs a lock screen feature
This app screws up my workout every time because it shuts off unpredictably. A lock screen would solve the problem. (See C25K app.)
— -cw
★★★★★
Doesn’t work
App resets itself at each interval. Doesn’t work
— dtanghx
★★★★★
No Details
This app is essentially a timer, there is no guided instruction, which is difficult as a beginner. Also, when the app went in the background, it closed and kept starting over again during my workout. Do not recommend.
— ErnLantry
Newest first, from Apple's public reviews feed. Agents can pull hundreds per storefront with the reviews tool.
Where does it rank? Chart position is one signal — most installs come from keyword search. Check where Norwegian 4x4 Protocol ranks for any keyword, free, with the rank checker.
this page is one tool call
{ "tool": "app", "arguments": { "appId": 6499464775, "countries": [ "US" ], "subtitle": true } }
The app tool returns this listing as stable JSON for any storefront — one of thirteen ASO tools your agent gets over MCP. Get a free key.