Boost VO2 vs SendPin

Boost your VO2 max and running performance with the Norwegian 4x4 interval training method. WHAT IS 4X4 TRAINING? The Norwegian 4x4 method consists of 4-minute high-intensity intervals followed by 3-minute recovery periods, repeated 4 times. This training protocol has been extensively researched and proven to significantly improve VO2 max and aerobic capacity. KEY FEATURES: Personalized Training Plans Create custom 4x4 training programs based on your fitness level Choose from 4-8 week plans with 1-4 workouts per week Get estimated VO2 max improvements for your specific plan Guided Workout Experience Audio coaching with clear interval timing and instructions Visual cues and haptic feedback during workouts Automatic phase transitions (warmup, intervals, recovery, cooldown) Voice coach selection for personalized motivation PERFECT FOR: Runners looking to improve aerobic capacity Athletes training for endurance events Fitness enthusiasts wanting to boost VO2 max Anyone following the Norwegian 4x4 method WHY CHOOSE BOOST VO2? Unlike generic interval training apps, Boost VO2 is specifically designed for the Norwegian 4x4 protocol. Our app provides the exact timing, structure, and guidance needed to maximize your VO2 max improvements through this proven training method. Start your journey to better aerobic fitness today with Boost VO2 - the ultimate 4x4 interval training companion.

SendPin is a companion app for the Hammerhead Karoo, a cycling GPS computer. It sends a destination from the iPhone to the Karoo over Bluetooth Low Energy: the iPhone advertises a custom BLE service holding the destination in a GATT characteristic, and a Karoo-side extension — built on Hammerhead's own officially supported third-party extension framework (karoo-ext) — reads it and hands the coordinates to the Karoo's built-in navigation. PURPOSE AND TARGET AUDIENCE The audience is cyclists who own a Hammerhead Karoo and want to search for a destination using their phone rather than the Karoo's own limited on-device search and keyboard. The problem: cyclists often want to find somewhere to go — a café, a shop, a place a friend recommended — while already out riding, especially somewhere unfamiliar. Doing that safely is hard: checking a phone one-handed while riding is dangerous, and a bike computer's small keyboard and limited search make it a poor tool to look something up in the moment. The value: SendPin makes it easy to search for a destination on the iPhone — Apple Maps reviews, a larger screen, or simply opening a pin a friend sent over iMessage — and then navigate to it on the bike computer, instead of riding one-handed with the phone out to check it. SETUP, ACCESS, AND WHAT'S VERIFIABLE WITHOUT A KAROO No login, account, or credentials of any kind — there is nothing to provision for review. 1. Install SendPin. 2. Find a place in Apple Maps, tap Share, select SendPin. 3. A card appears over Maps and begins advertising the destination over Bluetooth Low Energy immediately. This much is fully testable without any additional hardware: • The empty state and welcome screen explain the full flow in plain text. • After about 25 seconds with nothing reading it, the card reports that nothing picked up the destination — the expected result with no Karoo present. • The shared place is saved in the app's history. Opening SendPin and tapping it resends the same destination the same way, and the live Bluetooth log is visible under Settings → Connection details. 4. A Hammerhead Karoo running the free, open-source SendPin extension receives it within about two seconds and shows the pin, ready to navigate. This half requires hardware Apple does not have, which is what the attached recording demonstrates. SCREEN RECORDING A screen recording is attached demonstrating the app's functionality, starting with launching the app. The only part of the flow it cannot show is the Karoo itself — a separate physical device — receiving the location and confirming the pin was picked up, since that happens on hardware outside the iPhone. The recording does show the iPhone side completing successfully: the destination is picked up and sent. • No account registration, login, or account deletion — the app has no accounts of any kind. • No user-generated content. • No paid content or features — the app is free with no in-app purchases. EXTERNAL SERVICES, TOOLS, OR PLATFORMS USED None. SendPin makes no network requests of any kind — no analytics, no crash reporting, no authentication service, no payment processor, no AI service, no data provider, no backend of any kind. The only communication it performs is a direct, local Bluetooth Low Energy transmission from the iPhone to a Karoo within a few metres — the same category of connection a power meter or heart rate strap uses. There is nothing external to list. REGIONAL DIFFERENCES None. There is no server-side component, no geofencing, no region-specific content or feature gating anywhere in the app. It functions identically in every region. REGULATED INDUSTRY OR PROTECTED THIRD-PARTY MATERIAL Not applicable. SendPin does not operate in a regulated industry and includes no protected or licensed third-party material. It uses only Apple's own frameworks (MapKit, CoreBluetooth) and displays only content the user has personally selected in Apple Maps.