***Validation published in the Journal of Sports Sciences*** Dorsiflex is the first scientifically designed app to measure your ankle dorsiflexion. You just need to place your iPhone or iPad on your tibia while doing a lunge test, and the accelerometer and gyroscope of your device will calculate your dorsiflexion angle in a simple and accurate way. Reduced ankle's dorsiflexion is related to different lower body injuries such as plantar fasciitis, and it can negatively affect performance in several tasks like the squat. That's how doctors, physical therapists and sport scientists have been measuring dorsiflexion for years. Now, you can test your ankle dorsiflexion in an accurate and reliable way just with your iPhone or iPad! Also, Dorsiflex has several great features such as: -Multiple users: create as many users as you want -Unlimited tests per user: you can make as many tests as you want with each user, so you can see his/her evolution over time -Export data to a CSV file for further analysis Dorsiflex, test your ankles' dorsiflexion at a glance just with your iPhone or iPad!