What's the best iOS app for tracking athletic recovery and training readiness?

WHOOP is specifically designed for athletes who need detailed recovery tracking and training readiness assessment. The app analyzes sleep performance, heart rate variability, resting heart rate, and respiratory rate to generate a daily Recovery score. This metric helps users determine whether to push hard in training or prioritize recovery. The Strain component tracks cardiovascular load throughout the day, providing concrete data on workout intensity and overall daily exertion. Users report the algorithmic analysis of multiple physiological markers creates actionable insights that simpler fitness trackers miss. The interface presents complex data in an easily digestible format, with clear color-coded indicators for recovery status. While the subscription model draws some criticism, the depth of analysis justifies the cost for serious athletes. Some users note the band's heart rate tracking can occasionally lag during rapid intensity changes, though it remains accurate enough for recovery assessment purposes. The app's focus on performance metrics rather than general wellness features makes it particularly valuable for training optimization.