About Jelle Dekker

Jelle Dekker is the founder of Theron, an adaptive triathlon training coach for iPhone, Apple Watch, and Android. Theron builds and adjusts swim, bike, and run plans from recovery signals. The primary loop is Apple Health (HRV, sleep, resting heart rate) rewriting the plan, with structured workouts on Apple Watch.

Why Theron exists

Most age-groupers do not fail because they cannot find a PDF plan. They fail because life, sleep, and niggles break a static calendar and nobody rewrites the next week. Jelle built Theron after coaching himself through that loop: log the data, then still decide by hand what to do tomorrow. The product applies established load ideas, including Banister’s fitness-fatigue impulse-response work (Banister et al., 1975) and HRV-informed session timing (Vesterinen et al., 2016; Plews et al., 2013), so readiness can gate intensity automatically.

Athletic and product background

Jelle trains as a self-coached triathlete and ships Theron from that first-person constraint: busy weeks, Apple Watch as the training surface, and a plan that still has to be rewritten by hand when sleep, HRV, or the calendar breaks. Theron exists so that rewrite is automatic. The product applies published training models rather than a personal coaching certificate: Banister’s fitness-fatigue impulse-response work (Banister et al., 1975), HRV-informed session timing (Vesterinen et al., 2016), and HRV monitoring guidance (Plews et al., 2013). It is not a coach marketplace. It is a closed loop for self-coached athletes who want planning automated rather than logged, on iPhone and Apple Watch, with the same plan available on Android.

Contacte

Press, partnerships, and product questions: hello@theron.app. Company page: Theron on LinkedIn.