Order the steps to calculate heart rate limits for each training zone:
1️⃣ Recovery Zone: Lower Limit = 50% of MHR, Upper Limit = 60% of MHR
2️⃣ Endurance Zone: Lower Limit = 60% of MHR, Upper Limit = 80% of MHR
3️⃣ Tempo Zone: Lower Limit = 80% of MHR, Upper Limit = 90% of MHR
4️⃣ Interval Zone: Lower Limit = 90% of MHR, Upper Limit = 100% of MHR