Training Thresholds are based on Heart Rate and are set to make sure that people train at an effective but safe level.
aerobic training zone
60-80% of Max HR
anaerobic training zone
80-90% of Max HR
max HR
Maximum Heart Rate = 220 - Age
weight training thresholds
-Muscular Endurance training should be performed at below 70% of your one rep max.
-Strength/Power training should be performed at above 70% of your one rep max.