Training intensity

In general, training intenity refers to the quality of exercise, how hard/stressful the exercise is. The more work athlete performs in the unit of time, the higher the intensity of the exercise and during exercise intensity may vary from very low level (shooting, archery) to a very high level (100 m sprint, weightlifting etc). To measure intensity there are different options:
• Exercises involving speed can me tracked as km/h, m/s etc
• Intensity might be the percentage of the maximum effort. For example in resistance training usually 1 repetition maximum (RM) is used. This indicates the weight that can be lifted one time and is therefore 100% effort. Further weights can be determined like 6 times 80% 1RM, meaning the weight that is 80% of the maximum and lift it for 6 times. In this case intensity basically cannot be higher than 100%.
• Intensity can also be used as a fraction of competitive speed. For, example for 10 k runner his best 10k time (speed) is his 100% competitive pace. In this case intensity can also be 110% if an athlete runs 3k distance.
• An amount of energy expended during a time period (kcal/h). This method, however needs a special device, or heart rate monitor.
Probably the most universal and common method to determine intensity is to use heart rate, as heart rate increases in accordance to increases in exercise intensity. However, heart rate in not a good indicator of intensity in resistance exercises and short maximal intensity exercises due to the lag period in heart rate response to increases in exercise. In order to use heart rate as intensity indicator you must bear in mind that different training intensities, also called intensity zones, have different impact to your body. Also there is a threshold level beyond which significant training gains take place. For endurance type of exercise this threshold is somewhere around 60% of your maximal heart rate, meaning that in order to have increases in performance your heart rate should be higher than 60% of your maximal heart rate. In resistance exercise the threshold intensity has proposed to be 30-30% of your 1RM.
An average calculation method to describe training intensities based on heart rate. (According to Bompa, 1999), however there are several other methods or criteria to set up intensity zones.
Zone Intensity type Heart rate/min Heart rate % of maximum

Reference: Bompa T. Periodization. Theory and methodology of training. Human Kinetics, Chicago, IL. 1999.