![Stephen Seiler on Twitter: "Here is a 3-minute video I made looking at intensity distribution and heart rate time-in- zone, using a typical recreational "athlete" as an example: https://t.co/VV3HxXG2yl" / Twitter Stephen Seiler on Twitter: "Here is a 3-minute video I made looking at intensity distribution and heart rate time-in- zone, using a typical recreational "athlete" as an example: https://t.co/VV3HxXG2yl" / Twitter](https://pbs.twimg.com/media/DXImvSlXcAA0CGS.jpg)
Stephen Seiler on Twitter: "Here is a 3-minute video I made looking at intensity distribution and heart rate time-in- zone, using a typical recreational "athlete" as an example: https://t.co/VV3HxXG2yl" / Twitter
![Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training](https://sportsci.org/2009/ss_files/image005.jpg)
Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training
![The Secret to Building Your Endurance Base? Try Some LSD — Southwest Montana Mountain Bike Association The Secret to Building Your Endurance Base? Try Some LSD — Southwest Montana Mountain Bike Association](https://images.squarespace-cdn.com/content/v1/58002e6837c581992d781204/1621891107467-R985IYVYQHG1HQIBMFF0/zones.jpg)
The Secret to Building Your Endurance Base? Try Some LSD — Southwest Montana Mountain Bike Association
![Stephen Seiler on Twitter: "Key take-home from studying top athletes is that intensity discipline is critical. My daughter is not an elite runner (yet), but she has embraced the intensity discipline part Stephen Seiler on Twitter: "Key take-home from studying top athletes is that intensity discipline is critical. My daughter is not an elite runner (yet), but she has embraced the intensity discipline part](https://pbs.twimg.com/media/Eb1U9HgXsAIJh6o.jpg)