How many runs do I need to make outside (GPS on) to trigger lactate threshold, FTP and maximum heart rate ?
As chunckywizard noted, FTP is essentially the same thing as Lactate Threshold - but for cyclists, so let's skip that for the moment. You might also hear Lactate Threshold (running) and FTP (cycling) referred to as "Anaerobic Threshold."
Your Forerunner 935 should be able to detect your Lactate Threshold during any single run provided that these three conditions are met.
1. You have GPS activated - as you note 2. You are using a chest belt for HR-data; one of the key elements used to detect your Lactate Threshold is captured from your HRV, which can be difficult to isolate reliably during running from the optical sensor onboard the device. 3. Your run includes enough of the right kinds of data. This simply means running for long enough at different intensities/paces to make the calculation. There is a guided test you can perform to ensure you hit these marks, but your Lactate Threshold will also be calculated and updated during any normal run that satisfies the requirements.
Lastly, regarding maximum HR (HRmax). That bit of information isn't 'detected' - rather it's simply estimated using a commonly used age-based formula. If you actually know your own HRmax, you can go ahead and enter it into your device manually. That's usually a good idea/best practice that will boost the accuracy of most your feedback across the board.
Herman, nice explanation of what I said! One thing though, you can set the 935 to auto-update the MaxHR figure based on what has been measured on activities
Herman, nice explanation of what I said! One thing though, you can set the 935 to auto-update the MaxHR figure based on what has been measured on activities
chunkywizard when you're right, you're right. I misspoke a bit.
That auto-detect max HR option comes into play when a high-confidence HR is recorded in excess of your estimated max HR value. If your real max HR is lower than the estimate, then that won't be picked up - so it kind of only works in one direction. Your HRmax doesn't bounce around or respond to training, it's relatively stable (declining gradually as you age), so once you identify it, it doesn't need to be updated all that that often.
LT not detecting with treadmill running vs indoor cycling?
For running you'd need some sort of pace/speed input and for cycling you'd need input from a power meter - so if you were on a stationary bike that was feeding watts to your watch, then I imagine it would give you your FTP - but I'm not familiar with that particular case.
Your HRmax doesn't bounce around or respond to training,
Yep, although your ability to attain your true physiological HRmax improves as you develop better fitness, especially starting from a low base. However, the only caveat I'd offer to allowing the detection of HRmax automatically is that you only do this when wearing a chest strap as WHR is not stable enough at the intensity required. Even then, it's possible to get spikes, or extended peaks that have triggered an errant HRmax. I have mine set manually primarily because of the number of times I've experienced this over the years.
