Wife asked an interesting question... (Page 4)

Wish I could ride a 5:15 on that IF...

Serious question.  How did you determine the TSS score to hit for the IM?  Was this based on past races and your ability to run, or something else.  Also curious what % you would aim for in an HIM and what TSS that factors out to.

That does make sense.   Now, I know that this next question is going to get dangerously close to another topic that has been beaten to death in other treads, but if your goal for the workout is to get to a TSS of 250 (or x for any particular rider), where would you think that the increase in intensity and shortening the duration starts to not paying sufficient return?  While riding for a certain duration at 100% FTP/IF of 1.0 would give the same TSS, at some point I think you need a certain time in the saddle.  So, to try and give some guidance to the OP and for my increased knowledge, why is 4:15 the long ride that you have chosen in this example?  Why not 4:00 or 3:45 at a higher intensity?

I guess the way I was looking at it (without perhaps knowing it, or being right) was getting to a higher TSS through increasing the duration.

You're now kind of saying something different than what I responded to.  You stated you were going to ride for eight hours.  Now you're basically saying the eight hour bike ride will be used to somehow simulate a 1:00S/6:00B/1:00R.  An eight hour bike ride is in no way equivalent to a 1:00 swim, 6:00 bike and 1:00 run, especially if you're trying to simulate or replicate nutrition.  Why not just do a 1:00S/6:00B/1:00R as opposed to an 8:00 bike?  Nutritional screw-ups aren't going to manifest itself on a slow 8:00 bike ride like it would if you did a 6:00 bike and 1:00 run at IM pace.  I could take in 500 cal/hour just riding my bike and not have any ill effects.  I couldn't do that on the bike during a tri and expect to run after.  Trust me, I tried that once.  Would you like to see my hospital bills after that experiment went horribly wrong? 

You're right, there's no exact science as to when nutritional snafus are going to rear their ugly head on the run but I'm sure you've read some race reports in which people have had gut problems and the vast majority of those people knew they were in distress very early in the run.  Could it happen 2 hours into the run?  3 hours into the run?  4 hours into the run?  Sure.  Are you going to run for three hours after a training ride to see if that happens?  Nope, at least I hope not.  You can't simulate or replicate every race day scenario.  My point stands that super long days (especially those with runs) have a recovery hole that is often overlooked and not properly appreciated.

Yes, I'm assuming an 8:00 bike ride is slogging along in Z1.  It has to be.  You may have had moments in which you were riding out of Z1 (like on the climbs you mentioned) but the overall workout wasn't out of Z1.  I'd love to see a power file telling me otherwise because it's highly improbable that a MOP AG'er can ride out of Z1 for eight hours.  I'm FOP on the bike and I know I couldn't do it.

You mention you need more bike fitness.  There's other ways to accomplish that which don't involve spending eight hours in the saddle.  I'm just thinking of your comfort, bro. 

We have a winner folks!

Getting back to the nutrition, are you able to quantify at all how much the additional intensity in your long training rides are able to help expose nutritional issues? Even though I'll do 100 mile rides, I only go up to HIM for races, so am not quite sure how much it will translate to this. Just that with more intensity it becomes a bit more difficult to take on food.