I dread these runs more than most, probably even more than pace runs. I missed the last 4 mile tempo run scheduled for a few weeks ago. I decided that since I ran a 5K race a few days before that, that I'd done quality work. The last time I had a tempo like run was when I did a 10K race a few weeks after the marathon. I didn't run it at my true 10K speed so it was a very effective LT run as a result. Actually, looking back, it was a tad faster than LT pace at times.
I also ran the 5 miler race last week at a fast pace so I could have used it as an out, but everything i've read about lactate threshold training says that you have to run it at a specific pace (15K to half marathon speed) so your body can benefit from the buildup to your threshold. By simply racing at faster distances, you get obvious benefits but not LT training benefits.
So I decided not to cop out. The schedule called for 9 miles with 4 at LT. I ran one warmup mile then launched into it. LT for me should be around 6:55 to 7 minute miles or around 4:18 to 4:20 kliometres.
Here are the mile splits
A few seconds off but I think i've got the feel down for LT speed.