As your Threshold effort starts to become manageable for the length of a 10K race, your training should start to introduce some 10K specific speed work to help create another gear for your running speed.
When running at 10K effort, you should be looking at a heart rate of around 90% of maximum or at a perceived effort level of 9 out of 10, around a 2-word answer pace.
Make sure that your 10K effort level is realistic and that you aren’t running at a pace that you couldn’t sustain for the whole of a 10K race.
Training may also include some 5K effort level running and perhaps even quicker.
This sort of work is done in short intervals, with short recoveries. It teaches your body to run at a pace that would be uncomfortable to maintain for an extended period of time. This type of work teaches your body to work at a faster pace