Zone 4 – threshold
Your threshold is thought to be the effort you can sustain consistently for around 60 mins at a max. It is more stressful as an effort on the body than the lower zones so needs to be put into your training with confidence knowing your will be feeling good for it, whilst also paying respect to the effort by making sure its surrounded by recovery/lower stress or rest.
Your lactate threshold is the point at which your body accumulates more lactic acid than it can efficiently get rid of. At this point of effort, you will start to fatigue rapidly and your legs may start to feel sore, heavy, or achy.
What it is –
RPE – 7-8
% THR bike – 95-105%
%FTP bike – 90-105%
% THR run – 95-99% or half marathon-10 km feel
How do we factor it into training
From the first paragraph you can see its a demanding intensity so we have to be smart. In general threshold training of some sort will be in all phases of training. Using Zones 3-5. Ive spoken about 3 & 5in separate emails/blogs. Zone 4 training will in general become more used in the build and sharpening phase of training.
When adding in reps of zone 4 intensity you will be looking to have one of the intensities above and the length of the effort will have roughly matching recover before repeating due to the demand on the energy systems and the muscle tissue (breakdown of tissue). It means we will better prepared for the next interval.
Also Zone 4 intervals require recovery. We will make sure in your training plan that you have recover/easier sessions in order for you to be able to continue in a consistent manner. These sorts of sessions can take 24-72 hours to recover properly, but executed correctly can play a major part of your endurance fitness development
Eg in a session
6 x 4 mins Z4 with 4 mins easy Z1 recovery between
or 3 x 6 mins Z4 with 6 mins easy Z1 recovery between
The benefits of threshold training:
- Improve your VO2 Max
- Performing faster for longer
- Increase your lactate threshold
- Reduce fatigue at slower paces
- Improved performance when racing
- Easier running during training
- Body becomes more efficient