Disciplines and classifications

Just like the age categories (chicks, benjamins…) or weight categories in judo for example (under 70 kg, heavy…), athletes with disabilities are divided into classes (when they are eligible) for competitions. The tens digit corresponds to the disability family, the units to the class. In most cases, the larger the second number, the less severe the disability. Athletes run, jump, throw.

How does it work?

The classification letter is :

T = Track
F = Field

For more fairness, athletes run in numbered categories.
A first number (the tens digit) for the disability family

1 = visual impairment
2 = intellectual disability
3 = brain injury (standing or sitting)
4 = short stature, amputee or similar
5 = wheelchair (running or throwing)
6 = lower limb disability / deaf and hard of hearing

A second number (the unit number) for the degree of disability
1 being the highest degree of disability, and (it can go up to) 8 the lowest.
In summary, athletes competing in the World Para Athletics Championships are grouped into the following categories:

T/F 11-13 visually impaired athletes
T/F 20 athletes with intellectual disabilities
T/F 32-38 athletes with cerebral palsy or similar
T/F 40-41 athletes of small stature
T/F 42-47 amputees or similar athletes (except for lower limb amputees)
T/F 51-54 wheelchair athletes
T/F 51-57 wheelchair throwers
T/F 60 deaf and hard of hearing athletes
T/F 61-64 lower limb amputee athletes with aids

To learn more about classifications:

Para athletics – YouTube 
Glossary of classifications