The Paralympics is back on Channel 4 and the medals are already rolling in for GB, less than 24-hours after the games were officially opened. 

We are used to watching GB success in the velodrome at the Olympics and its the same story at the Paralympics, with Dame Sarah Storey winning her fifteenth gold medal on Wednesday. 

She is well on her way to becoming ParalympicsGB's most decorated athlete, a record currently held by swimmer Mike Kenny who won 18 medals over four games. 

Dame Storey competes in the C5 category, but what exactly does that mean?

Here's what you need to know...

How does Paracycling work?

Athletes with physical impairments compete on either handcycles, tricycles or bicycles, while athletes with visual impairments ride tandems with a pilot.

There are different classes, each with its own letter and number code. 

What do C1, C2, C3, C4 and C5 mean? 

Athletes whose impairments allow them to use a standard bike compete in one of five C classifications. 

The lower the number, the more severe the impairment, so athletes competing in C1 are those whose disabilities most impact their cycling. 

Dame Sarah Storey competes in the C5 category, having been born without a functioning left hand. 

What do H1, H2, H3, H4 and H5 mean?

H stands for handcycle. 

Handcycles are powered by the arms rather than the legs, and like with the C category, the lower the number the more severe the impairment. 

H1 athletes are likely to have spinal injuries which mean they have limited arm function and no leg or trunk function. 

Meanwhile on the other end of the scale, athletes in the H5 category compete in a kneeling position and will often have leg amputations or paraplegia.

What do T1 and T2 mean?

T refers to tricycle, with athletes in such categories unable to ride a bike due to problems associated with balance or uncoordinated movements.

Once again, T1 athletes have impairments which impact their cycling more severely than T2 athletes. 

What does TB stand for?

TB stands for tandem bike and this category is contested by athletes with visual impairments. 

A sighted pilot rides at the front of the tandem in charge of steering while the para-athlete provides the power.