Athletes are grouped in their sports and events, to ensure fair competition between athletes with a similar degree of disability. Originally, classifications were based on medical opinion alone, but are now evaluated on athlete's functional ability.

At Athens, medals are up for grabs in 19 different sports, but not every disability category can compete in all events. Each of the sports has differing demands, reflected in the various classifications.

Archery

The event will be contested by athletes with a physical disability and is divided into three classes.

W1: Cerebral palsy and spinal cord athletes impaired in all four limbs
W2: Wheelchair users with complete arm function
Standing: Athletes who have some disability in their legs, but none in their arms. Amputees, les autres and cerebral palsy standing athletes will also compete. A high stool may be used for support, but both feet much touch the ground during competition.

Athletics

Every disability group is able to compete in Athletics, but athletes are classified both by their physical and mental ability and whether they are a track or field athlete and given the following categorisation:

11-13: Visually impaired track and field athletes
20: Intellectually disabled track and field athletes
31-38: Cerebral palsy track and field athletes
T 51-56: Wheelchair track athletes
F 51-58: Wheelchair field athletes

Basketball

The sport is a wheelchair-athlete sport. Athletes are classified according to physical ability using a points scale system, between 1-4.5 (4.5 being the least disabled). Teams consist of five athletes, but the total 'points' for the team must never exceed 14 at any point in the game.

Boccia

The bowling game is contested by athletes with cerebral palsy who compete from a wheelchair. There are two broad categories:

1: Athletes who are dependent on an electric wheelchair
2: Athletes who are able to propel a wheelchair, but have poor functional strength in all four extremities

Cycling

Cerebral palsy, visually impaired, les autres and amputees are all able to compete in track and road events.

Cerebral palsy athletes have four categories - depending on their level of physical ability. Class four represents athletes with a greater physical ability.

Visually impaired athletes compete together with no distinguishing classifications. They're accompanied by a sighted guide.

Spinal cord injury, les autres and amputee athletes have specific groups:

LC1: Riders with upper limb disabilities
LC2: Riders with disabilities in one leg, but who are able to pedal normally
LC3: Riders with a handicap in one lower limb, who pedal with one leg
LC4: Riders with disabilities affecting both legs

Hand cycling, for athletes with more severe disabilities is also now included in the Paralympic programme and athletes are split into three categories – HCA, HCB and HCC.

Equestrian

Riders are split into four groups and all disability athletes can compete:

Grade 1: Severely disabled athletes with cerebral palsy, spinal cord injury and les autres
Grade 2: Athletes who have a reasonable amount of balance and abdominal control (includes amputees)
Grade 3: Athletes with leg movement, coordination and good balance (includes blind athletes)
Grade 4: Able to walk independently (ambulant) with either impaired vision or impaired limb function

Fencing

Limited to wheelchair athletes and divided into three categories:

Class A: Athletes possessing good balance & recovery and full trunk movement
Class B: Athletes possessing poor balance & recovery, but with full mobility in one or both upper limbs
Class C: Athletes who have severe physical impairment in all four limbs

Football

Contested by athletes with cerebral palsy and divided into categories ranging from 5-8, with eight being used to classify athletes who are least affected. A team must include at least one member from class 5 or 6.

Goalball

Played by VI (visually impaired) athletes and there is no classification. All competitors wear special masks which black out any vision, to ensure fair competition.

Judo

Competitors are divided by weight, so there is no classification. It is contested only by VI athletes.

Powerlifting

Open to all athletes and categories are decided by weight.

Sailing

Open to a range of athletes including amputees, cerebral palsy, visually impaired, les autres and wheelchair athletes. Unusually, athletes of different abilities compete together.

As with basketball, athletes are classified depending on their physical ability and given ranking accordingly. Any crew must have a maximum of 12 'points'.

Individual sailors, must have a distinguishing disability which would prevent them from competing on a par with able bodied sailors.

Shooting

There are wheelchair and standing groups, split into subclasses which determine the mobility equipment allowed to be used by competitors.

Swimming

Britain is envied around the word for its disability swimming programme and will be well represented at Athens. Athletes are divided into three different groups, each subdivided into levels of severity.

S1-S10: Physical impairment with the lower numbers representing the most severe disability
S11-S13: Visually impaired with S11 representing little or no sight and S13 representing greater vision (of no more than 20degrees)
S14: Intellectual disability

Table tennis

Contested by athletes with a physical or intellectual disability and divided into 11 classes.

1-5: Wheelchair athletes with 5 being the least disabled.
6-10: Athletes who are able to walk independently with class 6 the most severely disabled.
11: Intellectual disability.

Wheelchair Tennis

Competitors are grouped into 'open' (male & female) category, or 'quadraplegic' categories. The Quadraplegic category is mixed.

In Athens, there will be six medals up for grabs. Singles and doubles in the male and female 'open' category account for four, and the remaining two are in 'quad' singles and doubles.

Wheelchair Rugby

Like wheelchair basketball, players are classified using a points system, between 0.5 and 3.5 points (with 3.5 points representing the more able players). There are four players on each team, but points must not exceed 8 at any one time.

(Source: eis2win.co.uk)