The Paralympic Movement website (Paralympic.​org) details the different classifications of para-athletes that may compete in adaptive cycling. The four main classes of adaptive cycling include handcycling, tricycling, bicycling, and tandem cycling depending on the degree and type of impairments. Of the ten eligible impairments for the Paralympics, eight qualify for inclusion in adaptive cycling: impaired muscle power, impaired passive range of movement, limb deficiency, leg length difference, athetosis, hypertonia, ataxia, and visual impairment. Those with intellectual impairment or short stature are excluded from competitive adaptive cycling.

Handcycling has five classes (H1–H5) (Table 10.2) with lower numbers indicative of more severe impairment(s). H1 athletes are tetraplegic (C6 or above) and generally have severe upper limb impairment with no ability to use their trunk or leg. H2 athletes are also tetraplegic (C7/C8) with severe athetosis, ataxia, and/or dystonia. H3 athletes may have spinal cord lesions anywhere from T1–T10 (or equivalent injury) with limited trunk stability. H4 athletes will have impairment from T11 down, with normal or almost normal trunk stability, but be unable to kneel. Those competing in classes H1–H4 compete in a reclined position and compete on a recumbent handcycle, whereas H5 class athletes are paraplegics (T11 or below) and amputees who distinguish themselves from H1–H4 by being able to kneel and compete on a kneeling handcycle. Those competing in classes H1–H4 compete in a reclined position, whereas H5 competitors are capable of sitting on their knees and may use both their arm and trunk. Examples of H1–H4 athletes include those with spinal cord injury, cerebral palsy, or multiple sclerosis. H5 athletes may have leg amputation or congenital limb deficiency, paraplegia, or ataxia [4].

Tricycling has two classes (T1–T2) (Table 10.2), again with the lower number corresponding to a higher degree of impairment. Adaptive cyclists will use a tricycle if their coordination or balance is affected enough to require the tricycle for stability while riding. T1 tricyclists have severe athetosis, ataxia, or dystonia and generally with grade 3 spasticity or higher. T2 tricyclists have more moderate athetosis, ataxia, or dystonia with more fluent movements, grade 2 spasticity for hemiplegic and quadriplegic patients, and grade 3 spasticity for diplegic athletes.

Adaptive cyclists capable of riding a traditional upright bicycle will compete in one of five classes (C1–C5) (Table 10.2), once again with lower numbers corresponding to the highest degree of impairment. C1 cyclists have grade 3 spasticity in upper and/or lower limbs with poor strength in the trunk and/or extremities and can have single or double amputations. C2 cyclists have grade 2 spasticity throughout with greater lower limb involvement. C3 cyclists will have less spasticity in the upper limb (grade 1) versus the lower limb (grade 2) and with less athetosis, ataxia, or dystonia than C1 or C2 cyclists. C4 cyclists generally have grade 1 spasticity with the lower limb more involved and mild to moderate athetosis, ataxia, or dystonia. C5 cyclists have minimal impairment such as monoplegia spasticity with clear neurologic signs or single amputation. Classes C1–C4 may be amputees, whereas C5 athletes may not and have minimal impairments compared to the other classes. Examples of adaptive bicyclists include those with amputations, impaired muscle power or range of motion, and coordination deficits.

Tandem cyclists are typically visually impaired and ride with a sighted “pilot” cycler to their front. Visual impairments are classified from B1–B3 (Table 10.2), and they all typically compete together in the same event(s). B1 athletes have no sight. B2 athletes have the ability to recognize the shape of a hand up to visual acuity of 2/60 and/or visual field of less than 5°. B3 athletes have visual acuity of 2/60 up to 6/60 and/or visual field of more than 5° and less than 20°.