(1) Background: Regular participation in physical activity (PA) prevents many medical complications and improves the physical fitness of people with spinal cord injury, and in turn improves the functional independence, psychosocial status and quality of life. The goal of Active Rehabilitation Camps (ARCs) is to use various forms of PA in order for the participants to obtain the greatest efficiency and independence in everyday life. (2) Purpose: To evaluate the improvement in physical performance of people with chronic spinal cord disabilities moving in wheelchairs taking part in the Active Rehabilitation Camp depending on (a) sex, (b) type of disability, (c) the level of injury and (d) the type of wheelchair. (3) Methods: The study included 42 wheelchair users: 28 men and 14 women aged 18–65 years (34.7 ± 14.9 years) taking part in the Active Rehabilitation Camp. Finally, the study involved 27 paraplegics, 9 tetraplegics and 6 individuals with myelomeningocele. The participants took part in four fitness tests: (1) sprint test (SP)—individual time to cover a distance of 15 m in the wheelchair; (2) slalom test (SL)—time to ride between four cones front and back; (3) basketball ball throw at a distance (BT), (4) zig-zag test (ZZ)—riding continuously for 6 min on the designated track. The tests were performed at the beginning and at the end of the ACR. Active wheelchairs were used by 32 participants, and 10 participants used the classic wheelchairs. (4) Results: Paraplegics achieved the best average results in all the tests and the best improvement in physical performance in comparison to individuals with myelomeningocele and tetraplegics. People in active wheelchairs achieved a statistically significant improvement in the results of SL and ZZ (p < 0.001). People with injury above Th-9 level of the spinal cord achieved a statistically significant improvement in the results of SP (p < 0.01), SL and ZZ (p < 0.01). People with injury below Th6 achieved a statistically significant improvement (p < 0.05) in SP, SL and ZZ. (5) Conclusions: Regular PA during the Active Rehabilitation Camp improves the physical performance of disabled people in wheelchairs, but the scale of improvement of physical performance fitness depends on the type of wheelchair used and the level and the type of injury.