Wheelchair softball allows participation of athletes with impairment from multiple disability groups. However, the obvious requirement is the need for a wheelchair (see Picture 15.1). These disabilities include spinal cord injury, congenital malformations effecting the lower extremities, amputations, and injuries/illnesses effecting lower extremity strength and mobility. In order to allow fair competition between these athletes with varying disabilities, a classification system has been developed.

To ensure balanced and fair teams, players and teams are assessed via a point system as specified by the National Wheelchair Softball Association (NWSA) delineated below [1, 2]. The classification process assigns a certain number of points based on the level of injury, impairment, and/or function. A quadriparetic athlete is assigned one point, a Class I athlete is assigned one point, a Class II athlete is assigned two points, and a Class III athlete is assigned three points.

A Class I athlete is one that has complete motor loss at T7 or above or a comparable disability where there is total loss of muscle function originating at or above T7. Class I athletes should not have functional use of abdominal musculature, their trunk control and sitting balance should be poor to absent, and they should have a weak cough. A quadriparetic athlete is one that has motor impairments affecting all four extremities.

A Class II athlete is one with complete motor loss originating at T8 and descending through and including L2 where motor power of the hips and thighs may be present. Class II athletes should have no practical motor strength below L2, only grade 2 quadriceps strength, grade 3 hip abductors, and grade 4 hip flexors (see Appendix for muscle strength grades). This class also includes amputees with bilateral hip disarticulation.

A Class III athlete is one with any other physical disabilities leading to lower extremity paralysis or paresis at or below L3. Class III athletes should have motor paralysis or paresis originating at or below L3, good trunk control, good pelvic control, and good sitting balance. This class also includes all lower extremity amputees except ones with bilateral hip disarticulations.

Each team fields a maximum of ten players at a time. At any one time a team’s participating players can have a total value of no more than 22 points based on the above classification system.

Wheelchair softball follows the same basic rules and guidelines as those that were established by the American Softball Association (ASA) for 16 inch softball [1]. Due to the adaptive nature of the sport, there are a number of additions and modifications which we present below.

The manual wheelchair is the primary adaptive device the wheelchair softball player uses. It is important to consider the athlete’s goals and preferences when choosing the best manual wheelchair design for each player. For example, while higher backrests provide more trunk support, they limit range of motion that athletes would often prefer. All wheelchair softball players are required to have foot plates on their chairs. Many have an additional front bar that stretches from one side of the chair to the other passing in front of the feet to prevent injury to lower limbs during a collision. An important feature of the wheelchair that one should address is the camber of the wheels. Due to the quick turns required when rounding bases and making certain defensive plays, most athletes choose a significant amount of camber to prevent tipping laterally.

Wheelchair softball has unique equipment suited for batting. These devices are supportive wedges that are placed around the wheels of the manual wheelchair to provide stability while the athlete swings the bat (see Pictures 15.2 and 15.3). Some athletes choose to use these blocks, which are often referred to as “sticks” or “cages” by athletes. Others may prefer to stabilize one wheel manually with their hand, while using their free arm to perform a single-arm batting technique to hit the ball.

Softball gloves are also optional pieces of equipment that first basemen and catchers are allowed to use when fielding, but many players opt to play without them given the larger size and lower density of the 16″ softball. Helmet use is not required but in our opinion should be encouraged to reduce the risk of traumatic brain injuries or concussion.

Wheelchair softball athletes utilize adapted mechanics, when compared to able-bodied athletes, for overhead throwing, underhand pitching, and batting. For both athletes, throwing begins with the windup and is completed with the follow-through movements occurring after ball release. In able-bodied athletes, the throwing sequence includes kinetic chain movements of the lower limb and trunk to maximize force generation and transfer to the upper limb and hand [3]. During these series of rotational and sagittal movements, body weight transfers from the ipsilateral leg during the windup to the contralateral leg during the follow-through, and the pelvis, initially directed away, rotates towards the player intended to receive the thrown ball. As the acceleration phase begins, pelvic rotation occurs as body weight transfers to the contralateral leg, assisting the throwing arm as it transitions from abduction with external rotation into adduction with internal rotation and ultimately ball release. Similarly, underhand pitching and batting benefit most from the generation of forces created by the leg and core muscles.

In contrast to able-bodied athletes, many wheelchair athletes are not able to use their lower extremities, hip girdle, and other portions of their core musculature to develop force and torque for the throwing and swinging motions required of wheelchair softball. These muscles are also integral to deceleration during the follow-through phases of throwing and batting. Reduction in leg and core muscle control may result in greater eccentric loads on the upper limb and increase the risk of injury [4]. This leads to increased stress on the more peripheral joints such as the shoulder, elbow, and wrist. Instead of developing force for throwing and swinging from the lower limbs, hips, and core, there is increased likelihood of “throwing from the shoulder.” Able-bodied athletes are taught not to throw in this manner because this increases risk of injuries to the more peripheral joints. Additionally, while outside the scope of this discussion, the biomechanics of wheelchair propulsion itself creates additional risk for the development of sports-related acute and overuse injuries.

The popularity of wheelchair softball is growing and with it the need for more clinician awareness of potential injuries that these athletes may experience (see Fig. 15.2). The challenge for the sports physician is not only appropriately diagnosing and rehabilitating injured athletes but also providing education to participants for injury prevention. Although there are not any accurate incidence rates of wheelchair softball injuries available, they are most likely comparable to or higher than baseball and softball injuries in able-bodied participants. There have been higher reported injury rates among athletes participating in the Winter 2010 and Summer 2012 Paralympic Games than in the respective Olympic Games [5–8]. This included new onset acute injuries totaling 51.5% of the injuries reported during the London 2012 Paralympic Games [5]. Given the increase in Paralympic and adaptive sports participation, there is a great need for sport-specific epidemiological and rehabilitative research for these athletes. Wheelchair softball is a particular topic of tremendous potential and need for additional research given its growth. For wheelchair-using athletes, upper extremity injuries appear to be far more common than lower limb injuries. While there does not appear to be any significant relationship between the incidence of reported injuries and type of disability, adaptive overhead sports are associated with a higher risk of injury development [9].

Musculoskeletal injury assessment includes obtaining a relevant history and thorough evaluation. The most common mechanisms of acute softball injuries are being hit by a ball (20%), collisions with other players (16%), locomotion (11%), and while swinging a bat (3%) [10]. Common softball injuries include fractures, muscle strains, ligament sprains, lacerations, and concussions [10]. Acute and chronic wheelchair sports injuries appear to be near equal in incidence [9, 11]. It is important to understand the athlete’s history of similar injuries and potential biomechanical abnormalities in order to prescribe the proper rehabilitation plan. Athletes often desire to return to play as soon as possible, and one study found that 43% of athletes restarted training while still experiencing pain after an injury [12, 13]. Returning to play before resolution of pain may increase the risk of reinjury.