During the past few decades, participation in sports by athletes with disabilities has been increasing. As a result, awareness of the unique medical needs of this athlete population has been heightened. As with any athlete, sports participation can provide athletes who have disabilities with significant benefits in terms of their general state of health, functionality, life skills, self-esteem, and overall quality of life. It is thus incumbent upon medical providers to promote activity among their patients but also to be knowledgeable and proficient regarding common complications of exercise in order to maximize their patients’ safety and health.
This chapter provides clinicians with a broad overview of athletes with disabilities and important considerations regarding their optimal care. A brief overview of athlete competition classification systems and a discussion of each of the major athlete categories is provided, including any unique physiologic characteristics, medical needs, and adaptive equipment. Participation in the Paralympics is the primary context and framework for this discussion. However, the information and principles presented may be applied to nonelite athletes over a broad range of competition levels and sporting activities.
Athletes with disabilities are an inherently heterogeneous group with highly variable profiles of athletic capacity depending on the type, location, and severity of their inherent disability. Akin to the weight classes used in boxing and wrestling, classification systems have been developed to maintain a measure of fairness in competition, which most often apply to high-level athletes. The common purpose of the classifications systems is to (1) define eligibility for participation and (2) ensure that the level of disability does not preclude athletic success.
To be eligible for Paralympic sports, an athlete must have 1 of 10 permanent impairments: hypertonia, ataxia, athetosis, loss of muscle strength, loss of range of movement, loss of limb, limb deficiency, short stature, low vision, or intellectual impairment. Athletes are assigned to one of six main disability categories: Amputee, Wheelchair, Cerebral Palsy, Vision Impaired, Intellectual Disability, or “Les Autres” (a French term meaning “the others,” in reference to athletes who are unfit for an alternative category). Designation is based on their disability category and functional ability. For example, athletes within the Cerebral Palsy category may be classified according to one of several separate designations based on different combinations of functional strength and range of motion of the arms, legs, and trunk, the use of a wheelchair or the quality of ambulation and balance, and the distribution and severity of muscle spasticity. Direct observation of the athlete during play is also a characteristic of some categories that are able to use more objective measures, such as perception and field of view in the Vision Impaired category.
The sporting event also greatly influences the classification process, because different types and severities of disability affect performance to different levels in different sports. Depending on the sport and locale, designations may be condensed into fewer classes based on a wider range of disability. Additionally, some sports may have competitions between athletes from different general disability categories who maintain comparable functional levels. Team sports such as wheelchair basketball often incorporate a wide range of disability in direct competition via the use of point systems, where athletes with less disadvantageous levels of disability are assigned higher point values, with the team not permitted to exceed a given total point value for its players in the game.
Persons with partial or full loss of limb(s) are eligible to compete under the classification of Amputee Athlete. Limb loss may be congenital or traumatic and may involve the upper and/or lower extremities. The amputee athlete may compete as a standing or seated competitor depending on the sport and the participant’s level of limb loss. Given the variance of the location and length of the amputated extremity, these athletes have a wide range of functionality.
More than a million persons in the United States have limb loss of the upper and/or lower extremities, with an estimated ratio of 1 : 4.9 between upper extremity to lower extremity amputations. Upper extremity amputations are most commonly caused by trauma, cancer, and vascular disease. The most common level of amputation is the transradial level, which accounts for 57% of all upper extremity amputations, followed by transhumeral amputation (23%). The right upper extremity is most commonly involved in work-related injuries, with the vast majority of upper extremity amputations occurring in persons younger than 65 years and 60% occurring between the ages of 21 to 64 years.
Lower extremity amputations are a leading source of disability and account for a large majority of all amputations. Peripheral vascular disease accounts for the vast majority (82%) of limb amputations, followed by trauma (16%); amputation due to malignancy (0.9%) and congenital deformity (0.8%) is much less frequent. The vast majority of lower limb amputations are at the transtibial and transfemoral levels.
It is presumed that the cardiopulmonary physiology of amputee athletes with traumatic amputations or with vascular disease (dysvascular amputations) is similar to that of able-bodied athletes. Some exceptions may exist for persons who have had an amputation for congenital reasons when a cardiac abnormality may be a component of a syndrome.
Amputation of a lower extremity significantly affects the “energy cost” of ambulation. Various measurements have been used to quantify the “cost” of ambulation in persons with limb loss, and these calculations can be expressed in functions of distance, rate, and velocity. Persons with limb loss typically will walk more slowly than nonamputees to maintain a similar oxygen consumption rate. Therefore in athletic competition the amputee athlete will need to increase his or her rate of oxygen consumption to maintain a similar velocity of a nonamputee athlete ( Table 33-1 ). For example, when comparing ambulation of amputees to nonamputees, a unilateral traumatic transtibial amputee will use approximately 7% more energy to ambulate the same distance as a nonamputee, and a dysvascular transtibial amputee will require 25% more energy than a nonamputee.
|Level of Amputation||Etiology||Unilateral/Bilateral||% of Energy Increase per Unit of Distance|
|Transfemoral and transtibial||Bilateral||118|
Injury patterns among amputees are similar to those for athletes without disabilities; however, the severity and location of the amputation dictates the frequency and type of injury. Lower extremity amputees are at risk for injuries in both intact and residual limbs. The distal residual limb is often the site of skin trauma due to the prosthesis. Altered biomechanics because of the asymmetric need for power and propulsion may predispose athletes to hip, sacroiliac, and lumbar spine pain. Alternatively, an amputee may rely too heavily on the intact limb, which can increase the risk for overuse injuries and osteoarthritis.
Similarly, in upper extremity amputees, altered use and load patterns of the intact limb can result in pain and injury to either limb or axial structures. Overuse injuries such as shoulder impingement, rotator cuff tears, epicondylitis, and peripheral nerve entrapments are common in the intact limb of upper extremity amputees. Differences in weight and swing excursion between the upper extremities, as well as the need to compensate at the shoulder for loss of distal joint function, may cause significant asymmetry in the demands of the thoracic and cervical spines and paraspinal and parascapular musculature, resulting in pain and dysfunction. Treatment for many of these conditions is identical to that for nonamputees. Additionally, however, precise fitting of prostheses in this population is a critical aspect of beneficial treatment.
After amputation of the limb and subsequent fitting of a prosthesis, the skin of the distal portion of the residual limb becomes a weight-bearing surface and as a result is at increased risk for skin disorders. Rashes are frequently observed in persons who use prostheses. A noninfectious allergic rash should spur examination of the type of liner used, with the goal of incorporating material that is less irritating and that promotes greater perfusion of sweat away from the skin. Rashes can be prevented by cleaning the residual limb and prosthesis regularly.
Prevention of infections is a key priority and often a source of concern. Verrucous hyperplasia is a wartlike lesion that may develop at the distal end of the residual limb. It may occur as a result of proximal residual limb constriction from a socket or wrap that has caused decreased pressure in the distal residual limb. The prevention and treatment of verrucous hyperplasia consists of equal distribution of pressure through the residual limb, akin to a total contact socket.
Blisters and sores are very common and can occur as a result of friction between skin of the residual limb and the prosthesis. Skin breakdown may also occur when pressure is applied disproportionately to a pressure-sensitive area of skin on the residual limb, such as the tibial tubercle in a transtibial amputee. The risk may be compounded by impaired sensation in the residual limb, and sweating with athletic activity can increase moisture at the skin-socket interface and heighten the risk for skin breakdown. Environmental conditions may also play a role, especially in marine sports (e.g., swimming, kayaking, and rowing) and during participation in hot weather. Other risk factors include the increased frequency and intensity of weight bearing associated with athletic training and competition. A properly fitting socket will normally prevent blisters and sores, and it is important to maintain a good socket fit by adding and removing socks throughout the day to adjust for volume reduction and to periodically assess and adjust the fit to counter weight loss over a prolonged period. Other preventive measures include silicone liners, padded sleeves, socks, and additional padding.
The formation of bone in tissues that are not normally ossified, heterotopic ossification (HO), usually evolves after traumatic brain injury, spinal cord injury, burns, and total arthroplasty. Recently, HO has been reported to develop frequently in injured tissue of residual limbs in traumatic amputees, which may increase risk of skin breakdown or stimulate pain with weight bearing. HO is also more likely to develop around joints and muscle adjacent to trauma and typically develops within the first 6 months to a year after amputation. The development of HO typically occurs during the time an amputee is beginning prosthetic training. Thus the majority of persons with HO are diagnosed prior to engaging in athletic competition, which facilitates modifications in design of the socket and vigilance for signs of skin breakdown.
Numerous treatments for HO have been studied in nonamputee populations, but to date, an effective protocol for the prevention of HO after amputation is lacking. However, a beneficial effect of nonsteroidal antiinflammatory drugs in the prevention of HO after total hip arthroplasty is well documented. Bisphosphonates are widely used in the spinal cord injury population for osteoporosis and the prevention and treatment of HO. Unfortunately, significant gastrointestinal and renal adverse effects of these medications and of bisphosphonates in particular mandate extreme caution prior to their use in a competitive athlete. Eventually, surgical excision of HO may be essential if conservative measures fail to restore adequate levels of function.
Neuromas form at the distal end of transected nerves in the residual limbs of amputees. The development of a neuroma in a weight-bearing structure or in its vicinity can cause severe pain with ambulation and weight bearing and limit an athlete’s ability to train and compete. Treatments include prosthetic modification to relieve pressure, oral medications, including antiepileptic agents and tricyclic antidepressant drugs, injections of corticosteroids and local anesthetics into the neuroma, and radiofrequency ablation of neuromas. Many common medications that are used may be restricted in competition by the World Anti-Doping Agency (WADA), and clear knowledge regarding these limitations is vital for medical practitioners. We encourage medical practitioners who are caring for athletes with disabilities to visit WADA’s Web site at www.wada-ama.org to review approved and restricted medications “in and out of competition.” Surgical excision may ultimately be necessary if conservative treatments fail.
Adaptive Sports Equipment
Numerous sporting events incorporate adaptive sports equipment for amputees. It is beyond the scope of this chapter to discuss the numerous prosthetic modifications and other adaptive equipment for several sports and recreational activities. However, several pertinent facts should be considered by medical practitioners when they prescribe adaptive equipment. Compared with common prosthetic devices, a range of modifications should be considered in this population. Of particular importance is the prosthetic weight, particularly in sports where increased weight may negatively affect speed. Occasionally, use of a conventional prosthesis may be advantageous compared with a technologically advanced prosthesis. The clinician should also consider alignment, prosthetic foot dynamics, shock absorption, and the possible need for transverse rotation.
Most wheelchair athletes have spinal cord injuries. However, persons with multiple amputations or neurologic disorders such as polio, spina bifida, and cerebral palsy may also be eligible for this category. Discussion in this section is limited to the nuances of athletic participation of athletes with spinal cord injuries but could be applicable to other wheelchair athletes, depending on the extent of trunk and upper extremity function, level of sensation, and preservation of bowel and bladder function.
The exercise capacity and physiologic responses to exercise of wheelchair athletes are different from that of able-bodied athletes. Furthermore, inherent physiologic differences among wheelchair athletes are observed. Based on the level and severity of their injury, their maximal exercise capacity may range from being comparable with either able-bodied athletes or sedentary able-bodied persons.
Spinal cord injuries and other neurologic pathology induce a varying degree of paralysis of voluntary muscles, with a resultant decrease in muscle mass available for exercise. Diminished muscle mass also has a negative impact on performance via impaired supporting dynamic restraints, such as core musculature and impaired hand and arm function in tetraplegic athletes. These phenomena can reduce the efficiency of energy transfer from the athlete to the chair and other objects. However, these differences in muscle mass only partly explain differences in exercise capacity, because the arteriovenous oxygen difference in submaximal exercise is typically altered in wheelchair athletes compared with able-bodied athletes. This difference may be indicative of different levels of muscle recruitment to achieve a given work rate, as well as impairments in local and regional blood flow in response to exercise. In general, the lower the spinal level of the lesion, the more muscle mass is available for exercise, which translates to improved vasomotor regulation. Thus power output is inversely related to the level of the spinal lesion.
Cardiovascular responses to exercise are also altered in comparison with able-bodied athletes and demonstrate significant differences between wheelchair athletes with higher and lower level lesions. The loss of vasomotor regulation and active muscle pumping action below the level of the lesion results in impaired venous return, thus restricting central blood volume. Impaired sympathetic innervation to the heart, which is absent in persons with complete spinal cord lesions above the T1 level and reduced in persons with complete spinal cord lesions above the T6 level, results in a blunted cardiac response, and maximal heart rate is limited to 110 and 130 beats per minute via intrinsic sinoatrial activity. These factors lead to impaired cardiac performance, with reductions in cardiac output and stroke volume up to approximately 30% in persons with motor-complete cervical spinal cord injuries.
Pulmonary function is also often impaired and influenced by the level of the lesion. These deficits occur primarily via paralysis of the expiratory muscles; however, persons with cervical lesions may also have paralysis of inspiratory musculature, resulting in significant impairments in ventilation relative to paraplegic persons. Compared with able-bodied persons, the forced expiratory volume in one second, forced vital capacity, and tidal volume are approximately 90% in paraplegic patients and 60% in tetraplegic patients.
Wheelchair athletes are at risk for routine musculoskeletal injuries, such as muscle strains, at rates comparable with those of able-bodied athletes; however, the distribution of these injuries is obviously quite different because of upper extremity use for wheelchair propulsion. Injuries in this population may affect participation and performance to a disproportionately high degree compared with able-bodied athletes. One study noted that 32% of all injuries resulted in “time loss” of more than 3 weeks.
Shoulder and wrist injuries are common. The injuries maybe unilateral or bilateral, are equally frequent in location, and are often induced by overuse. However, sports such as alpine skiing that rely on outriggers or sports featuring contact such as wheelchair rugby may have a higher ratio of traumatic injuries relative to other events. A history of shoulder pain is reported in more than 90% of selected wheelchair athlete populations, with an increasing prevalence in proportion to the amount of trunk and upper extremity disability. Shoulder impingement syndrome is the most common injury; bicipital and rotator cuff tendinopathy and tears are also common. Wheelchair athletes often have a protracted scapular position with dynamic scapular dyskinesis, resulting in loss of subacromial space. Additionally, the humeral head is often elevated as a result of relative muscle strength imbalance, favoring shoulder abduction strength over adduction and rotational strength. This risk can potentially be modifiable by alterations in trunk inclination, backrest height, and the position of the wheelchair axle relative to the shoulder. Physical therapy should improve shoulder flexibility, correct scapular kinematics, and address shoulder muscle imbalances.
Lower extremity injuries are also common in this population, although they are less frequent than in ambulatory athletes. Compared with upper extremity injuries caused by overuse, these injuries are usually acute and posttraumatic. Direct contact with another wheelchair or an object during team sports and falls are common and increase the risk for trauma of the head and neck, which may be compounded by the high rates of osteoporosis observed in lower extremities in this population. Thus clinicians should be vigilant because even minor trauma may result in fractures, and any resulting deformity or angulation after healing may adversely affect available seating positions, increase the risk for pressure sores, and alter functional status.
Peripheral Nerve Entrapment
Peripheral nerve entrapments are commonly encountered in wheelchair athletes. The prevalence of carpel tunnel syndrome is approximately 50%. Other significant entrapment neuropathies include ulnar neuropathy at the wrist, ulnar neuropathy at the elbow, and radial neuropathy. Shoulder muscle imbalance and scapular dyskinesis may also result in suprascapular neuropathy at either the suprascapular or spinoglenoid notches. In addition to standard therapies, protection of the wrist and elbow with padded gloves and sleeves, use of a wheelchair that has been properly fit to the athlete, and use of an adequate range of motion and proper techniques during propulsion to decrease push rates and forces may help with prevention and treatment.
Altered sympathetic, vasomotor, and sudomotor responses and diminished rates of venous return from the loss of muscle-pumping action results in a diminished ability to sense and respond to thermal imbalance. The loss of skeletal muscle and function also impairs the response to negative thermal imbalances because of a reduced capacity for shivering. These factors increase the risk for hypothermia and exertional heat illness, especially in persons with spinal cord lesions above the T6 level.
Pressure sores are common among wheelchair athletes, particularly those with a spinal cord injury. Prolonged pressure, typically over bony prominences such as the sacrum and ischial tuberosities, combined with insensate skin that is moist from activity, increase compressive and shears forces, resulting in local tissue ischemia and injury. Wheelchair athletes with altered trunk stability often maintain a flexed lower extremity posture at the hips and knees that further distributes the athlete’s weight to “at-risk sites.” Vigilance is mandatory for pressure sore prevention, including skin checks, shifting of weight every 15 to 20 minutes to relieve pressure, the use of appropriately fit seat cushions, and maintenance of a dry environment.
Spasticity is common in wheelchair athletes who have spinal cord injuries and is manifested by involuntary muscle contraction, hyperreflexia, and velocity-dependent increases in tone. Synergistic muscle activation patterning may inhibit performance by altering positioning within the wheelchair, item control/accuracy, and propulsion. However, it is important to note that in some cases, spasticity may be beneficial for these functions when other voluntary muscle action is insufficient. It is important for the sports physician to remember that spasticity is primarily a velocity-dependent increase in tone, and thus a routine bedside examination may not be conducive to a thorough appreciation of the detrimental effects of spasticity unless sports activities are entirely replicated.
Spasticity is usually treated with oral medications, physical therapy that emphasizes range of motion, and tone-reducing orthoses. In more advanced cases or in cases in which the athlete cannot tolerate the sedative effects of antispasticity medications, Botox injections can focally reduce high levels of spasticity in a dose-dependent fashion. Surgical approaches such as muscle/tendon lengthening, tendon transfers, and selective dorsal rhizotomy may be considered in refractory cases.
Neurogenic Bladder and Bowel
Bladder dysfunction is common in wheelchair athletes who have spinal cord injuries and spina bifida. This dysfunction can result in urinary retention, often necessitating indwelling, suprapubic, or intermittent catheterization and resulting in increased rates of urinary tract infections and stone formation. Clinical presentation may include fever, fatigue, a general sense of unease, discomfort in the area of the bladder and kidneys, autonomic dysreflexia, incontinence, and an increased level of muscle spasticity.
Bowel dysfunction is also common in persons with spinal cord injuries and spina bifida. Injuries above the S2-S4 spinal cord segments results in a reflexic neurogenic bowel, whereas injuries distal to these segments or involving the destruction of anterior horn cells (at these levels) result in an areflexic bowel. In addition to utilizing other methods of facilitation, these persons are counseled to initiate regular bowel programs at the same time of day to condition the bowel to achieve effective defecation and avoid incontinence.
In the sports setting, the athlete may not adhere to appropriate frequency or technique of clean intermittent catheterization or appropriate timing of their bowel program because of an overfocus on training, which may propagate infection, reduce vigilance of hydration status, and increase the risk of incontinence. Clinicians should counsel athletes on the importance of bowel and bladder management, which has significant performance and practical implications. Athletes should also be counseled to undergo slow alterations in bowel management to best accommodate their expected competition schedule at upcoming events and to always be cognizant regarding the available facilities for bowel and bladder management at each venue.
HO may occur in up to 36% of patients with spinal cord injuries, and amputee athletes competing in the wheelchair class may also be at risk. The period of highest risk for development of HO is approximately 4 months after spinal cord injury. HO most commonly affects the hips but may also affect the knees, shoulders, and elbows. HO may limit function and performance by restricting range of motion for different seating positions, propulsion, and other tasks; it also may increase the risk for pressure sores and nerve entrapments.
Autonomic dysreflexia (AD) is a medical emergency usually seen in persons with complete spinal cord injuries involving or above the T6 segment. Noxious stimuli below the level of injury can cause reflexive sympathetic activity that cannot be modulated by supraspinal centers of control, resulting in high levels of sympathetic activity below the level of injury and incomplete parasympathetic compensation above the level of injury. During an episode of AD, persons typically experience hypertension and headache due to vasoconstriction below the level of injury, along with skin flushing, piloerection, diaphoresis, and bradycardia above the level of injury. Although mortality is rare, significant morbidity may result, including cerebral hemorrhage, seizures, and myocardial infarction. Treatment should include sitting the person upright, removing restrictive clothing, and searching for the source of the noxious stimulus, which is commonly a distended bladder or impacted colon, pressure sores, or another injury. Systolic pressures of 150 mm Hg should be treated with short-onset and half-life antihypertensive medications. Transdermal nitro paste is highly effective and can be removed easily after resolution of the episode of AD to avoid subsequent hypotension.
An unsettling trend among wheelchair athletes is the intentional use of AD to improve performance during competition, a phenomenon known as “boosting.” Athletes will create a self-induced noxious stimulus via methods such as kinking a bladder catheter, sitting on ball-bearings, fracturing a toe, or excessively tightening legs straps in order to induce AD. This strategy may lead to improvements in peak heart rate, peak oxygen consumption, and blood pressure and has been shown to enhance “racing time” by approximately 10%. For obvious health and safety reasons and to promote fairness during competition, the International Paralympic Committee has banned the use of induced AD from competition.
Wheelchairs used in sporting endeavors are typically designed specifically for the particular demands of the sport involved, such as speed and endurance for racing, rigidity and stability for throwing events, or agility and ruggedness for wheelchair basketball and rugby. Several variables can be manipulated to meet these needs: axle position (horizontally and vertically), wheels (number, size, and camber), hand rim size, seat back height and angle, seat cushioning, footplate (height and angle), the location and types of belts, and other fixations. For example, an elevated seat height may be advantageous for sports events such as wheelchair basketball, whereas a lower seat may be advantageous for sports requiring extra stability. The particular needs of the athlete and his or her disability level must be considered, including the level of truck support, altered location of the center of mass, and impaired hand function. These considerations are not only important to maximize performance but also to reduce the risk of injury and medical complications. Consultation with physical and occupational therapists, and prosthetists may be necessary depending on the needs and goals of the athlete.