Adaptive sports have seen a significant growth in participation and popularity over the past several years. With this increased participation and popularity, there has also been a rise in the level of competition and focus on injury evaluation at the Paralympic Games.1 Many of the common adaptive sports played are played in a manual wheelchair (MWC), and there has been a huge growth of wheelchair sport programs. The National Veterans Wheelchair Games hosted by the Paralyzed Veterans of America and the Department of Veterans Affairs is the world’s largest annual sports program. The most common wheelchair sports played competitively include wheelchair basketball, quad rugby, wheelchair track and field (para athletics), wheelchair tennis, wheelchair fencing, and wheelchair curling. One of the most common complaints of these wheelchair athletes includes shoulder pain and injury. Shoulder pain and injury can be especially devastating to this population as it can not only affect their sports performance, but also can negatively impact their quality of life. Understanding the shoulder anatomy, injury risk factors, and common shoulder pathology seen in these wheelchair athletes are important for providing appropriate care and treatment.
SHOULDER ANATOMY AND FUNCTION
The ultimate purpose and function of the shoulder complex is to guide placement of the hand and upper extremity.2 The shoulder joint complex is comprised of the glenohumeral, scapulothoracic, sternoclavicular, and acromioclavicular joints. Shoulder mobility is the product of motion in both the glenohumeral joint and scapulothoracic-gliding plane, with the majority of motion occurring in the glenohumeral joint.2,3 The glenohumeral joint is a multiaxial ball and socket synovial joint, which permits a tremendous amount of mobility while inherent stability is minimal. The shoulder complex allows range of motion of the upper extremity exceeding that of any other joint mechanism in the body.1 This large mobility is made possible because of the small articular surface of the scapula, the glenoid surface, as well as the loose connecting capsule.4 As the head of the humerus is larger than the glenoid fossa, this means that only a part of the humeral head (25% to 30%) can be in articulation with the glenoid fossa at any one time.1 This makes the joint inherently less stable. The muscles and ligaments surrounding the joint are essential in maintaining stability of the joint. The rotator cuff complex is a musculotendinous complex formed by the supraspinatus muscle, subscapularis muscle, teres minor muscle, and infraspinatus muscle. They provide dynamic stability for the shoulder joint. The rotator cuff muscles help provide a downward force which controls the upward migration of the humeral head pulled by the deltoid muscles during humeral elevation. In addition, these muscles help control the upward thrust of the humerus during wheelchair propulsion.5 This inherent anatomy makes the shoulder a poor weight-bearing joint. Any injury to the rotator cuff can cause instability of the shoulder and symptoms of pain.
SHOULDER PAIN AND MANUAL WHEELCHAIR USE
Manual Wheelchair Users
Using a manual wheelchair for everyday use can be very stressful to the upper extremity. As a result, manual wheelchair users may develop overuse injury and pain in their shoulder.6 The reported incidence of shoulder pain among persons with spinal cord injury (SCI) who have used a manual wheelchair range from 40% to 78%.7–12 There are multiple studies in the literature that show there is a higher prevalence of shoulder pain and pathology in manual wheelchair users compared to age matched control of able-bodied individuals, with studies showing significantly higher rate of rotator cuff tear among paraplegic patients.13,14 Other increased shoulder pathology noted in paraplegics/tetraplegics compared to able-bodied subjects include acromioclavicular joint pathology, irregularity and calcification of supraspinatus tendon, supraspinatus tendinopathy, thicker bicipital tendon sheath, and increased frequency of glenohumeral effusion.14–16 There are several risk factors for development of shoulder pain and pathology in this population. The most commonly agreed upon risk factors for shoulder pain and development of pathology include increased age,11,15,17,18 increased body mass index (BMI),17 higher level of spinal cord injury (tetraplegic vs. paraplegic),7,10,16,17 and increased years of manual wheelchair use.13,18,19
Biomechanics of Shoulder and MWC Use
Using a manual wheelchair in itself, can place the shoulder at higher risk for developing shoulder pain and injury. As shown above, the shoulder is poorly designed for ambulation and weight-bearing tasks and usage of it during manual wheelchair propulsion and transfers can expose it to higher intra-articular pressures as well as abnormal distribution of stresses across stabilizing structures. Proper techniques of wheelchair propulsion and transfers are very important for preventing shoulder pain and injury from developing. In general, a typical push-rim wheelchair propulsion has 2 phases: a push phase and a recovery phase. There are 4 general categories of recovery patterns reported in the literature: semicircular, single loop, double loop, and arc.20 Guidelines suggest that propulsion patterns such as semicircular and double loop be used to maximize the contact angle and minimize injury.20–22 Those with upper limb injury were found to propel with a higher stroke frequency, reduced hand-rim contact time, and smaller peak joint angles and joint excursion during the contact phase which led to propelling with decreased power and force.23 In addition, Hogaboom et al’s15 study showed that better transfer technique was correlated with less shoulder pathology and less shoulder pain. There has also been correlation with higher grades of supraspinatus tendinopathy noted in subjects with worse transfer quality.
High prevalence of shoulder pain seems to be related to increase demands on and overuse of the stabilizing soft tissues of the shoulder joint.24 The repetitive nature of wheelchair propulsion encourages repetitive protraction of the scapula, which has been shown to lead to weaker scapular stabilizers and tighter anterior muscles.25 Tightness of the anterior shoulder musculature, combined with weakness of the posterior shoulder musculature both seem to contribute to development of shoulder pain in wheelchair users.5,26–28 Compensatory muscle imbalances in the shoulder may develop because of this repetitive long-term propulsion and lack of strengthening program focusing on rotator cuff and scapular stabilizer muscles.25 This shoulder muscle imbalance in addition to the comparative weakness of the humeral head depressors (rotators and adductors) may be a factor in the development and perpetuation of rotator cuff impingement syndrome in this population. Research supports that those with rotator cuff impingement syndrome had a higher abduction: adduction and abduction: internal rotation strength ratios compared to those who did not have impingement syndrome.5
The constant sitting position in a MWC requires frequent and often prolonged overhead reaching for day to day and vocational tasks. Repetitive overhead reaching and pulling can place the shoulder at higher risk for pain and development of injury. A typical sitting position also involves a posterior pelvic tilt, increased thoracic kyphosis, and forward head position.25 This can result in an anterior displacement of the shoulder girdle, which causes an abnormal shortening of the anterior soft tissue structures with a compensatory lengthening posteriorly and relative weakness of the scapulothoracic muscles.25,29 Weakness of the scapulothoracic muscles potentially leads to abnormal positioning of the scapula, disturbances in scapula humeral rhythm, and generalized shoulder dysfunction.30,31
SHOULDER PAIN AND WHEELCHAIR ATHLETES
As adaptive sports has become more popular, the International Paralympic Committee (IPC) has started to keep track of injuries of adaptive sports as they occur during the Paralympics. It is without question that one of the most commonly injured body parts for wheelchair athletes is the shoulder.9,32–37 Current shoulder complaints in wheelchair athletes range widely with reportedly up to 76% of athletes studied.5,8,36,38–46 Most studies report that more than half of their athletes have reported pain since manual wheelchair use.8,9,13 Wheelchair sports that have been found to have higher incidence of sustaining shoulder injuries include wheelchair track, road racing, rugby, field events and wheelchair basketball.8,33,35,40
Of note, studying this population is more challenging because there are a multitude of other factors to take into consideration than when studying able-bodied sports. For example, there are athletes participating in each sport with multiple different types of impairment affecting them (ie, spinal cord injury, amputee, spina bifida, cerebral palsy, and stroke). Some wheelchair sports also involve multiple categories of severity of disability on the same team (ie, wheelchair basketball and quad rugby). Some sports are also modified by rules or equipment for particular classes of athletes (ie, sled hockey). There is also an ever changing of the technology and equipment being used for sports chairs and equipment that have changed performance parameters injury risk characteristics in the past 2 decades.1
There has been conflicting evidence of whether a manual wheelchair user’s participation in a wheelchair sport puts the shoulder at higher risk for sustaining injury or not. Several studies found that participation in a wheelchair sport could be protective of the shoulder from injury or pain. Wylie et al47 found in their study that shoulder degeneration was more likely to develop in less active patients. Fullerton et al found that the odds of having shoulder pain was twice as high among nonathletes as they were among athletes. They also found that nonathletes tended to develop shoulder pain and problems 4 years earlier than the athletic population with shoulder pain.42 A couple other studies, however, found that participation in wheelchair athletics showed no difference in the incidence of shoulder pain or quality of life compared to those who did not participate.41,45 Akbar et al38 showed that those who played wheelchair basketball actually had an increased risk of developing a rotator cuff tear than those who did not play a sport. Regardless, it has been shown that there is proven benefit to participate in an adaptive sport on health, employment, mood, and quality of life.48–50 New participation in a wheelchair sport should be discussed with a medical provider to discuss individualized risks and benefits.
Risk factors for shoulder pain in the wheelchair athlete population have reported to be overuse,5,8,37,43 imbalance of muscle strength or muscle weakness,5,43 and decreased trunk control.36,38,46 There is mixed evidence supporting whether increased number of training hours per week,40,45 and female gender51,52 are risk factors for injury. A players’ role on a team may also determine the specific shoulder stresses they face.8,53
As described above, using a manual wheelchair daily can biomechanically place users at a higher risk for developing shoulder pain. These biomechanical risk factors may be even more exaggerated in the wheelchair athlete population. Studies have shown that participants involved in wheelchair sports have a higher percentage of abnormal scapular resting position with the highest incidence being in wheelchair basketball.25 In addition, the excessive scapular internal rotation and downward movement during athletic movements could increase the potential for shoulder impingement in this population.54–56 It was also found that paraplegic athletes as a whole have relative weakness of shoulder adduction, as compared to abduction. The ratio of shoulder abduction to adduction strength is significantly higher in paraplegic athletes as compared with able-bodied athletes.5 Those with rotator cuff impingement syndrome have an even more exaggerated pattern of this (weakness with adduction, external rotation, and internal rotation).
Highest Risk Wheelchair/Seated Sports
When counseling patients on participation in wheelchair/seated sport, it is important to know which sports have highest rate of injuries (Table 1). The International Paralympic Committee (IPC) implemented the Paralympic Injury Surveillance Study in 2002 to gather and publish injury data. In the most recent injury report from the Rio 2016 Paralympic Summer games, it was reported that the category of sport disciplines that had the third highest injury rate compared with all the other categories was wheelchair basketball, wheelchair fencing, and wheelchair rugby. The anatomical area most affected by injury included the shoulder with reported injury incidence rate of 1.8 per 1000 athlete days.57 In the injury report from the most recent Sochi 2014 Winter Paralympics, it was reported that the sports with the second and third highest injury rate was sled hockey followed by wheelchair curling. Similar to the Rio Paralympic Games, the anatomical area most affected by injury was the shoulder with reported injury incidence rate of 6.4 per 1000 athlete days.58
History and Examination
The majority of shoulder pain in wheelchair athletes have an insidious onset with symptoms exacerbated by activities such as repetitive movement, wheelchair propulsion uphill, reaching overhead, and transfers.59 Questioning should be focused on identifying location and quality of pain, exacerbating and relieving factors, history of prior shoulder injury, and treatments tried. Additional questions should include inquiring about diagnosis, level and severity of impairment, sport and position being played, and equipment being used.60,61 It is also important to ask questions to rule out referred pain (ie, cervical spine, chest). Complete review of systems is always helpful to ensure there is no underlying neoplastic, autoimmune, or rheumatologic issue.61 An additional tool that may be helpful in quantifying shoulder pain in individuals who use wheelchairs is the Wheelchair User’s Shoulder Pain Index (WUSPI).9 This index was created to measure shoulder pain and difficulty during basic and instrumental activities of daily living and can be used as a great tool to monitor shoulder pain and its effect on function.
Physical examination should include a full screen of the cervical spine and shoulder including inspection (asymmetry, atrophy), palpation, range of motion (passive and active), and special tests. Special tests of the shoulder should include looking for impingement syndrome (Neer’s, Hawkin’s, Yocum, and painful arc), biceps tendon pathology (Speed’s, Yergason’s), supraspinatus pathology (Jobe, drop arm), infraspinatus pathology (resisted external rotation), subscapularis pathology (lift-off), glenohumeral instability (sulcus sign, Jobe relocation test, and apprehension test) and labral pathology (O’Brien’s, dynamic labral shear test). Special attention should be paid to scapula mechanics and seated posture in the wheelchair as it has been previously shown, that wheelchair use in itself can be a risk factor for asymmetric scapular motion.61 Baseline weakness from underling diagnosis and poor trunk control causing difficulty with balance for testing should be taken into consideration. If indicated, x-rays can be obtained to evaluate the alignment and bony structure pathology of the shoulder. Magnetic resonance imaging (MRI) can be obtained to evaluate the soft tissue structures including rotator cuff and biceps tendons, bursae, ligaments, labrum, or capsular pathology. Musculoskeletal ultrasonography is a great tool to evaluate rotator cuff and dynamic motion of the shoulder, but is dependent on operator skill.61 Proper identification of shoulder pain etiology is key.
Common Shoulder Pathology
The 2 most common ways to evaluate the shoulder for pathology are ultrasound and MRI. Using ultrasound, common pathology found in the wheelchair athlete population includes rotator cuff (most commonly supraspinatus) tendinopathy, cortical irregularity, and supraspinatus impingement.12 Rotator cuff pathology has been studied the most in the wheelchair population. One interesting finding that Escobedo et al found was that 16% of rotator cuff tears found in the paraplegic population studied were noted in posterior location, while none were noted in this location in the able-bodied population.10 The posterior location of tears in individuals with paraplegia may be related to extreme loading of the posterior cuff muscles, muscle imbalance, or repetitive external rotation. There have been very few studies done evaluating specific shoulder pathology found amongst different wheelchair sports. Table 2 shows a summary of the literature of shoulder pathology found on imaging in specific wheelchair sports.38,43,62 Shoulder pathology found can differ depending on sport being played because of different forces being subjected to. There is some evidence that suggests that overhead sports (ie, wheelchair basketball) can place the shoulder at increased risk for rotator cuff pathology.38
Treatment and Prevention
Treatment of shoulder pain in the wheelchair athlete population can be challenging.63 Predictors of better patient outcomes with any treatment of shoulder pain include less severe pain, younger age, better physical fitness, fewer medical comorbidities, and proper wheelchair propulsion/transfer technique and fit. Initial treatment of acute shoulder pain in this population can be managed similar to that of shoulder pain in able-bodied population with special considerations unique to the wheelchair athlete. The goal of treatment is to identify and help correct the underlying reason for the pain to prevent it from returning. Conservative management is recommended as first line treatment including rest, activity modification, control of pain and inflammation, and physical therapy.61 However, it is often difficult to give wheelchair users’ shoulders full rest without greatly interfering with their quality of life. It can be helpful to have the athlete work with a physical therapist who is familiar with working with wheelchair users as they can also help identify and correct biomechanical issues with transfers and wheelchair propulsion. Sometimes, injection of a corticosteroid medication may help provide short-term pain relief to help reduce the pain enough to allow a patient to begin an exercise program. Risk and benefits will need to be discussed as corticosteroid medications may also weaken surrounding tendons. If surgery is indicated, a discussion of risk and benefits is important as recovery from surgery will often mean approximately 6 to 8 weeks without use of the affected shoulder.59 In the able-bodied population, although postsurgical restrictions can limit use of the affected arm, they are often still able to maintain their independence with daily life activities. However, in the wheelchair athlete population, given the necessity of use of both shoulders for everyday activities, postsurgical restrictions often can leave this population no longer able to be fully independent with mobility and self-care. When discussing surgical intervention, extra preparation, planning, and education is required to ensure necessary help (ie, caregiver) and equipment (power wheelchair or scooter) can be put in place. There is also an additional risk of significant financial and caregiver burden during this period of time. It has been reported that success with rotator cuff surgery in patients with spinal cord injury occurs when a team of specialists (ie, surgeon, physiatrist, physical therapist, and social worker) is involved in the decision-making process.64 Given the increased complexity of postsurgical management in this population, it is extremely important to make sure conservative treatment is optimized before considering surgical interventions.65
Similar to other able-bodied sports, establishment of preventative and rehabilitation measures for shoulder pain is necessary to keep the shoulders of this population healthy. Research has shown that a home exercise program can be helpful in reducing shoulder pain and improving function in wheelchair users.66 Important things to think about incorporating into a prevention program include increasing flexibility of anterior musculature (pectoralis and biceps) and increasing/balancing muscle strength of weaker muscles in the posterior shoulder complex (external rotators, adductors, and scapular retractors).5,7,27,29,63 In addition, it also important to incorporate exercises to improve dynamic trunk control, as this is essential in maintaining proper scapula-thoracic and glenohumeral function.46 A different type of program may need to be considered for quadriplegics as the high level of their spinal lesion may also contribute to shoulder pain and pathology in this population. This population tends to have a significant deficit in adductor strength, which should be the focus of their preventative program.44
Shoulder pain is one of the most common complaints in wheelchair athletes. The anatomy of the shoulder as well as biomechanics of wheelchair use put the shoulder at higher risk for injury and pain. Evaluation of shoulder pain in these athletes tend to be more complex than when evaluating the able-bodied population as providers have to take into consideration type of impairment, severity of impairment, position in sport, and equipment used. Treatment is also often more challenging and multidisciplinary care can be helpful. It is important to ensure all wheelchair athletes incorporate a good shoulder strengthening program to ensure their muscles are well-balanced to help prevent injury.
1. Willick SE, Lexell J. Paralympic sports medicine and sports science-introduction. PM&R. 2014;6:S1–S3.
2. Peat M, Culham E, Wilk KE. The Athlete’s Shoulder, 2nd ed. London, UK: Churchill Livingston; 2009.
3. Veeger HEJ, van der Helm FCT. Shoulder function: the perfect compromise between mobility and stability. J Biomech. 2007;40:2119–2129.
4. Yu D. Shoulder pain
in hemiplegia. Phys Med Rehab Clin N Am. 2004;15:683–697.
5. Burnham RS, May L, Nelson E, et al. Shoulder pain
in wheelchair athletes: the role of muscle imbalance. Am J Sports Med. 1993;21:238–243.
6. Chow JW, Levy CE. Wheelchair propulsion biomechanics and wheelers’ quality of life: an exploratory review. Disabil Rehabil: Assist Technol. 2011;6:365–377.
7. Curtis KA, Tyner TM, Zachary L, et al. Effect of a standardized exercise protocol on shoulder pain
in long-term wheelchair users. Spinal Cord. 1999;37:421–429.
8. Curtis KA, Black K. Shoulder pain
in female wheelchair basketball players. J Ortho Sports Phys Ther. 1999;29:225–231.
9. Curtis KA, Roach KE, Applegate EB, et al. Development of the Wheelchair User’s Shoulder Pain
Index (WUSPI). Paraplegia. 1995;33:290–293.
10. Escobedo EM, Hunter JC, Hollister MC, et al. MR imaging of rotator cuff
tears in individuals with paraplegia. Am J Roentgenol. 1997;168:919–923.
11. Alm M, Saraste H, Norrbrink C. Shoulder pain
in persons with thoracic spinal cord injury: prevalence and characteristics. J Rehabil Med. 2008;40:277–283.
12. Brose SW, Boninger ML, Fullerton B, et al. Shoulder ultrasound abnormalities, physical examination findings, and pain in manual wheelchair users with spinal cord injury. Arch Phys Med Rehabil. 2008;89:2086–2094.
13. Akbar M, Balean G, Brunner M, et al. Prevalence of rotator cuff
tear in paraplegic patients compared with controls. J Bone Joint Surg Am. 2010;92:23–30.
14. Kivimaki J, Ahoniemi E. Ultrasonographic findings in shoulders of able-bodied, paraplegic, and tetraplegic subjects. Spinal Cord. 2008;46:50–52.
15. Hogaboom NS, Worobey LA, Boninger ML. Transfer technique is associated with shoulder pain
and pathology in people with spinal cord injury: a cross-sectional investigation. Arch Phys Med Rehabil. 2016;97:1770–1776.
16. Van Dronglen S, Boninger ML, Impink BG, et al. Ultrasound imaging of acute biceps tendon changes after wheelchair sports. Arch Phys Med Rehabil. 2007;88:381–385.
17. Ferrero G, Mijno E, Actis MV, et al. Risk factors for shoulder pain
in patients with spinal cord injury: a multicenter study. Musculoskelet Surg. 2015;99:S53–S56.
18. Akbar M, Brunner M, Balean G, et al. A cross-sectional study of demographic and morphologic features of rotator cuff
disease in paraplegic patients. J Shoulder Elbow Surg. 2011;20:1108–1113.
19. Dyson-Hudson TA, Kirshblum SC. Shoulder pain
in chronic spinal cord injury, part I: epidemiology, etiology, and pathomechanics. J Spinal Cord Med. 2004;27:4–17.
20. Boninger ML, Souza AL, Cooper RA, et al. Propulsion patterns and pushrim biomechanics in manual wheelchair propulsion. Arch Phys Med Rehabil. 2002;83:718–723.
21. Koontz AM, Cooper RA, Boninger MI, et al. Shoulder kinematics and kinetics during two speeds of wheelchair propulsion. J Rehabil Res Dev. 2002;39:635–649.
22. Richter WM, Rodriguez R, Woods KR, et al. Stroke pattern and handrim biomechanics for level and uphill wheelchair propulsion at self-selected speeds. Arch Phys Med Rehabil. 2007;88:81–87.
23. Finley MA, Rasch EK, Keyser RE, et al. The biomechanics of wheelchair propulsion in individuals with and without upper limb impairment. J Rehab Res Dev. 2004;41(3B):385–394.
24. Jayaraman C, Beck CL, Sosnoff JJ. Shoulder pain
and jerk during recovery phase of manual wheelchair propulsion. J Biomech. 2015;48:3937–3944.
25. Aytar A, Zeybek A, Pekyavas NO, et al. Scapular resting position, shoulder pain
and function in disabled athletes. Prosthet Orthot Int. 2015;39:390–396.
26. Powers CM, Newsam CJ, Gronley JK, et al. Isometric shoulder torque in subjects with spinal cord injury. Arch Phys Med Rehabil. 1994;75:761–765.
27. Millikan T, MorseM, Hedrick B. Prevention of shoulder injuries. Sports Spokes. 1991;17:35–38.
28. Van Drongelen S, de Groot S, Veeger HEJ, et al. Upper extremity musculoskeletal pan during and after rehabilitation in wheelchair-using persons with a spinal cord injury. Spinal Cord. 2006;44:152–159.
29. Dec KL, Sparrow KJ, Mckeag DB. The physically-challenged athlete: medical issues and assessment. Sports Med. 2000;29:245–258.
30. Hertling D, Kessler RM. Management of Common Musculoskeletal Disorders: Physical Therapy Principles and Methods. Philadelphia, PA: Lippincott-Raven; 1996:165–216.
31. Kamkar A, Irrgang JJ, Whitney SL. Nonoperative management of secondary shoulder impingement syndrome. J Orthop Sports Phys Ther. 1993;17:212–224.
32. Ferrara MS, Davis RW. Injuries to elite wheelchair athletes. Paraplegia. 1990;28:335–341.
33. McCormack DAR, Reid DC, Steadward RD, et al. Injury profiles in wheelchair athletes: results of a retrospective survey. Clin J Sports Med. 1991;1:35–40.
34. Slocum C, Blauwet CA, Allen JBA. Sports medicine considerations for the Paralympic athlete. Curr Phys Med Rehabil Rep. 2015;3:25–35.
35. Blauwet CA, Cushman D, Emery C, et al. Risk of injuries in paralympic track and field differs by impairment and event discipline: a prospective cohort study at the London 2012 Paralympic Games. Am J Sports Med. 2016;44:1455–1463.
36. Chung WM, Yeung S, Wong AYL, et al. Musculoskeletal injuries in elite able-bodied and wheelchair foil fencers. Clin J Sports Med. 2012;22:278–280.
37. Taylor D, Williams T. Sports injuries in athletes with disabilities: wheelchair racing. Paraplegia. 1995;33:296–299.
38. Akbar M, Brunner M, Ewerbeck V, et al. Do overhead sports increase risk for rotator cuff
tears in wheelchair users? Arch Phys Med Rehabil. 2015;96:484–488.
39. Curtis KA, Drysdale GA, Lanza D, et al. Shoulder pain
in wheelchair users with tetraplegia and paraplegia. Arch Phys Med Rehabil. 1990;80:453–457.
40. Curtis KA, Dillon DA. Survey of wheelchair athletic injuries: common patterns and prevention. Paraplegia. 1985;23:170–175.
41. Finley MA, Rodgers MM. Prevalence and identification of shoulder pathology in athletic and nonathletic wheelchair users with shoulder pain
: a pilot study. J Rehabil Res Dev. 2004;41 (3B):395–402.
42. Fullerton HD, Borckardt JJ, Alfano AP. Shoulder pain
: a comparison of wheelchair athletes and nonathletic wheelchair users. Med Sci Sports Exerc. 2003;35:1958–1961.
43. Jeon IH, Kochhar H, Lee JM, et al. Ultrasonographic evaluation of the shoulder in elite wheelchair tennis players. J Sports Rehabil. 2010;19:161–172.
44. Miyahara M, Sleivert GG, Gerrard DF. The relationship of strength and muscle balance and impingement syndrome in elite quadriplegic rugby players. Int J Sports Med. 1998;19:210–214.
45. Ustunkaya O, Edder AO, Donat H, et al. Shoulder pain
, functional capacity and quality of life in professional basketball players and non-athlete wheelchair users. Pain Clinic. 2007;19:71–76.
46. Yildirim NU, Comert E, Ozengin N. Shoulder pain
: a comparison of wheelchair basketball players with trunk control and without trunk control. J Back Musc Rehabil. 2010;23:55–61.
47. Wylie EJ, Chakera TMH. Degenerative joint abnormalities in patients with paraplegia of duration greater than 20 years. Paraplegia. 1988;26:101–106.
48. Martin Ginis KA, Jorgensen S, Stapleton J. Exercise and sport for persons with spinal cord injury. PM&R. 2012;4:894–900.
49. Lape EC, Katz JN, Losina E, et al. Participant-reported benefits of involvement in an adaptive sports program: a qualitative study. PM&R. 2018;10:507–515.
50. Blauwet C, Sudhaker S, Doherty AL, et al. Participation in organized sports is positively associated with employment in adults with spinal cord injury. Am J Phys Med Rehabil. 2013;92:393–401.
51. Tsnuoda K, Mutsuzaki H, Hotta K, et al. Correlates of shoulder pain
in wheelchair basketball players from the Japanese national team: a cross-sectional study. J Back Musculoskelet Rehabil. 2016;29:795–800.
52. Heyward OW, Vegter RJK, de Groot S, et al. Shoulder complaints in wheelchair athletes: a systematic review. PLoS ONE. 2017;12:1–20.
53. Lastuka A, Cottingham M. The effect of adaptive sports on employment among people with disabilities. Disabil Rehabil. 2016;38:742–748.
54. Kibler WB, McMullen J. Scapular dyskinesis and its relation to shoulder pain
. J Am Acad Orthop Surg. 2003;11:142–151.
55. Ludewig PM, Cook TM. Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement. Phys Ther. 2000;80:276–291.
56. Warner MB, Wilson D, Heller MO, et al. Scapular kinematics in professional wheelchair tennis players. Clin Biomech. 2018;53:7–13.
57. Derman W, Runciman P, Schwellnus M, et al. High precompetition injury rate dominates the injury profile at the Rio 2016 Summer Paralympic Games: a prospective cohort study of 51198 athlete days. Br J Sports Med. 2018;52:24–31.
58. Derman W, Schwellnus MP, Jordaan E, et al. High incidence of injury at the Sochi 2014 Winter Paralympic Games: a prospective cohort study of 6564 athlete days. Br J Sports Med. 2016;50:1069–1074.
59. Van Straaten MG, Cloud BA, Zhao KD, et al. Maintaining shoulder health after spinal cord injury: a guide to understanding treatments for shoulder pain
. Arch Phys Med Rehabil. 2017;98:1061–1063.
60. Apple DF, Cody R, Allen A. Overuse Syndrome of the Upper Limb in People With Spinal Cord Injury. In: Physical fitness: A Guide for Individuals With Spinal Cord Injury. Washington, DC: Dept of Veterans Affairs, Veterans Health Administration, Rehabilitation Research and Development Service, Scientific and Technical Publications Section; 1996:97–107.
62. You BC, Lee WJ, Lee SW, et al. Shoulder disease patterns of the wheelchair athletes of table-tennis and archery: a pilot study. Ann Rehabil Med. 2016;40:702–709.
63. Klenck C, Gebke K. Practical management: common medical problems in disabled athletes. Clin J Sport Med. 2007;17:55–60.
64. Fattal C, Coulet B, Gelis A, et al. Rotator cuff
surgery in persons with spinal cord injury: relevance of a multidisciplinary approach. J Shoulder Elbow Surg. 2014;23:1263–1271.
65. Diaz R, Stoll AH, Rho ME, et al. Preserving the shoulder function of an elite paratriathlete. Am J Phys Med Rehabil. 2018;97:e69–e72.
66. Nawoczenski DA, Ritter-Soronen JM, Wilson CM, et al. Clinical trial of exercise for shoulder pain
in chronic spinal cord injury. Phys Ther. 2006;86:10604–11617.