Adaptive Throwing Sports: Discus, Javelin, Shot Put, and Boccia


Amputee

Cerebral palsy

Visual impairment

Spinal cord injury

Intellectual disability

Les Autres (“The Others,” including dwarfism and multiple sclerosis)



The International Paralympic Committee Classification Code provides a universal template for further sub-classification within each sport that takes into account both the anatomical and functional limitations of the athlete. The purpose of subclassification is to allow for even competition by categorizing athletes in reference to the total impact of their impairment(s) [1]. Generally speaking, the greater the degree of disability present, the lower the athlete’s classification.



Field Events: Discus, Javelin, and Shot Put


In the sports of discus, javelin, and shot put, the goal is to hurl, throw, or put an object as far as possible. In the adaptive form of these sports, the distance is then converted to a score based on the athlete’s classification, thus allowing for fair competition among athletes with differing levels of impairment. Athletes participating in all field events, including discus, javelin, and shot put, are classified in the F10s through F50s. The “F” stands for “field,” and the number that follows signifies level of disability. The F10s are athletes with visual impairments; the F20s are athletes with intellectual impairment; the F30s are athletes with varying degrees of motor dysfunction, including cerebral palsy; the F40s are athletes with short stature, limb deficiencies, or amputations; and the F50s are wheelchair athletes, including tetraplegics and paraplegics [2]. As previously mentioned, the lower the classification number within each grouping, the greater the degree of disability. For more details on the classifications, see Table 24.2.


Table 24.2
Field classifications for discus, javelin, and shot put [2]





























































Classification

Description

F11

No light perception or small amount of light perception but incapable of recognizing the shape of a hand at any distance or in any direction

F12

Can recognize shape of hand and perceive clearly up to 20/600. Visual field is <5°

F13

Can recognize shape of hand and perceive clearly >20/600 but ≤20/200. Visual field is >5° but <20°

F20

IQ <75, with significant limitations in adaptive behavior, and age of onset before 18 years old

F31–34

Athetosis, ataxia, and/or hypertonia. Compete in seated position. Demonstrate increasing trunk and upper extremity control from 31 to 34

F35

Athetosis, ataxia, and/or hypertonia. Compete standing. Moderate dysfunction of lower limbs, good functional strength in upper limbs

F36

Athetosis, ataxia, and/or hypertonia. Compete standing. Involuntary movement affects all four limbs, cannot remain still

F37

Athetosis, ataxia, and/or hypertonia. Compete standing. Movement/coordination difficulties affect non-dominant side of the body

F38

Athetosis, ataxia, and/or hypertonia. Compete standing. Minimal functional loss, generally affecting only one limb

F40–41

Short stature

F42

Single side above knee amputation (AKA) + arm deficiency. Compete standing

F43

Double below knee amputation (BKA). Compete standing

F44

Single BKA. Compete standing

F45

Double above or below elbow amputation

F46

Single above or below elbow amputation

F51–54

No leg or trunk function. Demonstrate increasing degrees of shoulder, arm, and hand function from 51 to 54. Includes tetraplegics

F55–58

Upper limb function intact. Demonstrate increasing degrees of trunk and leg function from 55 to 58


Adaptive Discus


The purpose of discus is to throw a circular biconvex disk as far as possible from a designated circular throwing area. In an able-bodied throw, the athlete begins by facing away from the throwing field before forcefully spinning 1.5 times and then releasing the discus in a sidearm fashion, allowing the discus to spin off the fingers. In adaptive discus, some of the standing athletes use the able-bodied spin technique (see Fig. 24.1), while others use a more stationary standing technique, relying solely on trunk and upper extremity rotation to generate torque. The seated athletes also rely solely on trunk and upper extremity rotation as they throw from a stationary throwing frame. In both able-bodied and adaptive discus, all throws are made from a caged enclosure designed to prevent errant throws from traveling toward spectators or other participants. For a throw to count, the discus must land within a marked landing sector. The actual discuses used in adaptive sport weigh between 0.750 and 2 kg, depending on the classification, as compared to the able-bodied population which uses 1 kg discuses for women and 2 kg discuses for men [2, 3].

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Fig. 24.1
An F44 discus thrower (Photograph provided by the United States Olympic Committee. Photograph by Joe Kusumoto)


Adaptive Javelin


The purpose of javelin is to throw the spear-like javelin as far as possible from a designated throwing area. A runway leads up to the throwing area, and able-bodied athletes will run up this track before launching the javelin. The javelin is held by a single hand at the grip site near the center of the javelin and must be thrown over the shoulder or upper part of the throwing arm. For a throw to count, the tip of the javelin must be the first part to land on the ground within the marked landing sector. In adaptive javelin, the standing athletes use the runway just as the able-bodied athletes do, while the seated athletes throw from a stationary throwing frame (see Fig. 24.2). The actual javelins used in adaptive sport are 2.0–2.7 m in length and weigh between 500 and 800 g, depending on the classification. Comparatively in the able-bodied population, female competitors use 2.2–2.3 m javelins that weigh 600 g and male competitors use 2.6–2.7 m javelins that weigh 800 g [2, 4].

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Fig. 24.2
An F58 javelin thrower (Photograph provided by the United States Olympic Committee. Photograph by Becky Miller)


Adaptive Shot Put


The purpose of shot put is to throw a spherical metal shot as far as possible from a designated circular throwing area. The shot is held in close proximity to the neck/chin region and cannot be dropped below this position during the throw. In an able-bodied throw, or put, the athlete begins by facing away from the throwing field, just like discus. From here, the athlete may execute one of two force-generating techniques, the “spin” or the “glide.” The “spin” is essentially the same as the discus technique, with the athlete forcefully spinning 1.5 times before releasing the shot. The “glide” consists of a forceful turn from the rear-facing position, pushing off the dominant leg, before releasing the shot. The put itself is executed by one hand, in a pushing fashion, with the point of release being above the level of the shoulder. For a put to count, the shot must land within a marked landing sector. In adaptive shot put, the standing athletes use the able-bodied “spin” or “glide” techniques, while the seated athletes put from a stationary throwing frame (see Fig. 24.3). The puts used in adaptive sport weigh between 2.0 and 7.260 kg, depending on the classification, whereas in the able-bodied population, female competitors use a 4.0 kg shot and male competitors use a 7.260 kg shot [2, 5].

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Fig. 24.3
An F57 shot putter (Photograph provided by the United States Olympic Committee. Photograph by Becky Miller)


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Fig. 24.4
A BC 3 boccia athlete (Photograph provided by the United States Olympic Committee. Photograph by Shelly Higgins)


Boccia


Boccia is the adaptive sport equivalent of bocce. It was originally developed for athletes with cerebral palsy but is now inclusive of athletes of other impairment groups including stroke, traumatic brain injury (TBI), spinal cord injury (SCI), muscular dystrophy, and multiple sclerosis. It is played indoors on a flat, smooth surface and features individual as well as team play. Each individual, or team, has six leather balls (either red or blue), and the purpose is to land the ball as close as possible to the “Jack” or white target ball. To begin the game, or match, the red individual (or team) throws the Jack out onto the court. Athletes, depending on their impairments, are permitted to throw, kick, or use an assistive device known as a pointer to propel the ball from a designated throwing area. After throwing the Jack, that same player then throws his or her first red ball toward the Jack. Blue then throws their first ball. Whichever ball is closer to the Jack identifies the “in team.” The “in team” watches as the other team throws their balls one by one until they either displace the “in team” or run out of balls, after which the other team resumes throwing. A round, or “end,” is completed after all balls are thrown. At this point, the score is tallied. The individual, or team, that is closest to the Jack will score as many points as they have balls closer to the Jack than their opponent’s closest ball [1, 6].

Each match consists of four to six ends depending on the number of players per team (individuals and pairs play four ends, teams of three play six ends). Each player, or team, throws six balls per end (i.e., an individual throws six balls, pairs throw three each, and teams of three throw two each). The winning individual, or team, is the one with the most points at the end. If there’s a tie, a tie-breaker end is played. If at any time during an end the Jack is pushed or rolls out of bounds, the Jack gets placed in the center of the court and the closest ball determines the new “in team” [1, 6].

Individual and team play is comprised of seven different divisions, four divisions of individual play and three divisions of team play (two for pairs and one for teams of three). For a description of each division, please see Table 24.3. The actual boccia balls weigh 275 ± 12 g with a circumference of 270 ± 8 mm [6].


Table 24.3
Boccia divisions [6]































Division

Description

Individual BC 1

Sport assistant may provide assistance to athlete, such as passing athlete the ball, adjusting wheelchair orientation, or shaping the ball, but the athlete must specifically instruct these actions and the assistant must remain in a designated area behind the throwing area

Individual BC 2

No assistance from a sport assistant is permitted during a match. The referee, however, can provide some assistance, such as handing the athlete a ball that was accidentally dropped

Individual BC 3

A ramp is used as an assistive device to propel the ball (see Fig. 24.4). A sport assistant can assist in orienting the wheelchair or ramp or can roll the ball, but the athlete must specifically instruct these actions. Also, the assistant cannot look at the court and must keep their back toward the court

Individual BC 4

Athletes with locomotor disabilities of a non-cerebral origin and athletes that “throw” with their foot instead of their hand. The BC 4 foot players may receive assistance from a sport assistant as the BC 1 players do

Pairs BC 3

At least one of the two players must have cerebral palsy. Otherwise they operate under the same rules as Individual BC 3

Pairs BC 4

Same rules as Individual BC 4

Team (BC 1 or BC 2)

Teams of three composed of BC 1 and BC 2 athletes. There must be at least one BC 1 athlete on the court for each team at all times


Adaptive Equipment


Depending on the athlete’s impairment(s), adaptive equipment may include prosthetic limbs or wheelchairs. Beyond these, the adaptive equipment is more sport specific. As previously mentioned under the field events, seated athletes, specifically F31–34 and F51–58, utilize a throwing frame in discus, javelin, and shot put. The throwing frame is secured to the ground and the seat height cannot exceed 75 cm. Holding bars may be present which can be held by the hand of the non-throwing arm to assist in maintaining balance and generating greater force. There may also be footplates present for added support and stability. Straps can be placed over the thighs and/or pelvis. The use of gloves as an adaptive device to improve grip is permitted for classes F51–53 only [2].

For boccia, specific adaptive equipment may include ramps and pointers, as previously mentioned. BC 3 athletes who cannot throw or kick the boccia ball are eligible to use ramps and pointers. Ramps are slide-like structures that the boccia ball can be “launched” from, and pointers are devices fixed to the athlete’s head, mouth, or arm to push the ball down the ramp [6].


Sports Medicine Overview


Like all athletes, adaptive throwers are subject to injury. Many adaptive throwers have unique medical issues related to their underlying health conditions. It is important to be aware of these issues first and foremost. In addition to underlying medical issues, adaptive athletes are at risk for injuries related to both their disability and sport-specific activity.


Unique Medical Issues


Athletes that compete in adaptive sports often have unique medical issues based on the very health conditions that precipitate their impairments and disabilities, particularly the athletes with spinal cord injuries. Regardless of what sport they are participating in, athletes with spinal cord injuries are at varying risk, based on the level of lesion, for developing urinary stones, bladder infections, respiratory infections, pressure sores, and autonomic dysfunction [710]. While insensate individuals are at higher risk of pressure sores/ulcers at baseline, there are added risk factors which are pertinent to adaptive athletes that include increased moisture from sweating and repeated movements during sport activity [7, 11]. All athletes competing in wheelchairs are potentially subjected to this risk. Therefore, it is important for the athletes to have adequate cushioning of the buttocks, frequent pressure reliefs, high-performance moisture-wicking clothing, and optimal nutrition [10, 11]. Autonomic dysfunction, in the form of poor vasoregulation and impaired innervation of sweat glands, places the athlete at risk of hyperthermia, dehydration, and intolerance of environmental extremes, emphasizing the need for proper fluid hydration before, during, and after competition [7, 9, 10]. Another unique medical issue worth noting is the increased seizure risk associated with cerebral palsy. Athletes with cerebral palsy may be at higher risk as the seizure threshold may be lowered through stress encountered during competition, fatigue from training, or dehydration [7]. It is important to keep these underlying health issues in mind when caring for adaptive athletes.


Injuries by Disability


Underlying disability can predispose the adaptive athlete to specific injury patterns. Generally speaking, upper extremity injuries are more common in wheelchair athletes, while lower extremity injuries are more common in ambulatory disabled athletes [8, 1214]. More specifically, a study that looked at the 1996 Paralympics found that among US competitors with soft tissue injuries, wheelchair athletes had a predilection for shoulder, arm-elbow, and forearm-wrist injuries; visually impaired athletes a predilection for hip-thigh, cervicothoracic region, and shoulder injuries; and cerebral palsy athletes a predilection for lumbar region, foot-toe, and ankle injuries [14]. A separate study that looked at the 2004 Paralympic Games found that injury occurrence was different based on classification, with more injuries occurring among track/field (T/F) 11–13, followed by T/F 40–46, T/F 51–58, T/F 32–38, and finally BC 1–4 [15].

Among disabled athletes, the wheelchair athlete warrants special mention because of the factor of wheelchair use and the unique risk factor for injury from the wheelchair. Repeated contact with the wheelchair push rims for purposes of propulsion increases the risk of blister formation on the hands and fingers, though this is more common in wheelchair racers. To prevent further irritation, blisters should be treated with petroleum jelly and a tape or gauze dressing, while the use of gloves may prevent blister formation from occurring [10, 11].

In addition to blisters, soft tissue injuries and skin lacerations/abrasions are the most prevalent injuries sustained by wheelchair athletes, with estimates of 33% of all injuries being soft tissue injuries [10, 11, 16]. Soft tissue injuries, including strains, sprains, bursitis, tendinopathies, and peripheral nerve entrapments, are most likely to affect the shoulders, elbows, wrists, and hands, with the shoulders being the most commonly affected [11, 17]. The risk of shoulder pathology, including rotator cuff impingement, rotator cuff tears, glenohumeral instability, and biceps tendonitis, is unusually high among wheelchair users. Though this risk is essentially the same for wheelchair athletes in general compared to nonathletic wheelchair users, wheelchair athletes competing in overhead sports appear to be at increased risk [10, 1719]. Many of these injuries are the result of overuse and correlate with duration of impairment, duration of wheelchair use, and more training hours per week [1618]. Muscle imbalances of the shoulder girdle may be correlated with wheelchair-related overuse injuries. Training programs should therefore focus on shoulder flexibility and strengthening of the shoulder adductors, internal and external rotators, supraspinatus, pectoralis major, triceps, and anterior deltoid muscles [17, 20].

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Feb 25, 2018 | Posted by in SPORT MEDICINE | Comments Off on Adaptive Throwing Sports: Discus, Javelin, Shot Put, and Boccia
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