Michelle Minehan and Elizabeth Broad
Paralympic athletes compete with physical, visual or intellectual impairments. A classification system allows athletes with similar functional ability to compete against each other on an even playing field. Since the first Paralympic Games in Rome in 1960, the Paralympic movement has developed rapidly. Summer and Winter Paralympic Games now occur every four years and participation is consistently increasing. In 2016, 4333 athletes from 159 countries competed at the Rio Paralympic Games.
Working with Paralympic athletes can be challenging due to limited research and potentially complex interplay between athletes’ clinical, life and sporting needs. Modern Paralympic athletes train and perform at an elite level with increasingly competitive standards, with some events won by fractions of a second or by a single point. In many cases, the nutritional needs of Paralympic athletes are very similar to able-bodied athletes. In other cases, nutrition recommendations need to be modified to suit individual circumstances.
LEARNING OUTCOMES
Upon completion of this chapter you will be able to:
• understand the range of physical, visual and intellectual impairments that may affect Paralympic athletes
• describe key factors driving the need for modification of nutrition recommendations for Paralympic athletes
• consider how sports nutrition recommendations might need to be modified for different types of Paralympic athletes.
CLASSES OF PARALYMPIC ATHLETES
To compete as a Paralympic athlete, at least one of the impairments in Table 20.1 must be present. Some sports cater for only one type of impairment, while others have classes for all impairments. For example, goalball is played exclusively by athletes who are visually impaired, whereas athletics offers a full spectrum of events. Within each sport, athletes are classified based on their level of impairment. For example, the T42 category in athletics is for track athletes with a ‘lower limb affected by limb deficiency, leg length difference, impaired muscle power or impaired range of movement’. The goal of classification is to create an even playing field for competition. Discussion and recommendations in this chapter will focus on the needs of athletes with physical impairments.
Paralympic sports vary widely, from traditional events such as athletics to modified events such as boccia and goalball. Table 20.2 summarises the diverse mix of sports contested at summer and winter Paralympic games.
RESEARCH CHALLENGES
In 1993, the International Paralympic Committee (IPC) established a Sports Science Committee to advance knowledge of Paralympic sport across five central themes: (1) involving the academic world, (2) athlete health and safety, (3) classification, (4) socio-economic determinants of participation and success, and (5) Paralympic athlete, trainer and coach education. Research activity is increasing; to date, however, limited work has been done on nutritional issues for Paralympic athletes. Challenges to conducting research include:
• large variation in functional capacity of athletes
• athletes dispersed over large geographical distances
• medical contraindications to participation in experimental research (for example, use of particular medications)
• small athlete pool, which makes it difficult to set up designs with randomisation and control groups
• small number of scientists actively researching Paralympic athlete issues
• national focus, with many scientists working with Paralympic athletes having a mandate to help athletes from their own countries win medals, limiting opportunities for collaboration and sharing
• limited funding opportunities for sport-related research, especially Paralympic sport.
Table 20.1. Impairments in Paralympic sports
| Impairment | Explanation |
| Impaired muscle power | Reduced force generated by muscles or muscle groups in one limb or the lower half of the body, e.g. spinal cord injury. |
| Impaired passive range of movement | Range of movement in one or more joints is reduced permanently. Joints that can move beyond the average range of motion, joint instability and acute conditions such as arthritis are not considered eligible impairments. |
| Limb deficiency | Total or partial absence of bones or joints, from birth or as a consequence of trauma or illness. |
| Leg length difference | Bone shortening in one leg from birth or trauma. |
| Short stature | Reduced standing height due to abnormal dimensions of bones of upper and lower limbs or trunk, e.g. achondroplasia. |
| Hypertonia | Abnormal increase in muscle tension and a reduced ability of a muscle to stretch, which can result from injury, illness or a health condition, e.g. cerebral palsy. |
| Ataxia | Lack of coordination of muscle movements due to a neurological condition, e.g. cerebral palsy. |
| Athetosis | Unbalanced, uncontrolled movements and a difficulty in maintaining a symmetrical posture, e.g. cerebral palsy. |
| Visual impairment | Vision impacted by a physical or neurological impairment. |
| Intellectual impairment | A limitation in intellectual functioning and adaptive behaviour as expressed in conceptual, social and practical adaptive skills, which originates before the age of 18. |
Source: Adapted from www.paralympic.org/classification (accessed June 2017).
Table 20.2. Sports contested at Paralympic Games
| Summer Paralympic Sports | Winter Paralympic Sports | ||
Archery Para athletics Badminton Boccia Canoe Cycling Equestrian Football 5-a-side Goalball |
Judo Para powerlifting Rowing Shooting Para sport Sitting volleyball Para swimming Table tennis Taekwondo Triathlon |
Wheelchair basketball Wheelchair fencing Wheelchair rugby Wheelchair tennis |
Para alpine skiing Para biathlon Para cross-country skiing Para ice hockey Para snowboard Wheelchair curling |
Source: Adapted from www.paralympic.org/sports (accessed August 2018).
In the absence of a large Paralympic specific research base, it is necessary to extrapolate knowledge gleaned from studies of able-bodied athletes. Budding researchers are encouraged to consider projects with Paralympic populations.
TRAINING AGE
Paralympic athletes compete across a wide age range. The youngest athlete at the Rio Paralympics in 2016 was 13 years old, while the oldest was 73. Many Paralympic athletes follow a traditional sports career path, playing a sport from a young age and gradually improving until they compete at an elite level. Others take up Paralympic sport later in life, after acquiring a disability due to traumatic injury or disease progression.
It is also relatively common for Paralympic athletes to cross-over between and within Paralympic sports. The events offered at major events such as world championships and major games can change to balance the total number of events and according to participation rates. This might require a 400-metre runner to switch to 1500 metres, or a javelin thrower to convert to shotput in order to gain a spot on a national team. As new competition opportunities arise, some athletes transfer to new sports. For example, Para-Triathlon was contested at the Paralympic Games for the first time in 2016, enticing athletes to swap from sports such as athletics, cycling and swimming. Australian athlete Dylan Alcott competed in both wheelchair basketball and wheelchair tennis at different Paralympic Games.
Consequently, athletes can compete at major events with relatively few years of sports specific training under their belt. It is important to consider the training ‘age’ of an athlete as well as their chronological age. Nutritional needs can be different for an athlete with a long training history compared to an athlete rapidly adapting to a training stimulus. Altering body composition might be a lower priority while an athlete focuses on building up sufficient strength and stamina to cope with training. It can be easy to assume that older athletes have acquired significant knowledge about how to manage their nutrition intake for their sport, but in reality they might be very new to the sport and on a rapid learning trajectory.
ENERGY NEEDS
Estimating energy expenditure is arguably the biggest challenge when working with Paralympic athletes. The physiological demands of most Paralympic sports are unmeasured and predictive equations have limited applicability to many Paralympic athletes. Direct measurement of resting metabolic rate (RMR) via indirect calorimetry is useful but not easily accessible for all athletes. In general, predictive equations based on muscle mass (for example, the Cunningham equation) are more useful than equations based solely on height and weight (such as the Harris-Benedict equation). A trial-and-error process based on estimated energy intake and weight changes may be needed to fully understand individual energy requirements.
Athletes with conditions such as spina bifida and cerebral palsy might have proportionally higher energy requirements due to inefficient ambulation and conditions such as athetosis (involuntary movements). Some individuals who walk with a prosthesis might have a higher energy expenditure due to inefficiency of movement caused by gait asymmetry. In most cases, this additional energy cost is small and possibly offset by factors such as reduced muscle and reduced daily activity.
Energy expenditure of individuals who use a wheelchair is typically reduced compared with able-bodied individuals. as daily movements use a smaller muscle mass. RMR is typically lower (up to 25 per cent) in athletes with spinal cord injuries (SCI) due to non-functioning muscle and subsequent muscle wasting. The impact is greater the higher the injury to the spinal cord but can vary according to how complete the injury to the spinal cord is and whether the individual experiences involuntary muscle spasms.
Like able-bodied athletes, many Paralympic athletes strive to keep their physique lean. A reduced RMR means they can have a limited kilojoule budget and have to prioritise nutrient density. It can be a fine balance between supporting performance goals while achieving a suitable physique.
ENERGY AVAILABILITY
Low energy availability has emerged as an important issue for athletes. Energy availability refers to the amount of energy available to support bodily functions once the cost of training has been met. If energy availability is low, metabolism can slow, leading to negative hormonal changes and reduced bone density (Blauwet et al. 2017). This can put athletes at risk of injury, illness and suboptimal body composition.
Currently, little is known about the prevalence of low energy availability in Paralympic athletes. While diagnostic criteria are available for able-bodied athletes (see Chapter 18), specific criteria for different types of Paralympic athletes are currently unavailable. However, there is reason to suspect that many Paralympic athletes could be affected, as low energy availability can arise from both intentional (restricting intake to maintain a lean physique) and unintentional (insufficient opportunity to eat all required food or lack of understanding of total energy requirements) under-eating.
Athletes who do not weight-bear typically have reduced bone density. The primary cause is reduced skeletal loading which may be related to their sport (for example, swimming, cycling) and/or their disability (for example, spinal cord injury, amputation). However, the influence of low energy availability should also be considered.
MACRONUTRIENT AND MICRONUTRIENT NEEDS
Carbohydrate requirements are primarily influenced by the type of training completed. As with able-bodied athletes, adequate carbohydrate availability is required for long (>90 mins) sessions or sessions where maximum work output is required (such as repeated sprints) (see Chapter 10). Rates of glucose utilisation in arm cycling and wheelchair events are largely unknown. However, the capacity to store glycogen in the arms is less than in the large muscles of the legs. Athletes competing in long duration arm cycling and wheelchair events might have a higher need for carbohydrate replacement during sessions to compensate for reduced storage capacity. This can prove challenging as athletes with SCI typically do not like to eat or drink while exercising.
The protein needs of Paralympic athletes have not been documented. However, it is widely accepted that able-bodied athletes have higher protein requirements than sedentary individuals, as additional protein is required for repair, recovery and muscle growth. In general, the same is expected for Paralympic athletes. However, it is expected that athletes with less functional muscle (SCI, amputees) require lower absolute amounts of protein than able-bodied athletes but likely the same intake relative to functional muscle mass. Some Paralympic athletes with SCI or congenital defects have altered kidney function, which may require modifications to protein recommendations. Timing and spread of high-quality protein is as important for Paralympic athletes as for other athletes and, as such, optimal intakes need to be tailored to each individual.
Requirements for micronutrients are generally expected to be similar for Paralympic athletes. Athletes with restricted intakes due to low energy budgets might have difficulty meeting needs from food alone. Athletes with SCI might be at increased risk of vitamin D insufficiency due to inadequate diet, anticonvulsant medication and reduced sunlight exposure. Supplementation might be warranted in some circumstances. In these instances, vitamin D levels should be monitored and supplementation discussed with a doctor or dietitian.
HYDRATION AND HEAT REGULATION
In general, Paralympic athletes are encouraged to start exercise sessions in a euhydrated state and to match fluid intake to sweat losses during exercise. Fluid balance monitoring (weighing before and after exercise) is useful to track fluid losses and plan for individualised fluid replacement (see Chapter 11).
Fluid requirements for athletes with SCI need additional consideration. The ability of the brain to control body temperature through dilation of blood vessels and increased sweating is altered in athletes with SCI if the injury is at or above the T8 vertebrae (top half of the spinal column). The extent of the impact depends on the severity and level of the damage to the spinal cord. The higher the lesion, the greater the impairment to thermoregulation. Furthermore, some medications (diuretics, thyroid medication, muscle relaxants) can hamper thermoregulation. Reduced sweating means fluid losses are often less for athletes with SCI but it also means that capacity to cool is impaired; hence, messages around hydrating effectively may need to be modified, with more focus on external cooling strategies.
Acclimatisation is important when athletes are competing in the heat (Price 2016). Generally, 7–14 days are required for adaptation to exercise in the heat. However, some Paralympic athletes with coexisting medical conditions might require longer. Paralympic athletes need to schedule travel to allow sufficient time for acclimatisation before competing, or to implement acclimatisation strategies such as use of heat chambers before departure. The potential for acclimatisation in athletes with high-level SCI is undocumented. These athletes might consider limiting their exposure to hot environments prior to competition.
Various cooling strategies, such as water immersion, cooling jackets, ice slushies and water sprays, have been tested in athlete populations. Current evidence is mixed as to the effectiveness of these strategies in Paralympic athletes. Athletes with SCI can also have impaired shivering mechanisms and hence have difficulty warming the body when required. A balance needs to be found to deliver the optimal level of cooling.
Many athletes with SCI have disrupted signals from the brain to the bladder and require catheterisation to manage bladder function. It is common for athletes to time fluid intake carefully around competition and travel to manage catheterisation around events. Some athletes may limit fluid intake to avoid having to empty catheter bags or devices. Catheterisation practices need to be considered when planning fluid intake strategies and conducting hydration assessment. Measures such as morning urine specific gravity (USG) and fluid balance might require modification in some circumstances. It may be important to discuss and trial new strategies, including the use of electrolytes, with athletes to find the optimal balance between appropriate hydration (especially for travel) to minimise risk of developing a urinary tract infection and better support training and recovery.
INJURY AND ILLNESS
Athletes perform best when they consistently complete all scheduled training sessions. Hence, a goal is to minimise loss of training due to injury or illness. Some evidence suggests injury rates are higher in Paralympic sports. This may be due to Paralympic athletes being more likely to have coexisting medical conditions, to biomechanical inefficiencies that increase susceptibility to injury, or to exposure to high training loads before they are physically ready. Poor nutrition and low energy availability may also increase susceptibility to injuries and illness.
Athletes who use catheterisation to manage bladder function are more susceptible to urinary tract infections (UTI). Recurrent UTI can result in significant loss of training days over a season. A variety of catheterisation systems are available but all have the potential to expose the bladder to bacteria, leading to UTI (Compton et al. 2015). Key measures to prevent UTI include maintenance of good hygiene when using catheters, frequent emptying of catheters (every 3–4 hours) and sufficient fluid intake. Cranberry juice is a popular preventative measure for UTIs, although evidence for efficacy is inconsistent.
BODY COMPOSITION ASSESSMENT
Many athletes find it useful to monitor body composition over time as it provides useful feedback on the effectiveness of training and nutritional regimes. Surface anthropometry (skinfolds) and dual energy X-ray absorptiometry (DXA) are the most common methods for assessing body composition in athletes. However, other methods are also available and it is important to understand the assumptions and limitations that influence their validity. It is often necessary to modify techniques for Paralympic athletes. For example, according to the International Society for Advancement of Kinanthropometry (ISAK), skinfolds are routinely taken on the right side of the body. However, it is more relevant to measure the left side if an athlete has hemiplegia (weakness) or is missing a limb on the right side. The standard ISAK skinfold protocol involves measures at seven or eight body sites. However, for athletes with SCI, measures are often limited to the biceps, triceps, subscapular and abdominal sites.
DXA is useful for measuring body fat and lean tissue changes over time in athletes with a variety of physical impairments. There is little value in comparing data to normative data derived from able-bodied reference groups; rather, the data obtained can be useful for monitoring changes within the Paralympic athlete over time. It is often necessary to adjust standard positioning to obtain the most useful information for Paralympic athletes. For example, in standard DXA protocols athletes lie on their back in standard anatomical position with legs straight and arms alongside the body. Some Paralympic athletes cannot lie in standard position within the scanning area. While it is possible to customise positioning and analysis of DXA scans, these adjustments are yet to be validated.
GASTROINTESTINAL ISSUES
Athletes with SCI, congenital abnormalities of the gastrointestinal tract, a history of gastrointestinal injury or medication use are more likely to experience gastrointestinal issues than other Paralympic athletes. Some athletes have altered transit time (for example, SCI) while others have various food intolerances or food aversions. Many athletes who compete in wheelchairs avoid eating before training or competing as the bent position in the chair is uncomfortable when the stomach is full.
As such, it is important to work with Paralympic athletes to gain a full understanding of gastrointestinal issues when providing dietary advice. The timing of food and fluid intake around sessions typically needs to be adjusted according to individual tolerance. Some athletes need to focus on eating more in the later part of the day to compensate for restricted intake in the earlier part of the day; this is contradictory to most nutrition guidelines. Experimentation with quickly absorbed forms of carbohydrate such as gels and confectionery is often needed. This can be challenging when energy budget is limited.
MEDICAL ISSUES AND MEDICATION
Many Paralympic athletes have coexisting medical conditions such as epilepsy, high blood pressure, kidney impairment, osteoporosis, reflux, diabetes and heart conditions (Johnson et al. 2014). Some athletes require multiple medications. The impact of medical conditions and medications needs to be considered when providing nutrition advice. Some Paralympic athletes have a very poor understanding of their medical conditions, so it is useful to work closely with other support staff specifically trained in managing these clinical conditions—doctors, dietitians, physiologists and physiotherapists—to gain an accurate understanding.
SUPPLEMENTS
A recent report utilising data from 399 athletes from 21 different nationalities and 28 different sports indicated that the frequency of supplement use is similar in Paralympic and able-bodied athlete populations (Graham et al. 2014). Paralympic athletes in this survey identified using a range of products, including nutritional supplements (vitamins, minerals) sports foods (gels, protein powders, sports drinks) and ergogenic aids (such as caffeine and bicarbonate).
All athletes, including Paralympic athletes, are encouraged to meet their nutrient requirements from food. However, there might be circumstances in which nutritional supplementation is warranted. For example, some athletes might need to supplement key micronutrients if their energy budget does not allow for all nutrients to be consumed from food choices.
Minimal research has been conducted on the effect of ergogenic aids on Paralympic athletes. However, it is reasonable to assume that, in the absence of contradictory medical conditions or functionality, similar ergogenic effects are likely. When advising on use of supplements, potential interaction with any medication and health conditions needs to be considered. Timing and doses might need to be adjusted if gastrointestinal function is altered or muscle mass is significantly lower than in able-bodied athletes. It is wise to test individual tolerance and response during training sessions before use in competition.
TRAVEL
Travel is an inevitable and uncomfortable experience for all athletes (see Chapter 21). However, some Paralympic athletes face additional challenges. Airlines typically ask people with impaired mobility to board planes first and exit planes last. This can substantially increase time spent sitting on the plane. Additionally, some athletes choose to limit fluid intake to avoid having to use the toilet or empty a catheter during a flight. It is useful to prepare a fluid intake plan for flights to minimise dehydration.
Large events such as Paralympic Games and world championships typically cater well for athletes with myriad disabilities. However, modification might be needed when eating at venues unfamiliar with Paralympic athletes. Trays are useful for athletes in wheelchairs when eating buffet-style, although they are not always available. Food serveries are typically at an inconvenient height for people in wheelchairs; this might cause some athletes to avoid dishes towards the back of the servery, as they are difficult to access. Support staff need to look out for challenges and request modifications if required (for example, a temporary servery set up on a lower table, or pre-plated meals). As some Paralympic athletes need to modify eating times according to their gastrointestinal tolerance, provision of takeaway containers is useful to allow flexibility for when meals are consumed.
SUMMARY AND KEY MESSAGES
After reading this chapter, you should have an awareness of the athlete diversity in Paralympic sports. Paralympic athletes compete in a wide range of events and with wide-ranging functionality. Some Paralympic athletes have very similar needs to athletes competing in corresponding able-bodied events. Others require bespoke modifications to suit their individual characteristics. As research regarding the nutritional requirements of Paralympic athletes is limited, an individual approach to nutrition planning should be used along with a trial and modification process to determine optimal nutrition support.
Key messages
• Paralympic athletes compete in a diverse mix of sports and have diverse physiological requirements—there are no generic nutrition recommendations for Paralympic athletes.
• Limited research is available regarding nutritional requirements for Paralympic athletes.
• Athletes with SCI are more likely to have altered heat regulation, gastrointestinal tolerance and increased illness risk compared to other Paralympic athletes.
• Theoretically, ergogenic aids should have similar effects in Paralympic athletes; however, individual testing and adjustment is needed.
• Sports dietitians working with Paralympic athletes need to work closely with other support staff (medicine, physiotherapy, physiology) to fully understand the requirements of each individual.
REFERENCES
Blauwet, C.A., Brook, E.M., Tenforde, A.S. et al., 2017, ‘Low energy availability, menstrual dysfunction, and low bone mineral density in individuals with a disability: implications for the para athlete population’, Sports Medicine, vol. 47, no. 9, pp. 1697–708.
Compton, S., Trease, L., Cunningham, C. et al., 2015, ‘Australian Institute of Sport and the Australian Paralympic Committee position statement: Urinary tract infection in spinal cord injured athletes’, British Journal of Sports Medicine, vol. 49, no. 19, pp. 1236–40.
Graham, T., Perret, C., Crosland, J. et al., 2014, Nutritional Supplement Habits and Perceptions of Disabled Athletes, World Anti-Doping Agency, <https://www.wada-ama.org/sites/default/files/resources/files/TOLFREY-Final-2012-EN.pdf>, accessed 28 June 2017.
Johnson, B.F., Mushett, C.A., Richter, D.O. et al., 2014, Sport for Athletes with Physical Disabilities: Injuries and Medical Issues, USA: BlazeSports America, <http://www.blazesports.org/wp-content/uploads/2011/02/BSA-Injuries-and-Medical-Issues-Manual.pdf>, accessed 28 June 2017.
Price, M.J., 2016, ‘Preparation of Paralympic athletes: Environmental concerns and heat acclimation’, Frontiers in Physiology, vol. 6, p. 415.