Initially, sport for the disabled (including skiing) was only considered as a follow-up to medical rehabilitation and as a support of social, educational and professional integration with able-bodied individuals [1–3].
With time, modifications of the rules and classification of athletes (reducing the number of competitions classes) led to the fact that winning started to be determined more by sports performance and physical capacity than by the type of dysfunction or the level of disability [4–7]. Owing to this, at the turn of the century, competition in sports for the disabled increased, which, in turn, brought about the fact that for the first time in the history of Paralympic cross-country skiing, periodisation was implemented in the year-round training, as in the sport for able-bodied individuals [8]. It was implemented in a 4-year plan for the years 1999-2002 [9]. Therefore, training loads increased and there occurred the same risks of musculoskeletal system overloads as in cross-country skiing of healthy athletes [10].
Sports training as an example of physical activity of disabled individuals produces particular benefits in terms of treatment both for individuals and for the whole society in which they function, but only with proper medical care [11].
Thus, in compliance with the legal regulations regarding sports for healthy athletes [12], medical examinations of disabled athletes and tests of their physical capacity which affect results in a particular sport have gained significance [13]. The aforementioned factors led to the fact that in 2001 a new, more complex and regular assessment of health and physical capacity was implemented in the group of Polish cross-country skiers with disabilities preparing for Paralympic Games [14]. Therefore, the aim of the work is to present the methodology of the observation and to discuss the results of the study as exemplified by a female skier from the period of her greatest achievements.
The research group included Paralympic crosscountry skiers with motor disabilities who were selected by coaches to prepare for Paralympic Games in 2002, 2006 and 2010. The athletes were observed from July 2001 to February 2010.
A new model of sports and medical care of Paralympic cross-country skiers included a regular assessment of health state and physical capacity of the subjects. Health evaluation included medical examinations which were repeated every 6 months [14]. Physical capacity were evaluated in accordance with training periodisation [8] - 4 times in a one-year training cycle, i.e.:
a– prior to the commencement of the subperiod of general preparation,
b– after its finalisation,
c– after the subperiod of special preparation
d– before the main sports event in a competition period.
Medical examination – both initial and further (annual) examinations included a general medical check-up, orthopaedic test, anthropometric measurements, electrocardiograph, laboratory tests (peripheral blood smear test, erythrocyte sedimentation rate, urinalysis with microscopic examination of urinal sediment) and iron test. Moreover, initial examination also included ENT and eye examination. However, periodic evaluations performed every 6 months (after initial and annual tests) were limited to a general medical check-up and orthopaedic test only, but they could be extended depending on the state of health of a subject. In the case of any deviations that occurred during medical check-ups and regarded cardiovascular system, cardiological consultations were held and, if needed, such examinations as echocardiogram, Holter monitoring, etc. were performed. Each medical check-up finished with issuing a report on the lack of contraindications to training and participating in skiing competitions.
Physical capacity examinations were performed only in the case of athletes with valid periodic medical evaluation results. Moreover, prior to each physical capacity test, an additional medical check-up was done in order to exclude potential temporary contraindications to taking up maximal effort activities. Every time, at the beginning of the check-up such parameters as body weight (BW), percentage of fat tissue (% F) and total body water (TBW) were marked with the use of Tanita electronic scale.
In order to assess physical capacity, direct ergospirometry was performed with gradually increasing load to failure. Depending on the disability type, the subjects performed different physical capacity tests on Monark ergometer. Individuals with upper limb dysfunctions performed a test on Monark cycle ergometer, while the subjects with lower limb dysfunctions were tested on Monark ergometer adjusted to their needs. The group of athletes with upper limb dysfunctions exercised rhythmically according to metronome (60 beats per minute). An initial load was 60W and it increased by 30W every two minutes. In the group of subjects with lower limb dysfunctions an initial load was also 60W, but it increased by 15W every two minutes.
During a physical capacity test, such values as minute ventilation (VE), oxygen consumption (V02max), carbon dioxide production (VC02), respiratory quotient (RQ) and oxygen-ventilation coefficient (V02/VE) were measured. These values were measured with the use of MES computer analysers.
During the tests aimed at defining the concentration of lactate, two arterialised earlobe blood samples were taken, i.e. the first one in rest conditions, the other one three minutes after finishing the ergometer test. The concentration of lactate was marked with Dr Lange spectrophotometer.
In order to define mechanical effect of the effort during a test, a general amount of work done (kJ) and mean power (W) during the effort were calculated.
In all the subjects, heart rate (HR) was registered continuously at rest prior to the test, during the effort and for three minutes after the test with the use of Finnish Polar-Electro Sport Testers.
For training purposes, after each physical capacity test a report including an individual description of current physical capacity with regard to previous studies was created. The skiers were given results of their own physical capacity tests, while coaches received the results of the whole group. The results were discussed with athletes and coaches and served as a basis for modifying the subjects’ training.
The research was approved by the Ethical Commission of the Regional Medical Chamber in Cracow.
The results of health assessment and physical capacity tests from the observations carried out on a group of skiers with disabilities in the years 2001-2010 are exemplified in this study only by the results of examinations of one skier (KJ) performed in February 2006, i.e. 5 weeks before the first competition at the Paralympic Games in Turin in 2006. Health assessment was discussed by revealing only these results and states that did not breach medical confidentiality, in contrast to the results of physical capacity tests whose publication was approved by the subjects prior to the observation.
No medical or musculoskeletal contraindications to practising cross-country skiing were found. Due to the post-injury bilateral upper limb amputation, the skier was qualified to the LW5/7 group, which includes individuals with disabilities of both upper limbs who move on two skis without poles. Despite a slight movement asymmetry resulting from different lengths of stumps of the right arm and left forearm, long-term sports training of the subject did not cause any significant overload changes in particular segments of the spine.
ENT and eye consultations did not reveal any deviations from the norm. All the electrocardiograms which were performed regularly revealed proper results. Standard laboratory test results (peripheral blood smear test, erythrocyte sedimentation rate, urinalysis) as well as iron and magnesium test results were within the norm in the whole period of observation.
On the basis of medical examinations, the health state of the subject was every time confirmed with a doctor’s consent or lack of consent to participating in skiing training and competition.
Within the examination period, morphological examination results of the subject (KJ) who was 28 years of age at that time were as follows: height – 160 cm, body weight – 51.7 kg, fat tissue – 14.9%, total body water – 58.9% and fat-free body weight – 44 kg. Maximum values of selected indices obtained by the subject were: pulse 88 bpm, oxygen intake 51.30 ml/kg/min, ventilation – 107.4 l and concentration of hydrons - 9.65 mmol. The values of heart rate at the level of the first and second metabolic threshold were 122 bpm and 156 bpm respectively, which made it possible to determine three metabolic physical capacity spheres together with maximum values.
However, current physical capacity of the subject were characterised by the following results obtained during the test: duration of work – 13 min, peak power – 240 W, mean power – 143 W and its level at anaerobic threshold – 150 W.
At the end of performance, the subject’s heart beat in the first minute was 174 bpm, in the second minute – 123 bpm, in the third minute – 114 bpm, while the pace at which the frequency of heart beats decreased within three minutes after the test was 14, 65 and 74 bpm.
Physical capacity of the subject examined in the physical capacity tests were presented with regard to the previous studies in a following way:
“A further decrease in body mass by 1 kg and a slight increase in fat tissue were noted. It was reflected by a decrease in the amount of active muscle tissue by 1.7 kg. The BMI indicates proper weight-height proportions. The result of the test indicates a lower physical capacity potential compared to previous observations. However, it is really significant that the load with which the subject experienced non-compensatory metabolic acidosis did not decrease and peak power decreased slightly. Aerobic potential and maximal lung ventilation increased, which may have affected a lower post-effort lactate concentration level. A slightly higher lactate concentration at rest may stem from fatigue related to participating in recent competitions. It is also confirmed by a higher HR value and lower HR percentage value at the level of the 2nd metabolic threshold. Thus, a short-term decrease in physical capacity loads taking into account HR values seems justified.”
It has to be added that the results of these physical capacity tests and recommendations from the report were used by coaches to modify training loads in the period of direct preparations to Paralympic Games in Turin.
In the foreign literature from the 20th century there are virtually no studies indicating the need for medical examinations among disabled athletes. Only a few authors raised this problem regarding amateur athletes with disabilities [15]. In turn, in the present century, only a few works concerning athletes with disabilities practising winter sports have been published. Two publications regarded the topic of injuries during Paralympic Games [16,17], while other three studies analysed physical capacity of athletes practising various winter sports. For instance, Bhambhani [18] discussed physical capacity of a narrow group of subjects (9 individuals, including 1 female) with various disabilities, i.e. visual impairment (3 males and 1 female), spinal cord injury (3 males), traumatic brain injury (1 male) and cerebral palsy (1 male) participating in cross-country skiing in a standing position. In turn, Bernardi [19,20] described research on athletes with lower limb dysfunctions including sit skiers. However, among the Polish publications there is one study on physical capacity of 6 cross-country skiers with mental disabilities, including 3 females [21], and two studies on physical capacity of 5 alpine skiers with motor disabilities [22,23]. A review of literature revealed the lack of publications concerning the assessment of health and physical capacity of cross-country skiers with motor disabilities apart from initial reports of the author of the present study that presented results of research carried out on disabled athletes in autumn 2005, i.e. before the period of specialist preparation for the Paralympic Games in 2006 [24,25].
Medical examination of the athlete (KJ) conducted prior to the Paralympic Games in Turin did not reveal any health problems and the level of physical capacity reflected in the presented results enabled her to win 2 Paralympic gold medals in Turin in 5 km free style and 15 km classic style. Moreover, the subject finished fourth in 10 km free style and 7.5 km biathlon and sixth in 15 km biathlon and 3x2.5 km relay [26]. It ought to be added that the result in disabled skiing is affected by the fact that time achieved during competitions is recalculated on the basis of mathematical formula, i.e. Realistic Handicap Competition and Kreative Renn Ergebnise Kontrolle (RHC-KREK) [27], which depends on the level and type of disability. This coefficient, first introduced in cross-country skiing in 2003/2004 is verified after each season and is used in order to give equal chances to athletes with various levels of locomotor disability being in the same competition class [7]. In the case of the subject, the percentage coefficient during Paralympic Games in 2006 was at the level of 77% in classic style and 85% in free style. This results from the observation that in athletes with motor disability the type of dysfunction is an important differentiating factor and it significantly affects the technique in a particular sport, which, in turn, is directly reflected in energy expenditure during particular effort [28]. Moreover, in free style this expenditure is higher, which was scientifically confirmed after implementing it in crosscountry skiing [29].
Generally, in cross-country skiing sports result is influenced by many external factors such as equipment, waxing, snow conditions, area configuration and skiing tactics. However, physical features of an athlete, mainly physical capacity, are still the key factor. Its level is affected by many systems, where cardiovascular and respiratory systems are mainly responsible for aerobic potential of an athlete (particularly oxygen intake). Maximal oxygen intake achieved by the subject during the test was 51.30 ml/kg/min and was the highest in the course of observation. According to Astrand [30], it is a high result for a woman. In comparison, Bhambhani reported that the best result achieved by a visually impaired woman on a double poling ergometer (WEBA Sport) was 56.6 ml/kg/min [18]. In the case of 3 athletes with intellectual disability, an average V02max at the level of 51.8 ml/kg/min [21] was achieved in the treadmill test, where it is possible to achieve results higher by approx. 10-15% than on the cycle ergometer. Taking this into account, maximal oxygen intake of the subject (51.30 ml/kg/min) is relatively high. It is worth noting that compared to the initial cycle ergometer tests in 2001, maximal oxygen intake increased by nearly 20%. Moreover, it is worth noting that the subject started training cross-country skiing professionally relatively late, i.e. at the age of 22. Her maximal oxygen intake as well as the results of disabled athletes cited from the literature differ from the levels achieved by top healthy cross-country skiers that reach 65 to 70 ml/kg/min [31].
Limitations of achieving a higher level of V02 also depend on the level of disability, which was not really significant in the case of the subject (KJ) since the test was performed on the cycle ergometer that made up for the lack of engagement of upper limb muscle mass due to their amputation. In turn, significantly lower levels of V02max and maximal heart rate accompany spinal cord injuries (paraplegia, tetraplegia) in athletes with disabilities competing in a sitting position, including cross-country skiers [20].
However, it is hard to compare the results of particular studies since it is never certain whether different reactions to effort result from physiological differences or from the methodology/technique of performing physical capacity tests. These aspects gain even more significance in the case of research on disabled athletes as differences in capabilities and body reactions may result either from misunderstanding sports tasks and the lack of motivation in individuals with intellectual disability or from physical coordination disability connected with a specific type of dysfunction (e.g. cerebral palsy) [32]. Thus, performing regular physical capacity tests according to the same methodology is the basis for proper monitoring of physical capacity among disabled individuals and it gains particular significance when we move from rehabilitation to extreme effort in professional sport.
Medical examinations aimed at assessing the health of athletes are indispensable in the sport for the disabled, which is confirmed by current literature of the subject [33]. They are particularly significant in the case of athletes with disabilities due to the fact that their dysfunctions may worsen as a result of inadequate loads. Being aware of it led to the fact that in 2001, before the author of this work started cooperating with Paralympic cross-country skiers, an analysis of recommendations from available literature concerning medical examinations in professional sport of able-bodied athletes was made [12,34]. It allowed the author to determine the frequency of examinations and their range required in controlling the health of athletes undergoing intensive training. It should be highlighted that legal obligation and range of examinations for disabled athletes was sanctioned in Poland as late as in 2007 with the Minister’s Regulation [35]. In turn, the first official statement of the International Olympic Committee on medical examinations of athletes was published in 2009 [36]. However, a similar statement regarding athletes with disabilities announced during Paralympic Games in Sochi in 2013 has not been published to date [37].
From the medical point of view, physical capacity tests help to exclude cardiological contraindications to physical effort [38], while from the sports point of view, they may provide answers regarding a current level of physical capacity of athletes [39]. Thus, such examinations captured coaches’ attention, also in Paralympic sport. It resulted from increased competition caused by changes in regulations and the need for optimising the training of disabled skiers.
Therefore, the author’s own competition, training and medical experience as well as previous research on assessing physical capacity of elite athletes practising Olympic sports served as a basis for preparing and implementing a complex evaluation of physical capacity of Paralympic cross-country skiers aimed at assessing their endurance capacity and monitoring the effectiveness of a training process in Paralympic preparations.
Current studies in this field confirm a proper direction of medical examinations and assessment of physical capacity of athletes with disabilities. For instance, Bernardi et al. [19] concluded that with the present cumulation of competition classes and a given coefficient, V02max is a decisive factor for sports result both in the group of athletes competing in a standing position and among those competing in a sitting position. Similarly, on the basis of British experiences from the Olympic and Paralympic Games in London in 2012, it is recommended in the literature [40] to implement the model of combining medical care with a training process in order to achieve ethical and functional balance between medical care and optimisation of sports performance. Moreover, attention is paid to the need of changing the qualification and role of a doctor working with athletes from “the doctor interested in sport” to “sports medicine specialist” who should coordinate multi-specialist medical team cooperating in an integrated way with the coaches’ team [40].
To sum up, it may be concluded that the fact that in 2001 the author implemented a regular health assessment aimed at improving physical capacity of disabled athletes was justified and innovative in Paralympic sport. Although a legal obligation of medical qualification for practising sport regarding athletes with disabilities was introduced in Poland in 2007, there is still a long way to general awareness of the need for regular medical examinations of disabled athletes among athletes themselves, coaches and mainly among decision-makers [41].
Implementing a regular observation of health state of athletes with disabilities allows for medical intervention at the moment of occurrence of negative health effects resulting from increased training loads.
Monitoring physical capacity makes it possible to observe the reaction of the subject’s body to training tasks and modify them with regard to the needs in particular periods of Paralympic preparation.
Sports achievements of the subject confirm the significance of the conducted observation, while the quoted sports results confirm the effectiveness of monitoring the training process.
The presented morpho-functional characteristics of the subject is an example of the level of physical capacity which makes it possible to compete for the title of the Paralympic Champion in cross-country skiing for individuals with motor disability.
At the present level of competition, health state and the level of physical capacity are decisive success factors in Paralympic sport.