Paracanoe: particularities of functional classes in the structuring of the sports’ training

The performance of paracanoists is characterized by the ability of the athlete to advance at maximum speed, through a technically optimal paddling motion. It`s important to consider that in the case of para-athletes, the application of forces towards paddling is compromised by physical deficiencies. Thus, this study aims to assess the performance of athletes in the KL1, KL2 and KL3 sport classes, during a paralympic paracanoe event. The sample was composed of athletes from the Brazilian male paracanoe team, with a representative of each sport class: KL1, KL2, KL3 For performance analysis, we used a kayak ergometer (KayakPro®, Miami Beach, FL, USA) to simulate a 200-meter trial, during Rio 2016 Paralympic Games Road. The variables were evaluated: time trial, stroke frequency, mean speed, number of strokes, stroke length, stroke index, and power. According to results: I) the athlete KL3 had the lowest number of strokes, the longest stroke length and the highest stroke rate index; II) the athlete KL1 had the highest number of strokes, the lowest stroke length and the stroke rate index. This study puts into perspective the distinct characteristics of a paracanoe trial, analyzed in consideration to each sport class.


RESUMEN
El rendimiento de los paracanoistas se caracteriza por la capacidad del atleta para avanzar a la máxima velocidad, mediante un movimiento técnicamente óptimo.Es importante considerar que en el caso de los para atletas, la aplicación de fuerzas hacia el remo se ve comprometida por la discapacidad.Por lo tanto, este estudio tiene como objetivo evaluar el rendimiento de los atletas en las clases deportivas KL1, KL2 y KL3.La muestra estuvo compuesta por atletas de la selección brasileña masculina de paracanotaje, con un representante de cada clase deportiva.Para el análisis del rendimiento, utilizamos un ergómetro de kayak (KayakPro®, Miami Beach, FL, EE.UU.) para simular una prueba de 200 metros.Las variables monitoreadas fueran: tiempo, frecuencia de remada, velocidad media, número de remada, longitud de remada, índice de remada y potencia.Según los resultados: I) el atleta de la clase KL3 realizó el menor número de remadas, mayor longitud de remada y el mayor índice de remada.;II) el atleta de la clase KL1 realizó el mayor número de remadas, menor longitud de remada y índice de remada.Este estudio pone en perspectiva las distintas características de una prueba de paracanotaje, analizadas en consideración a cada clase deportiva.In a 200-meter race, optimal performance is judged by the ability of the athlete to advance at CAF 24(1) | 3 maximum speed, overcoming water resistance through a technically precise forward stroke action (Figure 1).The forward stroke has an aquatic phase -during which the paddle enters the water, is drawn and exits, propelling the canoe -and an aerial phase-during which the paddle prepares to repeat the paddling action at the opposite side (Mcdonnell et al., 2012(Mcdonnell et al., , 2013)).
Figure 1 Dynamics of forces acting to generate kayak propulsion during paddling.
These variables can be used by coaches as performance evaluation parameters, since they are related to the technical characteristics of the paddling; optimizing these parameters will allow for the most efficient application of force.
Particularly in the paralympic context, there is an interest in studies pertaining the effects of kayak ergometer training in the motor performance of recreational athletes and the influence of prostheses on the performance of athletes belonging to the KL3 (Bjerkefors et al., 2015(Bjerkefors et al., , 2018;;Ellis et al., 2017;Grigorenko et al., 2004;Norrbrink et al., 2012;Ribeiro et al., 2022;Rosen et al., 2022).Their results demonstrate that there are actual performance differences within sport classes themselves, a conclusion with direct implications over training prescriptions.However, the lack in the literature is perceived in the absence of studies comparing the different sports classes in locu condition or in a kayak ergometer simulation.Nevertheless, there is a lack of information regarding the performance standards of athletes within each sport class (Bjerkefors et al., 2019;Ribeiro et al., 2022;Rosen et al., 2022).
In this sense, this study aims to analyze KL1, KL2 and KL3 athlete's performance in a paralympic male paracanoe event, specifically regarding the variables total time, stroke frequency, mean speed, number of strokes, stroke length, stroke index, and power.

Sample-size
The sample-size was comprised of three voluntaries, paracanoe athletes from the Brazilian Male Paracanoe Team, including a male

Pre-test protocol
The athlete was allowed to select an adapted seat  In order to understand the development of athletes' individual performance throughout the race, the 25m, 100m and 200-meters points were selected for analysis, representing the beginning, middle and end of the race, as shown in Table 2.

DISCUSSION
The paddling action is a motor action that requires a high level of body control, since it involves complex coordination of upper limbs, trunk, hip and lower limbs under constant interaction, with reaction forces towards different directions, resulting in a forward propulsive force (Bjerkefors et al., 2019;Bjerkefors et al., 2018;Ribeiro et al., 2022;Rosen et al., 2022).However, The variables stroke frequency, speed and stroke index have been pointed out in the literature as significant indicators of efficiency, providing practical information to configure loads and monitor the performance of athletes during water training (Bjerkefors et al., 2015(Bjerkefors et al., , 2018;;Ellis et al., 2017;Grigorenko et al., 2004;Norrbrink et al., 2012;Rosen et al., 2022).
The efficiency of an athlete is associated with the ability to achieve the highest speed along with the highest energy saving during stroke cycles.In this sense, the coaches must understand the relationship between stroke frequency and speed, as well as the direct influence of the stroke length variable, in order to identify the efficiency of the athlete's technique, expressed as a stroke index value.
At the 25-meter mark, we can see an overlap of results between KL1 and KL2, which have lower values when compared to KL3 (Table 2).
Considering that, due to their deficiencies, the KL1 and KL2 athletes have lower active muscle mass and less efficiency in paddling force transmission, there is a compromise phase of acceleration.These athletes need to make a greater effort to place the canoe in motion.
At the half-way mark (Table 2), we observe an approximation between KL1 and KL3 in terms of stroke frequency, and a decrease of that same variable for the KL2 and KL3 athletes.The KL1 athlete maintains a constant increase in stroke frequency until the 150-meter mark (156.92 ± 9.0).
In spite of this approximation, in terms of the speed variable, the overall performance of the KL1 athlete is lower than that of the KL3 athlete.This conclusion is corroborated by SI values.
At the finish mark (Table 2), unlike at the starting point, there was no overlap of results between the sport classes.However, the athlete belonging to KL3 presented the highest paddling efficiency, followed by the KL2 and KL1 athletes, respectively.
When analyzing the test in its entirety, the athlete who performed the least number of strokes and had the longest stroke length (KL3) also obtained the highest SI; the athlete who performed the highest number of strokes and had the lowest stroke length (KL1) obtained the lowest SI.This demonstrates the close relationship between sport class, stroke index, and the athlete's technical efficiency, evidencing efficiency differences between the functional classes.
Another important aspect is the symmetry of the stroke action between right and left sides, as a symmetrical propulsion force helps maintaining a constant speed ( Bjerkefors et al., 2019;Bjerkefors et al., 2018;Ellis et al., 2017;Michael et al., 2012).The three evaluated athletes presented minimal differences in their stroke length results when comparing the right and left sides.
The observed asymmetry in stroke length for the KL1 ( paracanoistas é caracterizado pela capacidade do atleta de avançar em velocidade máxima, através do movimento tecnicamente ideal.É importante considerar que no caso de para atletas, a aplicação de forças na remada é comprometida devido a deficiências apresentada.Assim, este estudo tem como objetivo avaliar o desempenho de atletas das classes esportivas KL1, KL2 e KL3, durante uma prova paralímpica de paracanoagem.A amostra foi composta por atletas da equipe brasileira de paracanoagem masculina, com um representante de cada classe esportiva.Para a análises do rendimento, foi utilizado o ergómetro de kayak (KayakPro®, Miami Beach, FL, EUA.) para simular uma prova de 200 metros.As variáveis avaliadas foram: tempo, frequência de remada, velocidade média, número de remada, comprimento de remada, índice de remada e potência.De acordo com os resultados: I) o atleta KL3 teve o menor número de remadas, o maior comprimento de remada e a maior índice de remada; II) o atleta KL1 teve o maior número de remadas, o maior comprimento de remada e índice de remada.Este estudo coloca em perspectiva as características de uma prova de paracanoagem, respeitando a especificidade de cada classe esportiva.first sports event dedicated to people with disabilities -the Stoke Mandeville Games organized by Sir Luwig Guttman in 1948, on the premises of the Stoke Mandeville Hospital in England (involving only 16 athletes with spinal cord injury)-to the opening ceremony of the 2016 Summer Paralympics in Rio (involving 4328 athletes) (Comité Paralímpico Internacional, 2021; Wilson & Ramchandani, 2017).The paralympic sport underwent several regulatory changes, aiming to achieve increasing numbers of participants and spectators.The 2012 Summer Paralympics in London achieved worldwide television coverage, winning the rank of the 3rd largest sporting event in the world, surpassed only by the Olympic Games and by the FIFA® Soccer World Cup (Duarte et al., 2017).Paracanoe is considered a cyclical sport, characterized by trials at the 200-meter distances.Athletes with impairment of both sexes, using one-person kayaks (K1) or va'a oneperson canoes (V1).It became a paralympic sport in the Rio 2016 Summer Paralympics, although only the 200-meter modality, for both men and women, was included (International Canoe Federation, 2022).
All procedures in this study were respected Helsinki Declaration.This research followed all the guidelines of Law 510/2016 of the National Council of Ethics in Research Involving Human Beings.The participants provided the term of free and informed consent.This project was submitted and approved by the Research Ethics Committee of the Faculty of Medical Sciences of the State University of Campinas, number 1997113.
, Brazil) scale, with a precision of 0.1 kg.Height measurements employed a wooden stadiometer with centimeter-level precision; athletes were measured in supinated and cephalocaudal positions.Experimental protocol During the preparatory period for the Rio 2016 Paralympic Games, a familiarization routine-in which all athletes used the same kayak ergometer (KayakPro®, Miami Beach, FL, USA) evaluation protocol it was necessary to calibrate the ergometer for each individual athlete, according to body weight.For the familiarization and testing sessions to take place under suitable environmental conditions, an air-conditioned room at a temperature of approximately 25 °C was used.The command to start the race simulation followed the international standard (International Canoe Federation, 2022), minimizing variations in the starting signals provided by evaluators.The familiarization session protocol consisted of two stages: the first was a free paddling section with a duration of 20 minutes, and the second a maximum performance simulation of a 200-meter race.All familiarization sessions and maximum performance simulations occurred at the same time of day.
with a high back (20 cm) and a wider base (50 cm), or the training device's original seat, which has the same dimensions as an official competition seat.This possibility was offered to the athlete for the test to better reproduce sport class-specific and competitive conditions.After selecting the necessary adaptations, evaluators collected information to fill out the specific values requested by E-Monitor® software: body weight, height, and age.Properly filling out the software's input form allows for an adequate load during the test's execution.Regarding the positioning of the lower limbs, the evaluators directed the athletes to seek a position similar to that used during an official trial.The athlete was allowed to perform a 10-minute warm-up on the Kayak Ergometer, with free load settings.Test procedure During the test, evaluators were allowed to verbally motivate athletes.As soon as the requested distance of 200 meters was completed, athletes were instructed to perform a low-effort lap for 5 minutes.On the day of the maximum performance evaluation, evaluators instructed all athletes to perform the usual precompetition procedures.The following variables were evaluated: trial time (TT), stroke number (SN), stroke frequency (SF) corresponds to the number of paddling cycles performed per minute and points to the intensity at which the athlete performed the test, mean speed (S_Km/h), stroke length at the right side (SL_R), stroke length at the left side (SL_L), stroke index (SI), and the mean power produced by the athletes corresponds to the sum of the work done in each stroke divided by the total number of strokes performed throughout the trial's 200 meters.Since the stroke is the main canoe propulsion action, SN is directly related to its CAF 24(1) | 5 efficiency, defined by the SI, which in turn is the product of speed multiplied by stroke length (SL) -the distance covered by the canoe during a stroke cycle.Statistic analysis Trial performance data were collected through the E-Monitor® online software and stored in a computer database.The statistical program GraphPad Prism 7 was used to analyze the data according to the following variables: stroke frequency, mean speed, power, right stroke length, left stroke length, and stroke index.Variables were presented as means (Mean ± Standard Deviation), representing 25-meter sections of the total trial distance.

Figure 2
Figure 2 presents stroke frequency, speed, and stroke index results (mean and standard

Figure 2
Figure 2Performance variables during a 200-meter race.

Figure 1
Figure 1 is not a perfect reproduction of force dynamics in paracanoe.Para-athletes present

CONCLUSION
Results found in this study in respect to stroke frequency, mean speed, and stroke index, show the different characteristics of paracanoe trials which, when analyzed according to each sport class, indicate the need for specific training adaptations.It is worth noting that in paralympic sports, although the functional classification has the objective of guaranteeing a fairer competition, there is a maximum and minimum range of performance among the athletes of each functional class, bringing them closer to the classes above or below the ones to which they officially belong: this approximation characterizes a 'borderline' athlete.In functional systems, the main factors that determine the class they are not diagnosis and medical evaluation, but how much a athlete's disability affects sports performance, highlighting the importance of maximizing training sessions and the specificity of the sport class.As such, in elaborating training processes, technical committee members, in addition to considering the general characteristics of each sport class, for example speed, stroke frequency and stroke index.The characteristics presented must be analyzed individually for the elaboration of the specific training should also consider the individuality of the athletes within the same sport class.In this sense, the present research brings to light techniques variables dearly in the Paracanoe, which can help in the determination of the sport's evolution and highlighting the need to carry out training sessions with athletes from the same sport class, eradicating multiclass training.

Table 1
Performance characterization for each sport class, according to studied variables (Mean ± SD).

Table 2
Individual performance of athletes throughout the test (Mean ± SD).