Para Swimmers Research Articles

Biomechanical Analysis of Limb Coordination in Front-Crawl Among Elite S10 and S12 Para Swimmers: Implications for Performance Optimization

Para swimmers categorized as S10 and S12 are of particular interest due to their disability grading being closest to that of able-bodied swimmers, making them an ideal group for investigating disparities in limb coordination patterns. This study aimed to investigate whether S10 and S12 para swimmers, whose disability grading for movement and visual ability, respectively, were the closest to that of able-bodied swimmers, would differ in terms of the biomechanics of limb coordination. This study recruited twenty para swimmers (ten with minor limb absence (S10) in the hand and ten with minor visual impairment (S12)). Using panoramic video, the phase duration, stroke length, stroke rate, index of coordination, synchronization, and inter-limb coordination were digitized and compared in the context of a front-crawl sprinting test. The results showed a significantly different duration of the recovery phase for S10 para swimmers at the affected side, where a more random coordination pattern between arm and leg at the pull and push phases was statistically seen. The variation of the inter-limb coordination gradually increased for S10 para swimmers from hand entry to the end of push, but gradually reduced for S12 para swimmers. These results suggest that the same pace was achieved by different hand–leg coordination patterns according to their physical constraints. Consequently, the unique coordination patterns of different para swimmers from this study offer an opportunity to explore the adaptive strategies and biomechanical adjustments that enable optimal performance for para swimmers.

Season changes in performance of upper limbs and trunk in para swimmers

ObjectivesTo evaluate upper limb performance, trunk extensor endurance, and serratus anterior strength in para swimmers over a sports season. DesignA cohort study conducted over eleven months. SettingsThree assessments were performed at pre-season, mid-season, and post-season, evaluating the CKCUEST, Sorensen Test, and isometric strength of the serratus anterior. ParticipantsTwelve para swimmers from a sports center. Main outcome measuresGeneralized Mixed Models were used to assess seasonal changes and the influence of sex, age, type of impairment, and season phase. Coefficients of variation for each variable were calculated along with 95% confidence intervals (CIs), with a 5% significance level. ResultsSorensen Test values decreased during the season (C: 22.0; CI: 33.9 to −10.4; p < 0.01). A serratus anterior isometric strength difference was observed post-season between para athletes with motor impairments and those with visual/intellectual impairments on the dominant side (C: 3.3; CI: 6.2 to −0.5; p = 0.02). ConclusionSorensen Test values declined in mid-season, and para athletes with motor impairments showed lower serratus anterior strength in post-season. CKCUEST values remained stable throughout the season.

Comparative Analysis of Performance Anxiety and Aggression in Swimmers and Para swimmers

Background: This study compares performance anxiety and aggression between female swimmers and female para-swimmers. It aims to identify significant differences and provide recommendations for enhanced psychological support for both groups. Objective: To compare and analyse performance anxiety and aggression levels between para and able-bodied swimmers, identify key contributing factors, and develop recommendations for improved psychological support and coping strategies for both groups. Method: This study involved a total of 50 national-level subjects, consisting of 25 female swimmers and 25 female para-swimmers, to identify previously unknown psychological drawbacks. All participants were aged between 18 and 30 years. Tests were administered to assess psychological variables including Aggression and Competitive State Anxiety as well as influencing factors in their sports careers. Result: The analysis revealed that female swimmers had significantly higher levels of aggression (M = 80.04, SD = 14.72) and competitive state anxiety (M = 19.35, SD = 3.01) compared to female para-swimmers, who had lower scores in both areas (aggression: M = 72.04, SD = 13.77; anxiety: M = 17.08, SD = 5.91). T-tests showed significant differences in aggression (t = 2.02, p = 0.048) and anxiety (t = 2.99, p = 0.004) between the two groups, indicating that female swimmers experience higher levels of both psychological variables than female para-swimmers. Conclusion: Female swimmers show significantly higher levels of aggression and competitive state anxiety compared to female para-swimmers. These findings highlight the need for targeted psychological support to address these elevated levels and improve overall athlete well-being and performance.

Comparative analysis of will to win, aggression, mental toughness, and anxiety in national swimmers and para swimmers

Comparative analysis of will to win, aggression, mental toughness, and anxiety in national swimmers and para swimmers

Effect of breathing conditions on relationships between impairment, breathing laterality and coordination symmetry in elite para swimmers.

The aim was to investigate the effect of breathing conditions and swimming pace on the relationships between the impairment, the breathing laterality and motor coordination symmetry in elite front crawl Para swimmers. Fifteen elite Para swimmers with unilateral physical impairment or with visual impairment and unilateral breathing preference performed eight 25m using four breathing conditions (every three strokes, every two strokes on preferred and non-preferred breathing side and apnea) at slow and fast paces in a randomized order. Multicamera video system and five sensors have been used to assess arm and leg stroke phases and to compute symmetry of arm coordination (SIIdC) and of leg kick rate (SIKR). Our findings emphasized motor coordination asymmetry whatever the breathing conditions and swimming paces, highlighting the influence of impairment. Multinomial logistic regression exhibited a high probability for motor coordination asymmetry (SIIdC and SIKR) to be present in categories of Para swimmers with impairment and breathing laterality on the same side, suggesting the joined effect of unilateral impairment and unilateral breathing. Moreover, unilateral physical impairment and breathing laterality could also occur on different sides and generate motor coordination asymmetry on different sides and different levels (arms vs. legs). Finally, visual impairment seems amplify the effect of unilateral breathing on motor coordination asymmetry.

The effect of swimming on the body posture, range of motion and musculoskeletal pain in elite para and able-bodied swimmers

BackgroundElite swimmers may be predisposed to disturbances in the range of motion (ROM) of hip joints and spinal curvatures, which are a factor that induces body’s compensatory mechanisms that may have an impact on sports training, athletic performance and health. This study aimed to identify compensatory mechanisms in body posture of elite Para and able-bodied swimmers (spinal curvatures, ROM), to indicate the dominant locations of the compensatory mechanisms in the groups of Para and able-bodied athletes, and to identify and compare the prevalence and location of musculoskeletal pain from the last week and the last six months in the context of compensatory mechanisms.MethodsThirty-five (nF = 8; nM = 27; age = 20.51 ± 4.24) elite Para and able-bodied swimmers from the Polish national team took part in the study and were divided into: study group (SG) of Para swimmers and control group (CG) of able-bodied swimmers. Depth of the anteroposterior spinal curvatures and sagittal spinal mobility testing were evaluated with a Medi Mouse device. The prevalence and locations of musculoskeletal pain were assessed with a Nordic Musculoskeletal Questionnaire for the last seven days (NMQ-7) and the last six months (NMQ-6).ResultsIn both groups lumbar hypolordosis, anterior pelvic tilt and pain in the shoulders, lower back and hips/thighs (NMQ-7) were reported the most frequent. In SG several significant relationships were found between duration of sport-specific training experience (years) and depth of angle the lumbar lordosis, the depth of the angle of pelvic inclination the ROM in the lumbar spine and thoracic spine, what was not reported in CG.ConclusionsExtrinsic compensatory mechanism was identified in both study groups, however only in SG it occurred as structural (depth of the angle of lumbar lordosis and pelvic inclination) and functional changes (ROM in the thoracic and lumbar spine) in the body posture. Internal compensatory mechanism was identified in SG, however external compensation showed only partially suppressive character regarding to internal compensation. The locations of the musculoskeletal complaints seems to result from both internal compensatory mechanism (SG) and continuous overload of the anatomy trains as a result of swimming training (SG, CG).

Experienced vs Inexperienced Disabled Swimmers: Training Load and Recovery in Preparation Period

The study purpose was to analyse the training load and recovery of experienced and inexperienced swimmers with disabilities. Materials and methods. The study subjects consisted of seven swimming athletes with disabilities at the provincial level who underwent training camps in preparation for the Indonesia Paralympics Games. The groups of athletes were divided based on their level of training and experience in national championships. For thirteen weeks, the athletes monitored their training load and recovery rate. Borg CR-10 was used to measure the internal training load, while the athlete’s recovery rate was measured using Total Quality Recovery (TQR). IBM SPSS Statistics version 22 was used to analyse normality and test differences between the two groups. The Mann-Whitney test was used to test the significance of the RPE Borg CR-10, while the unpaired T-test was used to test the significance of the TQR. Results. The Borg CR-10 mean for the experienced athlete group was 7.78±0.47, while it was 8.28±0.56 (p&lt;0.05) for the inexperienced athlete group. The RPE mean for the experienced athlete group was 18.24±1.47, while it was 18.52±1.57 (p&gt;0.05) for the inexperienced athlete group. Furthermore, the Borg RPE shows the training load of experienced athletes of 17.12±1.03, which is lower than the average RPE of inexperienced athletes of 18.21±1.24, and also the TQR average of experienced athletes was of 18.24±1.47, while it was of 18.52 ±1.55 (p&lt;0.05) in case of inexperienced athletes. Conclusions. Experienced para-swimmers had a significantly different training load than inexperienced para-athletes. In addition, the training load of experienced para athletes was also significantly different compared to the recovery rates of experienced and inexperienced para swimmers.

Froude Efficiency and Velocity Fluctuation in Forearm-Amputee Front Crawl: Implications for Para Swimming Classification.

The impact of physical impairment on Froude efficiency and intra-cyclic velocity fluctuation in Para swimmers is not well documented. Identification of differences in these variables between disabled and non-disabled swimmers could help develop a more objective system for assigning Para swimmers to classes for competition. This study quantifies Froude efficiency and intra-cyclic velocity fluctuation in unilateral forearm-amputee front crawl swimmers, and evaluates associations between these variables and performance. Ten unilateral forearm-amputee swimmers completed front crawl trials at 50 m and 400 m pace; three-dimensional video analysis provided mass centre, wrist and stump velocities. Intra-cyclic velocity fluctuation was calculated as: 1) maximum - minimum mass centre velocity, expressed as % of mean velocity, and 2) coefficient of variation in mass centre velocity. Froude efficiency was the ratio between mean swimming velocity and wrist plus stump velocity during each segment's respective: 1) underwater phase, and 2) propulsive underwater phase. Forearm-amputees' intra-cyclic velocity fluctuation (400 m: 22 ± 7%; 50 m: 18 ± 5%) was similar to published values for non-disabled swimmers, whilst Froude efficiencies were lower. Froude efficiency was higher at 400 m (0.37 ± 0.04) than 50 m pace (0.35 ± 0.05; p < .05) and higher for the unaffected limb (400 m: 0.52 ± 0.03; 50 m: 0.54 ± 0.04) than the residual limb (400 m: 0.38 ± 0.03; 50 m 0.38 ± 0.02; p < .05). Neither intra-cyclic velocity fluctuation nor Froude efficiency were associated with swimming performance. Froude efficiency may be a valuable measure of activity limitation in swimmers with an upper limb deficiency and a useful metric for comparing swimmers with different types and severity of physical impairment.

Performance progression and variability in 100 m freestyle Paralympic swimmers: A comparison of medallists and para classifications

ABSTRACT This study quantified the performance progression and variability of elite 100 m freestyle para swimmers according to classification and medal status. To depict progression, annual world ranking times from 2009 to 2016 were obtained for 253 male and 236 female para swimmers and expressed relative to their respective (2012 & 2016) Paralympic Games performances. Comparisons according to medalling status and para classification were made using linear mixed models. Although not always continuous, swimmers generally progressed year-on-year by≈0.53%. Medallists made significantly greater performance progressions (2.76 ± 0.63%) than non-medallists (2.15 ± 0.31%) over the years preceding a Paralympic Games. The most physically impaired swimmers (S1-S4 classes) made significantly greater performance progressions in the final 3 years before a Paralympic Games than all other subgroups (S5-S6, S7-S10 & S11-S13). Within-swimmer variation in swimmers overall, expressed as coefficient of variation, was 0.56 ± 0.39%, whilst between-swimmer variation was 0.9 ± 0.2%. In both scenarios, S1-S4 swimmers evidenced greater overall variation. These findings have implications for para swimmers, coaches and support staff when planning training and analysing competition outcomes. We also propose performance variation to be a useful metric in the identification of para swimmers warranting (re-)classification.

How do Para swimmers respond physiologically and cognitively when watching their performance at the Paralympic Games? A Case Study

El objetivo de esta investigación fue analizar la respuesta de activación cognitiva y fisiológica de nadadores paralímpicos (n= 12) al ver la grabación de su prueba en los Juegos Paralímpicos de 2016. El diseño metodológico del estudio fue transversal y se llevó a cabo en dos etapas. El video contenía tres momentos: línea de base (LB), video neutral (VN) y video de los Juegos Paralímpicos (VJUEGOS). Durante las pruebas, se analizaron la variabilidad de la frecuencia cardíaca (VFC) y la actividad electrodérmica (EDA) como una forma de evaluar la activación fisiológica. Antes y después del video, se recolectaron datos de activación cognitiva (Inventario de Ansiedad Estado). Se observó una reducción significativa en el tiempo medio de ritmo cardiaco y un aumento en los datos de conductancia con relación a VNxVJOGOS, demostrando activación fisiológica. No hubo diferencias significativas en las activaciones cognitivas. Si bien se puede explorar el uso de videos en los campos psicológico y deportivo, se debe prestar la debida atención al conocimiento de que su contenido puede provocar respuestas positivas o negativas al rendimiento. The aim of this study was to analyse the cognitive and physiological activation response of Paralympic swimmers (n= 12) when watching the recording of their events at the 2016 Paralympic games. The methodological design of the study was cross-sectional and carried out in two stages. The video contained three moments: baseline (BL), neutral video (NV) and Paralympic Games video (GAMESV). During the tests, Heart Rate Variability (HRV) and Electrodermal Activity (EDA) were analysed as a way to evaluate physiological activation. Before and after the video, cognitive activation data (State-Trait Anxiety Inventory) was collected. It was observed a significant reduction in the meantime of heartbeats and an increased conductance data in relation to NV×GAMESV, demonstrating physiological activation. However, no significant differences in cognitive activations were observed. While the use of videos in the psychological and sporting scope may be explored, certain weightings should be considered, knowing that their content may elicit positive or negative responses to performance. O objetivo desse estudo foi analisar a resposta de ativação cognitiva e fisiológica de nadadores paralímpicos (n= 12) ao assistirem à gravação da sua prova nos Jogos Paralímpicos de 2016. O desenho metodológico do estudo foi caracterizado como transversal e realizado em duas etapas. O vídeo conteve três momentos: linha de base (LB), vídeo neutro (VN) e vídeo dos Jogos Paralímpicos (VJOGOS). Durante os testes foram analisados a Variabilidade da Frequência Cardíaca (VFC) e Atividade Eletrodérmica (EDA) como forma de avaliar a ativação fisiológica. Antes e após o vídeo foram coletados os dados de ativação cognitiva (Inventário de Ansiedade-Estado). Foi observada redução significativa da média de tempo dos batimentos cardíacos e aumento dos dados de condutância em relação a VNxVJOGOS, demonstrando ativação fisiológica. No entanto, não foram observadas diferenças significativas nas ativações cognitivas. Ao mesmo tempo que o uso de vídeos no âmbito psicológico e esportivo pode ser explorado, devidas ponderações devem ser consideradas sabendo que seu conteúdo pode eliciar repostas positivas ou negativas ao desempenho.

Idade relativa em nadadores e paranadadores brasileiros

abstract This study aimed to analyze the relationships between swimming competitive events, functional classification and relative age and to detect if the relative age affects performance in Brazilian swimmers and para swimmers. Data were retrieved from public databases and birth dates were classified in four quartiles (Q1 = January-March; Q2 = April-June; Q3 = July-September; Q4 = October-December). Descriptive statistics, Chi-square tests and ANOVA were used. The 50 m freestyle is the competitive event with 2349 swimmers, followed by 100 m (n = 1817) and 200 m freestyle (n = 905), and 200 m butterfly with 42 swimmers. Para swimmers are mainly distributed to S14, S6 and S5 functional classes (n = 140, 87 and 45), and individual medley events were less represented at SM3, SM9 and SM11 (n = 1 swimmer). Most of swimming events (86.36%) and para swimming functional classes (51.43%) are represented by swimmers and para swimmers born in the first and second quartiles. Moderate associations between functional classification and relative age were observed (p &lt; 0.0001, Cramer’s V = 0.277). No effects of relative age on swimmers and para swimmers’ performance were noticed (p &gt; 0.05). The great functional class seems to be related to great para swimmers’ relative age. Quartiles distribution shows the advantage of being born in the first months of the year to be registered among the most talented Brazilian swimmers and para swimmers.

Time cost associated with sports participation for athletes with high support needs: a time-motion analysis of tasks required for para swimming

ObjectivesPeople with cerebral palsy and high support needs (CP&HSN) are profoundly inactive but also under-represented in studies evaluating physical activity interventions. Reasons for their exclusion have not been evaluated. We...

Classification changes in para swimming and their impact on the Czech Para Swimming Team

This aim of this article is to describe up-to-date polices and main classification issues in Paralympic sport with focus on Paralympic swimming. Using narrative review, it determines the influence of recent classification changes by reviewing available research data on how the classification system works and what direction it has taken after January 2018 when the new Classification Manual for swimming was published. It analyzes those changes in Czech Para Swimming Team during 4-year-period leading up to Tokyo Paralympic Games 2020 including 3 major swimming competetions and Paralympic Games itself. The results show the changes directly influenced the performance of Czech para swimmers in mentioned major competetions in a positive way. Czech Para Swimming Team added two more medals and gained more spots for both men and women for Tokyo Paralympic Games 2020 effectively extending relatively small Czech Paralympic Team in Tokyo.

Not all Forms of Muscle Hypertonia Worsen With Fatigue: A Pilot Study in Para Swimmers.

In hypertonic muscles of patients with upper motor neuron syndrome (UMNS), investigation with surface electromyography (EMG) with the muscle in a shortened position and during passive muscle stretch allows to identify two patterns underlying hypertonia: spasticity and spastic dystonia. We recently observed in Para swimmers that the effect of fatigue on hypertonia can be different from subject to subject. Our goal was, therefore, to understand whether this divergent behavior may depend on the specific EMG pattern underlying hypertonia. We investigated eight UMNS Para swimmers (five men, mean age 23.25 ± 3.28 years), affected by cerebral palsy, who presented muscle hypertonia of knee flexors and extensors. Muscle tone was rated using the Modified Ashworth Scale (MAS). EMG patterns were investigated in rectus femoris (RF) and biceps femoris (BF) before and after two fatiguing motor tasks of increasing intensity. Before the fatiguing tasks, two subjects (#2 and 7) had spasticity and one subject (#5) had spastic dystonia in both RF and BF. Two subjects (#3 and 4) showed spasticity in RF and spastic dystonia in BF, whereas one subject (#1) had spasticity in RF and no EMG activity in BF. The remaining two subjects (#6 and 8) had spastic dystonia in RF and no EMG activity in BF. In all the 16 examined muscles, these EMG patterns persisted after the fatiguing tasks. Spastic dystonia increased (p < 0.05), while spasticity did not change (p > 0.05). MAS scores increased only in the muscles affected by spastic dystonia. Among the phenomena possibly underlying hypertonia, only spastic dystonia is fatigue-dependent. Technical staff and medical classifiers should be aware of this specificity, because, in athletes with spastic dystonia, intense and prolonged motor activity could negatively affect competitive performance, creating a situation of unfairness among Para athletes belonging to the same sports class.

Metabolic, kinematic and coordinative behavior of a para swimmer with cerebral palsy

BACKGROUND: It has been increasingly necessary to assess and monitor the physiological and biomechanics variables of para swimmers to enlarge the current knowledge on how different impairments limit swimming performance and explain each competition class variability in metabolic and technical terms. AIM: To characterize the front crawl metabolic, kinematic, and coordination behaviors of a trained para swimmer subjected to an incremental protocol. METHOD: A 44-year-old male, with moderate right side hemiparesis of the body, performed a 200-m front crawl at 5 incrementally paces until exhaustion (0.05 m/s increases and 30-s intervals), with images from two cycles at each step recorded by two video cameras (one surface and one underwater). Kinematic and coordinative variables were collected. Lactate concentrations, heart rate, and blood pressure were also measured. RESULTS: The para swimmer achieved the anaerobic threshold at the fourth 200-m step, followed by an increase in heart rate and blood pressure. Speed and stroke frequency were higher and stroke length was lower along the 200-m steps. In contrast, a slight increase in stroke index and stability in intracyclic velocity variations occurred across intensity increments, and index of interlimb coordination was maintained as a superposition mode. CONCLUSION: The findings suggest that the swimming intensity seems to influence the para swimmer metabolic, kinematic, and coordinative behavior, with sharper alterations after the point when AnT is achieved. In addition to having practical interest for adapted swimming, coaches should emphazise the physiological and biomechanical evaluation on training monitoring to better prescribe and improve the adapted swimming performance.

Injury and Injury Prevention in United States Para Swimming: A Mixed-Methods Approach.

BackgroundPara swimming has experienced increased participation in recent years. Injury and injury prevention research on Para swimmers is lacking compared to swimmers without impairment.PurposeThis study aimed to gather data in Para swimmers on typical injuries, injury prevention programs, and attitudes toward injury and injury prevention in this population.Study DesignCross-sectional, mixed-methods design evaluating injuries, injury management, and injury prevention in elite Para swimmers in United States (U.S.).MethodsPara swimmers on the U.S. Paralympics Swimming National teams at multiple competition levels were invited to complete an online survey. Qualitative interviews with six U.S. Paralympics National team Para swimmers were conducted to provide detail on athlete experiences with injury and prevention.ResultsTwenty-one of 56 surveys were returned: 11 of 21 participants (52.4%) reported experiencing an injury that altered their weekly training. All (21/21) reported participating in strength training and 19 of 21 (90.5%) reported incorporating stretching into their training regimen, although strengthening/stretching regimens included routines that may not have been specifically targeted toward injury prevention. Six of 21 (28.6%) reported participation in an injury prevention program. Qualitative interview themes included the impact of swimmers’ compensated body mechanics on injury risk, the value of individualized injury prevention programs, and the importance of knowledgeable coaching and rehabilitation staff.ConclusionsInjury prevention programs are important components in Para swimming training although they are underutilized based on responses in this study. These programs should be individualized to address swimming biomechanics and athlete-specific impairments. Increasing coaching knowledge and access to individualized programs may reduce injury prevalence among this at-risk population.Level of Evidence3

Is the visual impairment origin a performance factor? Analysis of international-level para swimmers and para athletes

ABSTRACT The aim of this study was to investigate the effect of congenital and acquired visual impairments on the international performance of Para swimmers and Para track and field athletes. We collected results from visually impaired Para athletes competing in Para swimming or Para athletic events at all IPC-labelled competitions between 2009 and 2019. The dataset contained 20,689 events results. Impairment origin was collected from the International Paralympic Committee (IPC) website. We separated impairment origin into two groups to distinguish those with a congenital impairment from those with an acquired impairment. In visual impairment sport classes (11–12-13), the performance level and the age performance relationship were investigated according to the impairment origin. In classes 11 and 12, peak performance was achieved earlier by male and female swimmers with a congenital impairment compared with those who had an acquired impairment (p < 0.05). No differences were present in class 13 or in any class in Para athletics (p > 0.05). A similar performance level was observed among the two sport disciplines for each class (p > 0.05). This study demonstrated that impairment origin can influence the performance pathway among visually impaired swimmers.

Para Sport Development Experiences: Perspectives of Para Swimmers and Parents

This study examined para swimmers' athlete development experiences from the perspectives and reflections of athletes, and parents of athletes, with a focus on the constraints and challenges experienced. Guided by interpretive phenomenological analysis, 12 participants engaged in the interview process (seven parents and five athletes). Five themes were identified: fundamental skill development, personal connection, coaching, classification, and connecting with others "like me." Through a discussion of the differences in development experiences between the participants in this study and the current literature on athlete development, the authors highlight areas of concern in applying a non-para-specific athlete development model to para swimmers. This study identifies several areas of consideration in the future design of a para athlete development framework or model.

Kinematic Variables of Disabled Swimmers and Their Correlation With the International Paralympic Committee Classification.

This study described the kinematic variables of disabled swimmers' performance and correlated them with their functional classification. Twenty-one impaired swimmers (S5-S10) performed 50-m maximum front-crawl swimming while being recorded by four underwater cameras. Swimming velocity, stroke rate, stroke length, intracycle velocity variation, stroke dimensions, hand velocity, and coordination index were analyzed. Kendall rank was used to correlate stroke parameters and functional classification with p < .05. Swimming velocity, stroke length, and submerged phase were positively correlated with the para swimmers functional classification (.61, .50, and .41; p < .05, respectively), while stroke rate, velocity hand for each phase, coordination index, and intracyclic velocity variation were not (τ between -.11 and .45; p > .05). Thus, some objective kinematic variables of the impaired swimmers help to support current classification. Improving hand velocity seems to be a crucial point to be improved among disabled swimmers.

Passive drag in Para swimmers with physical impairments: Implications for evidence-based classification in Para swimming.

The inherent hydrodynamic resistance force, or passive drag, of a swimmer directly influences how they move through the water. For swimmers with physical impairments, the strength of association between passive drag and swimming performance is unknown. Knowledge on this factor could improve the World Para Swimming classification process. This study established the relationship between passive drag and 100m freestyle race performance in Para swimmers with physical impairments. Using a cross-sectional study design, an electrical-mechanical towing device was used to measure passive drag force in 132 international-level Para swimmers. There was a strong, negative correlation between normalized passive drag force and 100m freestyle race speed in the combined participant cohort (ρ=-0.77, p<0.001). Type of physical impairment was found to affect the relationship between passive drag and 100m freestyle race speed when included in linear regression (R2 =0.65, χ2 =11.5, p=0.025). These findings contribute to the body of evidence that passive drag can provide an objective assessment of activity limitation in Para swimmers with physical impairments. The effect of physical impairment type on the relationship between passive drag and swimming performance should be accounted for in Para swimming classification.