Abstract
hysiological parameters give an indication of the potential swimming performance. Studies regarding swimmers with impairments which gather information on physiological parameters are scarce. The aim of this study was to summarize the results of studies involving oxygen uptake, blood lactate and heart rate in swimming protocols for swimmers with physical impairments. A comprehensive search of the literature was performed on PubMed, EMBASE, Web of Science and EBSCO for complete studies between database inception and May 22 nd , 2023. Ten studies (n = 142) fulfilled the inclusion criteria (including swimmers with physical impairments that monitor oxygen uptake, blood lactate and heart rate responses). A numerical summary and a narrative description of the results in relation to the research eligibility criteria were summarized. The risk of bias was assessed by Quality Assessment Checklist. In swimming protocols, swimmers with a lower functional impact of the impairment to perform sport- specific tasks showed higher oxygen uptake and blood lactate than those with a higher impact (6 studies, n = 79). The highest concentrations of blood lactate were reached in maximal anaerobic tests, followed by maximal aerobic tests (7 studies, n = 98). The relative heart rate was close to 90% in most cases (8 studies, n = 83). The studies also showed great variability in the physiological parameters concerning the categories or classifications of swimmers with physical impairments. The oxygen uptake, blood lactate concentration and relative heart rate assessments should consider functionalities and absences according to specific morphophysiological impairment. Keywords: swimming; physiological; performance; disability Introduction Physiological parameters are determinants of performance in competitive swimming (Morouço et al., 2014). Oxygen uptake (VO2), blood lactate concentration ([La - ] b ), and heart rate (HR) are
swimmers with physical impairments. The oxygen uptake, blood lactate concentration and relative heart rate assessments should consider functionalities and absences according to specific morphophysiological impairment. Keywords: swimming; physiological; performance; disability Introduction Physiological parameters are determinants of performance in competitive swimming (Morouço et al., 2014). Oxygen uptake (VO2), blood lactate concentration ([La - ] b ), and heart rate (HR) are standard parameters to be monitored (Barbosa et al., 2010; Pelarigo et al., 2017b; Toubekis & Tokmakidis, 2013). Among the physiological parameters of performance, in order of importance, coaches and competitive swimmers can benefit from the ability to maintain a high percentage of maximal oxygen uptake (VO2max) (gold-standard) over a long period, to maintain a certain rhythm during sets of repetitions when associated with the intensity of swimming, and to improve the recovery after several repetitions during training (Zacca et al., 2019). Assessments of the [La - ] b are often used to avoid training load irregularities, to adjust the pace of aerobic endurance training, and to assess the anaerobic
European Journal of Adapted Physical Activity 2023, 16, 16; doi: 10.5507/euj.2023.008 2 of 18 eujapa.upol.cz energetic capacity of swimmers (Sousa et al., 2014). The percentage of maximal HR (%HRmax) and maximal heart rate (HRmax) can be used to monitor and prescribe training intensity as the most common secondary method, due to fast increases in HR through fast increase in oxygen delivery to muscle activity and in the reduction of peripheral fatigue (Amann & Calbet, 2008; Psycharakis, 2011). Swimmers with physical impairments are grouped into ten Sport Classes (S1 to S10) that rank the highest to smallest impact of the disability for carrying out certain specific sport tasks (International Paralympic Committee, 2018). These swimming classes are heterogeneous concerning the impairment type, for example Sport Class S4 includes swimmers with motor sensory polyneuropathy (injury and malfunctioning of the nerves of the feet and legs that can also affect the thighs and arms); complete or incomplete spinal cord injuries; cerebral palsy, with severe diplegia or severe dysmelia of three limbs; or arthrogryposis affecting four limbs, with fair propulsion from upper limbs (International Paralympic Committee [IPC] Explanatory guide to Paralympic classification in Paralympic summer sports, 2015). Functional limitations and mobility restrictions, common in swimmers with impairments, influence the magnitude of physiological responses (Garatachea et al., 2006; Mujika et al., 2015). The physical characteristics of Paralympic swimmers, related to the main physiological parameters obtained in swimming tests or protocols, can therefore provide information regarding the type, cause, and effect – that is, the deficiency and its respective physiological effect on performance in swimming tests (e.g. cerebral palsy, spinal cord injuries, malformations, or amputations of the upper and lower limbs) can compromise muscle action, muscle perfusion, training load, performance, and recovery after exercise, and influence VO2, [La - ] b , and HR (DiRocco et al., 1985; Garatachea et al., 2006; Janssen et al., 2002; Saltin et al., 1998; Toubekis & Tokmakidis, 2013). This can contribute to a better understanding and evolution of adaptive sports, by showing, in a systematic way, how physiological responses to swimming in people with physical impairments can be altered, when compared
[La - ] b , and HR (DiRocco et al., 1985; Garatachea et al., 2006; Janssen et al., 2002; Saltin et al., 1998; Toubekis & Tokmakidis, 2013). This can contribute to a better understanding and evolution of adaptive sports, by showing, in a systematic way, how physiological responses to swimming in people with physical impairments can be altered, when compared to people without impairments. This systematic review focuses on swimmers with physical impairments who are classified into 10 Sport Classes according to the impact of an eligible impairment on the execution of specific sports tasks and activities (Sport Classes S1 to S10) (International Paralympic Committee, 2018). It is common to note, swimmers with physical impairments have some loss of horizontal body alignment relative to the water surface, with deeper positions of the hips and lower limbs in the water, increasing drag. In addition, swimmers with physical impairments (e.g. swimmers with cerebral palsy, spinal cord injury, amputations and malformations) show the same characteristics in swimming parameters. Swimming speed (SS), stroke length (SL), and stroke rate (SR) are higher in swimmers with a lower functional impact of physical impairment to perform sport-specific tasks (Feitosa et al., 2022; Pérez-Tejero et al., 2018). The SR is more valued than the SL to achieve high SS in swimmers with upper limb physical impairments (Feitosa et al., 2022). These positions and swimming parameters during front crawl stroke impose a great propulsive force to overcome the increased drag (Capelli et al., 1995), leading to increased VO2 (Chatard et al., 1992). [La - ] b is a product of the physiological system disability, in response to the effort of swimmers with low mobility and consequent reduction of blood flow, especially in the lower limbs (Bentley et al., 2002). Analyses of [La - ] b reflect the effort intensity (Donovan & Brooks, 1983). Complementarily, increases in sympathetic and parasympathetic activity also reflect, respectively, increases and decreases in HR (Koenig et al., 2014). Paralympic swimming has been developing steadily over the past decades. Likewise, there is an increase in evidence-based insights on the performance and physiological response of swimmers with
Analyses of [La - ] b reflect the effort intensity (Donovan & Brooks, 1983). Complementarily, increases in sympathetic and parasympathetic activity also reflect, respectively, increases and decreases in HR (Koenig et al., 2014). Paralympic swimming has been developing steadily over the past decades. Likewise, there is an increase in evidence-based insights on the performance and physiological response of swimmers with impairments. However, to the best of our knowledge, no reviews
European Journal of Adapted Physical Activity 2023, 16, 16; doi: 10.5507/euj.2023.008 3 of 18 eujapa.upol.cz on the VO2, [La - ] b , and HR response of swimmers with impairments was found by the authors. The present systematic review adds information particularly focused on providing physiological responses of swimmers with physical impairments who have participated in protocols for assessing swimming performance. In addition, the physiological responses arising from performance assessment protocols for swimmers with physical impairments can provide evidence for a better understanding of performance in training and competitions (de Souza et al., 2016), bridging theory and practice, by assisting coaches in their training prescription and highlighting areas for further research. The aim of this study was to summarize the results of studies involving VO2, [La - ] b , and HR in swimming protocols for swimmers with physical impairments. Materials and Methods Eligibility criteria This systematic review was carried out following the recommendations of the PRISMA Statement (Page et al., 2021). The eligibility criteria were based on the inclusion of studies recruiting swimmers with physical impairment, aiming to monitor the physiological response (any term: VO2, [La - ] b , and HR). There was no language restriction, as long as the studies had titles and abstracts in English, and full text were available studies No restrictions were applied regarding the time of publication. The exclusion criteria were: absence of information or incomplete data in articles and multiple publications in which the results were repeated – only one of these studies would be included if found. Protocols, editorials, discussion papers, and commentaries were also excluded. Databases and search strategies Data were gathered through searches on PubMed, EMBASE, Web of Science and EBSCO (SPORTDiscus, MEDLINE and Academic Search Premier). Completed published studies were screened between database inception and May 22 nd , 2023. Reference lists of the articles found were also searched. The search strategy used the Medical Subject Headings (MeSH) descriptors of health science subjects and term BIREME – DeCS, as well as their synonyms and combinations between the words for the following categories: population – amputees OR “disabled person”
studies were screened between database inception and May 22 nd , 2023. Reference lists of the articles found were also searched. The search strategy used the Medical Subject Headings (MeSH) descriptors of health science subjects and term BIREME – DeCS, as well as their synonyms and combinations between the words for the following categories: population – amputees OR “disabled person” OR “disabled swimmers” OR “sports for persons with disabilities” OR “physical impairments” OR impairment; Intervention – freestyle OR “front crawl” OR swimming; outcome – aerobic OR anaerobic OR “blood lactate concentration” OR “heart rate” OR “oxygen consumption” OR “uptake oxygen” OR “peak oxygen” OR physiological OR physiology. The Boolean operators ‘AND’ and ‘OR’ were used for tracing during the searches in the electronic databases. Selection of studies and extraction of results The selection of the studies was carried out in two stages: 1 st – reading the titles and abstracts of all the articles identified during the search strategy, independently by two researchers (WF and RC). Studies that did not provide enough details about the inclusion and exclusion criteria were selected for complete article evaluation; 2 nd – the same reviewers, independently (WF and RC), assessed the full content of the articles and made their selection according to the eligibility criteria. Disagreements between reviewers were resolved by a third independent reviewer (FC). Data extraction was performed using a standardised form. Duplicates were removed with Endnote software support by manually checking the similarities in the studies, reference by reference. Physiological outcomes
European Journal of Adapted Physical Activity 2023, 16, 16; doi: 10.5507/euj.2023.008 4 of 18 eujapa.upol.cz Absolute (L∙mim −1 ) VO2 was identified in studies that demonstrated any form of collection of expired gases, by a gas analyser or metabolic cart (de Jesus et al., 2014). The [La - ] b was identified from intravenous collection, collected through the ear lobe or fingertip, represented by the highest value achieved after the effort in swimming tests (Sousa et al., 2010). The HR in beats∙min −1 was identified in absolute values. The %HRmax was calculated from the values of the HRmax, based on the equation [208 – 0.7 × age] (Tanaka et al., 2001), minus the maximal HR of the swimming tests, split by the absolute value and multiplied by 100: [(HRmax – HR swim test)/ (HRmax)] × 100 (Wilmore & Costill, 2004). Risk of bias assessment The Downs and Black Quality Assessment Checklist was used to provide a score on the overall quality of the studies (Downs & Black, 1998). Higher scores represented articles with superior quality. The scores obtained were expressed as a percentage: [(total number of points achieved/total number of applicable points) × 100]. Additionally, results of the quality of the studies were also presented by the point variation obtained in the quality index and values of mean and standard deviation. Adjustments were deemed as necessary: the word ‘patient’ was changed to ‘participant’ and ‘treatment’ interpreted in the context of ‘test’, and item 27, which sought to assess whether the negative findings of the study could be due to chance, was excluded. This tool was used by two reviewers independently (WF and RC). Whenever necessary, a third reviewer (FC) was required to reconcile on the different opinions. Data analysis Quantitative analysis was performed based on the main characteristics of the studies, with information about: authors’ names and year of publication, data samples, and main methods with selected outcomes. A numerical summary and a narrative description of the results in relation to the research eligibility criteria were summarized. The mean (M) values and standard deviation (SD) of the results were registered
analysis was performed based on the main characteristics of the studies, with information about: authors’ names and year of publication, data samples, and main methods with selected outcomes. A numerical summary and a narrative description of the results in relation to the research eligibility criteria were summarized. The mean (M) values and standard deviation (SD) of the results were registered when available. Results The search strategy returned 227 articles, of which 107 were duplicates and were removed. In the first phase of analysis, 108 studies were excluded based on the title or abstract. In the second phase, four studies were excluded after being read in full. Two complete studies were included from other sources (e.g., article in a book, and from the references of the original articles.). Ten studies were examined extensively because they matched the inclusion criteria (Figure 1). The characteristics of the studies included are shown in Table 1. They were published between 1985 and 2021. The quality of studies ranged between 50% and 69.23% (13 to 18 points, average score for all papers: M = 15.36, SD = 1.80). The most common missing items included: probability values, items related to the invitation and the representativeness of the participants, the randomization procedures for intervention groups, intervention task, and loss of study participants. We gathered the samples from each study (overall n = 142 participants) in order to increase the evidence on the responses of the physiological parameters in swimmers with physical impairment.
European Journal of Adapted Physical Activity 2023, 16, 16; doi: 10.5507/euj.2023.008 5 of 18 eujapa.upol.cz Figure 1. Flowchart of the systematic literature search. The included studies had methodological differences regarding the protocols used to assess the physiological response: tethered swimming, 4 × 50m max; different percentage of critical swimming speed; one maximal anaerobic test (the swimmers performed the first test over a distance of 50m to 100m, according to their swimming speed), and aerobic- anaerobic test of intensities (the swimmers performed the second test over a distance of 150m to 200m, or 300m to 400m, depending on their swimming speed); an all-out 200m front-crawl stroke test; tests of increased speed (200m, 400m or 800m tests [swum at a steps of progressively speed at 50m, 100m or 200m, depending on physical impairment]); and 21min aerobic, 5 × 200m, 6 × 300m, 7 × 200m. A high variability of the participants’ classifications across studies was also noted. Oxygen uptake The selected physiological variables and sport classes (or physical impairment) were examined (Table 1). VO2 (n = 79) was assessed in six studies. The VO2 obtained in different swimming protocols were higher for most swimmers with less impact of a physical impairment on their ability to perform the specific activities requested. In most cases, the VO2 results ranged from the highest to the lowest values of the sport classes S10 to S1 . In the tethered swimming test, the VO2 was elevated according to the spinal cord injury level in male swimmers (highest spinal cord injury in C7 to less spinal cord injury in T12 – increasing VO2 from 1.06 to 2.6 L∙min −1 , n = 4; DiRocco et al., 1985). Two other female swimmers from the tethered swimming study had spinal cord injury due to the poliomyelitis virus and had VO2 of 0.76 to 1.18 L∙min −1 (DiRocco et al., 1985). No similar study with the tethered swimming test was found for swimmers with other physical impairments. Analysis of VO2 in the 200m front-crawl stroke test was also found (VO2; M = 3.1, SD = 0.6 L∙min −1 for males; and
cord injury due to the poliomyelitis virus and had VO2 of 0.76 to 1.18 L∙min −1 (DiRocco et al., 1985). No similar study with the tethered swimming test was found for swimmers with other physical impairments. Analysis of VO2 in the 200m front-crawl stroke test was also found (VO2; M = 3.1, SD = 0.6 L∙min −1 for males; and M = 1.9, SD = 0.3 L∙min −1 for females, sport classes S5, S7 to S10; Ongaratto et al., 2021). During the swimming tests of 200m, 400m and 800m freestyle swim (depending on the disability), at progressively increasing speed until exhaustion, the following results were obtained for swimmers in sporting classes S1 and S2, male VO2; M = 2.2, SD = 0.1 L∙min −1 ,
European Journal of Adapted Physical Activity 2023, 16, 16; doi: 10.5507/euj.2023.008 6 of 18 eujapa.upol.cz female VO2; = M 1.5, SD = 0.1 L∙min −1 and swimmers in sporting classes S3 and S4, male VO2; M = 3.2, SD = 0.7 L∙min −1 , female VO2; M = 2.1, SD = 0.3 L∙min −1 (Chatard et al., 1992). The Sport Classes S5 and S6 had similar VO2 in tests with increased swimming speed (7 × 200m, 6 × 300m) with VO2 values ranging from 3.2 to 3.9 L∙min −1 for males and 2.4 L∙min −1 for females (de Souza et al., 2016; Rodrigues Junior et al., 2016). The sport classes S5–S9, presented increased values for VO2 from the lowest sport classes to the highest sport classes in the incremental speed test (de Souza et al., 2016; Feitosa et al., 2019; Rodrigues Junior et al., 2016). Blood lactate The [La - ] b was assessed in seven studies (n = 98). The [La - ] b obtained in different swimming protocols were higher for most swimmers with less impact of a physical impairment (higher results from sport classes S10 to S1). The [La - ] b increased when: (i) the intensity of exercise increased and (ii) activated muscle mass was increased during physical exercise (de Aymerich et al., 2010). The [La-]b was higher in the 4 × 50m max tests for sport classes S3 or S7 ([La-]b; M = 14.35, SD = 4.08 mmol∙L-1; Pelayo et al., 1995), than in the maximal anaerobic test, 50m to 100m, depending on the swimming speed of each swimmer ([La-]b; M = 11.93, SD = 0.63 mmol∙L-1 for sport classes S6 to S10; de Aymerich et al., 2010) and, then by the results of the 5 × 100m or 5 × 200m for swimmers with partial or total loss of movement of the lower limbs ([La-]b; approximately 11.3 mmol∙L-1; Bentley et al., 2002). The next highest values were for the aerobic swimming tests of 21 minutes of effort for sport classes S4, S5 and S7 ([La-]b; M = 10.80, SD = 3.50 mmol∙L-1; Pelayo et