Incremental Swimming Test Research Articles

Estimating maximum oxygen uptake of fishes during swimming and following exhaustive chase - different results, biological bases and applications.

The maximum rate at which animals take up oxygen from their environment (ṀO2,max) is a crucial aspect of their physiology and ecology. In fishes, ṀO2,max is commonly quantified by measuring oxygen uptake either during incremental swimming tests or during recovery from an exhaustive chase. In this Commentary, we compile recent studies that apply both techniques to the same fish and show that the two methods typically yield different mean estimates of ṀO2,max for a group of individuals. Furthermore, within a group of fish, estimates of ṀO2,max determined during swimming are poorly correlated with estimates determined during recovery from chasing (i.e. an individual's ṀO2,max is not repeatable across methods). One explanation for the lack of agreement is that these methods measure different physiological states, each with their own behavioural, anatomical and biochemical determinants. We propose that these methods are not directly interchangeable but, rather, each is suited to address different questions in fish biology. We suggest that researchers select the method that reflects the biological contexts of their study, and we advocate for the use of accurate terminology that acknowledges the technique used to elevate ṀO2(e.g. peak ṀO2,swim or peak ṀO2,recovery). If the study's objective is to estimate the 'true' ṀO2,max of an individual or species, we recommend that pilot studies compare methods, preferably using repeated-measures designs. We hope that these recommendations contribute new insights into the causes and consequences of variation in ṀO2,max within and among fish species.

Relationship between blood glucose response and respiratory exchange ratio during intermittent incremental swimming test in well trained swimmers

Relationship between blood glucose response and respiratory exchange ratio during intermittent incremental swimming test in well trained swimmers

Training periodization for a world-class 400 meters individual medley swimmer.

We present a case study of the periodized training by a world-class 400-m Individual Medley (IM) swimmer (4th in 2019 World Championships) in the season leading to a bronze medal in the 2018 European Championship. The complexity of this IM preparation was based on the experiences, observations and innovations of an Olympic swimming coach. Over 52 weeks, a traditional periodization model was employed using three macrocycles. A total of 15 competitions were completed in the season increasing in frequency in the third macrocycle. The training intensity distribution (TID) followed the pattern of a traditional pyramidal model in general training and polarized and threshold models during specific training before competitions. Weekly training volume ranged from 25 to 79 km, 24 to 87 km, and 25 to 90 km in each of the three macrocyles. Altitude training comprised 23% of total training weeks. Haemoglobin [Hb] increased from 14.9 to 16.0 g/100 ml and haematocrit from 45.1 to 48.1% after altitude training. Heart rate (HR) and [La-] decreased at submaximal swimming intensities, while swimming velocity increased in the 8 × 100 m incremental swimming test in A2 (1.4%) and in AT (0.6%). Pull up power was increased 10% through the season.

Exercise Intensity during Olympic-Distance Triathlon in Well-Trained Age-Group Athletes: An Observational Study

The aim of this study was to examine the exercise intensity during the swimming, cycling, and running legs of nondraft legal, Olympic-distance triathlons in well-trained, age-group triathletes. Seventeen male triathletes completed incremental swimming, cycling, and running tests to exhaustion. Heart rate (HR) and workload corresponding to aerobic and anaerobic thresholds, maximal workloads, and maximal HR (HRmax) in each exercise mode were analyzed. HR and workload were monitored throughout the race. The intensity distributions in three HR zones for each discipline and five workload zones in cycling and running were quantified. The subjects were then assigned to a fast or slow group based on the total race time (range, 2 h 07 min–2 h 41 min). The mean percentages of HRmax in the swimming, cycling, and running legs were 89.8% ± 3.7%, 91.1% ± 4.4%, and 90.7% ± 5.1%, respectively, for all participants. The mean percentage of HRmax and intensity distributions during the swimming and cycling legs were similar between groups. In the running leg, the faster group spent relatively more time above HR at anaerobic threshold (AnT) and between workload at AnT and maximal workload. In conclusion, well-trained male triathletes performed at very high intensity throughout a nondraft legal, Olympic-distance triathlon race, and sustaining higher intensity during running might play a role in the success of these athletes.

Using aerobic exercise to evaluate sub-lethal tolerance of acute warming in fishes

ABSTRACTWe investigated whether fatigue from sustained aerobic swimming provides a sub-lethal endpoint to define tolerance of acute warming in fishes, as an alternative to loss of equilibrium (LOE) during a critical thermal maximum (CTmax) protocol. Two species were studied, Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus). Each fish underwent an incremental swim test to determine gait transition speed (UGT), where it first engaged the unsteady anaerobic swimming mode that preceded fatigue. After suitable recovery, each fish was exercised at 85% of their own UGT and warmed 1°C every 30 min, to identify the temperature at which they fatigued, denoted as CTswim. Fish were also submitted to a standard CTmax, warming at the same rate as CTswim, under static conditions until LOE. All individuals fatigued in CTswim, at a mean temperature approximately 2°C lower than their CTmax. Therefore, if exposed to acute warming in the wild, the ability to perform aerobic metabolic work would be constrained at temperatures significantly below those that directly threatened survival. The collapse in performance at CTswim was preceded by a gait transition qualitatively indistinguishable from that during the incremental swim test. This suggests that fatigue in CTswim was linked to an inability to meet the tissue oxygen demands of exercise plus warming. This is consistent with the oxygen and capacity limited thermal tolerance (OCLTT) hypothesis, regarding the mechanism underlying tolerance of warming in fishes. Overall, fatigue at CTswim provides an ecologically relevant sub-lethal threshold that is more sensitive to extreme events than LOE at CTmax.

Measuring maximum oxygen uptake with an incremental swimming test and by chasing rainbow trout to exhaustion inside a respirometry chamber yields the same results.

This study hypothesized that oxygen uptake (ṀO2 ) measured with a novel protocol of chasing rainbow trout Oncorhynchus mykiss to exhaustion inside a static respirometer while simultaneously monitoring ṀO2 (ṀO2chase ) would generate the same and repeatable peak value as when peak active ṀO2 (ṀO2active ) is measured in a critical swimming speed protocol. To reliably determine peak ṀO2chase , and compare to the peak during recovery of ṀO2 after a conventional chase protocol outside the respirometer (ṀO2rec ), this study applied an iterative algorithm and a minimum sampling window duration (i.e., 1 min based on an analysis of the variance in background and exercise ṀO2 ) to account for ṀO2 dynamics. In support of this hypothesis, peak ṀO2active (707 ± 33 mg O2 h-1 kg-1 ) and peak ṀO2chase (663 ± 43 mg O2 h-1 kg-1 ) were similar (P = 0.49) and repeatable (Pearson's and Spearman's correlation test; r ≥ 0.77; P < 0.05) when measured in the same fish. Therefore, estimates of ṀO2max can be independent of whether a fish is exhaustively chased inside a respirometer or swum to fatigue in a swim tunnel, provided ṀO2 is analysed with an iterative algorithm and a minimum but reliable sampling window. The importance of using this analytical approach was illustrated by peak ṀO2chase being 23% higher (P < 0.05) when compared with a conventional sequential interval regression analysis, whereas using the conventional chase protocol (1-min window) outside the respirometer increased this difference to 31% (P < 0.01). Moreover, because peak ṀO2chase was 18% higher (P < 0.05) than peak ṀO2rec , chasing a fish inside a static respirometer may be a better protocol for obtaining maximum ṀO2 .

Validation of a New Incremental Swim Test as a Tool for Maximum Oxygen Uptake Analysis in Lifeguards

This study was designed to validate an incremental test predicting maximum oxygen uptake for lifeguards. A maximum incremental test was performed in the laboratory (i.e., treadmill run) and in the pool (i.e., swim) by 10 certified lifeguards. The values of maximum oxygen uptake (VO2Max), maximum heart rate (HRMax), and lactate (LaMax) achieved during both tests were analyzed. The VO2Max (0.87, p =.001), HRmax (0.85, p = .002) and LaMax (0.67, p

Effects of a 6-Week Period of Polarized or Threshold Training on Performance and Fatigue in Elite Swimmers.

To quantify the impact of a polarized distribution of training intensity on performance and fatigue in elite swimmers. Twenty-two elite junior swimmers (12 males, age = 17 [3]y, and 10 females, age = 17 [3]y) participated in a crossover intervention study over 28 wk involving 2- × 6-wk training periods separated by 6 wk. Swimmers were randomly assigned to a training group for the first period: polarized (81% in zone 1, blood lactate concentration, [La]b ≤ 2mmol·L-1; 4% in zone 2, 2mmol·L-1 < [La]b ≤ 4mmol·L-1; and 15% in zone 3, [La]b > 4mmol·L-1) or threshold (65%/25%/10%). Before and after each period, they performed a 100-m maximal swimming test to determine performance, maximal [La]b, and oxygen consumption and an incremental swimming test to determine speed corresponding to [La]b = 4mmol·L-1 (V4mmol·L-1). Self-reported indices of well-being were collected with a daily questionnaire. Polarized training elicited small to moderately greater improvement than threshold training on 100-m performance (within-group change ± 90% confidence interval: 0.97% ± 1.02% vs 0.09% ± 0.94%, respectively) with less fatigue and better quality of recovery. There was no substantial gender effect. No clear differences were observed in physiological adaptations between groups. In elite junior swimmers, a 6-wk period of polarized training induced small improvements in 100-m time-trial performance and, in combination with less perceived fatigue, forms a viable option for coaches preparing such cohorts of swimmers for competition.

Gender Differences in Water-Based Aerobic Capacity During Freestyle Swimming to Exhaustion

Aerobic capacity plays an essential role in physical performance. Females have been shown to have lower aerobic capacity during land-based incremental testing when compared to their male counterparts. However, there have been few studies on gender differences in aerobic capacity during water-based incremental swimming. Understanding the gender differences is an important step in coaching/training. PURPOSE: The purpose of this study was to examine aerobic capacity gender differences. METHODS: A total of 15 males (23.6±6.7yrs, 179.3±6.4cm, 75.2±11.5kg) and 15 females (22.6±6.3yrs, 167.6±6.4cm, 65.7±9.5kg) participated in the study and completed an incremental swimming test to exhaustion. The protocol involved swimming a minimum of 250 meters (10 lengths) using the freestyle stroke. Rest periods following each 22.9 meter length decreased from 10 seconds to 3 seconds throughout the test. Following 9 lengths, subjects continuously swam at maximal velocity until VO2max had been achieved or until exhaustion occurred. Aerobic capacity was measured with a portable metabolic system suspended above the swimmer using a cable pulley system, enabling a standard freestyle stroke with continuous measure of VO2. Ratings of perceived exertion (RPE), blood lactate (BLa), and maximal heart rate (HRmax) were also measured at the end of the test. Data were tested for normality, and independent samples t-tests or Mann–Whitney U tests were used, as appropriate (p<0.05). RESULTS: Males had significantly higher aerobic capacity (males: 48.4±7.4ml/kg/min, females: 39.8±5.3ml/kg/min, p=0.001) and lower HRmax (males: 173.3±6.9bpm, females: 180.7±7.7bpm, p=0.032) compared to females. There were no gender differences in RPE (males: 9.6±0.7, females: 9.5±0.7, p=0.689) or BLa (males: 11.3±3.5mmol/L, females: 9.9±2.9mmol/L, p=0.269). CONCLUSIONS: The current results have revealed significant gender differences in aerobic capacity at the maximal effort (with similar RPE scale and BLa values). These findings are in accordance with other land-based gender studies on aerobic capacity, largely due to smaller stature/lung in females. Future studies should examine the effects of gender-specific and customized land/water-based training on their aerobic capacity. Supported by ONR: N00014-14-1-0022/N00014-15-0069

Ventilatory Strategies Of Competitive Swimmers During Incremental Swimming And Cycling Tests To Exhaustion

Ventilatory Strategies Of Competitive Swimmers During Incremental Swimming And Cycling Tests To Exhaustion

Performance Decrement and Skill Deterioration During a Water Polo Game are Linked With the Conditioning Level of the Athletes.

The aim of the study was to examine whether physical and technical performance deterioration after a water polo game is related to the athletes' conditioning level. Blood lactate concentration was measured during a 5 × 200-m incremental swimming test in 10 male water polo athletes to calculate the velocities corresponding to 4.0, 5.0, and 10.0 mmol·L lactate concentration (V4, V5, and V10, respectively) and define their conditioning level. All athletes participated in 5 competitive water polo games. Before (Pre), at half time (Mid), and after (Post) the first 2 games, handgrip strength and repeated sprint ability (8 × 20-m) were measured. Pre and Post the next 2 games, ball throwing velocity, shooting accuracy, and 400-m swim were evaluated. Pre, Mid, and Post the last game, the eggbeater kick test was performed. Handgrip strength, repeated sprint ability, 400-m swim performance, and ball shooting accuracy decreased after the game (8.4 ± 6.2%, 6.3 ± 3.4%, 7.0 ± 4.1%, and 20.3 ± 23.4%, respectively, p ≤ 0.05). V4, V5, and V10 were not significantly correlated with changes in physical or technical performance after the game. Performance in 400-m swim correlated with V4 and V5 whereas changes in 400-m swim Pre-Post, correlated with changes in ball shooting accuracy and throwing velocity (r = 0.73 and r = 0.80, p ≤ 0.05). These data suggest that V4, V5, and V10 may not correlate with performance decline in water polo. Interestingly, the 400-m swim test is connected with the decline in repeated sprints, ball shooting accuracy, and throwing velocity after a water polo game in well-trained athletes.

Role of exercise intensity on GLUT4 content, aerobic fitness and fasting plasma glucose in type 2 diabetic mice.

Type 2 diabetes mellitus (T2D) results in several metabolic and cardiovascular dysfunctions, clinically characterized by hyperglycaemia due to lower glucose uptake and oxidation. Physical exercise is an effective intervention for glycaemic control. However, the effects of exercising at different intensities have not yet been addressed. The present study analysed the effects of 8 weeks of training performed at different exercise intensities on type 4 glucose transporters (GLUT4) content and glycaemic control of T2D (ob/ob) and non-diabetic mice (ob/OB). The animals were divided into six groups, with four groups being subjected either to low-intensity (ob/obL and ob/OBL: 3% body weight, three times/week/40 min) or high-intensity (ob/obH and ob/OBH: 6% body weight, three times per week per 20 min) swimming training. An incremental swimming test was performed to measure aerobic fitness. After the training intervention period, glycaemia and the content of GLUT4 were quantified. Although both training intensities were beneficial, the high-intensity regimen induced a more significant improvement in GLUT4 levels and glycaemic profile compared with sedentary controls (p < 0.05). Only animals in the high-intensity exercise group improved aerobic fitness. Thus, our study shows that high-intensity training was more effective for increasing GLUT4 content and glycaemia reduction in insulin-resistant mice, perhaps because of a higher metabolic demand imposed by this form of exercise.

Dietary nitrate supplementation

Dietary nitrate NO3 intake through a diet rich in vegetables has been reported to exert several health effects, due to its transformation into the biological messenger nitric oxide (NO), which induces smooth muscle relaxation leading to haemodynamic effects like vasodilatation, increased blood flow and reduced blood pressure. The healthy effects of dietary nitrate have also been tested in sport, like cycling, walking and running, due to the reduction of O2 uptake during exercise. Dietary nitrate intake can be greatly enhanced making appropriate selections of high nitrate-containing foods or dietary supplements. A recent study [1], done on 10 healthy men, who ingested the supplement 2.5 h prior to moderate-intensity and severity-intensity cycle exercise tests, reported that dietary supplementation with beetroot juice (BRJ), containing 0.06 nmol/ml (about 4 mg/ml) nitrate concentration, altered the physiological responses to exercise, with 70 ml (4.2 nmol) having no effects, while 140 (8.4 nmol) and 280 ml (16.8 nmol) reduced the steady-state oxygen uptake during moderate-intensity exercise by 1.7% (p=0.06) and 3% (p=0.05), respectively. The time-totask failure was extended by 14% and 12% (both p=0.05), respectively. Although plasma nitrite (NO2) levels were increased dose dependently, with peak occurring at 2–3 h, there is no additional improvement in exercise tolerance after ingestion of 8.4 or 16.8 nmol NO3. The positive effect of 140 ml/day of BRJ was confirmed also after repeated ingestion [2]. In this randomised, double-bind, crossover study, nine healthy, physically active subjects were assigned to receive BRJ or placebo for 6 days. On Days 4, 5 and 6, the subjects completed a double-step exercise followed immediately by moderateto severe-intensity exercise. BRJ elevated plasma nitrite concentration compared to placebo (348 ± 170 and 65 ± 32 nM respectively, p<0.01), but the time constant of oxygen uptake (VO2) kinetics (τ) was reduced by 22% (p<0.05) only during severe-intensity exercise, not during moderateto severe-intensity exercise. The near-infrared spectroscopy-derived muscle deoxyhaemoglobin kinetics was faster and the time-to-task failure was 22% greater (p<0.05) during severe-intensity exercise. The Authors concluded that BRJ supplementation speeds VO2 kinetics and enhances exercise tolerance during severe-intensity exercise when initiated from an elevated metabolic rate, possibly via specific effects on type II muscle fibres. In addition to early reports in cycling, walking and running, BRJ supplementation has recently been tested in swimming [3]. The study recruited 14 moderately trained male swimmers (master athletes regularly involved in regional and national competition, who trained about 6 h per week, with a frequency of 3–4 times per week) in the middle phase of their training season. They underwent two incremental swimming tests, before (control) and after six days of BRJ supplementation (about 5.5 nmol nitrate/500 ml). Workload at anaerobic threshold was significantly increased and the aerobic energy cost was significantly reduced by BRJ supplementation. Although this study lacks a placebo group, thus requiring further studies to confirm, it suggests that BRJ supplementation might positively affect swimmers’ performance. Nitrate per se is relatively non-toxic, but concerns can be raised for its metabolites (like N-nitroso compounds). It is of interest that the doses of nitrate used in these studies are all above the World Health Organization’s acceptable daily intake (ADI) of 3.7 mg nitrate/kg body weight/day, equivalent to 222 mg nitrate/day for a 60 kg adult [4]. The highest BRJ dose utilised in the first study (16.8 nmol) is about 5-fold above this ADI and more than 2-fold above the one recommended by United States Environmental Protection Agency (7.0 mg nitrate/kg body weight/day for a 60 kg individual). Therefore, in light of the reported health benefits of nitrate, it seems that revision of its ADI would be useful.

Effect of Beetroot Juice Supplementation on Aerobic Response during Swimming

The beneficial effects of beetroot juice supplementation (BJS) have been tested during cycling, walking, and running. The purpose of the present study was to investigate whether BJS can also improve performance in swimmers. Fourteen moderately trained male master swimmers were recruited and underwent two incremental swimming tests randomly assigned in a pool during which workload, oxygen uptake (VO2), carbon dioxide production (VCO2), pulmonary ventilation (VE), and aerobic energy cost (AEC) of swimming were measured. One was a control swimming test (CSW) and the other a swimming test after six days of BJS (0.5l/day organic beetroot juice containing about 5.5 mmol of NO3−). Results show that workload at anaerobic threshold was significantly increased by BJS as compared to the CSW test (6.3 ± 1 and 6.7 ± 1.1 kg during the CSW and the BJS test respectively). Moreover, AEC was significantly reduced during the BJS test (1.9 ± 0.5 during the SW test vs. 1.7 ± 0.3 kcal·kg−1·h−1 during the BJS test). The other variables lacked a statistically significant effect with BJS. The present investigation provides evidence that BJS positively affects performance of swimmers as it reduces the AEC and increases the workload at anaerobic threshold.

Intensity Control in Swim Training by Means of the Individual Anaerobic Threshold

This study aimed at evaluating the homogeneity of physiological responses during swim training bouts with intensities prescribed by reference to the individual anaerobic threshold (IAT). Eighteen competitive front crawl swimmers (female 5, male 13, 10 long-distance, and 8 short-distance swimmers [LDSs, SDSs], age: 17 ± 1.7 years, training history: 7.0 ± 2.8 years, training volume per week: 35 ± 5.7 km) performed an incremental swimming test to determine the IAT. Within a maximum of 3 weeks, 4 training programs were conducted: 20 × 100-m low-intensity endurance training (EN(low), 97% IAT), 5 × 400-m high-intensity endurance training (EN(high), 101% IAT), 5 × 200 m (IT1, 105% IAT), and 10 × 100 m (IT2, 108% IAT) intensive interval training. Blood lactate concentrations (bLa) were determined during each training session. The results are given as median (25th and 75th percentiles). During EN(low) and EN(high), the mean bLas were 1.8 mmol·L(-1) (1.3/3.0 mmol·L(-1)) and 4.4 mmol·L(-1) (3.9/6.4 mmol·L(-1)). The bLas were higher during both IT programs: IT1, 6.3 mmol·L(-1) (5.6/7.2 mmol·L(-1)); IT2, 5.8 mmol·L(-1) (5.0/6.5 mmol·L(-1)). The bLas of most individuals were close to the median values (±2.4 mmol·L(-1)). However, in each of the training programs, some subjects showed bLa values that were clearly above (3-7 mmol·L(-1) higher). In particular, SDSs reached higher bLas at the same intensity compared with LDSs. It is concluded that intensity prescriptions by means of IAT seem to elicit an expected metabolic response in approximately 85% of swim training sessions. The observed average bLa is in the range of those recommended in the scientific literature.

Capsaicin increases the aerobic capacity of Wistar rats submitted to an incremental swimming test (IST): preliminary results

Capsaicin increases the aerobic capacity of Wistar rats submitted to an incremental swimming test (IST): preliminary results

Swimming performance and behaviour of young-of-the-year shortnose sturgeon (Acipenser brevirostrum) under fixed and increased velocity swimming tests

Swimming performance and behaviour in fish has been shown to vary depending on the investigation method. In this study, an endurance swimming curve was generated for young-of-the-year shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818) (~7 cm total length, ~2 g) and compared with values determined in a separate incremental swimming (critical swimming, Ucrit) test. Using video, tail-beat frequency (TBF) was quantified and compared for fish swimming under both swimming tests. From the endurance-curve analysis, it was found that sturgeon did not display a statistically significant burst swimming phase. Maximum sustainable swimming speed (calculated to be 18.00 cm·s–1) from the endurance curve occurred at ~80% of Ucrit(22.30 cm·s–1). TBF was similar at all speeds for both swimming tests, except at speeds approaching Ucrit, where fish displayed TBFs of 4.29 Hz for the endurance protocol and 2.26 Hz for the Ucritprotocol. TBF was more variable between individuals swimming at the same speed within the Ucritcompared with the endurance protocol. Finally, a significant negative correlation was found between TBF and Ucritin individual fish, suggesting that station-holding may be an important energy saving strategy during swimming in this size class of sturgeon.

Lactate Threshold and Performance Adaptations to 4 Weeks of Training in Untrained Swimmers: Volume Vs. Intensity

The purpose of this study was to investigate the impact of 4 weeks of high-intensity vs. high-volume swim training on lactate threshold (LT) characteristics and performance. Thirteen untrained swimmers with a mean age of 19.0 ± 0.5 undertook an incremental swimming test before and after 4 weeks of training for the determination of LT. Performance was evaluated by a 50-m maximum freestyle test. The swimmers were assigned to 1 of each of 2 training groups. The high-intensity group (n = 6) focused on sprint training (SP) and swam a total of 1,808 ± 210 m. The high-volume group (n = 7) followed the same program as the SP group but swam an additional 1,100 m (38% more) of endurance swimming (SP + End). A training effect was evident in both groups as seen by the similar improvements in sprint performance of the 50-m maximum time (p < 0.01), peak velocity increases and the lower value of lactate at the individual LTs (p < 0.01). Lactate threshold velocity improved only in the SP + End group from 1.20 ± 0.12 m·s(-1) pretraining to 1.32 ± 0.12 m·s(-1) posttraining (p = 0.77, effect size = 1, p < 0.01), expressed by the rightward shifts of the individual lactate-velocity curves, indicating an improvement in the aerobic capacity. Peak lactate and lactate concentrations at LT did not significantly change. In conclusion, this study was able to demonstrate that 4 weeks of either high-intensity or high-volume training was able to demonstrate similar improvements in swimming performance. In the case of lack of significant changes in lactate profiling in response to high-intensity training, we could suggest a dissociation between the 2.

Physiological and Stroke Parameters to Assess Aerobic Capacity in Swimming

To identify the speed corresponding to anaerobic threshold using the D-max method for both blood lactate and biomechanical stroke parameters determined in an incremental swimming test and to compare this information with the speed corresponding to the maximal lactate steady state (SMLSS). Five male long-distance swimmers and 8 triathletes (N=13; age 23.8±9.5 y, height 1.76±0.1 m, weight 71.3±9.8 kg) performed the following protocols: maximal 400-m test to determine maximal aerobic speed (S400); 7×200-m incremental test to determine the speed corresponding to the D-max point on the blood lactate (SLa), stroke-rate (SSR), stroke-length (SSL), and stroke-index (SSI) responses; and two to four 30-min submaximal tests to determine the SMLSS. SLA (1.18±0.08 m/s), SSI (1.18±0.08 m/s), SSR (1.17±0.1 m/s), and SSL (1.16±0.09 m/s) were not significantly different from each other or from SMLSS (1.13±0.08 m/s). There were high correlations between SLA, SSI, SSR, SSL, and SMLSS (r=.91, .89, .85, and .80, respectively). The typical errors of estimate for SLA (3.2%), SSI (3.7%), SSR (4.1%), and SSL (4.7%) suggest good validity of these variables to predict SMLSS. Furthermore, all physiological and biomechanical variables were moderately to highly correlated with S400 (r=.73-.95). It is possible to obtain a physiological index of aerobic capacity and performance using simple biomechanical measurements during an incremental test without performing blood lactate analyses.

Effect of increasing energy cost on arm coordination in elite sprint swimmers

The purpose of this study was to analyze the changes in stroke parameters, motor organization and swimming efficiency with increasing energy cost in aquatic locomotion. Seven elite sprint swimmers performed a 6×300-m incremental swimming test. Stroke parameters (speed, stroke rate and stroke length), motor organization (arm stroke phases and arm coordination index), swimming efficiency (swimming speed squared and hand speed squared) and stroke index were calculated from aerial and underwater side-view cameras. The energy cost of locomotion was assessed by measuring oxygen consumption and blood lactate. Results showed that the increase in energy cost of locomotion was correlated to an increase in the index of coordination and stroke rate, and a decrease in stroke length (p<.05). Furthermore, indicators of swimming efficiency and stroke index did not change significantly with the speed increments (p<.05), indicating that swimmers did not decrease their efficiency despite the increase in energy cost. In parallel, an increase in the index of coordination IdC and stroke rate were observed, along with a decrease in stroke length, stroke index and hand speed squared with each increment, revealing an adaptation to the fatigue within the 300m.