5 km front crawl in pool and open water swimming: breath-by-breath energy expenditure and kinematic analysis.

PURPOSE: Breath-by-breath energy expenditure during open water swimming has not yet been explored in an ecological environment. This study aimed to investigate and compare energetics and kinematics of 5 km swimming, in both swimming pool and open water conditions. METHODS: Through four independent studies, oxygen uptake ([Formula: see text]2) kinetics, heart rate (HR), blood lactate concentration ([La-]) and glucose level (BGL), metabolic power ([Formula: see text]), energy cost (C) and kinematics were assessed during 5 km front crawl trials in a swimming pool and open water conditions. A total of 38 competitive open water swimmers aged 16-27 years volunteered for this four part investigation: Study A (pool, ten females, 11 males), Study B (pool, four females, six males), Study C (pool case study, one female) and Study D (open water, three females, four males). RESULTS: In the swimming pool, swimmers started with an above average swimming speed (v), losing efficiency along the 5 km, despite apparent homeostasis for [La-], BGL, [Formula: see text]2, [Formula: see text] and C. In open water, swimmers started the 5 km with a below average v, increasing the stroke rate (SR) in the last 1000 m. In open water, [Formula: see text]2 kinetics parameters, HR, [La-], BGL, respiratory exchange ratio and C were affected by the v and SR fluctuations along the 5 km. CONCLUSIONS: Small fluctuations were observed for energetic variables in both conditions, but changes in C were lower in swimming pool than in open water. Coaches should adjust the training plan accordingly to the specificity of open water swimming.

Critical velocity, anaerobic distance capacity, maximal instantaneous velocity and aerobic inertia in sprint and endurance young swimmers.

Critical velocity (CV), anaerobic distance capacity (ADC), maximal instantaneous velocity (V (max)), and aerobic inertia (tau) were calculated from two (CV(2par) and ADC(2par)), three (CV(3par), ADC(3par), and V (max 3par)), and four-parameter model data (CV(4par), ADC(4par), V (max 4par), and tau), which were obtained from six different times and distances (50, 100, 200, 400, 800, and 1,500 m) swum in front crawl stroke under maximal intensity. Fourteen swimmers (14-15-year-old; sprint and endurance groups, each group n = 7) volunteered in this study. CV values were not influenced by the groups. The model effects showed that CV(2par) was higher than CV(3par) and CV(4par) regardless of the group used. In addition, CV(3par) and CV(4par) were similar. ADC seems to be better estimated using both three- and four-parameter models. V (max) was higher in the sprint group regardless of the model used. The models effects showed that the V (max 4par) was higher than the V (max 3par) regardless of the group. Sprint and endurance groups showed similar tau values. The analysis of the models (F test, coefficient of determination R (2), and adjusted coefficient of determination R (adjusted) (2) ) showed that the three-parameter model was more appropriate among the applied models. Although the four-parameter model showed better correlation for the endurance group, the inclusion of tau (fourth parameter) did not significantly improve the quality of adjustment. However, it is important to emphasize the availability of another parameter for the study of bioenergetics in swimming and other sports.

A Biophysical Analysis on the Arm Stroke Efficiency in Front Crawl Swimming: Comparing Methods and Determining the Main Performance Predictors.

Purpose: to compare different methods to assess the arm stroke efficiency (?F ), whenswimming front crawl using the arms only on the Measurement of Active Drag System (MADSystem) and in a free-swimming condition, and to identify biophysical adaptations to swimming onthe MAD System and the main biophysical predictors of maximal swimming speed in the 200 mfront crawl using the arms only (?200m). Methods: fourteen swimmers performed twice a 5 × 200 mincremental trial swimming the front crawl stroke using the arms only, once swimming freely, andonce swimming on the MAD System. The total metabolic power was assessed in both conditions.The biomechanical parameters were obtained from video analysis and force data recorded on theMAD System. The ?F was calculated using: (i) direct measures of mechanical and metabolic power(power-based method); (ii) forward speed/hand speed ratio (speed-based method), and (iii) thesimplified paddle-wheel model. Results: both methods to assess ?F on the MAD System differed (p< 0.001) from the expected values for this condition (?F = 1), with the speed-based method providingthe closest values (?F~0.96). In the free-swimming condition, the power-based (?F~0.75), speedbased(?F~0.62), and paddle-wheel (?F~0.39) efficiencies were significantly different (p < 0.001).Although all methods provided values within the limits of agreement, the speed-based methodprovided the closest values to the "actual efficiency". The main biophysical predictors of ?200mwere included in two models: biomechanical (R2 = 0.98) and physiological (R2 = 0.98). Conclusions:our results suggest that the speed-based method provides the closest values to the "actual ?F" andconfirm that swimming performance depends on the balance of biomechanical and bioenergeticparameters.

The Effects of Leg Kick on Swimming Speed and Arm-Stroke Efficiency in the Front Crawl.

PURPOSE: To analyze the effects of swimming pace on the relative contribution of leg kick to swimming speed and to compare arm-stroke efficiency (ηF) assessed when swimming with the arms only (SAO) and while swimming front crawl (FCS) using individual and fixed adjustments to arm-stroke and leg-kick contribution to forward speed. METHODS: Twenty-nine master swimmers (21 men, 8 women) performed SAO and FCS at 6 self-selected speeds from very slow to maximal. The average swimming speed (v), stroke frequency (SF), and stroke length (SL) were assessed in the central 10 m of the swimming pool. Then, a 2nd-order polynomial regression was used to obtain values of v at paired SF. The percentage difference in v between FCS and SAO, for each paired SF, was used to calculate the relative contributions of the arm stroke (AC) and leg kick (LC) to FCS. Then ηF was calculated using the indirect "paddle-wheel" approach in 3 different ways: using general, individual, and no adjustments to AC. RESULTS: The LC increased with SF (and speed) from -1% ± 4% to 11% ± 1% (P < .05). At the lower FCS speeds, ηF calculated using general adjustments was lower than ηF calculated using individual adjustments (P < .05), but differences disappear at the fastest speeds. Finally, ηF calculated using individual adjustments to LC in the FCS condition did not differ with ηF assessed in the SAO condition at all the investigated speeds. CONCLUSIONS: The relative contributions of the arm stroke and leg kick should be individually estimated to reduce errors when calculating arm-stroke efficiency at different speeds and in different swimmers.

Effect of walking speed in heart failure patients and heart transplant patients.

BACKGROUND: Chronic heart failure patients present higher cost of transport and some changes in pattern of walking, but the same aspects have not yet been investigated in heart transplant patients. METHODS: The aim of this study was to investigate both metabolic and mechanicals parameters, at five different walking speeds on treadmill, in chronic heart failure and heart transplant patients. Twelve chronic heart failure patients, twelve healthy controls and five heart transplant patients participated in the study. Tridimensional kinematics data and oxygen uptake were collected simultaneously. FINDINGS: In both experimental groups the self-selected walking speed was lower than in controls, and lower than the expected optimal walking speed. At that speed all groups showed the best ventilatory efficiency. On contrary, chronic heart failure and heart transplant patients reached the minimum cost of transport and the maximum recovery at greater speeds than the self-selected walking speed. Their mechanical efficiency was lower than in controls, while their metabolic cost and mechanical work were on average larger. INTERPRETATION: We conclude that actions, like a physical training, that could increase the self-selected walking speed in these patients, could also increase their economy and optimize the mechanical parameters of walking. We propose a rehabilitation index, based on the theoretical optimal walking speed, to measure the improvements during a physical rehabilitation therapy. These results have an important clinical relevance and can help to improve the quality of life of heart failure and transplant patients.

The Functional Test for Agility Performance is a Reliable Quick Decision-Making Test for Skilled Water Polo Players.

The reliability of the Functional Test for Agility Performance has only been evaluated in water polo players in a small group of novice athletes. Thus, the aim of this study was to evaluate the reliability of the Functional Test for Agility Performance in skilled water polo players. Forty-two athletes (17.81 ± 3.24 years old) with a minimum of 5 years of competitive experience (7.05 ± 2.84 years) and playing at the national or international level were evaluated. The Functional Test for Agility Performance is characterized as a specific open decision-making test where a tested player moves as quickly as possible in accordance to a pass made by another player. The time spent in the test was measured by two experienced coaches. Descriptive statistics, repeated measures analysis of variance (ANOVA), 95% limit of agreement (LOA), intraclass correlation coefficient (ICC) and standard error of measurements (SEM) were used for data analysis. Athletes completed the Functional Test for Agility Performance in 4.15 0.47 s. The ICC value was 0.87 (95% IC = 0.80-0.92). The SEM varied between 0.24 and 0.38 s. The LOA was 1.20 s and the CV average considering each individual trial was 6%. The Functional Test for Agility Performance was shown to be a reliable quick decision-making test for skilled water polo players.

The reliability of a functional agility test for water polo.

Few functional agility tests for water polo take into consideration its specific characteristics. The preliminary objective of this study was to evaluate the reliability of an agility test for water polo players. Fifteen players (16.3 ± 1.8 years old) with a minimum of two years of competitive experience were evaluated. A Functional Test for Agility Performance (FTAP) was designed to represent the context of this sport. Several trials were performed to familiarize the athlete with the movement. Two experienced coaches measured three repetitions of the FTAP. Descriptive statistics, repeated measures analysis of variance (ANOVA), 95% limit of agreement (LOA), intraclass correlation coefficient (ICC) and standard error of measurements (SEM) were used for data analysis. It was considered that certain criteria of reliability measures were met. There was no significant difference between the repetitions, which may be explained by an effect of the evaluator, the ability of the players or fatigue (p > 0.05). The ICC average from evaluators was high (0.88). The SEM varied between 0.13 s and 0.49 s. The CV average considering each individual was near 6-7%. These values depended on the condition of measurement. As the FTAP contains some characteristics that create a degree of unpredictability, the same athlete may reach different performance results, increasing variability. An adjustment in the sample, familiarization and careful selection of subjects help to improve this situation and enhance the reliability of the indicators.