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This study assessed the energy cost in swimming (C) during short and middle distances to analyze the sex-specific responses of C during supramaximal velocity and whether body composition account to the expected differences. Twenty-six swimmers (13 men and 13 women: 16.7 ± 1.9 vs. 15.5 ± 2.8 years old and 70.8 ± 10.6 vs. 55.9 ± 7.0 kg of weight) performed maximal front crawl swimming trials in 50, 100, and 200 m. The oxygen uptake ( V ˙ O2) was analyzed along with the tests (and post-exercise) through a portable gas analyser connected to a respiratory snorkel. Blood samples were collected before and after exercise (at the 1st, 3rd, 5th, and 7th min) to determine blood lactate concentration [La-]. The lean mass of the trunk (LM Trunk ), upper limb (LM UL ), and lower limb (LM LL ) was assessed using dual X-ray energy absorptiometry. Anaerobic energy demand was calculated from the phosphagen and glycolytic components, with the first corresponding to the fast component of the V ˙ O2 bi-exponential recovery phase and the second from the 2.72 ml × kg-1 equivalent for each 1.0 mmol × L-1 [La-] variation above the baseline value. The aerobic demand was obtained from the integral value of the V ˙ O2 vs. swimming time curve. The C was estimated by the rate between total energy releasing (in Joules) and swimming velocity. The sex effect on C for each swimming trial was verified by the two-way ANOVA (Bonferroni post hoc test) and the relationships between LM Trunk , LM UL , and LM LL to C were tested by Pearson coefficient. The C was higher for men than women in 50 (1.8 ± 0.3 vs. 1.3 ± 0.3 kJ × m-1), 100 (1.4 ± 0.1 vs. 1.0 ± 0.2 kJ × m-1), and 200 m (1.0 ± 0.2 vs. 0.8 ± 0.1 kJ × m-1) with p < 0.01 for all comparisons. In addition, C differed between distances for each sex (p < 0.01). The regional LM Trunk (26.5 ± 3.6 vs. 20.1 ± 2.6 kg), LM UL (6.8 ± 1.0 vs. 4.3 ± 0.8 kg), and LM LL (20.4 ± 2.6 vs. 13.6 ± 2.5 kg) for men vs. women were significantly correlated to C in 50 (R 2 adj = 0.73), 100 (R 2 adj = 0.61), and 200 m (R 2 adj = 0.60, p < 0.01). Therefore, the increase in C with distance is higher for men than women and is determined by the lean mass in trunk and upper and lower limbs independent of the differences in body composition between sexes.

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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.

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Synchronised swimming involves a variety of sculling movements essential for body support and propulsion but its study is scarce. We aimed to biomechanically compare standard and contra-standard sculling techniques, and to observe the relationship between measures. Six synchronised swimmers performed two, 30 s maximal intensity, fully tethered standard and contra-standard sculling motions. Kinetic and kinematic data were obtained using a load-cell and underwater cameras, respectively. Force decreased along both techniques' bouts, but no differences in-between techniques were noted for any kinetic variables. Standard sculling presented a higher cycle rate and a lower elbow mean angle than the contra-standard sculling (2.4 ± 0.3 vs. 2.0 ± 0.2 cycles/s and 134.1 ± 5.8 and 141.5 ± 4.7°, p < 0.05). In the standard sculling, by removing and maintaining the variation between participants (r w and r, respectively), the absolute mean force was directly related with cycle rate (r w  = 0.60) and wrist angular velocity during flexion (r = 0.82), while in the contra-standard condition the force was inversely associated with wrist mean angle (r = -0.95) and directly with hand speed (r w  = 0.76), and elbow angular velocity (r w  ≈ 0.60). Therefore, technique learning and training require different attention by coaches and swimmers.

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Pelarigo, JG, Fernandes, RJ, Ribeiro, J, Denadai, BS, Greco, CC, and Vilas-Boas, JP. Comparison of different methods for the swimming aerobic capacity evaluation. J Strength Cond Res 32(12): 3551-3560, 2018-This study compared velocity (v) and bioenergetical factors using different methods applied for the swimming aerobic capacity evaluation. Ten elite female swimmers (17.6 ± 1.9 years, 1.70 ± 0.05 m, and 61.3 ± 5.8 kg) performed an intermittent incremental velocity protocol until voluntary exhaustion to determine the v associated with the individual anaerobic threshold (IAnT), ventilatory threshold (VT), heart rate threshold (HRT), lactate threshold fixed in 3.5 mmol·L (LT3.5), and maximal oxygen uptake (V[Combining Dot Above]O2max). Two-to-three 30-minute submaximal constant tests for the v assessment at maximal lactate steady state (MLSS). The v, gas exchange, heart rate, and blood lactate concentration variables were monitored in all tests. The values of all parameters at the v corresponding to MLSS, IAnT, VT, and HRT were similar (p ≤ 0.05), with high agreement (r > 0.400), except for carbon dioxide (V[Combining Dot Above]CO2) that was higher for MLSS compared with VT (p ≤ 0.05). However, the v at LT3.5 was higher when compared with other methods for v and bioenergetical factors. It is suggested that IAnT, VT, and HRT methods are better predictors of the intensity corresponding to the commonly accepted gold-standard method (i.e., MLSS) for the aerobic capacity evaluation compared with LT3.5.

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The aim of this study was to evaluate the determinants of front crawl sprint performance of young swimmers using a cluster analysis. 103 swimmers, aged 11- to 13-years old, performed 25-m front crawl swimming at 50-m pace, recorded by two underwater cameras. Swimmers analysis included biomechanics, energetics, coordinative, and anthropometric characteristics. The organization of subjects in meaningful clusters, originated three groups (1.52 ± 0.16, 1.47 ± 0.17 and 1.40 ± 0.15 m/s, for Clusters 1, 2 and 3, respectively) with differences in velocity between Cluster 1 and 2 compared with Cluster 3 (p = .003). Anthropometric variables were the most determinants for clusters solution. Stroke length and stroke index were also considered relevant. In addition, differences between Cluster 1 and the others were also found for critical velocity, stroke rate and intracycle velocity variation (p < .05). It can be concluded that anthropometrics, technique and energetics (swimming efficiency) are determinant domains to young swimmers sprint performance.

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INTRODUÇÃO: Tradicionalmente, os estudos da cinética do consumo de oxigênio são conduzidos a intensidades de exercício baixas, bem distintas daquelas em que o desempenho desportivo acontece. OBJETIVO: Considerando que a magnitude da cinética deste parâmetro fisiológico depende da intensidade a que o esforço é realizado, pretendeu-se com este trabalho comparar a cinética do consumo de oxigênio em 200 m crowl nadados a duas intensidades distintas: moderada e extrema. MÉTODOS: Dez nadadores do sexo masculino, de nível internacional, realizaram dois testes separados: (i) protocolo progressivo e intervalado de7 x200 m, com 30 segundos de intervalo e incrementos de 0,05 m.s-1 para determinação do patamar correspondente ao limiar anaeróbio; e (ii) 200 m à máxima velocidade. Em ambos, realizou-se uma recolha contínua de gases expirados respiração-a-respiração. RESULTADOS: Diferenças significativas foram obtidas na amplitude e constante temporal determinadas nos 200 m nadados à intensidade extrema e moderada, respectivamente: 38,53 ± 5,30 versus 26,32 ± 9,73 ml. kg-1.min-1 e 13,21 ± 5,86 versus 18,89 ± 6,53 s (p ≤ 0,05). Não foram encontradas diferenças no atraso temporal (9,47 ± 6,42 versus 12,36 ± 6,62 s (p ≤ 0,05), à intensidade extrema e moderada, respectivamente. O atraso temporal correlacionou-se negativamente com a constante temporal à intensidade moderada (r = -0,74, p ≤ 0,05). CONCLUSÕES: Ambas as intensidades estudadas foram bem descritas por aproximações mono-exponenciais, tendo-se verificado diferenças significativas entre as mesmas no que concerne à amplitude e constante temporal.

INTRODUCTION: Traditionally, studies regarding oxygen consumption kinetics are conducted at lower intensities, very different from those in which the sports performance occurs. OBJECTIVE: Knowing that the magnitude of this physiological parameter depends on the intensity in which the effort occurs, it was intended with this study compare the oxygen consumption kinetics in the 200 m front crawl at two different intensities: moderate and extreme. METHODS: Ten international male level swimmers two separate tests by 24h: (i) progressive and intermittent protocol of 7 x 200 m, with 30 seconds intervals and with increments of 0.05m.s-1, to determine the anaerobic threshold correspondent step; and, (ii) 200 m at maximal velocity: in both expiratory gases were continuously collected breath-by-breath. RESULTS: Significant differences were obtained between amplitude and time constant determine in the 200 m at extreme and moderate intensities, respectively (38,53 ± 5,30 ml. kg-1.min-1 versus 26,32 ± 9,73 ml. kg-1.min-1 e 13,21 ± 5,86 s versus 18,89 ± 6,53 s (p ≤ 0,05). No differences were found in time delay (9,47 ± 6,42 s versus 12,36 ± 6,62 s, at extreme and moderate intensity, respectively (p ≤ 0.05). A negative correlation between time delay and time constant at the moderate intensity was reported (r = - 0,74, p ≤ 0,05). CONCLUSIONS: Both intensities were well described by double-exponential fittings, and there were significant differences between them in terms of amplitude and time constant.