José A. Bragada

Physiological adaptations to head-out aquatic exercises with different levels of body immersion.

The purpose of this study was to compare the physiological adaptations to basic head-out aquatic exercises with different levels of body immersion. Sixteen young and clinically healthy subjects (9 women and 7 men) volunteered to participate in this study. Each subject performed 3 repetitions (on land, immersed to the hip, and immersed to the breast) of the aquatic exercise “rocking horse” for 6 minutes. The rating of perceived effort (RPE), the maximal heart rate achieved during the exer- citation (HRmax), the percentage of the maximal theoretical heart rate estimated (%HRmax), the peak of oxygen uptake during the exercise (&OV0622;O2peak), and the energy expenditure (EE) were evaluated. The RPE was significantly higher when exercising immersed to the hip than on land (p < 0.01) and immersed to the breast (p = 0.03). The HRmax and %HRmax were significantly lower when exercising with immersion to the breast than on land (p < 0.01) and with immersion to the hip (p < 0.01). The &OV0622;O2peak was significantly different between all conditions. The lower mean value was verified when exercising immersed to the breast, followed by immersion to the hip and on land. The EE was significantly higher when performing aquatic exercises on land than when immersed to the hip (p = 0.02) and the breast (p = 0.01). So, physiological responses when exercising immersed to the hip are higher than when immersed to the breast. The physiological responses when exercising on land are higher than when exercising with immersion to the hip and to the breast.xs

Effects of musical cadence in the acute physiologic adaptations to head-out aquatic exercises.

Barbosa, TM, Sousa, VF, Silva, AJ, Reis, VM, Marinho, DA, and Bragada, JA. Effects of musical cadence in the acute physiologic adaptations to head-out aquatic exercises. J Strength Cond Res 24(1): 244-250, 2010-The purpose of this study was to analyze the relationships between musical cadence and the physiologic adaptations to basic head-out aquatic exercises. Fifteen young and clinically healthy women performed, immersed to the breast, a cardiovascular aquatic exercise called the “rocking horse.” The study design included an intermittent and progressive protocol starting at a 90 b·min−1 rhythm and increasing every 6 minutes, by 15 b·min−1, up to 195 b·min−1 or exhaustion. The rating of perceived effort (RPE) at the maximal heart rate achieved during each bout (HRmax), the percentage of the maximal theoretical heart rate estimated (%HRmax), and the blood lactate concentration ([La-]) were evaluated. The musical cadence was also calculated at 4 mmol·L−1 of blood lactate (R4), the RPE at R4 (RPE@R4), the HR at R4 (HR@R4), and the %HRmax at R4 (%HRmax@R4). Strong relationships were verified between the musical cadence and the RPE (R2 = 0.85; p < 0.01), the HRmax (R2 = 0.66; p < 0.01), the %HRmax (R2 = 0.61; p < 0.01), and the [La-] (R2 = 0.54; p < 0.01). The R4 was 148.13 ± 17.53 b·min−1, the RPE@R4 was 14.53 ± 2.53, the HR@R4 was 169.33 ± 12.06 b·min−1, and the %HRmax@R4 was 85.53 ± 5.72%. The main conclusion is that increasing musical cadence created an increase in the physiologic response. Therefore, instructors must choose musical cadences according to the goals of the session they are conducting to achieve the desired intensity.

Stability of elite freestyle performance from childhood to adulthood

Abstract Stability of athletic performance is important for practitioners and coaches, since it allows the selection of appropriate training methods and prediction of ages for best results. We performed a longitudinal study of 1694 season-best performances of 242 elite-standard swimmers throughout their careers, from 12 to 18 years of age. Mean stability (descriptive statistics and one-way repeated-measures ANOVA, followed by a Bonferroni post-hoc test) and normative stability (Cohens kappa tracking index and the Pearson correlation coefficient) were determined for seven consecutive seasons. Performance improvements in all events were observed (14.36–18.97%). Bonferroni post-hoc tests verified changes in almost all events assessed. Cohens kappa demonstrated low stability (0.17–0.27) in relative performance. Pearson correlations only became high from 15 to 16 years in the 50-m and 100-m events, and from 16 to 17 years in the 200-m, 400-m, and 1500-m events. Our results show that: (a) swimmers should display a substantial improvement (14–19%) to become elite standard as adults, such as at 18 years; (b) 16 is the age at which the ability to predict adult performance increases markedly.

Effects of swim training on energetics and performance

The aim of this study was to determine the effect of several months of training on performance and energetic profile of elite swimmers. 9 elite swimmers were evaluated at 3 different time periods during the 2010-2011 calendar. Swimming performance was assessed based on lists of times for the 200 m freestyle event. An incremental set of 7×200 m swims was applied to obtain the energetic data. Measurements and/or estimations were made for the: velocity at 4 mmol l(-1) of lactate concentrations, highest value of lactate concentrations, maximal oxygen consumption, minimum swimming velocity where the maximal oxygen consumption is reached and total energy expenditure (Etot). The performance and most of the energetic variables assessed presented no significant variations during the study period. The only exception was the Etot with significant differences between all measurements. Correlation coefficients suggested a high stability for all variables. Cohens Kappa tracking index demonstrated high variability in the individual adaptations to training. It is concluded that elite swimmers demonstrate a slight improvement in performance and energetic profile in response to several months of training. Each subject has an individual way of adapting to the training load, combining the different energetic confounders to enhance performance.

Longitudinal Assessment of Swimming Performance in the 200-m Freestyle Event

The aim of this study was to track and analyze the 200-m Freestyle performance stability throughout elite swimmers career. 29 Portuguese male top-50 were analyzed for seven consecutive seasons between 12 and 18 years old. Best performances were collected from ranking tables. Longitudinal assessment was performed based on two approaches: (i) mean stability was analyzed by descriptive statistics and ANOVA repeated measures for each season followed by a post-hoc test (Bonferroni test), (ii) normative stability was analyzed with self-correlation (Malina, 2001) and the Cohens Kappa tracking index (Landis and Koch, 1977). There was a 200-m Freestyle performance enhancement from children to adult age. The overall career performance prediction was moderate. The change from 13 to 14 years can be a milestone, where the ability to predict the final swimmers performance level strongly increases.

The Aging Influence on Cardiorespiratory, Metabolic and Energy Expenditure Adaptations in Head-Out Aquatic Exercises: Differences between Young and Elderly Women.

ABSTRACT The purpose of this study was to: (1) establish the relationship between acute physiological responses and musical cadence; and (2) compare physiologic responses between young and older women. Eighteen older (mean = 65.06 ± 5.77 years) and 19 young (mean = 22.16 ± 2.63 years) women underwent an intermittent and progressive protocol performing the head-out aquatic exercise the “rocking horse.” Results showed that older women demonstrated lower mean heart rate, blood lactate concentration (bLa), and oxygen uptake (VO2) at rest. Hierarchical linear modeling showed that variations in the rating of perceived effort and individual metabolic equivalent of task did not differ significantly by age group. However, during exercise, physiological responses of younger women were significantly different than for older women: in mean values, for each increased musical beat per minute, mean bLa was 0.003 mmol/l, VO2 was 0.024 ml/kg/min, and energy expenditure was 0.0001 kcal/kg/min higher for younger women. This study shows that increases in musical cadence increased the cardiorespiratory, metabolic, and energy expenditure responses. However, these responses during increasing intensity seemed to differ between young and older women, with lower values for the elderly group, when performing head-out aquatic exercises.