Laboratory-based ergometry for swimmers: a narrative review

INTRODUCTION: First widely available dry-land training machines for swimmers were introduced about 40 years ago. They were designed so that swimmers could perform resistance exercise whilst more-closely replicating the movements of swimming, than when using other gymnasium-based resistance training machines. This narrative review categorises and summarises what has been shown by the studies that have utilised laboratory-based ergometry for swimmers. EVIDENCE ACQUISITION: A systematic search was conducted in PubMed, Web of Science, ScienceDirect and Scopus (1970-2018) and relevant publications were included. Publications were grouped into 4 main areas of research: (i) physiological responses to exercise, (ii) functional evaluation of swimmers, (iii) monitoring of training, and (iv) muscular work output of swimmers. EVIDENCE SYNTHESIS: Significant differences were showed between swim bench exercise and real swimming, especially in regard to the muscles involved. The difficulties of accurate reproduction of the movements and coordinated dynamic actions of swimming have not been overcome. Nevertheless, the literature shows that the use of these devices has provided a valuablecontribution to swimming physiology, while overcoming difficulties presented by attempting to make physiological measurements in the water. CONCLUSIONS: In spite of its limitations, laboratory-based ergometry has allowed a valuable contribution to the understanding of the physiology, effects of training and efficiency of swimming

Isolated core training improves sprint performance in national-level junior swimmers

Purpose: The aim of our study was to quantify the effects of a 12-week isolated core training programme on 50-m front crawl swim time and measures of core musculature functionally relevant to swimming. Methods: Twenty national-level junior swimmers (ten male and ten female, 16 ± 1 y, 171 ± 5 cm, 63 ± 4 kg) participated in the study. Group allocation (intervention [n=10], control [n=10]) was based on two pre-existing swim training groups who were part of the same swimming club but trained in different groups. The intervention group completed the core training, incorporating exercises targeting the lumbo-pelvic complex and upper region extending to the scapula, three times per week for 12 weeks. While the training was performed in addition to the normal pool-based swimming programme, the control group maintained their usual pool-based swimming programme. We made probabilistic magnitude-based inferences about the effect of the core training on 50-m swim time and functionally relevant measures of core function. Results: Compared to the control group, the core training intervention group had a possibly large beneficial effect on 50-m swim time (-2.0%; 90% confidence interval -3.8 to -0.2%). Moreover it showed smallmoderate improvements on a timed prone-bridge test (9.8%; 3.9 to 16.0%) and asymmetric straight-arm pull-down test (21.9%; 12.5 to 32.1%), there were moderate-large increases in peak EMG activity of core musculature during isolated tests of maximal voluntary contraction. Conclusion: This is the first study to demonstrate a clear beneficial effect of isolated core training on 50-m front crawl swim performance

Serum Levels of Choline-Containing Compounds Are Associated with Aerobic Fitness Level: The HUNT-Study

Background: Cardiovascular disease (CVD) is a leading cause of death worldwide, and the number of people at risk is continuously growing. New methods for early risk prediction are therefore needed to actuate prevention strategies before the individuals are diagnosed with CVD. Several studies report that aerobic fitness level, measured as maximal oxygen uptake (VO2max), is the single best predictor of future CVD mortality in healthy people. Based on this, we wanted to study differences between healthy individuals with a large difference in VO2max-level to identify new biomarkers of low aerobic fitness that may also have potential as early biomarkers of CVD risk. Methodology/Principal Findings: Serum samples from 218 healthy individuals with a low VO2max (n = 108, 63 women) or high VO2max (n = 110, 64 women) were analysed with MR metabolomics. In addition, standard clinical-chemical analyses for glucose, lipids, liver enzymes, micro-CRP, and colorimetric analysis on circulating choline were performed. Individuals in the low VO2max-group had increased serum levels of free choline, decreased phosphatidylcholine, increased glucosę and decreased unsaturated fatty acids compared to the individuals in the high VO2max–group. Conclusions/Significance: Aerobic fitness dependent differences in serum levels of free choline and phosphatidylcholine are observed. They should be further studied as potential early markers of CVD risk

Representative ¹H NOESYGPPR 1D spectra with assignments of the main metabolites.

<p>The spectra in red (and black) consist of 5 spectra (superimposing) from two of the subjects. The reproducibility was evaluated by PCA and the score plot shows the spectra from all 6 subjects, clearly depicting larger inter subject variance compared to intra subject variance. NACl and NAC2 refer to composite acetyl signals from <b>α</b>1-acid glycoprotein. PCA: Principal Component Analysis.</p

Visualization of the metabolic differences in MR spectra.

<p>The green spectrum is from a high VO_2max subject (green dots in PCA score plot) and the red spectrum is from the low VO_2max (red dots in PCA score plot). VO_2max: Maximal oxygen uptake.</p

A statistical overview of the participants in this study.

<p>VO_2max: Maximal oxygen uptake, CI: Confidence Interval, BMI: Body Mass Index, HDL: High Density Lipoprotein. P-values below 0.05 are flagged. **p<0.005, *p<0.05.</p

Principal Component Analysis (PCA) of the serum 1H MR spectra.

<p>(A) In the score plot, high VO_2max subjects are shown in green (higher density in upper left part) and low VO_2max subjects are shown in red. (B) The loadings plot visualizes the differences in metabolites between the two groups. The signals originating from within the core of the serum lipoprotein particles (-CH₃ at 0.86 ppm, -CH₂- at 1.3 ppm) and choline-containing compounds (-N (CH₃)₃⁺, at 3.24 ppm) are mainly responsible for the clustering. VO_2max: Maximal oxygen uptake.</p