Maximal physiological responses to deep and shallow water running.

The maximal physiological responses to treadmill running (TMR), shallow water running (SWR) and deep water running (DWR) while wearing a buoyancy vest were compared in 15 trained male runners. Measurements included oxygen consumption (VO2 max), respiratory exchange ratio (RER) and heart rate (HR). Treadmill running elicited VO2 max and HRmax, which were higher than the peaks attained in both water tests (p < 0.01). VO2 peak averaged 83.7 and 75.3% of VO2 max for SWR and DWR respectively. Peak HR for SWR and DWR were 94.1 and 87.2% of the HRmax reached in the TMR. RER responses were similar between the three modalities. The observations suggest that the training stimulus provided by water is still adequate for supplementary training. While SWR is potentially an efficient method of maintaining cardiovascular fitness, it needs to be investigated further to establish if it is a viable technique for the injured athlete to employ

Impact of inactivity and exercise on the vasculature in humans

The effects of inactivity and exercise training on established and novel cardiovascular risk factors are relatively modest and do not account for the impact of inactivity and exercise on vascular risk. We examine evidence that inactivity and exercise have direct effects on both vasculature function and structure in humans. Physical deconditioning is associated with enhanced vasoconstrictor tone and has profound and rapid effects on arterial remodelling in both large and smaller arteries. Evidence for an effect of deconditioning on vasodilator function is less consistent. Studies of the impact of exercise training suggest that both functional and structural remodelling adaptations occur and that the magnitude and time-course of these changes depends upon training duration and intensity and the vessel beds involved. Inactivity and exercise have direct “vascular deconditioning and conditioning” effects which likely modify cardiovascular risk

Exercise and cardiovascular risk reduction: Time to update the rationale for exercise?

Although it is generally accepted that the promotion of exercise accords with clinical best practice, the anecdotal experience of many primary care physicians, cardiologists, and exercise physiologists is that, even when exercise prescriptions are adhered to, risk factors often fail to demonstrate marked improvement. Since modification of traditional risk factors fails to fully explain the magnitude of exercise-mediated risk reduction (18), we propose that there are direct effects of exercise on the vascular wall, which confer cardioprotection via a vascular conditioning effect

Exercise training-induced gender-specific heat shock protein adaptations in human skeletal muscle

This study investigates the effects of short-term endurance training on heat shock protein (HSP) adaptations of male and female human skeletal muscle. The data demonstrate that females did not respond to continuous or interval training in terms of increasing HSP content of the vastus lateralis muscle. In contrast, males displayed HSP adaptations to both training interventions. These data provide a platform for future human studies to examine a potential gender-specific stress response to exercis

Proteomic investigation of changes in human vastus lateralis muscle in response to interval-exercise training

No previous study has used proteomics to investigate the effects of exercise training on human skeletal muscle. Five recreationally active men completed a 6-wk training programme involving three sessions per week, utilising six 1-min bouts at maximum oxygen uptake (V̇ O2max) interspersed with 4 min at 50% V̇ O2max. Vastus lateralis was biopsied at standardised times before and after the training intervention. Protein expression profiling was performed using differential analysis of 2-DE gels; complemented with quantitative analysis (iTRAQ) of tryptic peptides from 1-DE gel lane-segments using LC-MALDI MS/MS. Interval training increased average V̇ O2max (7%; p<0.001) and was associated with greater expression of mitochondrial components, including succinate dehydrogenase, trifunctional protein-α and ATP synthase α- and β-chains. 2-DE resolved 256 spots, and paired t-tests identified 20 significant differences in expression (false discovery rate <10%). Each differentially expressed gene product was present as multiple isoelectric species. Therefore, the differences in spot expression represent changes in post-transcriptional or post-translational processing. In particular, modulation of muscle creatine kinase and troponin T were prominent. Pro-Q Diamond staining revealed these changes in expression were associated with phosphorylated protein species, which provides novel information regarding muscle adaptation to interval training

Is the ratio of flow-mediated dilation and shear rate a statistically sound approach to normalization in cross-sectional studies on endothelial function?

Contains fulltext : 80072thijssen.pdf (publisher's version ) (Closed access)It has been deemed important to normalize flow-mediated dilation (FMD), a marker of endothelial function, for between-subject differences in the eliciting shear rate (SR) stimulus. Conventionally, FMD is divided by the area under the curve of the SR stimulus. In the context of a cross-sectional comparison across different age cohorts, we examined whether this ratio approach adhered to established statistical assumptions necessary for reliable normalization. To quantify brachial artery FMD and area under the curve of SR, forearm cuff inflation to suprasystolic pressure was administered for 5 min to 16 boys aged 10.9 yr (SD 0.3), 48 young men aged 25.3 yr (SD 4.2), and 15 older men aged 57.5 yr (SD 4.3). Mean differences between age groups were statistically significant (P < 0.001) for nonnormalized FMD [children: 10.4% (SD 5.4), young adults: 7.5% (SD 2.9), older adults: 5.6% (SD 2.0)] but not for ratio-normalized FMD (P = 0.10). Moreover, all assumptions necessary for reliable use of ratio-normalization were violated, including regression slopes between SR and FMD that had y-intercepts greater than zero (P < 0.05), nonlinear and unstable relations between the normalized ratios and SR, skewed data distributions, and heteroscedastic variance. Logarithmic transformation of SR and FMD before ratio calculation improved adherence to these assumptions and resulted in age differences similar to the nonnormalized data (P = 0.03). In conclusion, although ratio normalization of FMD altered findings about age differences in endothelial function, this could be explained by violation of statistical assumptions. We recommend that exploration of these assumptions should be routine in future research. If the relationship between SR and FMD is generally found to be weak or nonlinear or variable between samples, then ratio normalization should not be applied