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Summary: Background: Water immersion and aquatic exercise can be an important therapeutic tool in patients suffering from heart disease (HD). However, the effects of water immersion on heart rate variability (HRV) in HD participants remain unknown. Methods: Twenty‐eight volunteers in sinus rhythm within the same age range took part in this study: 18 HD and ten healthy controls (HC). Heart rhythm was collected with a heart rate monitor (sampling rate 1000 Hz) for periods of 10 min at rest in the supine position on land, standing on land (STL) and standing in water (STW) to the xiphoid process. Results: Heart disease participants had the same response as HC participants to the three experimental conditions (no significant between‐group differences in all HRV variables). STW (immersion) caused in both groups to increase HRV when compared to supine and STL. Conclusion: Heart disease participants demonstrate similar beneficial adaptations as HC participants to the effects of immersion, reinforcing the concept that immersion can be a valuable aquatic cardiac rehabilitation tool to acutely increase HRV. Approaches that improve HRV in both healthy and cardiac patients may have a positive impact on the reduction of morbidity and mortality. [ABSTRACT FROM AUTHOR]

Physical activity is often avoided or practised at a low-intensity level because of the limited ability of patients with heart disease ( HD) to provide sustained effort. Immersible training has been suggested as a possible alternative as hydrostatic pressure can modify some hemodynamic parameters in healthy patients and potentially increase the exercise capacity in patients with HD. The purpose of this study was to examine the acute cardiorespiratory adaptations at different levels of immersion using an immersible ergometer ( IE) in patients with HD. Twenty-one patients and 13 healthy controls ( HC) participated in this study. Several cardiorespiratory parameters were assessed at two levels of immersion (hips and xiphoid) for five different pedalling rates (40, 50, 60, 70 and peak rpm). At submaximal intensity, HD and HC participants did not differ significantly for most variables. However, for nearly and/or maximal workload, HD participants showed significantly lower values for VO2 and higher values for VE/VO2 and VE/VCO2 for both immersion levels. The increase in immersion level from hips to xiphoid resulted in a significant decrease in VO2 in both HC and HD groups at the same exercise intensity. In addition, the increase in the effects of size values based on the exercise workload indicates that group differences are accentuated with the highest pedalling rates. Our data suggest that participants with HD may benefit from the hydrostatic effect during IE cycling by allowing them to alleviate their submaximal efforts and increasing their maximal cardiorespiratory capacity during hip immersion. [ABSTRACT FROM AUTHOR]

The external power output (Pext) is unknown during chest-level immersion exercise on water immersible ergocycles (IE). This knowledge will allow the practitioner to prescribe accurately exercise on an IE to the same workload on dryland ergocycle (DE). To develop a mathematical model to calculate Pext during chest-level immersion exercise on IE at different pedalling rates (rpm) taking into account the water external force exerted on the legs and pedalling mechanism. Thirty healthy participants (age: 33 ± 10 years) performed a maximal incremental exercise test on IE (chest-level immersion) and on a DE. Pedalling rate was increased by 10 rpm every minute beginning at 40 till 120 rpm. Pext was calculated by applying the general fluid equation on all elements exposed to water external force exertions (legs and pedalling system). Regression analysis yielded the following equations to determine (1) IE Pext (W) based on pedalling rate (rpm): Pext (W) = 0.0004 (rpm)2.993 (r2 = 0.99, SEE = 7.6 W, p < 0.0001) and (2) when DE Pext (W) is known, IE pedalling rate (rpm) = 13.91 × DE Pext (W)0.329 (r2 = 0.99, SEE = 1.5 W, p < 0.0001). This study provides a mathematical model based on the general fluid equation to calculate IE Pext during chest-level immersion exercise using pedalling rate (rpm), IE pedalling system physical characteristics and lower limb size. This model can be used to determine Pext for any IE type for exercise training prescription. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare three methods to assess vertical jump height, to determine their limitations and to propose solutions to mitigate their effects. The chosen methods were the contact mat, the optical system and the Sargent jump. The testing environment was designed such that all three systems simultaneously measured the vertical jump height. A total of 41 kinesiology students (18 women, 23 men, mean age 23·2 ± 4·5 years) participated in this study. Data show that the contact mat and the optical system essentially provide similar results ( P = 0·912) and that the correlation coefficient between the two systems was 0·972 ( r2 = 0·944). However, it was found that the Sargent jump has a tendency to overestimate the height, providing a measurement that is significantly different from the other two methods as the jumps are higher than 30·64 cm ( P = 0·044). Through the design of the experiment, several sources of errors were identified and mathematically modelled. These sources include optical sensor placement, flat-footed landing and hip/knee bend. Whenever possible, the errors were quantified and solutions were proposed. [ABSTRACT FROM AUTHOR]