Rating of Perceived Exertion and Physiological Responses in Water-Based Exercise

[Water aerobics training: selection and control of the exercise intensity using the Borg scale]

OBJECTIVE

To evaluate the opportunity of Borg scale using for applying and monitoring the aerobic training intensity in the pool as well as the relationship between the Borg scale and the heart rate (HR) in the aquatic environment.

MATERIAL AND METHODS

The study involved 11 healthy individuals (mean age 46.4±7.5 years). After a cardiopulmonary test on a treadmill and a probation lesson the training was conducted in the pool using a set of basic aerobic exercises lasting 45 minutes. During training the subjects had to maintain a load level corresponding to 12-14 points on the Borg scale. Every 10 minutes of the main training part the heart rate was calculated and the rating of perceived exertion (RPE) was determined according to the Borg scale.

RESULTS

The average heart rate in the main part of the training was 126.8±14.0 beats/min. The intensity of aerobic exercise was 82% of the maximum heart rate determined during the cardiopulmonary test and 68% of the reserve heart rate which corresponded to a high level of intensity. Between the heart rate and the Borg scale a significant correlation was found in the first period of training (r=0.67, p<0.02). At RPE 12-13 in almost ¹/₂ cases the subjects felt a subjectively lower intensity of the load than they actually performed (by heart rate) while at RPE 14 a high percentage of coincidences was observed between different measurement methods (p<0.05).

CONCLUSION

During water aerobics training the use of the Borg scale to prescribe and maintain a level of exercise allows to achieve a sufficient intensity level which is necessary to improve cardiorespiratory fitness and physical performance in order to influence risk factors for cardiovascular disease. The Borg Scale as a stand-alone method of controlling intensity when using water-based aerobic training, especially with high-intensity training should be used with caution. Further investigation is needed to determine the relation between subjective measures of exercise intensity and HR and validity of their use during water aerobics training.

Validity of differentiated ratings of perceived exertion for use during aquatic cycling

BACKGROUND

Although aquabiking has become widespread, the assessment of the intensity for aquatic cycling remains poorly defined.

METHODS

This study investigated the validity of differentiated ratings of perceived exertion (dRPE) recorded from the chest (RPE-chest) and legs (RPE-legs) during aquatic cycling and aimed to determine a simple and accurate estimate of dRPE to regulate aquabiking. Twelve active young subjects performed a pedaling task on an immersed ergocycle using randomly imposed cycling cadences ranging from 50 to 100 rpm in 3-minute steps interspersed by 3-minute active recovery periods. dRPE and cardiorespiratory responses (heart rate [HR]; percentage of heart rate peak value [%HR<inf>peak</inf>]; oxygen uptake [V̇O<inf>2</inf>]<inf>;</inf> and percentage of peak oxygen uptake [%V̇O<inf>2peak</inf>]) were measured during the last minute of each level.

RESULTS

The data described three-step relationships between dRPE and rpm. RPE-chest and RPE-legs increased linearly only for cadences between 60 and 90 rpm (r=0.81 and r=0.88, respectively; P<0.001). At these cadences, significant relationships were also observed between dRPE and all the physiological data (highest Pearson product moment for %V̇O<inf>2peak</inf>: 0.81 for RPE-chest and 0.88 for RPE-legs, P<0.0001). Last, the classic signal dominance from the legs was observed (RPE-legs>RPE-chest, P<0.0001) but was reduced compared with data obtained during dryland cycling, suggesting a modulating effect of the aquatic medium.

CONCLUSIONS

Cycling cadence was the better estimator of RPE-legs, which seemed to be the more appropriate dRPE to regulate the intensity of aquabiking in a safe range of pedaling rates.

Relationship between Oxygen Uptake, Heart Rate, and Perceived Effort in an Aquatic Incremental Test in Older Women

Different parameters can be used to control the intensity of aerobic exercises, a choice that should consider the population and exercise environment targeted. Therefore, our study aimed to verify the relationship between oxygen uptake (VO₂), heart rate (HR), rating of perceived exertion (RPE), and cadence during an aquatic incremental test in older women. Nine older women (64.3 ± 4.4 years) engaged in a water-based aerobic training performed an aquatic incremental test using the stationary running exercise (cadence increases of 15 b·min⁻¹ every 2 min) until participants’ volitional exhaustion. VO₂, HR, and RPE data were measured, and the percentage of peak VO₂ (%VO_2peak) and percentage of maximal HR (%HR_max) were calculated. Linear and polynomial regression analyses were performed (α = 0.05). Polynomial regressions revealed the best adjustments for all analyses. Data showed a significant relationship (p < 0.001) between %VO_2peak and %HR_max (r = 0.921), %VO_2peak and RPE (r = 0.870), and %HR_max and RPE (r = 0.878). Likewise, significant relationships between cadence (p < 0.001) and %VO_2peak (r = 0.873), %HR_max (r = 0.874), and RPE (r = 0.910) were also observed. In summary, the physiological, subjective, and mechanical variables investigated were highly associated during an aquatic incremental test to exhaustion in older women. Therefore, these different parameters can be employed to adequately prescribe water-based programs according to preference and availability.

Concurrent and Construct Validation of a Scale for Rating Perceived Exertion in Aquatic Cycling for Young Men

Aquatic cycling is a program of physical exercises performed with immersed stationary bikes. Few studies have provided evidence about the intensity control during its practice. Therefore, the primary aim of this study was to examine the concurrent and construct validity of a new scale for rating perceived exertion (RPE) during aquatic cycling in young men. Thirty physically active, healthy young men performed a load-incremented aquatic cycle ergometer protocol. Concurrent validity was established by correlating the Aquatic Cycling Scale (ACS) with oxygen uptake, pulmonary ventilation (VE), heart rate (HR), and blood lactate concentration (BL) responses to the maximal load-incremental test. Construct validity was established by correlating RPE derived from the Aquatic Cycling Scale (0-10) from the Borg Scale (6-20). RPE-overall, maximal oxygen uptake (VO2max), oxygen uptake indexed to body weight (VO2), VE, HR, and BL were measured during each exercise stage. The range of exercise responses across the incremental test were VO2max = 1.07-3.55 L/min, VO2 = 14.26-46.89 ml/Kg/min, VE = 23.17-138.57 L/min, HR = 99.54-173.31 beats/min, BL= 1.18-11.63 mM, ACS RPE-overall = 1.11-9.33. Correlation/regression analyses showed ACS RPE as a positive linear function of VO2max (r = 0.78; p < 0.05), VO2 (r = 0.87; p < 0.05), VE (r = 0.86; p < 0.05), HR (r = 0.77; p < 0.05), and BL (r = 0.85; p < 0.05). RPE-ACS distributed as a positive linear function of the RPE-Borg Scale (r = 0.97; p < 0.05). ANOVA indicated that an incremental pedalling cadence of 15 revolutions per minute (rpm) provoked significant differences (p < 0.05) regarding previous stages in the majority of the variables analysed. The Aquatic Cycling Scale is an appropriate tool for monitoring exertion intensity during aquatic cycling in fit men. A brief increment in aquatic pedalling cadence of 15 rpm increases the intensity of the aquatic pedalling exercise.