Test-retest reliability of a 30-min fixed perceived effort cycling exercise

PURPOSE

Using exercise protocols at a fixed rating of perceived effort (RPE) is a useful method for exploring the psychophysical influences on exercise performance. However, studies that have employed this protocol have arbitrarily selected RPE values without considering how these values correspond to exercise intensity thresholds and domains. Therefore, aligning RPE intensities with established physiological thresholds seems more appropriate, although the reliability of this method has not been assessed.

METHODS

Eight recreationally active cyclists completed two identical ramped incremental trials on a cycle ergometer to identify gas exchange threshold (GET). A linear regression model plotted RPE responses during this test alongside gas parameters to establish an RPE corresponding to GET (RPE_GET) and 15% above GET (RPE_+15%GET). Participants then completed three trials at each intensity, in which performance, physiological, and psychological measures were averaged into 5-min time zone (TZ) intervals and 30-min 'overall' averages. Data were assessed for reliability using intraclass correlation coefficients (ICC) and accompanying standard error measurements (SEM), 95% confidence intervals, and coefficient of variations (CoV).

RESULTS

All performance and gas parameters showed excellent levels of test-retest reliability (ICCs =  > .900) across both intensities. Performance, gas-related measures, and heart rate averaged over the entire 30-min exercise demonstrated good intra-individual reliability (CoV =  < 5%).

CONCLUSION

Recreationally active cyclists can reliably replicate fixed perceived effort exercise across multiple visits when RPE is aligned to physiological thresholds. Some evidence suggests that exercise at RPE_+15%GET is more reliable than RPE_GET.

Applying ubiquitous sensing to estimate perceived exertion based on cardiorespiratory features

Reliable monitoring of one’s response to exercise intensity is imperative to effectively plan and manage training, but not always practical in impact sports settings. This study aimed to evaluate if an inexpensive mobile cardio-respiratory monitoring system can achieve similar performance to a metabolic cart in estimating rated perceived exertion. Eight adult men volunteered to perform treadmill tests under different conditions. Cardiorespiratory data were collected using a metabolic cart and an instrumented oral-cavity device, as well as their ratings of perceived exertion. Pearson correlation corrected for repeated measurements and stepwise regression analysis were used to observe the relationship between the cardiorespiratory features and the ratings of perceived exertion and determine the proportion of the variance of exertion that could be explained by the measurements. Minute ventilation was found to be the most associated variable to perceived exertion, closely followed by a novel metric called the audio minute volume, which can be collected by the oral-cavity device. A generalised linear model combining minute ventilation, audio minute volume, heart rate and respiration rate accounted for 64% of the variance in perceived exertion, whilst a model with only audio minute volume accounted for 56%. Our study indicates that minute ventilation is key to estimating perceived exertion during indoor running exercises. Audio minute volume was also observed to perform comparably to a lab-based metabolic cart in estimating perceived exertion. This research indicates that mobile techniques offer the potential for real-world data collection of an athlete’s physiological load and estimation of perceived exertion.

Twelve-week intradialytic cycling exercise improves physical functional performance with gain in muscle strength and endurance: a randomized controlled trial

Objective:

To evaluate the effect of intradialytic cycling exercise on physical functional performance with gain in muscle strength and endurance in end-stage renal disease patients with haemodialysis.

Design:

Randomized controlled trial, with repeated measurements at baseline and after 4, 8, and 12 weeks of intradialytic cycling exercise.

Setting:

A 50-bed haemodialysis centre in a regional hospital in Taiwan.

Subjects:

Seventy-six regular haemodialysis patients, recruited and equally and randomly assigned to exercise and control groups.

Intervention:

The intradialytic cycling exercise was performed for 12 weeks and comprised warm-up, main, and cool-down exercise phases. A stationary cycling equipment was used, which involved aerobic and resistance modalities. The intensity was maintained at somewhat hard exertion. Each intradialytic cycling exercise was implemented for 30 minutes, starting at the second hour of treatment.

Main measure:

Measured outcomes were 6-minute walk distance, time taken to complete 10 sit-to-stand-to-sit cycles and number of sit-to-stand-to-sit cycles in 60 seconds.

Results:

Average (standard deviation) participant age was 55.47 (13.00) years. Therefore, the 6-minute walk distance was significantly different at weeks 8 ( P = 0.01) and 12 ( P < 0.001) in the exercise group compared with that in the control group at baseline. Notably, sit-to-stand-to-sit outcomes ( P = 0.01) significantly influenced the 6-minute walk distance. Sit-to-stand-to-sit outcomes significantly improved in the exercise group ( P < 0.05).

Conclusion:

Twelve-week intradialytic exercise for patients on haemodialysis can improve physical functional performance with gain muscle strength and endurance. This is a safe and effective method for improving health.