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Cardiovascular and perceptual responses to isometric exercise
Archives of Physical Medicine and Rehabilitation
|May 1, 1982
Summary
Perception of effort during isometric handgrip exercise increases with intensity and time. This perception is a strong predictor of cardiovascular responses, suggesting its clinical utility for exercise prescription.
Area of Science:
- Exercise Physiology
- Cardiovascular Physiology
- Human Performance
Background:
- Isometric handgrip contractions are commonly used in exercise testing.
- Understanding the relationship between perceived exertion and physiological responses is crucial for safe exercise programming.
- Maximal voluntary contraction (MVC) is a standard measure of muscle strength.
Purpose of the Study:
- To examine the impact of varying isometric handgrip contraction intensities on cardiovascular parameters and perceived exertion.
- To establish the correlation between cardiovascular responses and the perception of effort.
- To explore the clinical applicability of perceived exertion in exercise prescription.
Main Methods:
- Seven healthy participants performed isometric handgrip contractions at 15%, 25%, and 35% of their MVC.
- Cardiovascular parameters (heart rate, systolic blood pressure, diastolic blood pressure) and perception of effort were recorded at 1-minute intervals during 3-minute contractions.
- Data were analyzed using correlation coefficients and multiple regression analysis.
Main Results:
- All measured cardiovascular parameters and perception of effort significantly increased with higher contraction intensities and longer durations (p < 0.05).
- Perception of effort showed strong correlations with systolic blood pressure (r=0.76), diastolic blood pressure (r=0.64), and heart rate (r=0.63).
- A multiple regression model combining these factors yielded a cumulative r-value of 0.82, indicating a robust predictive relationship.
Conclusions:
- Perception of effort is a reliable indicator of cardiovascular stress during isometric handgrip contractions.
- This subjective measure can be a valuable tool for clinical exercise prescription, guiding patients to exercise within safe cardiovascular limits.
- Utilizing perceived exertion may allow individuals to engage in appropriate levels of isometric activity rather than complete avoidance.