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Cardiorespiratory responses to fatiguing dynamic and isometric hand-grip exercise
V Louhevaara1, J Smolander, T Aminoff
1Finnish Institute of Occupational Health, Helsinki. veikko.louhevaara@occuphealth.fi
European Journal of Applied Physiology
|August 25, 2000
Summary
Occupational hand-grip exercises, both dynamic and isometric, showed similar peak cardiorespiratory responses but differed in breathing patterns. Endurance times were short for both, highlighting the need for ergonomic design in repetitive tasks.
Area of Science:
- Exercise Physiology
- Occupational Health
- Cardiorespiratory Responses
Background:
- Occupational work involving continuous repetitive and isometric upper extremity actions can lead to local muscle strain and musculoskeletal disorders.
- These actions may also adversely affect the cardiorespiratory system, notably by increasing blood pressure.
Purpose of the Study:
- To compare peak cardiorespiratory responses between fatiguing dynamic hand-grip exercise (DHGE) and isometric hand-grip exercise (IHGE).
- To assess differences in endurance time, ventilatory gas exchange, heart rate (HR), and blood pressure between DHGE and IHGE.
Main Methods:
- Twenty-one untrained healthy men (aged 24-45 years) participated in the study.
- DHGE was performed with the left hand at 57% of maximal voluntary contraction (MVC) at 51 grips/min.
- IHGE was performed with the right hand at 46% of MVC. Endurance time, ventilatory gas exchange, HR, and blood pressure were measured.
Main Results:
- Mean endurance times were significantly different: 170s for DHGE vs. 99s for IHGE (P < 0.001).
- Peak breathing frequency and tidal volume differed significantly between DHGE and IHGE (P < 0.01).
- Peak oxygen consumption, pulmonary ventilation, HR, and systolic blood pressure were similar for both exercise types.
Conclusions:
- Peak cardiorespiratory responses (gas exchange, HR, blood pressure) are comparable during fatiguing DHGE and IHGE.
- Breathing patterns significantly differ between dynamic and isometric hand-grip exercises.
- Findings underscore the importance of ergonomic principles in occupational settings to minimize force output, especially in tasks involving isometric or repetitive one-sided muscle actions.