Stress Effects of Isometric Contraction in Occupational Therapy

Medical literature reports that isometric muscle contraction can cause potentially dangerous increases in blood pressure and pulse rate. This research shows the effects on blood pressure and pulse of four isometric activities performed by 40 subjects, 19 to 30 years old, with normal resting blood pressure and pulse. A repeated measures ANOVA of three isometric activities (pinching gripping and pushing) for 3, 6, 10 and 3P seconds led to conclusions that there was a significant increase in blood pressure and pulse as time of contraction increased, and that the pushing activity had a significantly greater effect on blood pressure and pulse than did pinching or gripping. A t-test resulted in a significant difference between measures of blood pressure and pulse taken before and during a manual muscle test. Because occupational therapists in all specialty areas have clients potentially at risk from effects of isometric muscle contractions, better guidelines for activities with isometric components should be developed.