Cardiovascular stress in isokinetic trunk strength test.

STUDY DESIGN

In this experimental study, the participants served as their own controls.

OBJECTIVE

To estimate cardiovascular stress in isokinetic trunk extension-flexion strength test.

SUMMARY OF BACKGROUND DATA

Thirty-one women with low back or neck pain who participated in the physical reconditioning program were the study participants.

METHODS

Trunk extension and flexion strength was measured at three angular velocities with heart rate recording and standard graded submaximal bicycle ergometer test. Power output at the maximal age-predicted heart rate level was estimated separately by trunk extension-flexion and bicycle ergometer tests.

RESULTS

Torque decreased and heart rate and power increased with angular velocity (P < 0.0001). Power and heart rate values at the highest angular velocity of 120 degrees s-1 in isokinetic trunk strength testing were comparable to those measured during bicycle ergometer test at the submaximal level. In trunk strength testing 13 subjects exceeded the power and 23 subjects exceeded the heart rate they achieved in the bicycle ergometer test. Power output at the maximal age-predicted heart rate level estimated by isokinetic trunk strength test and bicycle ergometer test had a clear correlation 0.76 (confidence interval 95% 0.55-0.88).

CONCLUSIONS

The cardiovascular capacity is an important factor-limiting performance in isokinetic trunk strength testing, particularly at high velocities. Patients with suspected heart problems need special attention. Heart rate recording may help estimate degree of effort.