Comparison of Exercise Indexes between Knee Extension-Flexion Exercise and Treadmill Exercise

OBJECTIVE: To obtain clinical usefulness of knee extension- flexion exercise by comparing the exercise indexes between treadmill exercise and knee extension-flexion exercise and to collect reference of exercise indexes using knee extension-flexion exercise. METHOD: Sixty four young healthy subjects participated in two modes of exercise. Subjects performed exercise using isokinetic dynamometer in one leg knee extension-flexion exercise and treadmill running using Bruce protocol in treadmill exercise. We recorded oxygen consumption, heart rate during rest and exercise. RESULTS: When comparing exercise indexes using treadmill exercise, we obtained relative exercise indexes using knee extension-flexion exercise, male 15.96%, female 15.77% in work rate, male 48.46%, female 52.53% in peak oxygen consumption, male 73.57%, female 80.82% in peak heart rate, male 65.97%, female 65.20% in oxygen pulse, male 56.07%, female 62.50% in peak tidal volume, male 82.56%, female 82.53% in peak respiratory rate, male 47.79%, female 49.48% in peak minute ventilation. In dynamic variables, we obtained male 266.82%, female 292.98% in ratio increase in oxygen consumption to increase in work rate. CONCLUSION: Knee extension-flexion exercise showed enough response to evaluate cardiorespiratory function through low work rate. Therefore knee extension-flexion exercise may be used for an exercise tolerance test in patients who cannot perform established exercise tolerance test.

Evaluation of Exercise Efficiency with Change in Oxygen Uptake and Work Rate in Stroke Patients

OBJECTIVE: To evaluate exercise capacity of subacute stroke patients with nonambulatory exercise stress test and to determine whether reduced exercise efficiency is associated with functional performance. METHOD: Experimental design was prospective and observational study. Eighteen patients with moderate to severe impairment after recent stroke performed exercise stress test by repeated knee flexion and extension exercise using isokinetic dynamometer. Work rate, oxygen consumption, heart rate were assessed during exercise stress test. The dynamic response, the ratio of change in oxygen uptake to change in work rate, was measured for correlation with FIM (Functional Independence Measure) scores. Occupational therapist recorded FIM scores on the day of transfer to inpatient rehabilitation unit and on discharge. Age-matched healthy group also performed exercise stress test in same settings. RESULTS: The patients group who had similar dynamic response with age-matched healthy group showed higher FIM scores than the patients group having higher dynamic response. CONCLUSION: Nonambulatory exercise stress test could be effectively used in subacute stroke patients and the ratio of change in oxygen uptake to change in work rate was a useful variable to reveal low exercise efficiency in subacute stroke patients who had a abnormal skeletal muscle metabolic capacity.

Effects of Agonistic and Antagonistic Isometric Contraction on Motor Evoked Potentials in the Forearm

OBJECTIVE: To evaluate the effect of agonistic and antagonistic isometric contraction on the motor evoked potentials (MEP). METHOD: The MEP responses of right flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles were simultaneously recorded during constant isometric flexion and extension of wrist. The intensities of isometric flexion and extension were 30%, 50%, and 100% of maximal voluntary contraction, which were achieved by isokinetic dynamometer. Background electromyographic activities in surface and needle electrodes were used for selective contraction. RESULTS: In agonistic muscles, the amplitudes of MEP responses were significantly increased according to the intensity of isometric contraction. In antagonistic muscles, the amplitudes of MEP responses in ECR were significantly increased with increasing intensity of isometric flexion. The amplitudes of MEP responses in FCR were increased with increasing intensity of isometric extension in spite of suppression in H-reflex of FCR during isometric extension. CONCLUSION: In antagonistic muscles, facilitation of MEP response in ECR and FCR during isometric contraction was occurred as in the agonistic isometric contraction.