No abstract

Concern over the development of tolerance in patients on continuous intrathecal baclofen therapy has arisen as this new form of treatment for spasticity has gained wider use. We have studied time-dose relationships in 18 spinal cord injured patients who have undergone intrathecal baclofen infusion pump implantation since February 1988 in our facility. Our data show that there was a significant increase in baclofen dosage needed to control spasticity during the first 12 months post implantation. After 12 months, however, no significant changes in dosage requirement was detected. In addition, there was no significant difference between completely and incompletely spinal cord injured patients with regard to both the initial dose and the tolerance trend.

When using Borg's 6-20 scale during pregnancy, ratings of perceived exertion (RPE) did not significantly correlate with exercise heart rates (HR) (P > 0.05). The The aim of this study was to assess the accuracy of ratings of perceived exertion (RPE) in pregnant women using Borg's 6-20 point scale as a predictor of the exercise heart rate (HR) in response to several commonly undertaken weight-bearing and nonweight-bearing activities, namely cycling, walking, aerobics and circuit training.Borg' developed this 6-20 scale after observing a linear correlation between RPE and HR during cycling in non-pregnant subjects (Table 1) has been questioned6 because the exercise responses of several of the physiological variables that influence RPE are altered during pregnancy6-8. Two previous studies in pregnant women observed that RPE were unchanged with moderate intensity cycling9 but higher with step-testing at the same target HR10. In view of these conflicting opinions and findings, the applicability of RPE during pregnancy requires further evaluation. Materials and methodsHealthy women with uncomplicated singleton pregnancies were tested. Women were dassified as 'trained' if they had exercised for 6 weeks or more before the test, at least three times per week for 30 min or more at an intensity that was high enough to cause perspiration and shortness of breath. 'Sedentary' subjects never participated in exercise sessions and subjects classified as 'neither' exercised once or twice per week or had started or stopped training in the 6 weeks preceding their test. The protocol was approved by the Institutional Ethical Review Committee and all subjects gave informed consent. Questionnaires were filled out during the 30-min rest period before the test.Women in Group 1 exercised on a treadmill at 23-28 weeks and 34-37 weeks gestation and again at 8 weeks or more after delivery. The subjects walked continuously for a total of 26 min -comprising 10 min Br J Sp Med 1992; 26(2) 121

(P < 0-001). Fetal heart rate, measured in the recovery period immediately after exercise, increased significantly only after tests B and C (P < 0.01). Exercise related changes in temperature and fetal heart rate weakly correlated in tests B (P < 0-02) and C (P < 0 01). Conclusions-Temperature and fetal heart rate changes were more marked after higher intensity (test B) or longer duration exercise (test C) compared with moderate exercise, but none of the tests caused adverse fetal heart rate changes (decrease in accelerations, bradycardia, or decelerations) or individual temperatures above 380C. (BrJ Sports Med 1996;30:32-35)

Fourteen women performed treadmill exercise for continuous 10-minute periods at levels of 2, 3 and 4 mets in the second and third trimester of pregnancy and again postpartum. The percentage increase in heart rate in response to exercise was similar during pregnancy and postpartum while systolic blood pressure was increased only during pregnancy. Maternal plasma noradrenaline levels at peak exercise increased 64% (p less than 0.005), 42% (p less than 0.005) and 29% (NS) in the 3 studies respectively compared to resting levels at these times. Ten women experienced increased uterine activity during the exercise or recovery periods. Fetal heart rate was increased (p less than 0.05) by exercise but this was independent of uterine contractions and plasma noradrenaline levels.