Safety And Efficacy Of Supervised Moderate Intensity Resistance Training Adopted During Pregnancy: 621

Purpose. Explore the safety and efficacy of a supervised moderate intensity resistance training program adopted during pregnancy. Methods. 32 pregnant women (~23 weeks gestation) both at low risk for pregnancyrelated complications and at increased risk for low back pain adopted resistance training (2 x week for 12 weeks) that involved lumbar extension, transverse abdominis, leg curl, leg extension, leg press, and lat pull exercises. Exercises were performed at a low-to-moderate perceived intensity (mean RPE = 10.5 to 12.9). As perceived intensity decreased across workouts the external load was increased to maintain a low-to-moderate perceived intensity. Data on injuries, symptoms, blood pressure and the absolute external load used for five of the six exercises were obtained daily. A three minute lumbar extension endurance exercise test was performed at weeks 5, 10 and 13. Results. The mean (± SD) attendance rate was 80.5 (± 11.3%). No musculoskeletal injuries occurred during the resistance training program. Potentially problematic symptoms (e.g., dizziness) were mild and infrequent (1.7% of exercise sessions). Two additional sets of transverse abdominis exercise were being performed at week 12 vs. week 1. For those exercises that used an external load, repeated measures ANOVA showed large increases in the external load used across 12 weeks (eta squared range = .431 to .691; all p values < .001). The percentage increases from weeks 1 to 12 were 35.8% for leg press, 38.7% for leg curl, 39.0% for lat pull, 40.5% for lumbar extension and 56.4% for leg extension. Training was associated with a 13.6% increase in lumbar endurance (P=.001) and a decrease in perceived effort during the endurance test (0.93 raw units; P