The purpose of this study was to compare strength and physical activity (PA) changes in postpartum women randomly assigned to either a four-month progressive resistance training (RT) program or a four month flexibility program. Sixty healthy women between six weeks and eight months postpartum initiated the study and 43 completed the entire study. The women tended to be overweight, were all non-smokers, and most were breastfeeding (97%) at the beginning of the study. Both groups (RT and flexibility) completed training exercises twice weekly. Both groups improved in all measures of strength (RT group: leg press, P < 0.001; bench press, P < 0.001; curl-ups, P < 0.001. Flexibility group: leg press, P = 0.009; bench press, P < 0.001; curl-ups, P = 0.005); however, the RT group had higher strength gains compared to the flexibility group over time (leg press, P < 0.005; bench press, P < 0.001; curl-ups, P < 0.007). In addition, both groups increased in low back flexibility but the group*period interaction did not reach significance (P = 0.096). Light-intensity PA increased in the RT group but not the flexibility group (P < 0.05). A group*period interaction was significant for light-intensity PA time (P = 0.031) and borderline significant for sedentary time (P = 0.054). However, controlling for the number of months postpartum and weight gain during the previous pregnancy resulted in a significant interaction for sedentary time (P < 0.05). No changes were found in moderate, vigorous, or moderate to vigorous PA within or between groups over time. In conclusion, twice-weekly RT increases strength and is associated with improvements in several PA outcomes in postpartum women; however, the mechanisms for this are unclear. The training sessions and/or increased spontaneous activity may have contributed.



College and Department

Life Sciences; Exercise Sciences



Date Submitted


Document Type





postpartum, resistance training, physical activity