Musculoskeletal Differences Between Healthy Postpartum Runners And Nulliparous Controls

Abstract

PURPOSE: Running has become a popular form of exercise for women during and after pregnancy. A host of changes occur during pregnancy and childbirth that can affect running mechanics. Currently due to a lack of research in this area, peer reviewed clinical recommendations on how to safely return to running are non-existent. This could be the reason up to 84% of postpartum runners report pain when running. Due to the lack of research on pregnancy and childbirth related changes on the musculoskeletal system, the purpose of this study was to examine strength and range of motion differences between healthy postpartum female runners and nulliparous controls. METHODS: Participants were grouped into either a postpartum runner (PPR) or a control group. Manual muscle testing was performed at the hip, knee, and ankle using handhold dynamometry for both participant groups. Lower extremity flexibility and range of motion testing and hypermobility screens were performed. Data was averaged over three trials and then normalized to bodyweight (NBW). Independent sample t-tests were conducted using α = 0.05. RESULTS: 33 PPR’s (BMI 24.31 ± 4.33; < 36 months postpartum) and 30 BMI matched nulliparous women (BMI 23.10 N ± 3.80) participated. PPR’s had 10.9% greater strength on left ankle inversion than controls (PPR 0.10 N ± 0.04; control 0.08 N ± 0.03; p 0.04). PPR’s had less right hip internal rotation strength than their controls (PPR 0.11 N ± 3.80; control 0.08 N ± 0.04; p 0.03). CONCLUSION: These findings suggest there might be potential differences in muscular strength between PPR and their control. PPR should be evaluated individually for specific impairments in muscular strength, flexibility, and range of motion to adequately return to running. Future studies should combine musculoskeletal measures with data on kinematics and kinetics to further understand running after childbirth.