Data from: Vastus lateralis architecture changes during pregnancy - a longitudinal study

While the incidence of falls has been described to increase with
pregnancy, the mechanism behind this is unclear. Pregnancy associated
changes in lower extremity muscle strength could be a possible factor
influencing injury risk. Thus, the aim of this longitudinal study was to
investigate muscle strength and architectural properties of the lower
limbs in different stages of pregnancy and postpartum. In nineteen
pregnant women (30±4years) and fifteen non-pregnant controls (28±4years)
muscle strength and architectural properties of the vastus lateralis
muscle were assessed combining dynamometry, ultrasound, kinematic and
electromyographic measurements. Body mass and body composition were
determined using bioimpedance analysis. In the pregnant women, the
measurements were conducted in the 16±4th (EP) and 29±4th week of
pregnancy (LP) as well as in the 32±9th week postpartum (PP). Muscle
thickness and pennation angle of the fascicles significantly increased at
LP, while muscle strength remained constant during and after pregnancy.
Body mass, skeletal muscle mass, fat mass, intracellular and extracellular
water also peaked at LP. Postpartum values did not differ from the
controls. Changes in the muscle properties were not related to changes in
body mass and body composition. Conditions during pregnancy promote
changes in the vastus lateralis architecture indicating muscle
hypertrophy. However, pregnancy did not increase muscle strength while
body mass progressively increases. Therefore, in the event of balance
perturbations pregnant women may not be able to meet the requirements for
the increased physical demand.