Hides JA, Lambrecht G, Sexton CT, et al. - A prospective longitudinal series was conducted to explore the variations in muscle size and function of the lumbar multifidus (MF) and anterolateral abdominal muscles in response to exposure to 6- months of microgravity on the International Space Station and in response to a 15-day reconditioning program on Earth. Researchers obtained data from 5 astronauts who undertook 7 long-duration missions on the International Space Station. They performed ultrasound imaging of trunk muscles at 4 timepoints (pre-flight, post-flight, mid-reconditioning, and post reconditioning). They examined data using multi-level linear models to calculate the change in muscle parameters of interest across three time periods. The findings implied that for people with chronic low back pain, the principles underpinning the exercises developed for astronauts following prolonged exposure to microgravity (emphasizing strength and endurance training to re-establish normal postural alignment and distribution of load with respect to gravity) can also be used, as the MF and anterolateral abdominal muscles were influenced in similar ways in both populations.