Objective evaluation of muscle strength in infants with hypotonia and muscle weakness

► The IMS-meter allows a valid and reliable measurement of muscle strength in infants. ► A model is available to predict muscle strength in infants 6-36 months of age. ► Muscle strength is decreased in infants with Prader Willi Syndrome (PWS). ► In typically developing infants motor development is not related to muscle strength. ► In PWS infants muscle strength is a determining factor in motor developmental level.