Complex sentence: One of the main research methods is involves developing tasks that challenge infants, children, and adults with novel predicaments, such as crawling over bridges, squeezing through apertures, swinging over monkey bars, and reaching for targets with the body in motion.
Split into simpler sentences: One of the main research topics is challenging infants, children, and adults with novel predicaments. These include crawling over bridges, squeezing through apertures, brachiating over monkey bars, and reaching for targets with the body in motion.