barefoot:Pure male feet, CC0, via Wikimedia Commons
foot:Public Domain
heel drop:HLHJ, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
ankle:OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons
feet:Public Domain
joints:Laboratoires Servier, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
flexible:GuillemMedina, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons