barefoot - Pure male feet, CC0, via Wikimedia Commons
foot - Public Domain
muscles - Laboratoires Servier, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
feet - Public Domain
soft tissues - Cancer Research UK, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
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
ankle - OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons
heel drop - HLHJ, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
proprioceptive - Onearmer, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
bones - Mikael Häggström, Public domain, via Wikimedia Commons
moment forces - Zoiros, CC0, via Wikimedia Commons
Achilles tendon - J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0, via Wikimedia Commons
hip flexors - InjuryMap, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
muscle - Laboratoires Servier, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons