This study looked to evaluate the relationships between peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height.
"The results showed (1) a moderate correlation between ankle dorsiflexion range of motion and countermovement jump height and (2) a high correlation between peak first toe flexor muscle strength and countermovement jump height. Peak first toe flexor muscle strength and ankle dorsiflexion range of motion are the main contributors to countermovement jump performance."
There could be variables missing here, and plenty of caveats. We should try to get the full text on this one to be fair. None the less, interesting facts to brain juggle however.
These muscles are posterior compartment muscles so it makes sense, however, when the first great toe (the hallux) is in relative flexion, the arch is easier to drop (conversely, hallux dorslflexion causes the arch to raise and keeps the ankle dorsiflexion more purely in the ankle mortise) where as, with relative toe flexion, the arch can drop, this can generate some pronation and arch splay, which can increase the "appearance" of more ankle dorsiflexion when in fact some could be from the arch drop/pronation. I wonder if the researchers are aware of this variable or if this study took it into consideration. Certainly when someone is dropping into ankle dorsiflexion ready to jump, is is easy to drop the arch. Go ahead, dry doing it with the toes down , and then with the toes up in extension, its very different in the amount of dorsiflexion you can get out of the entire arch-ankle mortise complex combined. IT is these kinds of things that can easily be over looked and skew findings.
Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump
Sung Joon Yun1) 2), Moon-Hwan Kim2), Jong-Hyuck Weon3), Young Kim4), Sung-Hoon Jung5), Oh-Yun Kwon5)
Journal of Physical Therapy Science
Vol. 28 (2016) No. 8 August p. 2241-2244
link : https://www.jstage.jst.go.jp/article/jpts/28/8/28_jpts-2016-202/_article?platform=hootsuite