When we push off of the ground, the powerful first metatarsal should be free to plantar flex (move downward towards the ground) with most of the weight on the 2nd through 5th metatarsals (2nd the most). As push off continues (aka propulsion), the sign of great push off is strong wear under the hallux (big toe) itself.
In the photo above, the right foot shows the typical signs of great push off (also called a propulsive gait pattern), and the left shows minimal to no active push off (confusingly called an apropulsive gait pattern). The right side shows dramatically more pressure under the first through third metatarsals seen in a good push off.
Overall, however, the left side shows more mid foot and metatarsal area pressure, so that side is bearing more weight. These top covers were put on at the same time, and are only used for walking. The patient does a lot of walking each day.
For those biomechanical afficianodos, this patient has forefoot varus with a Root Balanced Technique. I do not like the first metatarsal pressure on both sides, and would personally convert the orthotic to a Kirby skive with first ray cutout or the Inverted Orthotic Technique.
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