Changes in kinematic chain dynamics between calcaneal pronation/supination and shank rotation during load bearing associated with ankle position during plantar and dorsiflexion.
Masahiro Edo, Sumiko Yamamoto
PMID 30568339WHAT IT FOUND
Ankle position changed the coupling between foot pronation/supination and shank rotation.
The coupling was lowest in plantar flexion and highest in dorsiflexion. Age did not change it.
Key findings
01The coupling ratio changed with ankle position, but age and the combination of ankle position and age did not change it.
02Across all participants, the coupling ratio averaged 0.90 ± 0.29 in plantar flexion, 1.00 ± 0.23 in the intermediate position, and 1.31 ± 0.38 in dorsiflexion.
03The young group averaged 0.83 ± 0.26 in plantar flexion, 1.00 ± 0.22 in the intermediate position, and 1.32 ± 0.43 in dorsiflexion; the elderly group averaged 0.95 ± 0.31, 1.00 ± 0.24, and 1.30 ± 0.34 in the same positions.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The participants were healthy adults with no previous lower limb history, so the results do not show how patients with foot, ankle, or gait problems would behave. The study measured a standing lab task with motion capture, not walking, pain, function, or treatment response. The Discussion proposes possible mechanisms and a foot-plate check, but those ideas were not tested in this study. Each leg was analysed separately, so the 54 participants contributed 108 legs.
Declared interests
The authors declared no conflict of interest.
The easy way to misread this
Do not read the higher dorsiflexion ratio as proof that placing the ankle in dorsiflexion or using a foot plate will improve patient movement. This study measured healthy adults in a standing lab task and did not test a clinical intervention or patient outcome.