Effects of wearing foot orthosis with medial arch support on the fifth metatarsal loading and ankle inversion angle in selected basketball tasks.
METHODS
Preintervention and post-intervention, repeated-measures experimental design.


OBJECTIVE
The objective was to investigate the effects of foot orthoses with medial arch support on ankle inversion angle and plantar forces and pressures on the fifth metatarsal during landing for a basketball lay-up and during the stance phase of a shuttle run.


BACKGROUND
Proximal fractures of the fifth metatarsal, specifically the Jones fracture, are common in sports. Wearing foot orthoses with medial arch support could increase the ankle inversion angle and the plantar forces and pressure on the fifth metatarsal that may increase the risk for fifth metatarsal fracture,


METHODS
Three-dimensional (3-D) videographic, force plate, and in-shoe plantar force and pressure data were collected during landing after a basketball lay-up and during the stance phase of a shuttle run with and without foot orthoses with medial arch support for 14 male subjects. Two-way ANOVAs with repeated measures were performed to compare ankle inversion angle, maximum forces, and pressure on the fifth metatarsal head and base between conditions and between tasks.


RESULTS
The maximum ankle inversion angle and maximum plantar force and pressure on the base of the fifth metatarsal during both tasks as well as the maximum plantar force and pressure on the head of the fifth metatarsal during the stance of the shuttle run were significantly increased (P< or =026) when wearing foot orthoses. No significant differences were found in the maximum vertical ground reaction forces between foot orthotic conditions.


CONCLUSIONS
Generic use of off-the-shelf foot orthoses with medial arch support causes increased plantar forces and pressures on the fifth metatarsal and may increase the risk for proximal fracture of the fifth metatarsal. Future studies are needed to investigate this risk, acknowledging that the differences noted in our study were small in magnitude and the foot type was not measured.
Yu
Bing
B
Center for Human Movement Science, Division of Physical Therapy, Department of Allied Health Sciences, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. byu@med.unc.edu
Preston
Jennifer J
JJ
Queen
Robin M
RM
Byram
Ian R
IR
Hardaker
W Mack
WM
Gross
Michael T
MT
Davis
J Marc
JM
Taft
Timothy N
TN
Garrett
William E
WE
D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001490:Basketball / Q000502:physiology*; D001696:Biomechanical Phenomena; D004867:Equipment Design; D005528:Foot / Q000502:physiology; D050723:Fractures, Bone / Q000503:physiopathology / Q000534:rehabilitation; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008683:Metatarsophalangeal Joint / Q000502:physiology*; D009989:Orthotic Devices; D026741:Physical Therapy Modalities / Q000295:instrumentation; D011403:Pronation / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values