CONTEXT:
Intrinsic foot muscle (IFM) exercises are utilized clinically in the treatment of foot and ankle conditions. However, the effectiveness of training on IFM motor function is unknown.
OBJECTIVE:
To study the effects of a 4-week IFM exercise program on motor function, perceived difficulty, and IFM motor activation measured using ultrasound imaging (USI) during three IFM exercises.
DESIGN:
Single-blinded randomized control trial.
SETTING:
Laboratory.
PARTICIPANTS:
24 healthy, recreationally-active young adults without history of ankle-foot injury who have never performed IFM exercises participated (12 males, 12 females; mean age=21.5±4.8 years; BMI=23.5±2.9 kg/m2) Intervention: Following randomization, participants allocated to the intervention group received a 4-week progressive home IFM exercise program performed daily. Participants in the control group did not receive any intervention.
MAIN OUTCOME MEASURES:
Clinician-assessed motor performance (4-point scale: 0=does not initiate movement, 3=performs exercise in standard pattern), participant-perceived difficulty (5 point Likert scale: 1=very easy, 5=very difficult), and USI motor activation measures [Formula: see text] of the abductor hallucis (AbdH), flexor digitorum brevis (FDB), quadratus plantae (QP), and flexor hallucis brevis (FHB) were assessed during a toe-spread-out, hallux-extension, and lesser-toe-extension exercise.
RESULTS:
The intervention group demonstrated significant improvement in motor performance in the toe-spread-out exercise (pre=1.9±0.5, post=2.6±0.5, p=.008) and less perceived difficulty in the toe-spread-out (pre=3.1±1.3, post=2.3±1.2, p=.01), hallux-extension (pre=3.2±1.5, post=2.0±1.2, p=.005), and lesser-toe-extension (pre=1.9±0.7, post=1.2±0.4, p=.03) exercises. Both groups demonstrated increased USI motor activation in the AbdH during the toe-spread-out exercise (intervention: pre=1.07±.06, post=1.11±.08; control: pre=1.08±.06, post=1.11±.06, p=.05). No other significant main effects or group by time interactions were observed.
CONCLUSION:
A 4-week IFM exercise intervention resulted in improved motor performance and decreased perceived difficulty when performing the exercises, but not changes in USI measures of IFM activation compared to a control group.
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