Article

Limb movements involving contraction times of 50-200 ms occur in many everyday
activities, such as gait, which is faster than the time required to generate
maximal force. Therefore, the ability to rapidly produce force may be even more
important for the performance of functional activities. In this study rate of
force development (RFD) and impulse of the knee extensors were examined in 12
ambulatory children with cerebral palsy (CP) (age: 11.9 +/- 2.9 years) and 11
with typical development (TD) (Age: 11.3 +/- 3.0 years). The relationship with
muscle architecture and functional mobility was also determined. RFD and impulse
were calculated during a maximal isometric knee extension contraction. Rectus
femoris (RF) cross-sectional area and RF and vastus lateralis (VL) muscle
thickness (MT), fascicle length (FL), and fascicle angle (FA) were measured using
ultrasound imaging. Gait temporal-spatial parameters, Pediatric Outcomes Data
Collection Instrument (PODCI), and Activities Scale for Kids performance version
(ASKp) were collected. Although VL MT was the primary determinant of RFD and
impulse in CP, FA and FL were also significant predictors in the TD group. RFD
and impulse were significantly lower in CP compared to TD (70% decrease) in
addition to maximal strength (50% decrease). RFD and impulse were predictive of
measures of functional mobility, including gait, transfers, and sports and higher
level activities but not temporal-spatial gait measures. Results suggest that the
ability to rapidly generate torque may be of greater importance than maximal
strength during certain tasks, such as transfers and sports and higher level
activities.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS