Research on foot orthotics is primarily restricted to their effect on the lower limb during running. Research is limited, however, on the potential of foot orthotics to control the mechanics of the foot during walking. The purpose of this study was to examine the interactive effect of foot orthotics and two walking speeds on the angular changes at the rearfoot, ankle, and knee, and temporal events during stance. Ten subjects demonstrating a minimum of 3° of calcaneal eversion in relaxed standing participated in the project. All subjects routinely wore functional orthotics that were used during testing in conjunction with personal athletic shoes. Individuals were tested with and without the orthotics while walking on a treadmill at 2 and 3 mph. A four-camera motion analysis system was used to capture three-dimensional motion at 60 frames per second. Angle plots illustrated changes in joint motion at the knee, ankle, and rearfoot. Temporal data for heel strike, heel rise, and toe off of the foot during the stance were calculated. A two-factor repeated analysis of variance was used to determine the main and interactive effects of the orthotic and sped on the dependent variables. When walking with the orthotic, there was a significant reduction in the degree of pronation throughout stance as well as an increase in the duration of stance time as measured from heel strike to heel rise. The orthotic did not significantly reduce the velocity of pronation during the first 20% of stance. There was a speed effect for peak dorsiflexion and knee flexion. The data are discussed with respect to a biomechanical rationale for the effects noted and the need for the use of orthotics during walking as well as during more strenuous exercise.

J Orthop Sports Phys Ther 1993;17(1):2-10.

Key Words: orthotics, gait, kinematics

Study Design: Single group repeated measures design. Objective: To determine if the rate of transition between knee flexion and extension influences the subsequent concentric activation of the quadriceps and knee extension torque during reciprocal movements. Background: Preloading a muscle by stretching, a prior isometric or eccentric muscle action, or a prior movement controlled concentrically by the antagonist muscle group increases the maximal torque-generating capability of the agonist. We hypothesized that the rate of transition from the prior movement may be the critical factor that influences the degree of muscle facilitation and torque potentiation. Rapid reversal of antagonistic movements has been postulated as a potential facilitatory mechanism. Methods: Knee extension torque and electromyographic (EMG) amplitude (dependent variables) from 2 of the vasti muscles were recorded while subjects (N = 20; 12 men, 8 women, mean age, 28.5 ± 2.68 years) maximally activated their quadriceps at 3 constant angular velocities, 100°/s, 200°/s, and 300°/s, and 2 preload conditions, SLOW and RAPID (independent variables). In the SLOW transition condition, subjects actively flexed their knee to 110° from an extended position, paused in this position for 3 seconds, and then extended to O°. In the RAPID transition condition, the same movement from knee flexion to extension was performed without a pause. Results: Peak torque, the root-mean-square (RMS) average, peak (peak rectified and smoothed), and initial (100 milliseconds prior to torque onset) EMG amplitudes were all significantly greater during the RAPID transition condition. Peak torque decreased with increasing movement velocity. There were no interactions between the preload conditions and angular velocity on peak torque or the EMG amplitude variables. There was also no influence of velocity on the EMG amplitude variables. Conclusions: The effect of preloading the quadriceps by prior concentric activation of the hamstrings is dependent on the rate of transition between the flexion and extension movements and is due primarily to neural facilitation.

J Orthop Sports Phys Ther. 2001;31(4):122-132.

Key Words: exercise, muscle training. proprioceptive neuromuscular facilitation, quadriceps

There is a need to better document the reliability and validity of assessment measures used in physical therapy. Studies documenting the reliability of measurement of the pelvic angle and its relationship to sacral motion are presently inconclusive. The purpose of this study was twofold. First, we wanted to determine the reliability and validity of a goniometric measurement of the pelvic angle. We also wanted to test the hypothesis that there is a relationship between the pelvic angle and the sacral angle. Intertester and intratester reliability of goniometric pelvic angle measurements of 23 healthy young adults were examined using 3 different raters. Radiographic measurements of the pelvic and sacral angle using 2 raters and goniometric measurement of the pelvic angle using a single rater were taken from 15 patients with low back pain who had been referred for X-rays. Intraclass correlation coefficients (ICCs) of intratester reliability for goniometric measurements of the pelvic angle were 0.93, 0.96, and 0.96. The intertester reliability was 0.95. The ICCs for intratester reliability for radiological measurements were 0.92 and 0.95 for the sacral angle and 0.98 for both measurements of the pelvic angle. Intertester reliability coefficients were 0.86 and 0.88, respectively. The Pearson correlation coefficients for the goniometric and radiological measurements of the pelvic angle were 0.85 and 0.68. A comparison of the radiological and goniometric measurements of the pelvic angle with the sacral angle demonstrated low average correlations of 0.43 and 0.58, respectively. The results indicate a high level of correlation between and within testers for goniometric measurements of the pelvic angle, but only a fair correlation between goniometric and radiological measurements of the pelvic angle. A poor correlation was noted between the pelvic angle and the sacral angle. We suggest further examination of measurements correlating the pelvic angle and the sacral angle. Studies comparing several X-rays of the same patient by examining the pelvis at different positions would better demonstrate a relationship between the pelvic angle and the sacral angle.

J Orthop Sports Phys Ther. 1994;20(4):193-199.

Key Words: pelvic angle, sacral angle, goniometry