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Biomedical subjects

J V Danoff

Publications and source records attributed to J V Danoff.

7 recordsLinked to original sources
PubMed1992

Biomechanical comparison of the energy-storing capabilities of SACH and Carbon Copy II prosthetic feet during the stance phase of gait in a person with below-knee amputation.

In this study, the energy-storing capabilities of solid-ankle cushion heel (SACH) and Carbon Copy II prosthetic feet during the stance phase of gait were compared. A person with a unilateral below-knee amputation served as a component of the instrumentation to test the feet under dynamic loads. Ten trials per foot of bilateral stride at "free" velocity were collected with a video-based, three-dimensional data-acquisition system and two force plates. There were no differences between the prosthetic conditions in step length, single-limb support time, and swing period (analysis of variance) or in double-limb support time, cadence, and velocity (Student's t test). Angular kinematics and moments of the hip and knee were unaffected bilaterally by the type of foot. The progression of the center of pressure under the Carbon Copy II was delayed from 15% to 80% of stance as compared with the SACH foot. The Carbon Copy II showed slower unloading in late stance and a later peak propulsive force than did the SACH foot. The Carbon Copy II performed greater work in both the energy-storage (Carbon Copy II = 2.33 J, SACH = 1.16 J) and energy-return (Carbon Copy II = 1.33 J, SACH = 0.34 J) phases of stance and returned energy with 57% efficiency. Although the energy returned by the Carbon Copy II was clinically insignificant during level walking, these results confirm that it performs as an energy-storing device.

Adult↗
PubMed1991

Interrater reliability of videotaped observational gait-analysis assessments.

The purpose of this study was to determine the interrater reliability of videotaped observational gait-analysis (VOGA) assessments. Fifty-four licensed physical therapists with varying amounts of clinical experience served as raters. Three patients with rheumatoid arthritis who demonstrated an abnormal gait pattern served as subjects for the videotape. The raters analyzed each patient's most severely involved knee during the four subphases of stance for the kinematic variables of knee flexion and genu valgum. Raters were asked to determine whether these variables were inadequate, normal, or excessive. The temporospatial variables analyzed throughout the entire gait cycle were cadence, step length, stride length, stance time, and step width. Generalized kappa coefficients ranged from .11 to .52. Intraclass correlation coefficients (2,1) and (3,1) were slightly higher. Our results indicate that physical therapists' VOGA assessments are only slightly to moderately reliable and that improved interrater reliability of the assessments of physical therapists utilizing this technique is needed. Our data suggest that there is a need for greater standardization of gait-analysis training.

Adult↗
PubMed1989

Bilateral analysis of the knee and ankle during gait: an examination of the relationship between lateral dominance and symmetry.

This study examined the relationship between lower extremity dominance and kinematic symmetry during gait. Fourteen healthy volunteers without any observable gait deviations participated in the study. The subjects (8 male, 6 female) ranged in age from 19 to 56 years. Lower extremity lateral dominance was determined using an assessment method developed by Carol Coogler. Retroreflective spherical markers were placed bilaterally at points over the greater trochanter, the lateral joint line of the knee, the lateral malleolus, and the metatarsal break. A video-based data-acquisition instrument interfaced with a PDP 11/73 computer measured 12 kinematic variables while the subjects walked at self-selected speeds along a 10-m walkway. A multivariate analysis of variance with one repeated measure revealed significant differences between limbs, across subjects, for stance time and maximum knee extension. A within-subject analysis demonstrated significant differences for 10 variables; however, lateral dominance could not be related predictably to these variations. Our results indicate that symmetry cannot be generalized in view of intrasubject variability for these variables. [Valle DR, Gundersen LA, Barr AE, et al: Bilateral analysis of the knee and ankle during gait: An examination of the relationship between lateral dominance and symmetry.

Adult↗
PubMed1989

Ultrasound sector scanning used to define changes in muscle configuration.

Dynamic configurational changes in the rectus femoris muscle were examined using a real time ultrasound sector scanner in ten normal subjects. The angle of passive knee flexion was varied as transverse ultrasound scanning was performed at the mid-transverse thigh. Configurational changes in the rectus femoris were computed from a traced outline of the muscle and the geometric center of the mass was calculated at all degrees of knee flexion. The geometric center of the mass varied with knee position. The anterioposterior dimensions and cross sectional areas of the rectus femoris and vastus intermedius remained constant, however, despite changes in knee position. The pattern of change observed was reproducible and reflects consistent changes in muscle configuration. The technique and instrumentation should have value for non-invasive dynamic and static observation of individual muscles.

Adult↗