Enjoy the movement of a natural ankle with the Endolite Torque Absorber

This study investigated some aspects of the validity of walking speed recording in 15 normal subjects, 16 trans-femoral amputees and 8 knee disarticulation amputees . The variability and test-retest reliability of walking speed and the influence of simultaneous recording of E M G and goniometry on comfortable and fast walking speeds were studied. The variability between sessions was mainly determined by the variance within each session. The variance of speed within sessions while walking with East speed, was higher when walking without equipment than when walking with equipment . The variances of speed within sessions of the normal subjects were higher than those for both amputee groups. The testretest reliability, expressed by the intra-class correlation coefficient, was good: between 0.83 and 0.98. The speed when walking without equipment was significantly higher both in normal subjects and amputees than the speed when walking with equipment . Introduction Measurements of walking speed by means of gait analysis are based on the assumption that walking speed is a basic gait parameter which, when measured objectively, can be useful in characterizing an individual's walking ability. In studies of prosthetic components , walking speed is often used as a parameter for the quality of performance (Barth et al., 1992; Godfrey et al., 1975; Murray et al., 1983). Validity of speed recordings is essential. There are several aspects of validity. One of these is the test-retest reliability. Normal subjects show good reliability, but studies have been limited to the test-retest reliability of the natural walking speed (Kadaba et al., 1989; Waring and McLaurin, 1992; Winter , 1984) or have included only a few subjects (Winter , 1984). In neurologic patients (Holden et al., 1984; Wade et al., 1987) and post-polio patients (Waring and McLaurin, 1992) the test-retest reliability has been shown to be satisfactory. Another aspect of the validity concerns the question about the relationship between speed recordings measured during gait analysis and the walking speed of the patient in his/her own surroundings. So far, nobody has answered this question. A n important problem in gait analysis, affecting the validity, is the simultaneous recording of speed, goniometry and E M G . It is unknown how the walking speed is influenced by the equipment and the wires attached to a patient for gait analysis. In this paper , a study is presented of the variability of walking speed and the test-retest reliability, based on repeated recordings of comfortable and fast speed in normal subjects and amputees . The study also examined the influence of simultaneous recording of goniometry and E M G on walking speed. Material and methods