Biomedical subjects

T M Bach

Publications and source records attributed to T M Bach.

4 recordsLinked to original sources

PubMed1992

Steadiness in one-legged stance: development of a reliable force-platform testing procedure.

Postural steadiness in one-legged stance has potential for evaluation of unilateral injuries and disorders, but any test protocol must be demonstrated to be both feasible and reliable. A testing protocol for using a force platform to measure steadiness in one-legged stance with eyes opened and eyes closed was successfully developed, and its within-session retest reliability was investigated in a group of 24 young, healthy subjects. Strategies were used to minimize the loss of data for trials in which the subjects incurred significant loss of balance from the one-legged position. The performance scores examined were the standard deviation of the three orthogonal force components and the two horizontal center of pressure (CP) coordinates averaged over four consecutive five-second trials. The retest coefficients for all test conditions were substantially improved compared with testing protocols reported earlier. Retest reliability was higher for performance scores based on force measures than for performance scores based on CP measures. The difference was statistically significant in two of the stances, with a similar trend in the other two stances. Further, factor analysis showed that force measures were the best predictors of steadiness in one-legged stance. Analysis of variance failed to detect any systematic effect for leg preference or laterality on steadiness in one-legged stance with eyes opened or eyes closed in the healthy subjects with no history of injury (p greater than .05). The test protocol described enables the development of clinical or experimental trials with repeated-measures design using the subject's nonaffected leg as a control.

Adolescent↗

PubMed1992

Electrogoniometric feedback: its effect on genu recurvatum in stroke.

The purpose of this study was to determine the effect of combining electrogoniometric feedback with contemporary physical therapy procedures for treatment of genu recurvatum following stroke. Twenty-six patients suffering knee hyperextension resulting from cerebrovascular disorders were allocated to either a control group or an experimental group. Both groups received treatment for knee hyperextension during two consecutive phases. During phase I the control group received physical therapy and the experimental group received electrogoniometric feedback as an adjunct to physical therapy. In phase II both groups received physical therapy alone. Each phase lasted four weeks, during which time patients were treated 45 minutes daily, five days every week. Subjects in the experimental group showed greater reduction in knee hyperextension. This was particularly evident in phase II when the difference between groups for reduction in knee hyperextension reached statistical significance (U = 40, p = 0.011). These results suggest that the addition of electrogoniometric feedback to standard physical therapy enhanced the effectiveness of treatment for genu recurvatum in stroke.

Adult↗

PubMed1990

Effect of vertical jumping on the medial gastrocnemius and soleus muscles of rats.

Ten rats were trained to perform approximately 30 jumps/day, 5 days/wk for at least 8 wk, from a force platform that enabled the number and height of jumps to be quantified. There was considerable variation in height jumped during an activity session both within and between rats. The two highest-jumping rats attained a displacement of center of mass of approximately 30 cm, estimated to be approximately 67% of the maximum attainable. The two lowest-jumping rats jumped to approximately 30% of the estimated maximum. The activity was described as "habitual activity" rather than "training" because there were no significant increases in the height of jumping by any rat over the period of activity. The isometric properties of medial gastrocnemius (MG) and soleus muscles were studied in terminal experiments on anesthetised rats. Five significant effects on MG were evoked by this pattern of exercise ("habituation"): 1) a 15-18% increase in force at frequencies of stimulation between 60 and 150 Hz and a 15% increase in maximum tetanic tension to 14.9 N, 2) a 3% increase in the maximum rate of rise of tetanic force to 3.4% of maximum tetanic tension per millisecond, 3) an increase in fatigability expressed as a smaller fatigue index in active rats (33%) than in controls (58%), 4) a decrease of 4% in the percentage of type IIa muscle fibers, and 5) an increase of 6% in the percentage of type II fibers that could not be classified with certainty as IIa or IIb.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1989

Force platform measures for evaluating postural control: reliability and validity.

The reliability and validity of force platform measures used to evaluate steadiness of stance were investigated in a group of 28 healthy subjects in four basic stance positions: two-legged, step, tandem, and one-legged stance. In each stance position five indices of steadiness were obtained by sampling the three orthogonal force signals and the two horizontal center of pressure (CP) signals for 15 seconds and computing the standard deviation for each signal. Correlations between these five indices derived from the force platform showed that the relationship between force and CP measures was generally weak. In fact, approximately 40% of the correlations were nonsignificant (p greater than .05). There was a strong trend for the retest reliability of force measures to be higher than the retest reliability of CP measures. The difference was statistically significant in three stances (p less than .05). Force measures were more sensitive than CP measures in discriminating the changes in steadiness which resulted from alterations to the base of support in the four stance positions. Factor analysis showed that force measures were the best predictors of steadiness in each stance, but the axis varied according to the particular stance condition. Although it may be appropriate in some cases to justify the choice of measure according to the nature of the clinical condition being studied, these results provide a rationale for choosing force measures in preference to CP measures on the fundamental principles of reliability and validity.

Adult↗