Biomedical subjects

E A Harman

Publications and source records attributed to E A Harman.

21 records · Page 2Linked to original sources

PubMed1987

Exercise endurance time as a function of percent maximal power production.

To develop and validate a mathematical model of the relationship between endurance time (T) and power production, 15 male subjects were first tested for maximal power on an instrumented cycle ergometer at 60 rpm. On subsequent days, they were tested for T at various percentages of maximal power. Curves of T as a function of percent maximal power were curvilinear, and could be made to overlap among subjects by individual abscissa scaling, which resulted in the appearance of horizontal stretching or compression of the curves. The degree of stretching-compression was defined by a statistically obtained scaling factor (F) which served to quantify each subject's endurance ability at fractions of maximal power. F was used to transform percent of maximal power to a scaled power variable (Psc). A curve of the form T = a(Psc)b was developed on 10 of the subjects and validated on the remaining five. Correlation between predicted and actual T was 0.967 for the fitting group and 0.980 for the validation group. A maximal power test and a single endurance test at 40 to 50% of maximal power were found to establish individual endurance-power curves fairly well, with a correlation of 0.828 between actual and predicted T. The combination of F and maximal power for a given physical activity provide a useful profile of an individual's ability to perform at constant exercise intensity.

Adult↗

PubMed1982

Three-dimensional cinematography with control object of unknown shape.

A technique for reconstruction of three-dimensional (3D) motion which involves a simple filming procedure but allows the deduction of coordinates in large object volumes was developed. Internal camera parameters are calculated from measurements of the film images of two calibrated crosses while external camera parameters are calculated from the film images of points in a control object of unknown shape but at least one known length. The control object, which includes the volume in which the activity is to take place, is formed by a series of poles placed at unknown locations, each carrying two targets. From the internal and external camera parameters, and from locations of the images of point in the films of the two cameras, 3D coordinates of the point can be calculated. Root mean square errors of the three coordinates of points in a large object volume (5m x 5m x 1.5m) were 15 mm, 13 mm, 13 mm and 6 mm, and relative errors in lengths averaged 0.5%, 0.7% and 0.5%, respectively.

Mathematics↗

PubMedDate not supplied

Early phase differential effects of slow and fast barbell squat training.

To examine the importance of resistance training movement speed, two groups of women (24 +/- 4 years, 162 +/- 5 cm, 59 +/- 7 kg) squatted repeatedly at 1) 2 seconds up, 2 seconds down (slow, N = 11); or 2) 1 second up, 1 second down (fast, N = 10), doing three warm-up sets and three eight-repetition maximum sets, three times per week for 7 weeks. Tests included force platform and video analysis of the vertical jump, long jump, and maximum squat, and isometric and isokinetic knee extensor testing at speeds from 25 to 125 deg/sec. The groups improved similarly in many variables with training but also showed some differences. In the long jump, the fast group was superior in numerous variables including knee peak velocity and total-body vertical and absolute power. In the vertical jump, fast training affected the ankle and hip more (e.g., average power), and slow training mostly affected the knee (average torque). In isokinetic testing, the fast group improved strength most at the faster velocities, while the slow group strength changes were consistent across the velocities tested. Although both slow and fast training improved performance, faster training showed some advantages in quantity and magnitude of training effects.

Adult↗