The effectiveness of shock-absorbing insoles during normal walking

Abstract

This paper describes a study of the effectiveness of commercially available shock absorbing insoles when used in four different pairs of shoes during normal walking. The measurement method was based on the use of the Fourier Transform of the axial acceleration of the leg measured by an accelerometer mounted at the ankle. The magnitude of shock was measured by the “Shock Factor” which has been defined as the rms acceleration between 50 Hz and 150 Hz expressed as a proportion of that between 10 Hz and 150 Hz. Nine insoles were tested in each pair of shoes and the Shock factor for each combination was compared with the value obtained for the shoes alone. Statistically significant reductions of Shock Factor were noted in 58% of cases; the largest improvement (30% reduction in Shock Factor) was achieved by lightweight Sorbothane. The experimental technique has now been further developed to allow the measurement of Shock Factor by a portable Shock Meter.

Effect of Heating on the Mechanical Properties of Insole Materials

“…Plantar pressures between 2.8 and 3.6 kg/cm 2 have been utilized in prior studies of insole materials. 1,6,10,11,16 Percent compression was determined by measuring the thicknesses of the samples before and after heating with a fine caliper. The percentage of compression required to reach maximal load was compared for the native and heated individual materials and combinations.…”

“…Multiple authors have noted that in the current clinical climate the science of insole design and insole function appears to be somewhat obscured at times by unproven assumptions for their widespread prescription, especially in sports and other common conditions of the foot. 2,9,11,19 The clinical use of insoles is indeed considered fundamental to the treatment of patients with diabetes and other peripheral neuropathies with a risk for, or a history of, plantar ulcerations. 1,2,6,7,15 The purpose of insoles is to reduce force transmission to the plantar foot and lower limb and to protect the foot and reduce the occurrence or recurrence of plantar ulcers in the diabetic populations.…”

The effect of custom moulded ethyl vinyl acetate foot orthoses on the gait of patients with rheumatoid arthritis

“…The effectiveness of orthoses in terms of either static [25][26][27] or dynamic [28][29][30] kinetic parameters has been Mean Stride Without Mean Cadence Without Fig. 3 Change in cadence, with/without studied and shows reductions in pressure and ground reaction forces in non RA samples.…”

“…3 Change in cadence, with/without studied and shows reductions in pressure and ground reaction forces in non RA samples. The effectiveness of different types of materials in normal subjects 26,[28][29][30] has also been examined. No studies on EVA orthoses alone have been published, nor do any of the published comparative works include EVA.…”

Accelerations due to impact at heel strike using below-knee prosthesis

“…Mizrahi and Susak (1982) found that at impact with one straight leg, after fall from 50 mm, there only remains a maximum acceleration of 46ms-2 at the level of the greater trochanter. Johnson (1988) investigated the influence of shoe insoles on peak acceleration absorption. He defines a shock factor as the integral of the amplitude spectrum from 50 to 150Hz divided by the integral from 10 to 150Hz.…”