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Biomedical subjects

K Linge

Publications and source records attributed to K Linge.

16 recordsLinked to original sources

The adaptation of the foot to heavy loads: plantar foot pressures study.

INTRODUCTION:: The foot serves as the main shock absorber during various activities as walking running and jumping. There are static and dynamic mechanisms which play a role in the adaptation of the foot to weight bearing walking with weights. The function of the foot while weight bearing was studied mainly under static conditions. We designed an experiment to explore dynamically the adaptation of the foot to weight bearing walking with weights. METHODS:: Ten healthy subjects participated the study. They walked barefoot over an EMED force plate which based on multiple pressure capacitance sensors. Each subject walked three times. The first walk was without any weight, the second walk with weight of 20 kg in backpack and the third walk with weight of 40 kg. Contact area, peak pressures, peak forces and duration of contact time were measured in seven areas of interest of the foot-heel, midfoot, lateral, central and medial forefoot, lateral toes and hallux. RESULTS:: The pressure time integral and force time integral increased in most areas of the foot except for the midfoot in the 20 kg walk. The largest increase was at the central and medial forefoot. Adding additional 20 kg to the load did not increased the loads on the midfoot but increased further the loads mainly at the central and medial forefoot. CONCLUSIONS:: The human foot adapts itself under loading condition by maintaining the medial longitudinal arch. Increasing the loading further activates compensatory mechanisms which maintain the longitudinal arch and shifts the the loads to the central and medial forefoot.

Journal Article↗

Plantar foot pressures during treadmill walking with high-heel and low-heel shoes.

The effect of walking with high-heel shoes on plantar foot pressure distribution was investigated. Ten normal women walking in shoes with low heels were compared to women walking in high-heel shoes. It was shown that high-heel shoes increased the load on the forefoot and relieved it on the hindfoot. The load passed toward the medial forefoot and the hallux. The lateral side of the forefoot showed a decrease in contact area, reduced forces, and peak pressures. The medial side of the forefoot had a higher force-time and pressure-time integral. It is suggested that these higher loads on the medial forefoot may aggravate symptoms in patients with hallux valgus deformity.

Adult↗

A preliminary objective evaluation of leprosy footwear using in-shoe pressure measurement.

The primary function of leprosy shoes, insoles and podiatric orthoses is to provide an underfoot environment capable of distributing the inevitable vertical forces, so reducing areas of peak pressure and ideally the period through which they are applied. Many patients with Hansen's disease have both skeletal deformity and anesthetised feet and the presence of high plantar pressures is the key reason for foot ulceration. This objective investigation using in-shoe dynamic pressure measurements showed that the addition of a shank to control insole rigidity reduced the overall peak pressures under the foot. When a deep canvas shoe was used to test single- and double-thickness insoles of two different types of material it was found in each case that the double-thickness mode was advantageous overall. Microcellular rubber insoles in two types of leprosy shoe were replaced by the polymer Poron. The Poron proved to be superior to both microcellular rubbers. The peak pressure and pressure-time integral should be considered as complimentary variables when determining the efficacy of footwear.

Foot↗

Effect of the shoe on plantar foot pressures.

The bare foot plantar pressures were compared to in-shoe pressure measurements in 11 normal male volunteers using the EMED system. Shoes diminished pressures and forces in most areas under the foot except the medial forefoot. The hallux showed less force, a smaller contact area and a reduced contact time. Therefore a shoe can interfere with the toe-off mechanism. There was no difference between various types of shoes with rubber and leather soles. Heavier subjects tended to put less weight on the medial forefoot.

Adult↗

Forefoot arthroplasty and changes in plantar foot pressures.

The aim of this study was to determine how effective forefoot arthroplasty is at reducing the pressures under the forefoot. The EMED F pressure measuring system was used. Fifteen patients (23 feet) were included in the study. All patients had foot pressure studies performed before and after surgery. Our results show a significant increase in total pressure and pressure-time integral under the foot after surgery. This increase was most marked under the first metatarsal head region (P < .005). However, the midmetatarsal region showed a slight decrease in pressure, but this was not significant. Symptomatically, 13 patients felt improved by the operation. The results suggest that the procedure is successful because it transfers the pressure to areas better able to tolerate it, rather than reduces the total pressure.

Adult↗

Double-blind comparison of captopril with nifedipine in hypertension complicated by intermittent claudication.

In a double-blind, crossover trial 12 patients with hypertension and peripheral arterial disease were randomized to three months' treatment with captopril 25-50 mg twice daily or nifedipine SR 20-40 mg twice daily. While both treatments were equally effective at lowering blood pressure, postexercise calf blood flow availability was greater during treatment with captopril (P less than 0.04). This was not reflected in walking capacity assessed by treadmill exercise. The results suggest that both captopril and nifedipine are appropriate antihypertensive agents in patients with peripheral arterial disease.

Blood Pressure↗

Changes in stature during exercise and sports training.

Shrinkage in stature is used in ergonomics and sports contexts as an index of load on the spine. Measurement is now computer-aided to facilitate data collection. Applications of the technique to sport and exercise have included evaluations of weight-training, running and jumping drills. The technique has also been employed in assessing procedures for spinal unloading such as gravity inversion. Future applications include investigations of procedures used to prevent back injury as well as studies of sports that impose high transient loads on the spine.

Journal Article↗

Changes in stature following drop jumping and post-exercise gravity inversion.

Spinal shrinkage, measured by changes in stature, is used as an index of spinal loading as alterations reflect changes in intervertebral disc height. Shrinkage induced by various physical activities may be reversed using gravity inversion. The present purpose was to examine the shrinkage induced by a drop jumping regimen and evaluate gravity inversion post-exercise. Eight males, aged 20-31, performed two separate experimental protocols, each on different dates at 1400 h. Subjects stood for 30 min before undertaking an exercise regimen, consisting of five sets of five drop jumps from a height of 1 m, rebounding over a hurdle 0.5 m high. For 20 min, directly following the exercise regimen, subjects on one occasion stood and on a second occasion undertook gravity inversion. Shrinkage was monitored for 40 min after this post-exercise treatment. The stadiometer used to measure shrinkage was accurate to 0.05 mm. The exercise regimen caused a mean shrinkage of 1.68 and 1.81 mm for the two testing sessions. Post-exercise inversion and standing for 20 min increased stature by 5.18 and 0.76 mm, respectively (P less than 0.01). The 40-min standing period following inversion caused a rapid loss in stature (4.07 mm). At 30 min into this recovery period, there was no significant difference in shrinkage for either of the regimens. Results suggest that effects of an inversion treatment are short-lasting.

Adult↗

The importance of heel compression in the measurement of diurnal stature variation.

Heel pad thickness was measured in 20 subjects (18 males aged 21-39 years and two females aged 21 and 25 years) using a 2 MHz ultrasound transducer linked to an Echo Scan body composition meter, Thandar SC110A oscilloscope and M150 amplifier. With the subjects standing erect and weight-bearing equally through both feet, the average time to achieve equilibrium heel compression was 81.7 s. Compression of the heel pad soft tissue averaged 4.4 mm (range 0.8-8.9 mm). Following equilibrium with one foot weight-bearing, an additional average loss of 1.6 mm of thickness (range 0-4 mm) was observed occurring after an average time period of 51 s. This study has confirmed the suspicion that heel pad shrinkage may be a confounding factor in measurements of change of stature. The results of this study have indicated that a period of 2 min is needed for the heel pad thickness to compress sufficiently before measurements are taken.

Journal Article↗

Indirect measurement of skin blood flow and transcutaneous oxygen tension in patients with peripheral vascular disease.

The transcutaneous oxygen monitor was used in the vascular laboratory to give an objective measurement of the severity of arteriosclerotic disease in patients presenting with intermittent claudication. With the electrode operating at 44 degrees C on the leg, patients and normal volunteers performed treadmill exercises. It was observed that the resulting electrode heat consumption correlated closely with the degree of exercise. Claudicants, however, showed smaller changes than the normal group, the relationship forming an index of the severity of the disease.

Adult↗

The effect of age and sex of normal volunteers upon the transcutaneous oxygen tension in the lower limb.

The transcutaneous oxygen monitor, developed as a non-invasive method of measuring arterial oxygen tension in neonates, has recently been applied to measurement of skin ischaemia in peripheral vascular disease. Since peripheral vascular disease occurs in older age groups and more commonly in men than women, the effects of age and sex on the transcutaneous oxygen tension in the lower limb have been investigated. Two hundred and five normal volunteers of both sexes with a wide age range had measurements taken at a fixed point in the lower limb under similar conditions. The results showed no significant correlation between either the age or sex of the individual when compared to the transcutaneous oxygen tension.

Adolescent↗

Measurement of transcutaneous oxygen pressure in normal and ischaemic skin.

The transcutaneous oxygen pressure (tcPO2) was measured by a polarographic technique in the legs of 161 volunteers and compared with the levels found in 62 patients with ischaemic skin due to peripheral vascular disease. The results show that the tcPO2 was related to the degree of ischaemia and, in many cases, was a more accurate guide to the viability of the skin than clinical assessment. Measurement of the transcutaneous oxygen pressure in the leg at the site of amputation in 24 patients with peripheral vascular disease showed that a preoperative level greater than 40 millimetres of mercury at an electrode temperature of 44 degrees Celsius was necessary for the skin of the stump to heal. The technique is simple, non-invasive and reliable. The tcPO2 accurately reflects the physiological and pathological changes in the circulation of the skin. It has potential in many fields of surgery where careful assessment of the viability of the skin is necessary.

Adolescent↗

A comparison of two studies of the pressure distribution under the feet of normal subjects using different equipment.

There is growing interest in the use of foot pressure measurement both clinically and in the study of normal subjects. A number of systems are now commercially available, but comparison of the results is complicated by the different techniques employed. This paper compares the results of two studies. The first examined a large group of normal subjects using the dynamic pedobarograph. The second was identical to the first except that the EMED F system was used. The second study was carried out in order to verify existing results and to assess the clinical significance of the expected differences. Comparison of the results from the two studies showed that the median peak pressures demonstrated similar patterns with the highest pressure in the forefoot under the second/third metatarsal heads and the toes taking gradually reduced pressure from the first to the fifth toe. The EMED F showed higher peak pressures than the dynamic pedobarograph under the heel, the medial four metatarsal heads, and the great toe and showed lower peak pressures and shorter contact times under the lateral four toes. The pattern of loading across the metatarsal heads was further analyzed using an objective method of splitting the subjects into groups. Four groups were isolated from both sets of results, and this has confirmed that only a proportion of normal subjects demonstrate highest loading under the first metatarsal head whereas the remainder show highest loading centrally within the forefoot.

Adult↗