Symmetry of plantar pressures and vertical forces in healthy subjects during walking.

The purpose of this study was to determine the degree of symmetry for in-shoe plantar pressure and vertical force patterns between the left and right feet of healthy subjects during walking. Thirty subjects with a mean age of 29.6 years participated in the study. Each subject walked a distance of 8 m three times while in-shoe plantar pressure and vertical force data were collected. A total of 12 steps were analyzed for both feet, and maximum vertical force, peak pressure, and pressure-time integrals were calculated for four plantar regions of the foot. No differences in the three variables were noted between male and female subjects. Plantar pressure and vertical force patterns were found to be symmetrical between the left and right feet, except for two of the four plantar regions studied. Only the forefoot and rearfoot regions were found to show significant differences between the left and right feet for plantar pressure and vertical force, respectively. The degree of asymmetry for these two plantar regions in the same foot, however, was minimal.

Velocity of the center of pressure during walking.

The purpose of this study was to describe the velocity of the center of pressure during walking in a sample of young, healthy individuals. The velocity of the center of pressure was recorded in 60 subjects while they walked barefoot over a floor-mounted pressure platform. The results of this study indicate that the velocity of the center of pressure follows a predictable pattern during the stance phase of walking. Intraclass correlation coefficients calculated to measure between-trial reliability for specific parameters of the velocity of the center of pressure ranged from 0.361 to 0.912. These study results suggest that velocity of the center of pressure may be a useful measurement in future gait research.

The effect of foot orthoses on transverse tibial rotation during walking.

The purpose of this study was to determine the effectiveness of two types of foot orthoses in controlling the magnitude and rate of internal tibial rotation, measured by the tibial pointer device, during walking. Ten subjects between the ages of 23 and 43 years volunteered to participate in the study. Prior to data collection, each subject was issued two types of foot orthoses: a pair of rigid, plastic orthoses with posting in either the forefoot or the rearfoot, and a pair of soft, accommodative, premolded orthoses with no posting. All subjects wore standardized footwear. Following a controlled break-in period for both footwear and orthoses, each subject was asked to walk at a self-selected speed over a 12-m walkway while the movement of internal tibial rotation was recorded with a video camera during five trials. The results indicated that both the rigid plastic and the accommodative foot orthoses significantly reduced the magnitude and the rate of internal tibial rotation. No significant difference was noted between the soft and rigid foot orthoses conditions.

Plantar fasciitis: etiology and treatment.

Plantar fasciitis is a common pathological condition of the foot and can often be a challenge for clinicians to successfully treat. The purpose of this article is to present and discuss selected literature on the etiology and clinical outcome of treating plantar fasciitis. Surgical and nonsurgical techniques have been used in the treatment of plantar fasciitis. Nonsurgical management for the treatment of the symptoms and discomfort associated with plantar fasciitis can be classified into 3 broad categories: reducing pain and inflammation, reducing tissue stress to a tolerable level, and restoring muscle strength and flexibility of involved tissues. Each of these treatments has demonstrated some level of effectiveness in alleviating the symptoms of plantar fasciitis. Previous studies have grouped all forms of nonsurgical therapy together. It is, therefore, difficult to determine if one type of treatment is more effective compared with another. Until such research is available, the clinician would be wise to include treatments from all 3 categories.

Variability of plantar pressure data. A comparison of the two-step and midgait methods.

The number of trials required to obtain a reliable representation of the plantar pressure pattern is an important factor in the assessment of people with insensate feet or the use of plantar pressure data as a basis for fabrication of foot orthoses. Traditionally, the midgait method has been used for the collection of pressure data, but the large number of walking trials required by this method can increase the risk of injury to the plantar surface of the insensate foot. As a result, the two-step method of plantar pressure data collection has been advocated. The purpose of this investigation was to determine the degree of variability in regional plantar pressure measurements using the midgait and two-step methods of data collection. Plantar pressure data were collected from ten volunteers (five men and five women) between the ages of 20 and 35 years in 20 trials using both data-collection protocols. The results of the study indicate that three to five walking trials are needed to obtain reliable regional peak pressure and pressure-time integral values when the two-step data-collection protocol is used. Although either method can be used for pressure data collection, one method should be used consistently when repeated assessments are required.

Relative movement of the navicular bone during normal walking.

The purpose of this study was to determine the pattern and magnitude of navicular bone (NB) movement during walking as well as the relationship between dynamic NB and rearfoot movement. The angle of rearfoot and displacement of the NB was recorded in 106 subjects using the 6D Research electromagnetic tracking system. The relative change in the height of the NB between foot flat and heel-off was 7.9 mm. The NB seems to undergo significant vertical as well as medial displacement during the stance phase of normal walking. This motion is also correlated with rearfoot motion during walking.

Effect of ankle dorsiflexion range of motion on rearfoot motion during walking.

The purpose of this study was to investigate whether the amount of ankle passive dorsiflexion range of motion influences the pattern of frontal plane rearfoot motion during walking. Three-dimensional motion of the rearfoot was measured in two groups of subjects, those with ankle passive dorsiflexion range of motion less than or equal to 10 degrees, and those with ankle passive dorsiflexion range of motion greater than 15 degrees, while they walked along a 6.1-m walkway. The results indicated that the only statistically significant differences between the two groups were in the time to reinversion of the rearfoot and the time to heel-off. Slight-to-moderate limitation of ankle passive dorsiflexion range of motion significantly alters the timing, but not the magnitude, of frontal plane rearfoot motion during walking.

Three-dimensional movement of the foot during the stance phase of walking.

This study presents research on typical movement of the rearfoot during walking. The data demonstrate the global nature of foot pronation and supination during gait. Study participants (N = 153) walked along a walkway while the angular displacement of the calcaneus, navicular, and first metatarsal relative to the tibia was measured; three-dimensional movement patterns for all three bones were very similar. This study provides additional information on how the foot functions during walking. This information should help to define and refine clinical management strategies for treating foot dysfunction.

Variability of the center of pressure pattern integral during walking.

The objective of this study was to measure the between-trial variability of the center of pressure pattern integral (COPPI) at the shoe-floor interface and within the shoe. Ten trials of the COPPI were recorded simultaneously at the shoe-floor interface and within the shoe as ten subjects walked over ground in standardized footwear and with two types of foot orthoses. While the results showed that the within-shoe shoe-only and soft orthoses conditions caused the greatest decrease in the COPPI, it was extremely inconsistent-between trials, whether measured at the shoe-floor interface or within the shoe. This suggests that the COPPI is not an acceptable method of assessing the effectiveness of foot orthoses.

A comparison of two motion analysis systems for the measurement of two-dimensional rearfoot motion during walking.

The purpose of this study was to compare two-dimensional rearfoot motion during walking measured by a traditional video-based motion analysis system to that of an electromagnetic analysis system. Twenty-five individuals (15 men, 10 women) with a mean age of 29.8 years served as subjects for this study. The results of the study showed that there was a high correlation (r = 0.945) between the mean motion paths produced by the two systems, indicating that they were very similar. The electromagnetic motion analysis system was able to produce these similar results in a fraction of the time required by the video-based system.

The relationship between static lower extremity measurements and rearfoot motion during walking.

Despite the fact that clinicians regularly perform static lower extremity measurements on their patients, to date, little research has been published supporting their ability to predict dynamic rearfoot motion. The abilities of static measurements to predict dynamic foot motion could have important implications considering the fact that excessive rearfoot motion has been associated with various injuries of the lower extremity. The purpose of this study, therefore, was to determine if static lower extremity measurements could be used to predict the magnitude of rearfoot motion during walking. Rearfoot motion of each lower extremity was measured from videotape in 27 healthy young adult subjects with a mean age of 26.1 years. In addition, 17 static measurements were measured and recorded bilaterally for each subject. The results of a multiple regression analysis indicated that the only variable that was able to predict maximum rearfoot pronation was the "difference in navicular height" (r2 = .17). None of the 17 measurements were found to predict time to maximum pronation. These results indicate that static measurements of the lower extremity and foot are poor predictors of dynamic rearfoot motion as measured by maximum pronation or time to maximum pronation in healthy individuals without severe foot deformities.

Relationship between three static angles of the rearfoot and the pattern of rearfoot motion during walking.

The purpose of this study was to determine the relationship of the static angle of the rearfoot during single leg standing, relaxed standing foot posture, and subtalar joint neutral position with the pattern of rearfoot motion during walking. The authors felt that this study was important to gain a better understanding of the relationship between dynamic rearfoot motion and three static rearfoot angles which are often included in foot examination procedures. The pattern of rearfoot motion was assessed using two-dimensional video recordings for each lower extremity of 31 healthy young adult subjects with a mean age of 25.2 years. The mean path of rearfoot motion during walking crossed relaxed standing foot posture but did not cross single leg standing or subtalar neutral position. These findings suggest that the mean path of rearfoot motion during the first 60% of the walking cycle occurs between the static angles of relaxed standing foot posture and single leg standing. In addition, the static angle of the rearfoot in single leg standing may serve as a clinical indicator of the degree of maximum rearfoot eversion occurring during the walking cycle.

Variations in foot volume before and after exercise.

Foot volume measurements were taken on 12 feet of nine female intercollegiate volleyball players (mean age of 20 years) before and after a 2-hr rigorous practice session. No significant difference was found between foot volume before and after exercise. A slight reduction in the foot volume after exercise was noted in comparison with the foot volume before exercise. These findings suggest that fitting footwear with extra space in front of the longest toe to accommodate changes in foot length associated with foot volume increases following exercise is not necessary. However, providing extra space in front of the longest toe during shoe fitting should still be considered in order to accommodate anterior sliding of the foot during athletic activities.

A comparison of the dynamic pedobarograph and EMED systems for measuring dynamic foot pressures.

The purpose of this study was to compare the peak pressure and peak force values obtained from two pressure assessment systems, the Dynamic Pedobarograph and the EMED SF. Twenty-one individuals with a mean age of 31.6 years walked barefoot over both systems using a two-step data collection protocol. Peak plantar pressures and peak vertical force values were measured under the heel, central forefoot, hallux, and entire foot for both systems. The results of this study demonstrated that the EMED SF system produced larger peak pressures under the central forefoot and hallux. The Pedobarograph, on the other hand, produced greater pressures under the heel and entire foot. With respect to peak vertical forces, the Pedobarograph showed significantly greater values under the heel and central forefoot compared with the EMED SF, but were significantly lower under the hallux and entire foot.

Footwear and foot orthotic effectiveness research: a new approach.

Measurement of calcaneal inversion and eversion during walking is limited when subjects wear shoes. The authors of this study propose the use of transverse tibial rotation as a viable alternative measurement when barefoot assessment is not possible. The purpose of this study, therefore, was to: 1) determine the relationship between transverse tibial rotation and rearfoot motion during the stance phase of normal walking and 2) demonstrate the usefulness of measuring transverse tibial rotation when evaluating the effect of footwear and insole foot orthotic devices. Part 1 consisted of eight volunteers (five women, three men) whose rearfoot and transverse tibial motion was videotaped while they walked along a 12-m walkway. The results of this study showed that although absolute values were not comparable, the two motion patterns are related to each other. The correlation between the mean rearfoot and tibial motion patterns of all 16 feet was r = .953. Part 2 investigated the effect of footwear and orthotics on transverse tibial rotation using two case presentations. A video camera was positioned in front of each subject as they walked at a self-selected speed under various footwear or orthotic conditions. The results of the case studies revealed that footwear or foot orthotics decrease maximum tibial internal rotation compared with barefoot walking. In addition, internal tibial rotation velocity and acceleration were decreased by the use of shoes, an accommodative orthosis, and an inflatable medial longitudinal arch support. A rigid orthotic produced a slight increase in transverse tibial rotation and a dramatic increase in transverse tibial acceleration.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of rearfoot motion in overground versus treadmill walking.

The purpose of this study was to determine whether walking on a treadmill is a valid simulator of overground walking with respect to rearfoot motion. The tibial, calcaneal, and rearfoot motions of 10 subjects (2 males, 8 females) were videotaped while they walked on a treadmill and overground. The results of a series of t-tests showed that there was no statistically significant difference between the two conditions on any of the variables measured.

Motion of the first metatarsophalangeal joint. Reliability and validity of four measurement techniques.

The purpose of this study was to first determine the intra-rater reliability of four different static measurement procedures used to assess first metatarsophalangeal joint extension range of motion and, second, determine which of the four static procedures provided a valid measure of the amount of first metatarsophalangeal joint extension required for normal walking. Twenty healthy adult subjects between the ages of 21 and 43 years participated in the study. Four static techniques were evaluated and dynamic first metatarsophalangeal joint extension was also determined from video recordings during walking. The results indicate that 1) all static measurement techniques were reliable; 2) the degree of first metatarsophalangeal joint extension obtained for each of the four static measurement techniques exceeded the amount of first metatarsophalangeal joint extension required for walking; 3) although each of the static measurement techniques was reliable, they should not be considered interchangeable; and 4) approximately 65 degrees of first metatarsophalangeal joint extension are required for normal walking.

Comparison of 2-dimensional and 3-dimensional rearfoot motion during walking.

The purpose of this study was to investigate the validity of two-dimensional (2-D) analysis with respect to three-dimensional (3-D) analysis for recording rearfoot motion during walking. The results of this study indicated that rearfoot motion measured with either 2-D or 3-D analysis is essentially the same for the initial 60% of the stance phase. There was no significant difference between the two methods on variables typically measured in studies dealing with rearfoot motion. RELEVANCE: The assessment of rearfoot motion during walking in a clinical situation is frequently desirable yet the high cost of equipment and time required for 3-D analysis makes it unreasonable or impractical. The results of this study show that 2-D analysis can be used to measure rearfoot motion accurately and therefore is feasible for use in the clinic.

Comparison of three methods for obtaining plantar pressures in nonpathologic subjects.

The purpose of this study was to determine if pressure data, collected after taking one step or two steps, were similar to values obtained by using the traditional midgait method. Ten healthy subjects, with a mean age of 27 years, walked across a sensor platform sampling at 70 Hz. Each subject was randomly assigned to take one step, two steps, or multiple steps (midgait method) across the sensor platform. The results of the study indicate that the two-step method, in comparison with the one-step method, provides pressure data more representative of the midgait method, and different values for pressure and force will be obtained, depending on the method of pressure data collection selected by the clinician.

Pulmonary function test outcomes in healthy Navajo Native American adolescents.

Prediction equations for estimating lung volumes have been determined for Caucasians, African-Americans, and Mexican-Americans. These separate equations were determined because of differences in thoracic morphology between people of various racial groups, making it impossible to use one prediction formula to accurately estimate lung volumes for all individuals. One hundred ninety-one adolescent Navajo children (males, n = 110; females, n = 81) between 11 and 18 yr of age volunteered for the study and underwent a series of pulmonary function tests (PFT). New pulmonary function prediction equations for Navajo youth were generated for estimating pulmonary volumes and capacities that more accurately predict expected PFT outcomes than formulas in common use for Caucasian, Mexican-American, or African-American youth.