Electrodynographic evaluation of the foot during treadmill versus overground locomotion

1994 ◽  
Vol 84 (12) ◽  
pp. 598-606 ◽  
Author(s):  
B Van Gheluwe ◽  
J Smekens ◽  
P Roosen
Keyword(s):  
Statistical Analysis ◽  
Loading Rate ◽  
Peak Pressure ◽  
Ground Contact ◽  
Foot Pressure ◽  
Foot Function ◽  
Running Maximum ◽  
Propulsion Phase ◽  
Dynamic Variables ◽  
Different Parts

Biomechanical foot function as expressed by the duration of successive ground contact phases and by dynamic variables, such as the peak pressure on different parts of the foot, their respective loading rate, and duration, is compared for two walking and running conditions: overground on a 20-m walkway and on a treadmill. Statistical analysis revealed foot pressure characteristics as measured with a Electrodynogram during walking and running to alter significantly when using a treadmill. The differences were more pronounced for walking than for running. During walking, loading of the forefoot tends to last longer (longer propulsion phase) on a treadmill. Loading rate is decreased for the whole foot during either walking or running. Maximum heel pressure is diminished for walking but increased during running on a treadmill. Moderate variations of treadmill velocity were shown to have no significant influence on the measurements.

Changes in Plantar Foot Pressure with In-Shoe Varus or Valgus Wedging

2004 ◽  
Vol 94 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Bart Van Gheluwe ◽  
Howard J. Dananberg
Keyword(s):  
Pressure Distribution ◽  
Loading Rate ◽  
Peak Pressure ◽  
Center Of Pressure ◽  
Scientific Evidence ◽  
Peak Load ◽  
Foot Orthoses ◽  
Foot Pressure ◽  
Custom Made

Varus and valgus wedging are commonly used by podiatric physicians in therapy with custom-made foot orthoses. This study aimed to provide scientific evidence of the effects on plantar foot pressure of applying in-shoe forefoot or rearfoot wedging. The plantar foot pressure distribution of 23 subjects walking on a treadmill was recorded using a pressure insole system for seven different wedging conditions, ranging from 3° valgus to 6° varus for the forefoot and from 4° valgus to 8° varus for the rearfoot. The results demonstrate that increasing varus wedging magnifies peak pressure and maximal loading rate at the medial forefoot and rearfoot, whereas increasing valgus wedging magnifies peak pressure and maximal loading rate at the lateral forefoot and rearfoot. As expected, the location of the center of pressure shifts medially with varus wedging and laterally with valgus wedging. However, these shifts are less significant than those in peak load and maximal loading rate. Timing variables such as interval from initial impact to peak load do not seem to be affected by forefoot or rearfoot wedging. Finally, rearfoot wedging does not significantly influence pressure variables of the forefoot; similarly, rearfoot pressure remains unaffected by forefoot wedging. (J Am Podiatr Med Assoc 94(1): 1-11, 2004)

Implementation

The Age of Em ◽  
2016 ◽  
Author(s):  
Robin Hanson
Keyword(s):  
Statistical Analysis ◽  
Facial Expressions ◽  
Internal State ◽  
The Other ◽  
Subjective Time ◽  
Brain States ◽  
Tone Of Voice ◽  
Different Parts ◽  
Average State ◽  
Complete Match

Compared with ordinary humans, it is much easier to directly read the internal state of an em mind. This should allow some types of “mindreading.” Consider taking two ems and trying to match parts in one of them to parts in the other, to say which parts are the “same.” during the early opaque em era it will usually not be possible to make a complete match. Even so, some parts could be matched, such as the parts that receive initial inputs from eyes and ears. For matched parts, it should be possible to put the parts of one emulation into the same brain activation state as that of the matching parts in another emulation. So, for example, one might force an emulation to see and hear exactly what another emulation sees and hears. More parts can be matched for emulations of the same original human, especially if they have diverged for a shorter subjective time. Such more closely matched emulations could thus be arranged to more fully “read” each other’s minds. Mild mindreading might be used to allow ems to better intuit and share their reaction to a particular topic or person. For example, a group of ems might all try to think at the same time about a particular person, say “George.” Then their brain states in the region of their minds associated with this thought might be weakly driven toward the average state of this group. In this way this group might come to intuitively feel how the group feels on average about George. Of course this should work better for closer copies, and after this exercise participating individuals might still return to something close to their previous opinions of George. Even when minds cannot be matched part for part, statistical analysis of how activation in different parts and situations correlates with actions and stated feelings should allow cheap partial mindreading, at least for some shallow “surface” aspects of emulation minds. Both of these types of mindreading require access to the internal state of an emulation process. Those not granted such access have an even weaker ability to read minds than do humans today. Today, humans routinely leak many features of their brain states via tone of voice, gaze, facial expressions, muscle vibrations, etc.

scholarly journals Analysis of Differences in the Degree of Biomechanical Adaptation according to Habituation to Different Heel Heights

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yu-Jin Cha
Keyword(s):  
Peak Pressure ◽  
Plantar Flexion ◽  
Muscle Tension ◽  
Surface Emg ◽  
Foot Pressure ◽  
Maximum Voluntary Isometric Contraction ◽  
Heel Height ◽  
High Maximum ◽  
Eyes Open ◽  
Balance Ability

This study aims to comprehensively investigate whether there are any differences in the degree of biomechanical adaptation according to habituation to different heel heights. The biomechanical characteristics of 54 subjects in 3 groups habituated to three heel heights (low, medium-high, and high heels) were evaluated by the measurement of surface EMG, myotonometer (e.g., measurement of muscle tension), foot pressure, and lumbosacral angle, and comparative analysis was carried out to find out whether they showed differences in the comfort visual analog scale (comfort VAS). Wearers of high-heeled shoes (6 cm or more in heel height), in foot pressure comparison, showed significantly high peak pressure in the mask of the hallux, high maximum peak EMG in the gastrocnemius medius (GM), and a high percentage of maximum voluntary isometric contraction (%MVIC) in the plantar flexor. Wearers of low-heeled shoes (3 cm and below in heel height) showed the highest plantar peak pressure in the lateral forefoot and midfoot, the highest contact area in midfoot, the highest %MVIC in the plantar flexion and dorsiflexion of the tibialis anterior (TA), and the highest stiffness in the TA, and they showed the lowest static balance ability with eyes open (EO) among the three groups. It was found that there were significant differences between those habituated to high-heeled shoes and those not habituated to high-heeled shoes and that longtime wearing of high-heeled shoes brings about biomechanical adaptive changes in the human body.

scholarly journals Do Strike Patterns or Shoe Conditions Have a Predominant Influence on Foot Loading?

2018 ◽  
Vol 64 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Xiaole Sun ◽  
Yang Yang ◽  
Lin Wang ◽  
Xini Zhang ◽  
Weijie Fu
Keyword(s):  
Plantar Pressure ◽  
Loading Rate ◽  
Peak Pressure ◽  
Impact Force ◽  
Pressure System ◽  
Risk Of Injury ◽  
Maximum Loading ◽  
Peak Plantar Pressure ◽  
Foot Loading ◽  
The Impact

Abstract This study aimed to explore the effects of strike patterns and shoe conditions on foot loading during running. Twelve male runners were required to run under shoe (SR) and barefoot conditions (BR) with forefoot (FFS) and rearfoot strike patterns (RFS). Kistler force plates and the Medilogic insole plantar pressure system were used to collect kinetic data. SR with RFS significantly reduced the maximum loading rate, whereas SR with FFS significantly increased the maximum push-off force compared to BR. Plantar pressure variables were more influenced by the strike patterns (15 out of 18 variables) than shoe conditions (7 out of 18 variables). The peak pressure of midfoot and heel regions was significantly increased in RFS, but appeared in a later time compared to FFS. The influence of strike patterns on running, particularly on plantar pressure characteristics, was more significant than that of shoe conditions. Heel-toe running caused a significant impact force on the heel, whereas wearing cushioned shoes significantly reduced the maximum loading rate. FFS running can prevent the impact caused by RFS. However, peak plantar pressure was centered at the forefoot for a long period, thereby inducing a potential risk of injury in the metatarsus/phalanx.

scholarly journals Foot Insole Pressure Distribution during the Golf Swing in Professionals and Amateur Players

2021 ◽  
Vol 12 (1) ◽  
pp. 358
Author(s):  
Enrique Navarro ◽  
José M. Mancebo ◽  
Sima Farazi ◽  
Malena del Olmo ◽  
David Luengo
Keyword(s):  
Statistical Analysis ◽  
Pressure Distribution ◽  
Distribution Pattern ◽  
Video Camera ◽  
Golf Swing ◽  
Foot Pressure ◽  
Significant Difference ◽  
Reaction Forces ◽  
Left And Right ◽  
Weight Transfer

There are numerous articles that study the ground reaction forces during the golf swing, among which only a few analyze the pressure pattern distributed on the entire surface of the foot. The current study compares the pressure patterns on the foot insoles of fifty-five golfers, from three different performance levels, playing swings with driver and 5-iron clubs in the driving range. Five swings were selected for each club. During each swing, ultra-thin insole sensors (4 sensors/cm^2) measure foot pressure at the frequency of 100 Hz. To perform statistical analysis, insole sensors are clustered to form seven areas, with the normalized pressure of each area being our dependent variable. A video camera was used to label the five key instants of the swing. Statistical analysis demonstrates a significant difference between the pressure distribution pattern of the left and right feet for both driver and 5-iron. However, the pressure distribution pattern remains almost the same when switching the club type from 5-iron to driver. We have also observed that there are significant differences between the pattern of professionals and players with medium and high handicap. The obtained pattern agrees with the principle of weight transfer with a different behavior between the medial and lateral areas of the foot.

Material Properties of the Plantar Aponeurosis

1994 ◽  
Vol 15 (10) ◽  
pp. 557-560 ◽  
Author(s):  
Harold B. Kitaoka ◽  
Zong Ping Luo ◽  
Eric S. Growney ◽  
Lawrence J. Berglund ◽  
Kai-Nan An
Keyword(s):  
Material Properties ◽  
Loading Rate ◽  
Video Tracking ◽  
Two Dimensional ◽  
Plantar Aponeurosis ◽  
Tracking Method ◽  
Loading Rates ◽  
Failure Loads ◽  
Foot Function

Material properties of the plantar aponeurosis were determined by a two-dimensional video tracking method to simultaneously measure the aponeurosis deformation. Failure loads averaged 1189 ± 244 N and were higher in men. Average stiffness of the intact fascia was 203.7 ± 50.5 N/mm at a loading rate of 11.12 N/sec and it did not vary significantly for the loading rates of 11.12 to 1112 N/sec. The high tensile loads required for failure were consistent with clinical and biomechanical studies and indicated the importance of the aponeurosis in foot function and arch stability.

scholarly journals The Relationship Between Whole-Body External Loading and Body-Worn Accelerometry During Team-Sport Movements

2017 ◽  
Vol 12 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Niels J. Nedergaard ◽  
Mark A. Robinson ◽  
Elena Eusterwiemann ◽  
Barry Drust ◽  
Paulo J. Lisboa ◽  
...  
Keyword(s):  
Loading Rate ◽  
Mechanical Load ◽  
Statistical Parametric Mapping ◽  
Team Sport ◽  
Whole Body ◽  
External Loading ◽  
Ground Contact ◽  
Peak Acceleration ◽  
Contact Phase ◽  
The Relationship

Purpose:To investigate the relationship between whole-body accelerations and body-worn accelerometry during team-sport movements.Methods:Twenty male team-sport players performed forward running and anticipated 45° and 90° side-cuts at approach speeds of 2, 3, 4, and 5 m/s. Whole-body center-of-mass (CoM) accelerations were determined from ground-reaction forces collected from 1 foot–ground contact, and segmental accelerations were measured from a commercial GPS accelerometer unit on the upper trunk. Three higher-specification accelerometers were also positioned on the GPS unit, the dorsal aspect of the pelvis, and the shaft of the tibia. Associations between mechanical load variables (peak acceleration, loading rate, and impulse) calculated from both CoM accelerations and segmental accelerations were explored using regression analysis. In addition, 1-dimensional statistical parametric mapping (SPM) was used to explore the relationships between peak segmental accelerations and CoM-acceleration profiles during the whole foot–ground contact.Results:A weak relationship was observed for the investigated mechanical load variables regardless of accelerometer location and task (R2 values across accelerometer locations and tasks: peak acceleration .08–.55, loading rate .27–.59, and impulse .02–.59). Segmental accelerations generally overestimated whole-body mechanical load. SPM analysis showed that peak segmental accelerations were mostly related to CoM accelerations during the first 40–50% of contact phase.Conclusions:While body-worn accelerometry correlates to whole-body loading in team-sport movements and can reveal useful estimates concerning loading, these correlations are not strong. Body-worn accelerometry should therefore be used with caution to monitor whole-body mechanical loading in the field.

Pressure distribution beneath the human foot

1993 ◽  
Vol 83 (12) ◽  
pp. 674-678 ◽  
Author(s):  
PJ Bennett ◽  
LR Duplock
Keyword(s):  
Close Agreement ◽  
Reference Range ◽  
Healthy Adult ◽  
Force Plate ◽  
Descriptive Study ◽  
Foot Pressure ◽  
Normal Reference Range ◽  
Human Foot ◽  
Foot Function ◽  
Temporal And Spatial

A descriptive study was undertaken to establish the 95 percentile limits (proposed normal reference range) for pressure beneath the hallux, metatarsal heads, and heel in a group of healthy adult subjects. A new force plate device capable of accurately measuring discrete areas of pressure beneath the human foot with high temporal and spatial resolution was used. The system is capable of accurately measuring plantar foot pressure during dynamic and static foot function. The results of this research are in close agreement with other published studies of plantar foot pressure measurement with comparable systems.

scholarly journals Adaptation of Running Biomechanics to Repeated Barefoot Running: A Randomized Controlled Study

2019 ◽  
Vol 47 (8) ◽  
pp. 1975-1983 ◽  
Author(s):  
Karsten Hollander ◽  
Dominik Liebl ◽  
Stephanie Meining ◽  
Klaus Mattes ◽  
Steffen Willwacher ◽  
...  
Keyword(s):  
Passive Control ◽  
Loading Rate ◽  
Control Group ◽  
Ground Reaction Forces ◽  
Ground Contact ◽  
Barefoot Running ◽  
Loading Rates ◽  
Foot Strike ◽  
Reaction Forces ◽  
Running Biomechanics

Background: Previous studies have shown that changing acutely from shod to barefoot running induces several changes to running biomechanics, such as altered ankle kinematics, reduced ground-reaction forces, and reduced loading rates. However, uncertainty exists whether these effects still exist after a short period of barefoot running habituation. Purpose/Hypothesis: The purpose was to investigate the effects of a habituation to barefoot versus shod running on running biomechanics. It was hypothesized that a habituation to barefoot running would induce different adaptations of running kinetics and kinematics as compared with a habituation to cushioned footwear running or no habituation. Study Design: Controlled laboratory study. Methods: Young, physically active adults without experience in barefoot running were randomly allocated to a barefoot habituation group, a cushioned footwear group, or a passive control group. The 8-week intervention in the barefoot and footwear groups consisted of 15 minutes of treadmill running at 70% of VO2 max (maximal oxygen consumption) velocity per weekly session in the allocated footwear. Before and after the intervention period, a 3-dimensional biomechanical analysis for barefoot and shod running was conducted on an instrumented treadmill. The passive control group did not receive any intervention but was also tested prior to and after 8 weeks. Pre- to posttest changes in kinematics, kinetics, and spatiotemporal parameters were then analyzed with a mixed effects model. Results: Of the 60 included participants (51.7% female; mean ± SD age, 25.4 ± 3.3 years; body mass index, 22.6 ± 2.1 kg·m-2), 53 completed the study (19 in the barefoot habituation group, 18 in the shod habituation group, and 16 in the passive control group). Acutely, running barefoot versus shod influenced foot strike index and ankle, foot, and knee angles at ground contact ( P < .001), as well as vertical average loading rate ( P = .003), peak force ( P < .001), contact time ( P < .001), flight time ( P < .001), step length ( P < .001), and cadence ( P < .001). No differences were found for average force ( P = .391). After the barefoot habituation period, participants exhibited more anterior foot placement ( P = .006) when running barefoot, while no changes were observed in the footwear condition. Furthermore, barefoot habituation increased the vertical average loading rates in both conditions (barefoot, P = .01; shod, P = .003) and average vertical ground-reaction forces for shod running ( P = .039). All other outcomes (ankle, foot, and knee angles at ground contact and flight time, contact time, cadence, and peak forces) did not change significantly after the 8-week habituation. Conclusion: Changing acutely from shod to barefoot running in a habitually shod population increased the foot strike index and reduced ground-reaction force and loading rates. After the habituation to barefoot running, the foot strike index was further increased, while the force and average loading rates also increased as compared with the acute barefoot running situation. The increased average loading rate is contradictory to other studies on acute adaptations of barefoot running. Clinical Relevance: A habituation to barefoot running led to increased vertical average loading rates. This finding was unexpected and questions the generalizability of acute adaptations to long-term barefoot running. Sports medicine professionals should consider these adaptations in their recommendations regarding barefoot running as a possible measure for running injury prevention. Registration: DRKS00011073 (German Clinical Trial Register).

A Comparison Study of Plantar Foot Pressure in a Standardized Shoe, Total Contact Cast, and Prefabricated Pneumatic Walking Brace

1997 ◽  
Vol 18 (1) ◽  
pp. 26-33 ◽  
Author(s):  
J.F. Baumhauer ◽  
R. Wervey ◽  
J. McWilliams ◽  
G.F. Harris ◽  
M.J. Shereff
Keyword(s):  
Peak Pressure ◽  
Foot Pressure ◽  
Total Contact Cast ◽  
Recommended Treatment ◽  
Time Integral ◽  
Custom Made ◽  
Plantar Ulcers ◽  
Total Contact Casting ◽  
Peak Pressures ◽  
Sensor Locations

Total contact casting is the current recommended treatment for Wagner Stage 1 and 2 neuropathic plantar ulcers. The rationale for this treatment includes the equalization of plantar foot pressures and generalized unweighting of the foot through a total contact fit at the calf. Total contact casting requires meticulous technique and multiple cast applications to avoid complications before ulcer healing. An alternative to total contact casting is the use of a prefabricated brace designed to maintain a total contact fit. This study compares plantar foot pressure metrics in a standardized shoe (SS), total contact cast (TCC), and prefabricated pneumatic walking brace (PPWB). Five plantar foot sensors (Interlink Electronics, Santa Barbara, CA) were placed at the first, third, and fifth metatarsal heads, fifth metatarsal base, and midplantar heel of 10 healthy male subjects. Each subject walked at a constant speed over a distance of 280 meters in a SS, PPWB, and TCC. A custom-made portable microprocessor-based system, with demonstrated accuracy and reliability, was used to acquire the data. No significant differences in peak pressure or contact duration were found between the initial and repeat SS trials ( P > 0.05). Peak pressures were reduced in the PPWB as compared to the SS for all sensor locations ( P < 0.05). Similarly, peak pressures were reduced in the TCC compared to the SS for all sensor locations ( P < 0.05) with the exception of the fifth metatarsal base ( P = 0.45). Our results are summarized as follows: (1) the methods used in the current study were found to be reliable through a test-retest analysis; (2) the PPWB decreased peak plantar foot pressures to an equal or greater degree than the TCC in all tested locations of the forefoot, midfoot, and hindfoot; (3) compared to a SS, contact durations were increased in both the TCC and PPWB for most sensor locations; and (4) the relationship of peak pressure over time, the pressure-time integral, is lower in the brace compared to the shoe at the majority of sensor locations. The values are not significantly different between the cast and shoe. These findings suggest an unweighting of the plantar foot and equalization of plantar foot pressures with both the PPWB and TCC. Based on these findings, the PPWB may be useful in the treatment of neuropathic plantar ulcerations of the foot.

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