Application of Center-of-Pressure Data to Indicate Rearfoot Inversion-Eversion in Shod Running

2006 ◽  
Vol 96 (4) ◽  
pp. 305-312 ◽  
Author(s):  
Sharon J. Dixon
Keyword(s):  
Range Of Motion ◽  
Center Of Pressure ◽  
Correlation Coefficients ◽  
Ground Contact ◽  
Pressure Data ◽  
Contact Phase ◽  
Movement Data ◽  
Versus Peak ◽  
Rearfoot Eversion ◽  
Selection Of

Although pressure plates are used to help in the selection of appropriate footwear for runners, evidence relating aspects of pressure data to movement is lacking. A study was conducted to investigate whether center-of-pressure (COP) data obtained for shod running could be used to indicate the amount of rearfoot eversion. It was hypothesized that subjects exhibiting high rearfoot eversion during the initial ground contact phase of running would also show a large lateral-to-medial deviation in the COP. Pressure plate and rearfoot movement data were collected for 33 subjects. The COP was characterized using the lateral-to-medial deviation of the COP during the eversion phase of ground contact. Correlation coefficients were determined for COP deviation versus rearfoot range of motion and versus peak rearfoot eversion (P < .05). In addition, subjects were grouped as high, moderate, or low pronators, and analysis of variance was used to test whether there were significant differences in COP deviation for these three groups (P < .05). The COP deviation was found to have a low correlation with rearfoot range of motion (R = 0.46; P < .05) and with peak rearfoot eversion (R = .54; P < .05). High pronators had significantly higher COP deviation than the medium- and low-pronation groups (P < .05). These findings support the use of COP deviation to detect high pronation. However, caution is advised in using the COP to indicate absolute rearfoot eversion. (J Am Podiatr Med Assoc 96(4): 305–312, 2006)

Reliability and Validity of Center-of-Pressure Quantification

2003 ◽  
Vol 93 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Mark W. Cornwall ◽  
Thomas G. McPoil
Keyword(s):  
Center Of Pressure ◽  
Pearson Correlation ◽  
Phase 1 ◽  
Intraclass Correlation ◽  
Reliability And Validity ◽  
Correlation Coefficients ◽  
Frontal Plane ◽  
Area Index ◽  
Rearfoot Eversion ◽  
Medial Area

The purpose of this study was to determine the reliability and validity of two center-of-pressure quantification methods. One hundred five individuals (33 men and 72 women) with a mean age of 26.7 years participated in phase 1 of the study. Two measures of the center-of-pressure pattern, the lateral-medial area index and the lateral-medial force index, were calculated from plantar pressure data collected on all subjects. Between-trial reliability of the two measurements was assessed using intraclass correlation coefficients. In phase 2, frontal plane motion of the rearfoot was recorded in 30 individuals. Pearson correlation coefficients were then calculated between the two center-of-pressure indices and the magnitude of rearfoot eversion obtained from each subject during walking. Intraclass correlation coefficient values ranged from 0.374 to 0.889 for the lateral-medial area index and from 0.215 to 0.905 for the lateral-medial force index. Pearson correlation coefficients between the two center-of-pressure indices and the rearfoot kinematic variables ranged from 0.050 to 0.165. The lateral-medial area index and the lateral-medial force index may have adequate between-trial reliability but are not related to the magnitude of frontal plane rearfoot eversion during the stance phase of walking. (J Am Podiatr Med Assoc 93(2): 142-149, 2003)

IMPROVEMENT OF SPRING DURUM WHEAT SELECTION METHODOLOGIES UNDER CLIMATE CHANGE CONDITIONS

1970 ◽  
pp. 33-36
Author(s):  
А. I. Grabovets ◽  
V. P. Kadushkina ◽  
S. А. Kovalenko
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Correlation Coefficient ◽  
Harvest Index ◽  
Unit Area ◽  
Correlation Coefficients ◽  
Chemical Mutagenesis ◽  
Main Method ◽  
The Relationship ◽  
Selection Of

With the growing aridity of the climate on the Don, it became necessary to improve the methodology for conducting the  breeding of spring durum wheat. The main method of obtaining the source material remains intraspecific step hybridization. Crossings were performed between genetically distant forms, differing in origin and required traits and properties. The use of chemical mutagenesis was a productive way to change the heredity of genotypes in terms of drought tolerance. When breeding for productivity, both in dry years of research and in favorable years, the most objective markers were identified — the size of the aerial mass, the mass of grain per plant, spike, and harvest index. The magnitude of the correlation coefficients between the yield per unit area and the elements of its structure is established. It was most closely associated with them in dry years, while in wet years it decreased. Power the correlation of the characteristics of the pair - the grain yield per square meter - the aboveground biomass averaged r = 0.73, and in dry years it was higher (0.91) than in favorable ones (0.61 - 0.70) , between the harvest and the harvest index - r = 0.81 (on average). In dry years, the correlation coefficient increased to 0.92. Research data confirms the greatest importance of the mass of grain from one ear and the plant in the formation of grain yield per unit area in both dry and wet years. In dry years, the correlation coefficient between yield and grain mass per plant was on average r = 0.80; in favorable years, r = 0.69. The relationship between yield and grain mass from the ear was greater — r = 0.84 and r = 0.82, respectively. Consequently, the breeding significance of the aboveground mass and the productivity of the ear, as a criterion for the selection of the crop, especially increases in the dry years. They were basic in the selection.

Biomechanics Differ for Individuals With Similar Self-Reported Characteristics of Patellofemoral Pain During a High-Demand Multiplanar Movement Task

2020 ◽  
pp. 1-10
Author(s):  
Matthew K. Seeley ◽  
Seong Jun Son ◽  
Hyunsoo Kim ◽  
J. Ty Hopkins
Keyword(s):  
Ground Reaction Force ◽  
Injury Risk ◽  
Reaction Force ◽  
Patellofemoral Pain ◽  
Joint Torque ◽  
Whole Body ◽  
Ground Contact ◽  
High Demand ◽  
Contact Phase ◽  
Hip Extension

Context: Patellofemoral pain (PFP) is often categorized by researchers and clinicians using subjective self-reported PFP characteristics; however, this practice might mask important differences in movement biomechanics between PFP patients. Objective: To determine whether biomechanical differences exist during a high-demand multiplanar movement task for PFP patients with similar self-reported PFP characteristics but different quadriceps activation levels. Design: Cross-sectional design. Setting: Biomechanics laboratory. Participants: A total of 15 quadriceps deficient and 15 quadriceps functional (QF) PFP patients with similar self-reported PFP characteristics. Intervention: In total, 5 trials of a high-demand multiplanar land, cut, and jump movement task were performed. Main Outcome Measures: Biomechanics were compared at each percentile of the ground contact phase of the movement task (α = .05) between the quadriceps deficient and QF groups. Biomechanical variables included (1) whole-body center of mass, trunk, hip, knee, and ankle kinematics; (2) hip, knee, and ankle kinetics; and (3) ground reaction forces. Results: The QF patients exhibited increased ground reaction force, joint torque, and movement, relative to the quadriceps deficient patients. The QF patients exhibited: (1) up to 90, 60, and 35 N more vertical, posterior, and medial ground reaction force at various times of the ground contact phase; (2) up to 4° more knee flexion during ground contact and up to 4° more plantarflexion and hip extension during the latter parts of ground contact; and (3) up to 26, 21, and 48 N·m more plantarflexion, knee extension, and hip extension torque, respectively, at various times of ground contact. Conclusions: PFP patients with similar self-reported PFP characteristics exhibit different movement biomechanics, and these differences depend upon quadriceps activation levels. These differences are important because movement biomechanics affect injury risk and athletic performance. In addition, these biomechanical differences indicate that different therapeutic interventions may be needed for PFP patients with similar self-reported PFP characteristics.

scholarly journals Assessing Plyometric Ability during Vertical Jumps Performed by Adults and Adolescents

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 132 ◽  
Author(s):  
Brandon Snyder ◽  
Shawn Munford ◽  
Chris Connaboy ◽  
Hugh Lamont ◽  
Shala Davis ◽  
...  
Keyword(s):  
Contact Time ◽  
Analysis Data ◽  
Adolescent Male ◽  
Ground Contact ◽  
Strength Index ◽  
Basketball Players ◽  
Contact Phase ◽  
Adult Men ◽  
Drop Jumps ◽  
Vertical Jumps

The purpose of this study was to compare different methods for assessing plyometric ability during countermovement (CMJ) and drop jumps (DJ) in a group of adults and adolescents. Ten resistance-trained adult men (age: 22.6 ± 1.6 years) and ten adolescent male basketball players (age: 16.5 ± 0.7 years) performed a CMJ and a DJ from a height of 0.40 m. Jump height (JH), contact time, normalized work (WNORM), and power output (PONORM) during the absorption and propulsion phases were calculated from force platforms and 3-D motion analysis data. Plyometric ability was assessed using the modified reactive strength index (RSIMOD during CMJ) and the reactive strength index (RSI during DJ) as well as three indices using propulsion time, propulsion work (PWI), and propulsion power. Adults jumped significantly higher than adolescents (mean difference [MD]: 0.05 m) while JH (MD: 0.05 m) and ground contact time (MD: 0.29 s) decreased significantly from CMJ to DJ. WNORM (MD: 4.2 J/kg) and PONORM (MD: 24.2 W/kg) during the absorption phase of CMJ were significantly less than these variables during the propulsion phases of the jumps. The reactive strength index variants increased significantly from the CMJ to DJ (MD: 0.23) while all other plyometric indices decreased significantly. Neither RSIMOD nor RSI contributed significantly to the prediction of JH during CMJ and DJ, respectively, while PWI was able to explain ≥68% of the variance in JH. Variants of the reactive strength index do not reflect the changes in mechanical variables during the ground contact phase of CMJ and DJ and may not provide an accurate assessment of plyometric ability during different vertical jumps.

Intensity- and muscle-specific fascicle behavior during human drop jumps

2007 ◽  
Vol 102 (1) ◽  
pp. 382-389 ◽  
Author(s):  
F. Sousa ◽  
M. Ishikawa ◽  
J. P. Vilas-Boas ◽  
P. V. Komi
Keyword(s):  
Length Change ◽  
Medial Gastrocnemius ◽  
Ground Contact ◽  
Contact Phase ◽  
Drop Jumps ◽  
Synergistic Muscles ◽  
Braking Phase ◽  
Whole Muscle ◽  
Specific Length

The present study was designed to examine fascicle-tendon interaction in the synergistic medial gastrocnemius (MG) and soleus (Sol) muscles during drop jumps (DJ) performed from different drop heights (DH). Eight subjects performed unilateral DJ with maximal rebounds on a sledge apparatus from different DH. During the exercises, fascicle lengths (using ultrasonography) and electromyographic activities were recorded. The results showed that the fascicles of the MG and Sol muscles behaved differently during the contact phase, but the whole muscle-tendon unit and its tendinous tissue lengthened before shortening in both muscles. The Sol fascicles also lengthened before shortening during the ground contact in all conditions. During the braking phase, the Sol activation increased with increasing DH. However, the amplitude of Sol fascicle lengthening was not dependent on DH during the same phase. In the MG muscle, the fascicles primarily shortened during the braking phase in the lower DH condition. However, in the higher DH conditions, the MG fascicles either behaved isometrically or were lengthened during the braking phase. These results suggest that the fascicles of synergistic muscles (MG and Sol) can behave differently during DJ and that, with increasing DH, there may be specific length change patterns of the fascicles of MG but not of Sol.

Effect of Foot Morphology on Center-of-Pressure Excursion During Barefoot Walking

2008 ◽  
Vol 98 (2) ◽  
pp. 112-117 ◽  
Author(s):  
Lilian Wong ◽  
Adrienne Hunt ◽  
Joshua Burns ◽  
Jack Crosbie
Keyword(s):  
Regional Differences ◽  
Center Of Pressure ◽  
Pressure Data ◽  
Lateral Border ◽  
Foot Posture Index ◽  
Posture Index ◽  
Foot Posture ◽  
Foot Morphology ◽  
The Relationship

Background: The path of the center of pressure during walking varies among individuals by deviating to a greater or lesser extent toward the medial or lateral border of the foot. It is unclear whether this variance is systematic and is affected by foot posture. The aim of this study was to explore the relationship between foot morphology and center-of-pressure excursion during barefoot walking. Methods: Pressure data were collected from 83 participants whose foot type had been classified as supinated, normal, or pronated according to the Foot Posture Index. Three center-of-pressure variables were analyzed: medial excursion area, lateral excursion area, and total excursion area. Results: Across the spectrum of foot types, we found that the more supinated a participant’s foot posture, the larger the area of lateral center-of-pressure excursion, and, conversely, the more pronated the foot posture, the smaller the area of lateral center-of-pressure excursion. Furthermore, the supinated foot type had a relatively larger center-of-pressure total excursion area, and the pronated foot type had a relatively smaller center-of-pressure total excursion area. Conclusions: These results indicate the importance of assessing foot posture when measuring center of pressure and may help explain regional differences in pain and injury location among foot types. (J Am Podiatr Med Assoc 98(2): 112–117, 2008)

scholarly journals Influence of Foot Progression Angle on Center of Pressure During Stair Ascending in Subjects With Chronic Ankle Instability

2021 ◽  
Vol 15 ◽  
pp. 350-354
Author(s):  
Jung-Hyun Ban ◽  
Tae-Ho Kim
Keyword(s):  
Center Of Pressure ◽  
Ankle Instability ◽  
Chronic Ankle Instability ◽  
Foot Progression Angle ◽  
Significant Difference ◽  
The Stability ◽  
Neutral Posture ◽  
Criteria For Selection ◽  
Anterior Posterior ◽  
Selection Of

The purpose of this study was to identify changes in the center of pressure during stair ascending in subjects with chronic ankle instability while different angles of foot are applied. The subjects of this study were 20 male and female adults with chronic ankle instability were selected from among the employees of D Hospital in Daegu Metropolitan City. The criteria for selection of subjects with chronic ankle instability were those who felt wobbling in the ankle joint and scored not higher than 24 points in a test using the Cumberland Ankle Instability Tool (CAIT). The subjects carried out stair ascending in neutral, toe-in and toe-out postures, respectively, and changes in the center of pressure (COP) were compared and analyzed. The results of this study, no statistically significant difference appeared in the comparison between the toe-in posture and neutral posture or between the neutral posture and the toe-out posture but medial/lateral movements of the center of pressure showed significant differences between the toe-in and toe-out postures. In addition, the total travel range and the moving range of the center of pressure, the average velocity, and the anterior/posterior movements of the center of pressure showed no statistically significant difference among all three postures. As a result, it could be seen that when adults with chronic ankle instability climb the stairs, the toe-in posture reduce the medial/lateral movements of the center of pressure thereby increasing the stability of the ankle and effectively preventing re-injuries.

scholarly journals A comparison of two techniques for center of pressure measurements

2020 ◽  
Vol 7 ◽  
pp. 205566832092106
Author(s):  
Jessica DeBerardinis ◽  
Conner Neilsen ◽  
Daniel E Lidstone ◽  
Janet S Dufek ◽  
Mohamed B Trabia
Keyword(s):  
Strong Correlation ◽  
Path Length ◽  
Center Of Pressure ◽  
Single Step ◽  
Segment Length ◽  
Pressure Measurements ◽  
Pressure Data ◽  
Limited Sample ◽  
New Methods ◽  
Comparable Accuracy

Introduction Force platforms and pressure-measuring insoles are the most common tools used for measuring center of pressure. Earlier studies to assess these instruments suffered from limited sample sizes or an inadequate range of participant foot sizes. The purpose of this study was to propose new methods to extract and calculate comparably accurate center of pressure for the Kistler® force platform and Medilogic® insoles. Methods Center of pressure data were collected from 65 participants wearing pressure-measuring insoles (six different sizes). Participants walked over consecutive force platforms for three trials while wearing pressure-measuring insoles within socks. Onset force thresholds and center of pressure segment length thresholds were used to determine accurate center of pressure path length and width. A single step for each foot and trial was extracted from both instruments. Results A strong correlation was observed between instruments in center of pressure length (4.12 ± 6.72% difference, r = 0.74). Center of pressure width varied and was weakly correlated (–7.04 ± 4.48% difference, r = 0.11). Conclusions The results indicate that both instruments can measure center of pressure path length consistently and with comparable accuracy (differences < 10%). There were differences between instruments in measuring center of pressure path width, which were attributed to the limited number of sensors across the width of the insoles.

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