scholarly journals Shock absorption during transtibial amputee gait: Does longitudinal prosthetic stiffness play a role?

2016 ◽  
Vol 41 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Erin Boutwell ◽  
Rebecca Stine ◽  
Steven Gard
Keyword(s):  
Ground Reaction Force ◽  
Repeated Measures ◽  
Reaction Force ◽  
Shock Absorption ◽  
Appreciable Change ◽  
Normal Medium ◽  
Gait Biomechanics ◽  
Wide Range ◽  
Significant Difference ◽  
Transtibial Prosthesis

Background:Reduced-stiffness components are often prescribed in lower-limb prostheses, but their efficacy in augmenting shock absorption has been inconclusive.Objectives:To perform a systematic variation of longitudinal prosthetic stiffness over a wide range of values and to evaluate its effect on shock absorption during gait.Study design:Repeated-measures crossover experiment.Methods:Twelve subjects with a unilateral transtibial amputation walked at normal and fast self-selected speeds. Longitudinal prosthetic stiffness was modified by springs within a shock-absorbing pylon: normal (manufacturer recommended), 75% of normal (medium), 50% of normal (soft), and rigid (displacement blocked). The variables of interest were kinematic (stance-phase knee flexion and pelvic obliquity) and kinetic (prosthetic-side ground reaction force loading peak magnitude and timing).Results:No changes were observed in kinematic measures during gait. A significant difference in peak ground reaction force magnitudes between medium and normal ( p = 0.001) during freely selected walking was attributed to modified walking speed ( p = 0.008). Ground reaction force peaks were found to be statistically different during fast walking, but only between isolated stiffness conditions. Thus, altering longitudinal prosthesis stiffness produced no appreciable change in gait biomechanics.Conclusion:Prosthesis stiffness does not appear to substantially influence shock absorption in transtibial prosthesis users.Clinical relevanceVarying the level of longitudinal prosthesis stiffness did not meaningfully influence gait biomechanics at self-selected walking speeds. Thus, as currently prescribed within a transtibial prosthesis, adding longitudinal stiffness in isolation may not provide the anticipated shock absorption benefits. Further research into residual limb properties and compensatory mechanisms is needed.

Alterations in Peak Ground-Reaction Force During 60-cm Drop Landings Caused by a Single Session of Repeated Wingate Anaerobic Tests

2012 ◽  
Vol 21 (4) ◽  
pp. 306-312 ◽  
Author(s):  
David J Dominguese ◽  
Jeff Seegmiller ◽  
B. Andrew Krause
Keyword(s):  
Muscle Fatigue ◽  
Outcome Measures ◽  
Ground Reaction Force ◽  
Repeated Measures ◽  
Reaction Force ◽  
Lower Extremity Injury ◽  
Single Session ◽  
Drop Landing ◽  
Significant Difference ◽  
Drop Landings

Context:Lower extremity injury is prevalent among individuals participating in sports. Numerous variables have been reported as predisposing risk factors to injury; however, the effects of muscle fatigue on landing kinetics are unclear.Objectives:To investigate the effects of a single session of repeated muscle fatigue on peak vertical ground-reaction force (GRF) during drop landings.Design:Mixed factorial with repeated measures.Setting:Controlled laboratory.Participants:10 female and 10 male healthy recreational athletes.Intervention:Subjects performed 3 fatigued drop landings (60 cm) after four 20-s Wingate anaerobic tests (WATs) with 5 min of active recovery between fatigued conditions.Main Outcome Measures:Kinetic data of peak forefoot (F1) force, peak rear-foot (F2) force, and anteroposterior (AP) and mediolateral (ML) forces at both F1 and F2.Results:A significant main effect was observed in the nonfatigued and fatigued drop landings in respect to peak F2 force. The greatest significant difference was shown between the first fatigued drop-landing condition and the last fatigued drop-landing condition. No significant difference was observed between genders for all GRF variables across fatigue conditions.Conclusion:A single session of repeated conditions of anaerobic muscle fatigue induced by WATs caused an initial reduction in peak F2 force followed by an increase in peak F2 force across conditions. Muscle fatigue consequently alters landing kinetics, potentially increasing the risk of injury.

Measurements of Vertical Ground Reaction Force in Jumping Dogs

1992 ◽  
Vol 05 (02) ◽  
pp. 44-50 ◽  
Author(s):  
D. A. Hulse ◽  
H. A. Hogan ◽  
Margaret Slater ◽  
M. T. Longnecker ◽  
Susan Yanoff
Keyword(s):  
Body Weight ◽  
Ground Reaction Force ◽  
Repeated Measures ◽  
Reaction Force ◽  
Force Plate ◽  
Vertical Ground Reaction Force ◽  
Significant Difference ◽  
Working Dogs ◽  
Vertical Ground ◽  
Military Working Dogs

SummaryThe purpose of this study was: to quantitate the peak vertical ground reaction force acting on the forelimbs of dogs as they landed after jumping an obstacle; to compare that force at three heights; and to evaluate factors that may affect vertical ground reaction force. Thirteen military working dogs were studied. A strain gauge force plate was used to measure force. Three measurements were recorded for each dog at each height. The means of the medians of the three forces for each dog at each height were compared using a repeated measures analysis of variance. Mean force at 63 cm was 986.9 ± 221.5 N, mean force at 79 cm was 1175.0 ±227.4 N, and mean force at 94 cm was 1366.1± 268.5 N. There was a significant difference in mean force at the three jump heights (p = 0.0002). The significance was unchanged when force was normalized for body weight. Statistical models were used to evaluate the effect of other independent variables. Factors that were found to effect force were body weight, breed, and sex of the dog. Further studies are needed to determine the clinical significance of these findings.Vertical ground reaction force was measured in thirteen dogs landing on a force plate after jumping an obstacle. Three readings were taken for each dog at each of three heights, and the mean vertical ground reaction force was compared. Force readings were significantly different at each height, increasing as height increased. Factors that were found to effect vertical ground reaction force were body weight, breed, and sex.

Effect of Hopping Frequency on Bilateral Differences in Leg Stiffness

2013 ◽  
Vol 29 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Hiroaki Hobara ◽  
Koh Inoue ◽  
Kazuyuki Kanosue
Keyword(s):  
Ground Reaction Force ◽  
Center Of Mass ◽  
Reaction Force ◽  
Human Movement ◽  
Vertical Ground Reaction Force ◽  
Mass Model ◽  
Lower Extremity Injuries ◽  
Leg Stiffness ◽  
Significant Difference ◽  
Bilateral Differences

Understanding the degree of leg stiffness during human movement would provide important information that may be used for injury prevention. In the current study, we investigated bilateral differences in leg stiffness during one-legged hopping. Ten male participants performed one-legged hopping in place, matching metronome beats at 1.5, 2.2, and 3.0 Hz. Based on a spring-mass model, we calculated leg stiffness, which is defined as the ratio of maximal ground reaction force to maximum center of mass displacement at the middle of the stance phase, measured from vertical ground reaction force. In all hopping frequency settings, there was no significant difference in leg stiffness between legs. Although not statistically significant, asymmetry was the greatest at 1.5 Hz, followed by 2.2 and 3.0 Hz for all dependent variables. Furthermore, the number of subjects with an asymmetry greater than the 10% criterion was larger at 1.5 Hz than those at 2.2 and 3.0 Hz. These results will assist in the formulation of treatment-specific training regimes and rehabilitation programs for lower extremity injuries.

Does Delivery Length Impact Measures of Whole-Body Biomechanical Load During Pace Bowling?

2020 ◽  
Vol 15 (10) ◽  
pp. 1485-1489
Author(s):  
Samuel J. Callaghan ◽  
Robert G. Lockie ◽  
Walter Yu ◽  
Warren A. Andrews ◽  
Robert F. Chipchase ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Repeated Measures ◽  
Reaction Force ◽  
Practical Importance ◽  
Whole Body ◽  
Loading Rates ◽  
Biomechanical Loading ◽  
Repeated Measures Analysis ◽  
Load Monitoring ◽  
Monitoring Practice

Purpose: To investigate whether changes in delivery length (ie, short, good, and full) lead to alterations in whole-body biomechanical loading as determined by ground reaction force during front-foot contact of the delivery stride for pace bowlers. Current load-monitoring practices of pace bowling in cricket assume equivocal biomechanical loading as only the total number of deliveries are monitored irrespective of delivery length. Methods: A total of 16 male pace bowlers completed a 2-over spell at maximum intensity while targeting different delivery lengths (short, 7–10 m; good, 4–7 m; and full, 0–4 m from the batter’s stumps). In-ground force plates were used to determine discrete (vertical and braking force, impulse, and loading rates) and continuous front-foot contact ground reaction force. Repeated-measures analysis of variance (P < .05), effects size, and statistical parametrical mapping were used to determine differences between delivery lengths. Results: There were no significant differences between short, good, and full delivery lengths for the discrete and continuous kinetic variables investigated (P = .19–1.00), with trivial to small effect sizes. Conclusion: There were minimal differences in front-foot contact biomechanics for deliveries of different lengths (ie, short, good, and full). These data reinforce current pace bowling load-monitoring practices (ie, counting the number of deliveries), as changes in delivery length do not affect the whole-body biomechanical loading experienced by pace bowlers. This is of practical importance as it retains simplicity in load-monitoring practice that is used widely across different competition levels and ages.

scholarly journals The Kinematics and Kinetics Analysis of the Lower Extremity in the Landing Phase of a Stop-jump Task

2015 ◽  
Vol 9 (1) ◽  
pp. 103-107 ◽  
Author(s):  
L Yin ◽  
D Sun ◽  
Q.C Mei ◽  
Y.D Gu ◽  
J.S Baker ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Ground Reaction Force ◽  
Knee Flexion ◽  
Reaction Force ◽  
Flexion Angle ◽  
Contact Phase ◽  
Peak Knee ◽  
Significant Difference ◽  
The Impact ◽  
Kinematics And Kinetics

Large number of studies showed that landing with great impact forces may be a risk factor for knee injuries. The purpose of this study was to illustrate the different landing loads to lower extremity of both genders and examine the relationships among selected lower extremity kinematics and kinetics during the landing of a stop-jump task. A total of 35 male and 35 female healthy subjects were recruited in this study. Each subject executed five experiment actions. Lower extremity kinematics and kinetics were synchronously acquired. The comparison of lower extremity kinematics for different genders showed significant difference. The knee and hip maximum flexion angle, peak ground reaction force and peak knee extension moment have significantly decreased during the landing of the stop-jump task among the female subjects. The hip flexion angle at the initial foot contact phase showed significant correlation with peak ground reaction force during landing of the stop-jump task (r=-0.927, p<0.001). The knee flexion angle at the initial foot contact phase had significant correlation with peak ground reaction force and vertical ground reaction forces during landing of the stop-jump task (r=-0.908, p<0.001; r=0.812, P=0.002). A large hip and knee flexion angles at the initial foot contact with the ground did not necessarily reduce the impact force during landing, but active hip and knee flexion motions did. The hip and knee flexion motion of landing was an important technical factor that affects anterior cruciate ligament (ACL) loading during the landing of the stop-jump task.

scholarly journals Effectiveness of Insole Colour on Impact Loading and Lower-Limb Kinematics When Running at Preferred and Nonpreferred Speeds

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yi Wang ◽  
Wing-Kai Lam ◽  
Lok-Yee Pak ◽  
Charis K.-W. Wong ◽  
Mohammad F. Tan ◽  
...  
Keyword(s):  
Impact Loading ◽  
Ground Reaction Force ◽  
Lower Limb ◽  
Repeated Measures ◽  
Loading Rate ◽  
Reaction Force ◽  
Human Perception ◽  
Movement Variability ◽  
Mean Values ◽  
Maximum Loading

While colour of red can play a significant role in altering human perception and performances, little is known about its perceptual-motor effect on running mechanics. This study examined the effects of variations in insole colours on impact forces, ankle kinematics, and trial-to-trial reliability at various running speeds. Sixteen male recreational runners ran on instrumented treadmill at slow (90%), preferred (100%), and fast (110%) running speeds when wearing insoles in red, blue, and white colours. We used synchronized force platform and motion capturing system to measure ground reaction force, ankle sagittal and frontal kinematics, and movement variability. A two-way (colour x speed) ANOVA with repeated measures was performed with Bonferroni adjusted post hoc comparisons, with alpha set at 0.05. Data analyses indicated that participants demonstrated higher impact and maximum loading rate of ground reaction force, longer stride length, shorter contact time, and smaller touchdown ankle inversion as well as larger ankle sagittal range of motion (RoM), but smaller frontal RoM in fast speed as compared with preferred P < 0.05 and slow speeds P < 0.001 . Although insole colour had minimal effect on mean values of any tested variables P > 0.05 , participants wearing red-coloured orthoses showed higher coefficient of variation values for maximum loading rate than wearing blue insoles P = 0.009 . These results suggest that running at faster speed would lead to higher impact loading and altered lower-limb mechanics and that colour used on the tops of insoles influences the wearers’ movement repeatability, with implications for use of foot insole in running.

scholarly journals Vertical ground reaction force analysis during gait with unstable shoes

2015 ◽  
Vol 28 (3) ◽  
pp. 459-466
Author(s):  
Giulia Pereira ◽  
Aluísio Otavio Vargas Avila ◽  
Rudnei Palhano
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Force Plate ◽  
Vertical Ground Reaction Force ◽  
Significant Difference ◽  
Vertical Ground ◽  
The Subject ◽  
Unstable Shoes ◽  
The Right ◽  
The Impact

AbstractIntroduction Footwear is no longer just an accessory but also a protection for the musculoskeletal system, and its most important characteristic is comfort.Objectives This study aims to identify and to analyze the vertical ground reaction force in barefoot women and women with unstable shoes.Methodology Five women aged 25 ± 4 years old and mass of 50 ± 7 kg participated in this study. An AMTI force plate was used for data acquisition. The 10 trials for each situation were considered valid where the subject approached the platform with the right foot and at the speed of 4 km/h ± 5%. The instable shoe of this study is used in the practice of physical activity.Results The results showed that the first peak force was higher for the footwear situation, about 5% and significant differences between the barefoot and footwear situation. This significant difference was in the first and second peaks force and in the time of the second peak.Conclusion The values showed that the footwear absorbs approximately 45% of the impact during gait.

Effect of alveolar hypoxia on pulmonary fluid filtration in in situ dog lungs

1988 ◽  
Vol 65 (1) ◽  
pp. 46-52 ◽  
Author(s):  
L. A. Homik ◽  
Z. Bshouty ◽  
R. B. Light ◽  
M. Younes
Keyword(s):  
Repeated Measures ◽  
Edema Formation ◽  
Fluid Filtration ◽  
Wide Range ◽  
Significant Difference ◽  
Co2 Balance ◽  
Alveolar Hypoxia ◽  
Group 2 ◽  
Pulmonary Microcirculation

We have studied the effect of alveolar hypoxia on fluid filtration characteristics of the pulmonary microcirculation in an in situ left upper lobe preparation with near static flow conditions (20 ml/min). In six dogs (group 1), rate of edema formation (delta W/delta t, where W is weight and t is time) was assessed over a wide range of vascular pressures under two inspired O2 fraction (FIO2) conditions (0.95 and 0.0 with 5% CO2-balance N2 in both cases). delta W/delta t was plotted against vascular pressure, and the best-fit linear regression was obtained. There was no significant difference (paired t test) in either threshold pressure for edema formation [18.3 +/- 1.8 and 17.1 +/- 1.2 (SE) mmHg, respectively] or the slopes (0.067 +/- 0.008 and 0.073 +/- 0.017 g.min-1. mmHg-1.100g-1, respectively). In another seven dogs (group 2), delta W/delta t was obtained at a constant vascular pressure of 40 mmHg under four FIO2 conditions (0.95, 0.21, 0.05, and 0.0, with 5% CO2-balance N2). Delta W/delta t for the four conditions averaged 0.60 +/- 0.11, 0.61 +/- 0.11, 0.61 +/- 0.10, and 0.61 +/- 0.10 (SE) g.min-1.mmHg-1.100g-1, respectively. No significant differences (ANOVA for repeated measures) were noted. We conclude that alveolar hypoxia does not alter the threshold for edema formation or delta W/delta t at a given microvascular pressure.

Vertical ground reaction force in stationary running in water and on land: A study with a wide range of cadences

2018 ◽  
Vol 58 ◽  
pp. 279-286 ◽  
Author(s):  
Heiliane de Brito Fontana ◽  
Caroline Ruschel ◽  
Elisa Dell'Antonio ◽  
Alessandro Haupenthal ◽  
Gustavo Soares Pereira ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Vertical Ground Reaction Force ◽  
Wide Range ◽  
Vertical Ground

A Subject Specific Kinematic and Kinetic Relationship During a Single-Leg Drop Landing

2012 ◽  
Author(s):  
Chi-Yin Tse ◽  
Hamid Nayeb-Hashemi ◽  
Ashkan Vaziri ◽  
Paul K. Canavan
Keyword(s):  
Ground Reaction Force ◽  
Knee Flexion ◽  
Reaction Force ◽  
Vertical Ground Reaction Force ◽  
Valgus Angle ◽  
Drop Landing ◽  
Average Maximum ◽  
Significant Difference ◽  
Subject Specific ◽  
Vertical Ground

A single-leg landing is a common type of high-risk maneuver performed by athletes. The majority of anterior cruciate ligament injury is accounted for by non-contact mechanisms, such as single-leg landings. The purpose of this study was to develop a subject specific single-leg drop landing to analyze the kinematics and kinetics of two different types of landings. Kinematic data was analyzed at five points during the landing phase: initial contact (IC), peak vertical ground reaction force (pVGRF), peak joint reaction force (pJRF), maximum knee flexion (MKF), and maximum valgus angle (MFP). A linear relationship was noted in comparing the average maximum peak vertical ground reaction force, average maximum knee flexion, and average maximum valgus angle to the platform heights in both landing styles. An increase in platform height was directly related to increased knee valgus angle in both landing styles. Significant difference (p < 0.05) was noted in the peak vertical ground reaction force between the 60% and 80% platform heights, as well as between 60% and 100% with arms above. Landing with arms across the body yielded more significant difference (p < 0.05) between platform heights in both frontal and sagittal planes. However, comparing both landing styles to each other only yielded significant difference (p < 0.05) at the 100% platform height. A valgus-varus-valgus movement was observed in all landings, and is a probable contributor to single-leg landing ACL ruptures.

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