scholarly journals The effect of graded knee brace at two angles of 60 and 30 degrees on the frequency spectrum of ground reaction forces in individuals with genu valgum during landing

2021 ◽  
Vol 43 (2) ◽  
pp. 220-229
Author(s):  
AmirAli Jafarnezhadgero ◽  
Arefeh Mokhtari Malek Abadi ◽  
Ali Yadegar ◽  
Farshad Ghorbanloo ◽  
Aydin Valizadeh Orang
Keyword(s):  
Frequency Spectrum ◽  
Effect Size ◽  
Genu Valgum ◽  
Ground Reaction Forces ◽  
Median Frequency ◽  
Force Frequency ◽  
Frequency Content ◽  
Knee Brace ◽  
High Effect ◽  
Reaction Forces

Background: Genu valgum is a postural malalignment in the knee joint. This malalignment is accompanied by altered mechanical forces in the tibiofemoral and patellofemoral joints. The purpose of this study was to investigate the effect of using a graded knee brace in two angles of 60 and 30 degrees on the frequency spectrum of ground reaction forces in individuals with genu valgum during landing. Methods: The present study was semi-experimental. Twenty non-athlete male students with genu valgus (age range: 20-30 years) were volunteered to participate in the study. The landing task was done during three conditions including without a knee brace, with a brace at two 30 and 60 degrees of flexion from a height of equal to 30 cm. Bertec force plate was used to record ground reaction forces. Fourier transform was used to calculate ground reaction force-frequency content during both landing conditions with and without a knee brace. Results: The results of this study showed a significant reduction in the frequency content with a power of 99.5% in the mediolateral direction (P=0.02; high effect size) and vertical direction (P=0.075; high effect effect) during landing with a knee brace at 60 degrees of flexion angle compared with without knee brace condition. Also, the median frequency component in the mediolateral direction (P=0.019; low effect size) and in the anterior-posterior direction (P=0.019; high effect effect) showed a significant decrease during wearing a knee brace compared with without it. Conclusion: Regarding the decreasing of median frequency after using the knee brace, it might be effective in the reduction of injury rate in individuals with genu valgum. However, further study warranted to better establish this issue.

scholarly journals The acute effect of using of texture foot orthoses on ground reaction forces in older adults during walking

2021 ◽  
Vol 42 (6) ◽  
pp. 756-763
Author(s):  
Aydin Valizadeh orang ◽  
Arefeh Mokhtari Malekabadi ◽  
AmirAli Jafarnezhadgero
Keyword(s):  
Older Adults ◽  
Frequency Spectrum ◽  
Force Plate ◽  
Acute Effect ◽  
Comfort Level ◽  
Ground Reaction Forces ◽  
Median Frequency ◽  
Foot Orthoses ◽  
Lower Limb Muscles ◽  
Reaction Forces

Background:Walking is one the common daily activities. With the beginning of middle age, weakness in the lower limb muscles can reduce the ability to walk. The use of foot orthoses reduce the load on the limbs and supports the joints during walking. The purpose of the present study was to investigate the acute effect of foot orthoses on the frequency spectrum of ground reaction forces during walking in the older adults. Methods: In this semi-experimental and laboratory study, 21 elderly (15 females and 6 males) with a mean height of 164.19±4.26 centimeters and weight of 80.04±3.50 kg, and age of 66.00±3.50 years were volunteered to participate in the study. The walking trials were done during three conditions including walking without foot orthoses, walking with small and large textured orthoses. The Bertec force plate (made in USA) with dimensions of 40 * 60 cm was used to record ground reaction forces. Results: The results of this study did not show any significant differences between walking without foot orthoses, walking with small and large textured foot orthoses for frequency of 99.5%, median frequency, frequency band and number of essential harmonics (P>0.05). However, the comfort level during wearing of large texture insole condition significantly increased compared to other conditions (P<0.05). Conclusion: The textured foot orthoses do not affect the frequency spectrum of ground reaction forces; however, it improves the comfort of the individual while walking.

scholarly journals Frequency Domain analysis of Ground reaction forces in Deaf and blind people during walking

2021 ◽  
Author(s):  
mohsen barghamadi ◽  
mohammad Abdollahpour Darvishani
Keyword(s):  
Frequency Domain ◽  
Vertical Component ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Therapeutic Interventions ◽  
Control Group ◽  
Ground Reaction Forces ◽  
Blind People ◽  
Frequency Content ◽  
Reaction Forces

Background: The link between Frequency domain analysis of ground reaction forces and hearing loss and blind during walking is not well understood. Therefore, the purpose of this study was to investigate frequency domain analysis of ground reaction forces in deaf and blind people during walking. Methods: This study was quasi-experimental. The volunteer participants in current study consisted of thirty male that, were divided into three equal groups: blind, deaf and healthy (control) groups. Frequency Domain analysis of ground reaction forces in three groups was recorded by a foot scan system (sample rate: 300 Hz). The multivariate ANOVA test was used to compare between groups. The significance level was set at p < 0.05 for all analyses. Results: The results showed that, the frequency content with the power 99.5% in the vertical component of ground reaction forces in both deaf (p=0.020) and blind (p=0.021) groups reduced vs. control group. Also, frequency content with the power 99.5% in the Mid-foot in deaf (p=0.020) group was more than the blind group (p=0.036). Conclusion: The present study showed that the frequency content with the power 99.5% in the Mid-foot in deaf group was more than the blind group. It can be stated that the frequency domain analysis of ground reaction forces has the clinical value. Therefore, the use of therapeutic interventions to improve the frequency domain analysis of ground reaction forces in deaf and blind people is suggested.

Functional knee brace use effect on peak vertical ground reaction forces during drop jump landing

2012 ◽  
Vol 20 (12) ◽  
pp. 2405-2412 ◽  
Author(s):  
Neetu Rishiraj ◽  
Jack E. Taunton ◽  
Robert Lloyd-Smith ◽  
William Regan ◽  
Brian Niven ◽  
...  
Keyword(s):  
Ground Reaction Forces ◽  
Drop Jump ◽  
Knee Brace ◽  
Jump Landing ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

Immediate Effects of a Knee Brace with a Constraint to Knee Extension on Knee Kinematics and Ground Reaction Forces in a Stop-Jump Task

2004 ◽  
Vol 32 (5) ◽  
pp. 1136-1143 ◽  
Author(s):  
Bing Yu ◽  
Daniel Herman ◽  
Jennifer Preston ◽  
William Lu ◽  
Donald T. Kirkendall ◽  
...  
Keyword(s):  
Knee Kinematics ◽  
Knee Extension ◽  
Ground Reaction Forces ◽  
Knee Brace ◽  
Reaction Forces

Force-Velocity-Power Profiling During Weighted-Vest Sprinting in Soccer

2019 ◽  
Vol 14 (6) ◽  
pp. 747-756 ◽  
Author(s):  
Jorge Carlos-Vivas ◽  
Elena Marín-Cascales ◽  
Tomás T. Freitas ◽  
Jorge Perez-Gomez ◽  
Pedro E. Alcaraz
Keyword(s):  
Effect Size ◽  
Power Output ◽  
Field Method ◽  
Maximum Power ◽  
Soccer Players ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Time Data ◽  
Reaction Forces ◽  
Force Velocity

Purpose: To describe the load–velocity relationship and the effects of increasing loads on spatiotemporal and derived kinetic variables of sprinting using weighted vests (WV) in soccer players and determining the load that maximizes power output. Methods: A total of 23 soccer players (age 20.8 [1.5] y) performed 10 maximal 30-m sprints wearing a WV with 5 different loads (0%, 10%, 20%, 30%, and 40% body mass [BM]). Sprint velocity and time were collected using a radar device and wireless photocells. Mechanical outputs were computed using a recently developed valid and reliable field method that estimates the step-averaged ground-reaction forces during overground sprint acceleration from anthropometric and spatiotemporal data. Raw velocity–time data were fitted by an exponential function and used to calculate the net horizontal ground-reaction forces and horizontal power output. Individual linear force–velocity relationships were then extrapolated to calculate the theoretical maximum horizontal force (F0) and velocity and the ratio of force application (proportion of the total force production that is directed forward at sprint start). Results: Magnitude-based inferences showed an almost certain decrease in F0 (effect size = 0.78–3.35), maximum power output (effect size = 0.78–3.81), and maximum ratio of force (effect size = 0.82–3.87) as the load increased. The greatest changes occurred with loads heavier than 20% BM, especially in ratio of force. In addition, the maximum power was achieved under unloaded conditions. Conclusions: Increasing load in WV sprinting affects spatiotemporal and kinetic variables. The greatest change in ratio of force happened with loads heavier than 20% BM. Thus, the authors recommend the use of loads ≤20% BM for WV sprinting.

Catapult start likely improves sprint start performance

2021 ◽  
pp. 174795412110151
Author(s):  
Ryu Nagahara ◽  
Sam Gleadhill
Keyword(s):  
Effect Size ◽  
Force Production ◽  
Technical Training ◽  
Ground Reaction Forces ◽  
Control Effect ◽  
Forward Motion ◽  
Sprint Time ◽  
Reaction Forces ◽  
External Power

Sprint technical training, named the catapult start, is defined as partner assisted pulling of the hip backward at the set position and during block clearance, released by the forward motion of the athlete. This study investigated the characteristics of the catapult start and its influence on the following sprint start performance. Fourteen male sprinters performed a single 15-m control, catapult, and post-catapult sprint starts, during which ground reaction forces (GRFs) were measured using force platforms. All measured GRF variables during the block clearance, except for the impulses and mean forces on the front block and ratio of force for the rear block, were greater in the catapult start than the control (effect size [ES]=0.52–2.09). Waveform analyses revealed that the rear block anteroposterior GRF was greater for the catapult start than the control during the initial, middle and final phases (0 to 20%, 40 to 61% and 95 to 100%) of block clearance, while the rear block ratio of force was greater for the catapult start until 13% of block clearance. The catapult start resulted in greater rear block ratio of force (ES = 0.28), faster 10-m sprint time (ES = 0.31) and greater average horizontal external power during the initial 10-m (ES = 0.25) at the post-catapult trial. The results suggest that the catapult start can be accompanied with greater force production mainly for the rear block regardless of direction during the block clearance, and it can improve post-catapult sprint start performance in terms of the rear block ratio of force and 10-m sprint time.

Vertical Ground Reaction Force Estimation From Benchmark Nonstationary Kinematic Data

2021 ◽  
pp. 1-5
Author(s):  
Daniel J. Davis ◽  
John H. Challis
Keyword(s):  
Reaction Force ◽  
Cutoff Frequency ◽  
Heel Strike ◽  
Ground Reaction Forces ◽  
Second Derivative ◽  
Frequency Content ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Filtering Approach

Time-differentiating kinematic signals from optical motion capture amplifies the inherent noise content of those signals. Commonly, biomechanists address this problem by applying a Butterworth filter with the same cutoff frequency to all noisy displacement signals prior to differentiation. Nonstationary signals, those with time-varying frequency content, are widespread in biomechanics (eg, those containing an impact) and may necessitate a different filtering approach. A recently introduced signal filtering approach wherein signals are divided into sections based on their energy content and then Butterworth filtered with section-specific cutoff frequencies improved second derivative estimates in a nonstationary kinematic signal. Utilizing this signal-section filtering approach for estimating running vertical ground reaction forces saw more of the signal’s high-frequency content surrounding heel strike maintained without allowing inappropriate amounts of noise contamination in the remainder of the signal. Thus, this signal-section filtering approach resulted in superior estimates of vertical ground reaction forces compared with approaches that either used the same filter cutoff frequency across the entirety of each signal or across the entirety of all signals. Filtering kinematic signals using this signal-section filtering approach is useful in processing data from tasks containing an impact when accurate signal second derivative estimation is of interest.

scholarly journals The Effect of a Repetitive, Fatiguing Lifting Task on Horizontal Ground Reaction Forces

2005 ◽  
Vol 21 (3) ◽  
pp. 260-270 ◽  
Author(s):  
Yu Shu ◽  
Jonathan Drum ◽  
Stephanie Southard ◽  
Gwanseob Shin ◽  
Gary A. Mirka
Keyword(s):  
Motion Tracking ◽  
Tracking System ◽  
Work Environments ◽  
Erector Spinae ◽  
Whole Body ◽  
Ground Reaction Forces ◽  
Median Frequency ◽  
Materials Handling ◽  
Reaction Forces ◽  
Lifting Task

There are many outdoor work environments that involve the combination of repetitive, fatiguing lifting tasks and less-than-optimal footing (muddy/slippery ground surfaces). The focus of the current research was to evaluate the effects of lifting-induced fatigue of the low back extensors on lifting kinematics and ground reaction forces. Ten participants performed a repetitive lifting task over a period of 8 minutes. As they performed this task, the ground reaction forces and whole body kinematics were captured using a force platform and magnetic motion tracking system, respectively. Fatigue was verified in this experiment by documenting a decrease in the median frequency of the bilateral erector spinae muscles (pretest-posttest). Results indicate significant (p< 0.05) increases in the magnitude of the peak anterior/posterior (increased by an average of 18.3%) and peak lateral shear forces (increased by an average of 24.3%) with increasing time into the lifting bout. These results have implications for work environments such as agriculture and construction, where poor footing conditions and requirements for considerable manual materials handling may interact to create an occupational scenario with an exceptionally high risk of a slip and fall.

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