Showing 8 results for Ground Reaction Force
Mr. Amirali Jafarnezhadgero, Ms. Arezoo Madahi, Mr. Milad Piran Hamlabadi,
Volume 0, Issue 0 (11-2019)
Abstract
Background and Aims: The surface quality and type are an important factor that may influence the risk of sustaining injuries during running. The aim of the present study was to compare forces excreted on the foot while running on the ground and artificial turf in people with pronated and supinated feet.
Materials and Methods: The statistical population of the present study consisted of healthy men with pronated and supinated feet in Ardabil province. A statistical sample of 30 people aged 20-25 years was selected by available sampling and participated in the present study. Statistical samples were divided into three groups. There were 10 patients in the pronated foot group, 10 people in the supinated foot group and the third group of 10 people as the control group. The navicular drop test was used to measure foot type. A Bertec force plate was used to record ground reaction forces while running on ground and artificial turf at constant speed (about 3.2 m/s). The ground reaction forces in the vertical (Fz), anterior-posterior (Fy) and medio-lateral (Fx) directions were recorded during running.
Results: The results revealed greater medio-lateral ground reaction force at the heel contact in males with pronated feet while running on the ground than that artificial grass. In addition, the time to reach the peak of the vertical component at heel contact during running on grass was greater compared to the ground.
Conclusion: The results showed that the use of artificial turf can improve the risk factors for injury in people with pronated and supinated feet.
Dr Mohsen Barghamadi, Miss Roghayeh Parsa, Dr Amir Fatollahi,
Volume 0, Issue 0 (11-2019)
Abstract
Volleyball players are looking to apply their force at a short time speed to transfer more diagonal and vertical blows on the ball so that you land on the opposing team's field more quickly and make it difficult for the opposing team players to receive. It seems that various types of resistance training can improwe the vertical force of the spike skill.
Therefore the aim of the current study is to compare the effects of two types of resistance training (exercises with cable machines and exercise with barbells and free weights) on vertical force and impulse caused by diagonal hit on spike skill in college girl volleyball players. The present study method was semi-experimental. The statistical samples in this study included 45 girl volleyball players from university of Mohaghegh Ardabili. In three groups of 15 in groups 1 and 2 strength training intervention for two days a week, in 7 strenght movements with a cable bodybulding machine and barbell, dumbbell, and medicine training tools, observing the principle of overload in three movement intensities: 80%, 5 repetition, 90%, 2 repetition, 100%, one maximum repetition and in the third group in the form of a control group were identified. Strength training as an independent variable and vertical force and impulse as a dependent variable. Bertek force plate was used to record ground reaction forces. The table was used to adjust height, the invisible thread and the ball for the dominant hand shot in the volleyball players. In this study, ANOVA test was used with a significance level of 0.05. The effects of the force resulting from the diagonal impact on the ball in line with the vertical force of the ground reaction were significant in intervention group 1 (p< 0.008) and intervention group 2 was not significant (p< 0.133).The effect of the impulse time factor in the strength training group was significant in the vertical component of the ground reaction in intervention group1 (P<0.030) and in intervention group 2 (P<0.023). The difference between the groups in the intervention group shows the effect of the vertical force factor in the intervention group 1 with the impact factor (v = 0.016) compared to the group 2 also, in the impulse factor, impact factor was effective in intervention group1 (v = 0.190) and strength training in intervention group 2 (v = 0.167). It seems that barbell and medicine ball strength exercises increased force in diagonal strikes and produce the maximum vertical force in the shorter time to the ball in the spike skill of the diagonal strike of the volleyball players.
Mr. Milad Piran Hamlabadi, Dr. Amirali Jafarnezhadgero, Hamed Naghizadeh,
Volume 0, Issue 0 (11-2019)
Abstract
Background and Aims: Running is one of the most important activities for soldiers, and boots play an effective role in this activity. The aim of the present study was to investigate the effects of three types of military boots mileage on ground reaction force variables during running.
Materials and Methods: The current research was a clinical trial. 15 healthy male students (20-25 years old) used three different types of used and new boots. Using Bartec force plate with dimensions (60 x 40 cm2), ground reaction forces were measured in vertical (Fz), anterior-posterior (Fy) and medio-lateral (Fx) directions while running at constant speed. Two-way ANOVA was used for statistical analysis at a significance level of 0.05.
Results: Results demonstrated significant main effects of "Time" for FXHC (P=0.001, d=0.407), FXPO (P=0.001, d=0.674), TTPFXPO (P=0.001, d=0.394) and TTPFYPO (P=0.031, d=0.226). Findings showed significant main effect of group for FZHC (P=0.027, d=0.163) and TTPFYHC (p=0.035, d=0.150). Furthermore, significant group-by-time interactions was found for FZHC (P=0.001, d=0.404) and FXPO (P=0.014, d=0.272).
Conclusion: The results of this research showed that using military boots, the vertical ground reaction force, the medio-lateral force at heel contact and the peak medio-lateral force were increased. The increase of this value can be related to fracture injuries caused by pressure and patella femoral pain. The results of this study showed that the type of boots can be effective in preventing lower limb injuries. Therefore, using new operational boots is suggested for the military application.
Behnam Moradi, Amir Letafatkar, Malihe Hadadnezhad, Mehdi Hosseinzadeh, Mehdi Khalegi,
Volume 0, Issue 0 (11-2019)
Abstract
Introduction and aim: Fatigue of injury-prone athletes and their placement in situations such as performing shear maneuvers increases the risk of anterior cruciate ligament injury. Therefore, this research aims to answer the question, does functional fatigue change the effect of neuromuscular training on kinetic variables during cutting in injury-prone male athletes?
Methodology: The current research is semi-experimental and was carried out in two control and experimental groups as a pre-test and post-test design with and without fatigue before and after neuromuscular exercises. 32 males student-athletes aged 18 to 25 with trunk control defects were purposefully selected and randomly placed in the control group (16 people) and the experimental group (16 people). The force plane was used to measure ground reaction forces. Analysis of variance test was used for statistical analysis at a level smaller than P<0.05.
Results: The results of the present study showed a significant improvement in ground reaction force variables in the post-test of the experimental group compared to the pre-test (P<0.05). While none of these variables had significant changes in the control group (P>0.05).
Conclusion: It seems that doing trunk and hip neuromuscular training in athletes with a trunk control defect leads to a significant improvement in the stability of the trunk control, so in the conditions with and without fatigue, they were able to show a significant improvement in the selected parameters of the ground reaction forces. Therefore, this training method can probably be recommended as a beneficial method for athletes and the mentioned conditions
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Volume 11, Issue 6 (10-2013)
Abstract
Introduction: 24-67% of recreational runners suffer from running-related injuries. The purpose of this study was to test the effect of unstable shoes on selected ground reaction force (GRF) parameters during stance phase of running.
Method: 20 healthy men (age of 21±2.27 years, height of 176.93±5.39 cm, and mass of 72.30±8.84 kg) ran on the force plate placed in the middle of 15 m runway in barefoot, with unstable and control shoe conditions. Peak vertical GRF, posterior force, loading rate and impulsive passive force variables were calculated in the three conditions. A repeated measure of ANOVA and Duncan post-hoc tests applied to test the hypothesis (p<0.05).
Results: vertical loading rate and vertical peak passive force variables were significantly increased in unstable shoe condition compared to control shoes. In addition, peak posterior force and impulsive passive force variables were significantly increased in unstable shoe compared to control shoe.
Conclusion: unstable shoe could increase ground reaction force parameters on foot during running. This finding suggests that unstable shoes could possibly increase risk of running related to injuries.
Dr Amir Ali Jafarnezhadgero, Mrs Elham Sorkheh, Mr Goodarz Ghiasvand,
Volume 15, Issue 14 (10-2017)
Abstract
Introduction and aim: Taping is a common method used by athletes to improve muscular function. The aim was to assess the immediate effect of femoral external rotational and abductoral taping on three-dimensional ground reaction force characteristics, their time to peak, impulse, displacement of center of pressure, vertical loading rate, and free moment during stance phase of running. Method: 24 healthy men (age: 24.6±2.5 years; mass: 74.8±6.2 kg; 177.1±7.9 cm) were included in the study. Ground reaction force data was recorded by a Kistler force platform (sampling rate: 1000 Hz). Paired sample t-test was used for statistical analysis. Results: Compared to without taping condition, taping significantly reduced the peak impact and peak active vertical ground reaction forces during stance phase of running (P≤0.05; low to moderate effect size). Taping application increased and decreased the vertical loading rate (19%, P=0.047, moderate effect size) and the peak free moment values (P≤0.001), respectively. The values of the anterior-posterior and vertical impulses during taping condition were greater than that of without taping condition (P≤0.001; low effect size). Conclusion: Femoral external rotational and abductoral taping could improve the values of free moment, but this is not the case in vertical loading rate during the stance phase of running.
A.a Jafarnezhadgero, F Ghorbanlou, S.m Alavi-Mehr, M Majlesi,
Volume 17, Issue 18 (12-2019)
Abstract
Genu varus is one of the malalignment of the lower limbs, the failure to correct it leads to secondary abnormalities in adulthood. The purpose of this study was to investigate the effects of a corrective exercise program on ground reaction forces, loading rates, impulses and free moment during stance phase of walking. 17 children with genu varus were volunteered to participate in this study (Age:11.71±1.68 years, Height:1.40±0.09 meter, Weight:35.14±11.47 Kg, and BMI:17.49±3.61Kg/M2). Ground reaction forces were recorded with two Kisler force plates during pre and post-test. At the dominant limb, the amount of time to peak in the mediolateral ground reaction force component during heel contact decreased by of 61.90% (P=0.011). Also, the time to peak of the vertical ground reaction force component during mid-stance tend to increase significantly by 11.47% during the post-test compared to the pre-test (P=0.063). The values of peak ground reaction force components, loading rate, impulse and free moment did not show any significant differences between pre and post-test. The findings showed that the corrective exercise trainings used in the present study had the most effect on the time to peak components of the GRF, but there were no significant effects on the loading rate, impulses, and free moment components. The corrective exercises used in the present study have had the most effect on the time to peak of ground reaction forces and improve them. On the other hand, these exercises did not have any significant effect on the vertical loading rate, impact and free moment values.
A Golchini, N Rahnama,
Volume 18, Issue 19 (7-2020)
Abstract
Pronation distortion syndrome is one of the most common abnormalities in the body that causes distortions in the structures of the skeletal structures of the lower extremities and increases postural sways. The purpose of this study was to determine the effect of 12-week corrective exercises on postural sways in male students with pronation distortion syndrome. In this semi experimental research, 30 volunteers had pronation distortion syndrome, were selected and then randomly and equal divided into two groups of control and experimental (n=15). The experimental group performed corrective exercise consisting of inhibitory, stretching, strengthening, and integrated exercises for three months, but the control group carried out their routine exercise. The postural sways conterol were evaluated before and after of the three month of performing corrective exercises. Independent and dependent t-test were used to analyze the results (P≤0/05). The showed significant improvement in postural sways control and ground reaction force (P≤0/001), effect size 0.8 and 95% confidence interval after three months of corrective exercise, but in control group there was no significant difference (P≥0/05). In addition, after intervention, the experimental group were significantly lower in postural sways conterol and ground reaction force than the conterol group (P≤0/001), but this difference was not significant in the pre-test (P≥0/05). It seems that systematic corrective exercise led to improve the activity of the muscles responsible for body sways conterol, which also reduces postural sways and ground reaction force in people with pronation distortion syndrome, so it is recommended that researchers, trainers, and specialists consider systematic corrective exercise in order to improve posture sways conterol and ground reaction force in people with pronation distortion syndrome.
