Showing 15 results for Kinematic
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Volume 0, Issue 0 (11-2019)
Abstract
Introduction and Objective: One of the strategies that athletes can use to temporarily increase strength and muscle power is post-activation potentiation (PAP) during warm-up. However, the effect of this phenomenon on kinematics of special movement has not been determined. Therefore, the aim of this study is to investigate the acute effect of PAP during warm-up on lower extremity kinematic characteristics during heading in soccer players.
Methodology: The study sample consisted of 24 semi-professional youth soccer players with an average age of 18.67±1.11 years, height 182.32±7.12 cm, mass 74.17±7.46 kg. who performed four different warm-up methods, including PAP-take-off, PAP-landing, combined-PAP, and general warm-up, derived from the stages of soccer heading. Knee and hip angular velocities during the take-off phase, maximum knee flexion angle, and duration of knee joint pause during the landing phase were recorded using a three-dimensional motion analysis device (vicon peak ltd, oxford, vicon UK) with four T20 cameras with a frequency of 1000 Hz. Finally, analysis of variance with repeated measurements and post hoc Bonferroni test were used at a significance level of P<0.05.
Results: There was a significant increase in knee and hip angular velocities following combined-PAP and then PAP-take-off compared to other warm-up programs. Moreover, there was a significant increase in knee flexion angle after PAP-landing compared to other warm-up programs. Additionally, there was a significant increase in the duration of knee joint pause after general warm-up compared to other warm-up programs.
Discussion and Conclusion: PAP-take-off improves jumping performance, while PAP-landing improves landing performance. The combination of these two methods, i.e., combined-PAP, will yield better results overall.
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Volume 0, Issue 0 (11-2019)
Abstract
Since identifying the best way of performing the Judan Mai-Mawashi-Geri technique is one of the concerns of coaches and karatekas, the aim of this study was to compare the selected kinematic variables of four methods of implementing the Judan Mai-Mawashi-Geri technique by elite male karatekas. Eighteen elite male kumite practitioners voluntarily and purposefully participated in this study. Five markers were attached to the anatomical points of the hitting foot. The four methods of implementing the Judan Mai-Mawashi-Geri technique were filmed by three Hero3 cameras at an imaging speed of 240 Hz. Using SkillSpector software (version: 1.3.2), the resultant of the peak velocity of the lower limb joints, total distance, total velocity, and total acceleration was directly obtained. The one-way analysis of variance and the Bonferroni post-hoc test (p≤0.05) were used with SPSS software (version: 22) for statistical analysis due to the normality of data distribution. The results showed a significant difference in the four methods of performing the Judan Mai-Mawashi-Geri technique in the peak velocity of the pelvic, knee, and ankle joints as well as total distance, total velocity, and total acceleration. According to the research results, the first method of implementation can be recommended as a more efficient technique to kumite practitioners due to its high speed and the possibility of scoring in the shortest time interval and because it closes the opponent’s attack route, compared with Dai and Deashi tactics.
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Volume 11, Issue 6 (10-2013)
Abstract
The purpose of this study was to examine the difference between two types of
the soccer instep kick in temporal sequence of motion and muscle
electromyography, during forward swing phase of the kick. Ten elite soccer
players, volunteered as subjects in the study. To culculate the kinematics data,
we used DLT method with two video camera that filmed five markers fixed on
anatomical points of lower body, at 240 fpm. Moreover the electromyography of
rectus femoris, vastus medialis and tibialis anterior were estimated. Kinematic
data from ten players was extracted using image processing toolbox of
MATLAB software. Using these results, we compared sequences of joint motion
and progression of activation muscle in low drive and high drive kick. The
results indicate that there was a difference in ranks of muscle activation
between two kick, but there were no difference in muscles activation time and
sequence of joint motion between low drive and high drive kick. Furthermore
both kicks have a similar proximal-distal pattern and interaction in muscles
contraction and joints motion
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Volume 12, Issue 7 (4-2014)
Abstract
The main purpose of the present study was to investigate the kinematics and kinetics of successful versus
unsuccessful basketball free throw shots. Six professional basketball players (age= 23±2.09 years members
of Iranian premier basketball league participat in test. Kinematics of arm motion during basketball free throws
were recorded by two Casio zr200 camera in frequency of 240 Hz. Wilcoxon test was used for significant
differences between successful versus unsuccessful free throws (p ≤ 0/05). Angular velocity of the wrist was
found to be significantly higher in successful versus unsuccessful shots at the time of ball release (p ≤ 0/028).
Wrist (p ≤ 0/008) and shoulder (p ≤ 0/023) joints were found to have significantly more flexion in successful
versus unsuccessful shots while elbow (p ≤ 0/002) remained significantly less flexed in successful shots.
Angular displacement of wrist (p ≤ 0/034) and elbow (p ≤ 0/004) was shown to be significantly greater in
successful versus unsuccessful shots. Integrated EMG of Anterior Deltoid (AD), Triceps Brachii (TB) and
Flexor Carpi Radialis (FCR) muscles was more in successful free throw versus unsuccessful free throw, but
the only significant difference was observed in the Integrated EMG of the Triceps Brachii muscle (p ≤ 0/034).
In summery, increasing the wrist angular velocity and activity of triceps brachii muscle affected successful
free throws.
Sasan Naderi, Dr Fariborz Mohammadi Pour, Dr Mohammad Reza Amir Seifo Dini,
Volume 13, Issue 9 (4-2015)
Abstract
The purpose of current study was to investigate the spatio-temporal gait parameters and knee varus angle
during walking at different speeds in young with knee varus. 18 subjects with varus deformity classified at
grade 3 of bowleg and 17 healthy subjects, volunteered to participate in this study. The following variables
include stance, swing, double support and cycle time, cadence, stride length, angle of varus at the heel
contact, midstance and toe off when walking on the treadmill at speeds of 80, 100 and 120 percent of
preferred walking speed, were measured from using the three-dimensional motion analysis system with six
optoelectronic cameras. The results of between-group tests showed that spatio-temporal gait parameters
in the varus group is similar to the normal group. Also varus angular variables in varus group, was indicate
higher values in comparison to the healthy group, but there were no significant differences. The results of
inter-group tests also showed the knee varus angle generally increases with increasing speed, that none of
the differences were not significant. According to the results, the increase in walking speed will caused to
increase knee varus angle. Therefore, walking with speed less than the normal walking speed, probably is
a suitable solution to reduce the loads exerted on the knee joint and prevention of premature osteoarthritis
in young with knee varus.
Mr Saeid Eimani Zadeh, Dr Mansoor Sahebzamani, Dr Mohamad Taghi Amiri Khorasani,
Volume 13, Issue 10 (10-2015)
Abstract
The purpose of this study was to investigate the effect of soccer specific functional fatigue on hip and knee
joints angles during landing in professional players.15 soccer players with at least 2 years experience in
Kerman soccer clubs were selected randomly. To evaluate the lower extremity kinematics following
jumping and soccer specific- heading, three cameras (with50Hz) were used. To cause fatigue in subjects,
specific functional protocol similar to specific bangsbo soccer was used and Quantic sport v21 soft ware
was administrated for kinematic analysis of the recorded films. To statistical analyzing of data, descriptive
statistical methods, and paired-t test were administrated at α=0.05.Finding revealed that hip and knee
angles in sagittal and frontal plane in landing is influenced by functional fatigue. This results has been
reducing knee and hip flexion angles and increased varus in knee joint. Results demonstrated a more
erect landing posture due to a decrease in hip and knee flexion angles in the post fatigue condition.
However, functional fatigue significantly decrease lower extremity control ability in male soccer player
during landing.
Mr Mohammad Ali Naseri Rouhani, Dr Mohammad Taghi Amiri Khorasani, Dr Mohammad Reza Amir Seifaldini,
Volume 14, Issue 11 (4-2016)
Abstract
Objective: The aim of this study was to investigate the effect of non- stability surface of support leg on the instep kicking kinematics in soccer players. Materials and Methods: 30 male soccer players participated in this study. After the measurement of static and dynamic balance tests by the Biodex System, 20 players were selected who were at a desired level of the balance. Data were recorded using the three- dimensional motion analysis system with 6 optoelectronic cameras (200 HZ). The kinematic parameters in three critical moments of kicking (Forward swing of hip, Contact to ball, Follow through) were compared by using repeated measures of variance and independent t- test (0/05). Results: The results showed that the values of maximum angular velocity and displacement of hip and velocity of ball at the kicking over stability surface was significantly higher from the kicking over non- stability surface. Conclusion: These results indicate that the kicking over non- stability surface causes the lower of kinematic parameters in the more of the kicking skill phases and the movement prime velocity of ball
Mr Soroush Bagheri Koodakani, Dr Shahram Lenjan Nejhadian, Mr Mostafa Haj Lotfalian,
Volume 14, Issue 11 (4-2016)
Abstract
Motion analysis systems are useful and effective equipment in biomechanics research. Unfortunately these systems are available for few researchers because these are expensive equipment. The aim of this study was to design and validation of a practical and inexpensive software, to determine the exact markers position in space and compute the kinematic of movement. In designing the software, the exact image processing algorithms and Direct Liner Transformation (DLT) method were used to calculate markers position in space. To validate the software, the markers position in static, dynamic, linear, angular, 2D and 3D conditions were calculateted by other standard tools and compared with software outputs using Mann-Whitney U test and no significant difference were observed. The validity and reliability of the software was assessed using Pearson Correlation Coefficient and Intraclass Correlations Coefficient and during all test conditions, very high levels of these coefficients were found (≥0.97). In a nutshell, present software, with features such as automatic tracking markers, inexpensive price, the possibility to outdoor use and image processing in 2D and 3D conditions, is valid and reliable software for kinematics analysis
N Shaterkazemi, Sh Zandi, E Shirzad,
Volume 18, Issue 19 (7-2020)
Abstract
Regarding the effects of the kinematics of the movement on athletic performance and the Importance of promoting athlete’s performance on the sport fields, there is limited knowledge about the mechanism of the effect of different variables of volleyball spike. Therefore, the aim of this study was the prediction of jump performance in elite female volleyball players with selected kinematic variables. Thirty elite female volleyball players with mean age of 21.44±3.42 have volunteered for this study. Lower limbs kinematics have been recorded using 16 reflexive markers with Vicon motion analysis system during volleyball spike jump performance. Jump height and time of concentric phase of jump have been predicted by center of mas velocity during step, final step length and ranges of the motion of hip, knee and ankle with stepwise regression (α≤0.05). The results showed that knee range of motion center of mass velocity and step length could be the predictors for time of jump and center of mass velocity and hip range of motion could be the predictors for the jump height as well. Considering these results and the goal and situation of the volleyball match, the players should focus on different phases and affecting variables of the spike jump.
N Jamali, Kh Khayambashi, Sh Lenjannejadian, H Esmaeili,
Volume 18, Issue 19 (7-2020)
Abstract
Although hip muscle strengthening has been reported as an effective way to decrease PFPS symptoms, however its effect on lower extremity kinematics is less clear. The current study was done with the aim of investigating the effect of hip abductor and external rotator muscles strengthening exercises on lower extremity kinematics in static and dynamic states. In a randomized controlled trial, 33 patients with patellofemoral pain (PFP) were randomly assigned into exercise (8 female, 30±6.8 y/o, 23.8±2.6 BMI and 8 male, 31.2±7 y/o, 25.6±1.5 BMI) and control (9 female, 29.9±7.3 y/o, 23.2±3.2 BMI and 8 male, 32±6 y/o, 25.5±1.9 BMI) groups. In exercise group they received hip abductor and external rotator strengthening exercises by thera-band 3 times per week for 12 weeks under supervision by a physiotherapist. The control group did not receive any training intervention. Hip muscles strength and kinematics in static and dynamic states, were assessed at baseline and post-intervention. Repeated measures ANOVA by using SPSS were applied to assess the effects of the exercise on measured variables (α=0/05). After 12 weeks of strengthening program, by an increase in abductor muscle strength in women from 19.6 to 26.4 %BW (P=0.000) and in men from 29.9 to 38.1 %BW (P=0.003), and in hip external rotator muscles in women from 13.2 to 16.9 %BW (P=0.024) and in men from 26.3 to 34.9 %BW (P=0.000), dynamic knee valgus angle during single-legged squat improved in women from 170 to 174.6 degrees (P=0.018) and in men from 171.8 to 176.8 degrees (P=0.017) and contralateral pelvic drop angle during stair descending improved only in women from 7.9 to 6 degrees (P=0.04) in the exercise group. No significant difference was observed at quadriceps angle (P≥0.05). The findings suggest that hip muscles strengthening can alter the lower extremity kinematics, in dynamic state, at the frontal plane, and it might be said that due to these changes following hip abductor and external rotator muscles strengthening exercises by thera-band, the symptoms of PFP improve more consistent.
Azadeh Doroodgar, Khalil Khayambashi, Shahram Lenjannejadian, Ghasem Yadegarfar,
Volume 19, Issue 21 (9-2021)
Abstract
Hamstrings (Hams) to Quadriceps (Quadr) strength ratio is known as a risk factor for Anterior Cruciate Ligament (ACL) injury and affects by knee and hip flexion angles. Gluteus Maximus (Gmax) muscle acts as a synergist for Hams in hip extension in a closed kinetic chain. The aim of this study was to investigate the effect of Gmax strengthening exercises on the kinetic and kinematic risk factors of ACL injury when single-leg landing from a jump. 25 volunteer women aged 18-30 years were assigned into control (n =13) and experimental (n =12) groups. Maximum isometric strength of Gmax, hip and knee joint angles and ground reaction force (GRF) was measured at landing, by dynamometer, 2D imaging and foot scan respectively,. After 8 weeks of 3 sessions of Gmax resistance training, Following the significant within-subject difference for GRF (F=5.245, P=0.032) by using Two-way mixed model ANOVA, Pre and post-test Differences were significant with 16.63% decrease (P= 0.038, t=2.354). Differences between pre and post-test peak force, time to peak, mean joint angles, impact and load rate were not significant (α = 0.05). According to a 4.55% and 3.47% increase in Gmax strength and time to peak force, and considering the fact that at the beginning of landing, the mechanical advantage of Hams is lower than that of Gmax, the risk of ACL injury could be reduced by reducing GRF following an increase in the Gmax strength.
Ms Sepideh Samavati Sharif, Phd Abbas Ferjad Pezeshk, Phd Mohammad Yousefi,
Volume 19, Issue 22 (12-2021)
Abstract
This study aimed to determine the role of strength, expulsive power and range of motion of lower limb muscle on the fencing performance of elite florists. In this study, eight elite fencers’ participated. Kinetic variables measured using force plate and kinematic variable measured using motion analysis system. The squat jump test used to measure the compulsive power of the lower extremity muscles of the fencers. The Drop-jump test used to measure the lower strength of the muscles of the lower extremity muscles. Descriptive statistics (mean and standard deviation) used to describe the data and Pearson correlation coefficient used for determine the relationship between data (P≤0.05). The results of this study showed there is a significant relationship between squat jump power and mechanical energy and drop jump height with lunge speed and also between ankle range of motion with peak force and impulse in the anterior direction (P<0.05). Given the results of this study, coaches should have a special attention on the strength and explosive power of plantar flexor muscles.
Dr Amir Ghiamirad, Mr Farhad Esmkhani, Mr Salar Hariri,
Volume 19, Issue 22 (12-2021)
Abstract
The aim of this study was to investigate the kinematic characteristics of the two skills of Judan and Chudan Giakozuki Karate, professional and semi-professional male men. Methods: 10 Professional and 10 semi¬-professional amateur male Karate athlethes participated in this study and performed the techniques. The ground reaction force during the impact, which was an indirect parameter to calculate the impact power, was measured using a force plate with a frequency of 250 Hz. The ADXL320 accelerometer was also used to calculate the hand transfer acceleration. The motion data were recorded using Phase Space real time optical tracking system with 8 high speed cameras at 480 fps. Then the kinematic parameters associated with each fist were modeled and quantified by a three-dimensional imaging system.Paired t-test and independent t-test were used to analyze the research data.The test results in the parameters of wrist, elbow, shoulder movement in Judan and Chuadan Gyakozuki skills, ground reaction force, peak speed of elbow and shoulder in Chuan Gyakozuki skill, peak wrist velocity in Judan Gyakozuki skill in semi-professional karate and professional showed a significant difference. Fainaly, the results showed that the type of impact and the level of experience of karatekas were the main factors in determining the size of the displacement parameters and peak velocity, which are considered an important factor in success in competitions and lead to better scores in competitions.
Ali Abbasi, Heydar Sadeghi, Mehdi Zamanian , Anoshirvan Kazemnejad,
Volume 20, Issue 23 (9-2022)
Abstract
The purpose of present study was to examine the effects of short time static and dynamic stretching of muscles on kinematics variability of lower extremity in healthy active males during cycling. 15 physical education and sport sciences male students from Kharazmi University voluntarily participated in this study. Subjects referred to the laboratory during two days, with 48 hours intervals between each sessions, and lower extremity kinematics data were collected from 30 pedaling cycle on the stationary cycle in 70 RPM in situation of without stretching, after 2, 5, and 10 minutes post stretching by means of motion analysis camera in 50 Hz frequency. Hip, knee and ankle joints angular displacement and velocity were extracted for constructing time series and variability calculation. Results of repeated measure ANOVA did not show any significant differences in angular displacement and velocity variability in hip, knee and ankle joints after 2, 5, and 10 minutes post stretching (P>0.05). Regarding results, probably it can be use static and dynamic stretching in warm up programs before cycling or rehabilitation on stationary cycle.
Mr Masoud Sebyani, Dr Hooman Minoonejad, Dr Elham Shirzad, Dr Mohammadhossein Alizadeh,
Volume 21, Issue 25 (9-2023)
Abstract
The Prone Hip Extension test (PHE) is used to evaluate the quality of motor control in the lumbopelvic region. Because of the similarity of this test to the walking and running pattern, it seems that muscle interaction in this test is important in hamstring injury. Therefore, this study aimed to investigate the effect of changing the activation patterns of muscles in prone hip extension on kinematical variables affecting hamstring injury. 28 male soccer players participated in this study. The prone hip extension test was used to evaluate and classify subjects, and based on the activation pattern, they were divided into two groups: normal pattern (N=14) and altered pattern (N=14). We used the Myon electromyography device to evaluate the prone hip extension test muscles activation pattern. Also, the kinematic evaluation of running was done on a treadmill at a speed of 20 km/h. Two-dimensional and three-dimensional video analyses were used to extract kinematic data (pelvic tilt, trunk lateral flexion, and trunk flexion). The range of motion in a running cycle and the amount of each variable at the moment of initial foot contact were used. An Independent t-test was used to analyze the data. The results of this research showed that there is a significant difference in the amount of trunk lateral flexion (p= 0/002), and trunk flexion (p= 0/024) at the moment of the initial foot contact and the range of motion of trunk lateral flexion (p=0/019), and trunk flexion (p=0/035) and pelvic tilt (p=0/008) in a running cycle between the changed pattern group and the normal group. The results of this research showed that changing the pattern of muscle activation in the prone hip extension test can increase the risk of a hamstring injury.
