Islamic Azad University, Hamedan Branch
Journal of Sport Biomechanics
2476-4906
2
3
2016
12
1
Spatiotemporal Variables of Gait in Patients with Adolescent Idiopathic Scoliosis and Healthy Individuals
5
14
FA
Shirin
Yazdani
Faculty of physical education and sport science, University of Tabriz, Tabriz, Iran.
Nader
Farahpour
Faculty of physical education and sport science, Bu Ali Sina University, Hamedan, Iran.
Mojtaba
Habibi
Department of clinical health psychology, Shahid Beheshti University, Tehran, Iran.
Mohammad Sadegh
Saba
Department of Pediatrics, University of medical sciences of Hamedan, Hamedan, Iran.
Objective: The effects of scoliotic deformity on the biomechanics of gait are not clear. The aim of this study was to compare the spatiotemporal variables during gait in adolescent idiopathic scoliosis and healthy individuals.
Methods: Eighteen healthy adolescent girls and 19 adolescent patients with idiopathic scoliosis that were matched for age, height, mass and BMI participated in this study. Using a Vicon motion analysis system (100 Hz), subjects’ gait were recorded and spatiotemporal variables including velocity, cadence, stride and step length, initial heel contact and toe off instants (% of gait cycle), duration of single and double supports, duration of the steps and strides of the right and left feet as well as the asymmetry indices (AI) for all variables were evaluated. ANOVA was run at a significance level of p<0.05 to analyze the data.
Results: It was found that the cadence, velocity, stride and step length, stride and step time, duration of double support and single support, and heel contact and toe off instants were similar in both groups (p>0.05). Also, there were not any between group differences in asymmetry indices for all variables (p>0.05).
Conclusion: spatiotemporal variables in right thoracic scoliotic patients were similar to healthy individuals; there for, it could be suggested that scoliosis does not affect the spatiotemporal variables. Other biomechanical parameters should be examined for etiology of scoliosis.
Islamic Azad University, Hamedan Branch
Journal of Sport Biomechanics
2476-4906
2
3
2016
12
1
Biomechanical Modeling of Selected Methods of Load Carriage to Improve Military Capabilities of Troops
15
23
FA
Mostafa
Hajlotfalian
Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, University of Kharazmi, Tehran, Iran
Alireza
Redaei
Department of Chemical and Polymer Engineering, Faculty of Engineering, Yazd University, Yazd, Iran
Heydar
Sadeghi
Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, University of Kharazmi, Tehran, Iran
Objective: The purpose of this study was to develop a model to compare some selected methods of load carriage during sitting and rising, and to introduce the best method of reducing power consumption and the risk of injury among military men.
Methods: Ten subjects were selected to perform the required task to determine anatomical constraints, kinematic data and to extract some parameters for modeling. Subsequently, the center of mass position of four equipment for load carriage, including, Backpack, Double pack, Trunk vest and Double satchel, were determined and four different two- dimensional models of body with four segments were developed based on inverse dynamics equations. After applying constraints and cost functions, genetic algorithm was used to find the optimal model.
Results: Based on the results, power consumption in Backpack method was the lowest and double satchel method inserted the least momentum on hip torque.
Conclusion: A more practical choice for military operations is to carry a load as close as possible to the center of mass of the body in a nutshell, between all methods, carrying load through the Backpack method, according to its capabilities, is the best choice for carrying heavy and bulky equipment.
Islamic Azad University, Hamedan Branch
Journal of Sport Biomechanics
2476-4906
2
3
2016
12
1
The Effect of Ankle, Knee and Hip Isokinetic Fatigue on Shock Absorption and Rate of Loading during Pair-leg Landing
25
34
FA
Hamideh
Khodaveisi
Department of Physical Education and Sport Sciences, Islamic Azad University Hamedan, Hamedan, Iran
Ameneh
Hosseinzadeh
Department of Physical Education and Sport Sciences, Islamic Azad University, Karaj, Albaorz, Iran
Objective: This study aims at investigating the effects of ankle, knee, and hip ISO fatigue on shock absorption and rate of loading during paired-leg landing.
Methods: Fifteen female students with an average age of 19.67± 0.62 years,
weight of 54.60 ± 9.44 kg, and height of 163.30 ± 5.54 cm were selected randomly as subjects in this study. First, the participants were tested by jumping from a box with the height of 30cm, to land on a force plate. Then, the Isokinetic fatigue protocol of the ankles, knees, and hips muscles’ was implemented for everyone by an Isokinetic System, and related information was recorded. The second test of paired- leg landing with fatigue muscles, was carried out on a force plate immediately. For statistical analysis, SPSS version 18 was used and, Dependent samples T-test, at the significance level of P < 0.05, was used.
Results: the results of the dependent samples T- test results showed no significant difference in comparing the rate of load throughout landing before and after fatigue in the joints of the lower extremities.
Conclusion: Findings of this study indicate that the fatigue protocol using Isokinetic devices with uniform speed, increases muscle strength due to generating stress at all the joints, thereby, compensating the active and passive joints for shock absorption, and load distribution on the lower extremities.
Islamic Azad University, Hamedan Branch
Journal of Sport Biomechanics
2476-4906
2
3
2016
12
1
The Effect of Foot Position on the Muscles Activity of the Shoulder and Trunk Muscles in Load Lifting
35
42
FA
Arezoo
Noori
Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, Islamic Azad University, Brojerd branch, Brojerd, Iran.
Nader
Farahpour
Department of Physical Education and Sport Sciences, Faculty of Humanities, Islamic Azad University, Hamedan branch, Hamedan, Iran.
Mahdi
Majlesi
Department of Physical Education and Sport Sciences, Faculty of Humanities, Islamic Azad University, Hamedan branch, Hamedan, Iran.
Objective: This study aimed to investigate the effects of leg positioning on the activity of shoulders and body while lifting weights.
Methods: Employing an electromyography set (BTS free EMG 300) and surface electrodes, the activity of such muscles as biceps, triceps, anterior, medial and posterior deltoid, trapezius and erector spinae, while lifting a weight weighing %15 of body mass, in three leg positions (straight, bending and a leg on a step), were measured. Each muscle`s RMS data, during performing the skills, were divided by the amount of maxinmum voluntary isometric contraction (MVIC) then multiplied by 100. Repeated Measurewas used to analysis the data at the significance level of (p<0.05) in SPSS 16.
Results: The results showed no significant difference among the activity of such muscles as biceps, triceps, anterior, medial and posterior deltoid, trapezius and erector spinae in three different positions. However, there existed a significant different between the different pectoral gridle and erector spinae muscles in terms of their intensity of activity (p=0.01). The maximum of intensity of activity was respectively assigned to erector spinae, anterior deltoid, medial deltoid, trapezius, posterior deltoid, bicepts and tricepts. Moreover, the comparison of the activity of the muscle L3 in the three different leg positions in lifting a weight did not show a significant difference (p=0.05).
Conclusion: The way of lifting the object does not lead to a significant difference in the intensity of the activity of different muscles.
Islamic Azad University, Hamedan Branch
Journal of Sport Biomechanics
2476-4906
2
3
2016
12
1
Shoulder Muscles' Function during Arm Flexion with and without Load in Patient's with Chronic Low Back Pain and Healthy Individuals
43
50
FA
Nader
Farahpour
Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, Bu Ali Sina University, Hamedan, Iran.
Maryam
Kamari
Department of Physical Education and Sport Sciences, Faculty of Humanities, Islamic Azad University, Broojerd branch, Broojerd, Iran.
Amirali
Jafarnezhadgero
Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, Bu Ali Sina University, Hamedan, Iran.
Amirhosein
Yazdani
Physical medicine and rehabilitation specialist, Hamedan University of Medical Sciences, Hamedan, Iran.
Objective: Shoulder muscle injuries are very prevalence. So determining of injuries mechanism could be a suitable way for identifying rehabilitation methods. The purpose of this study was to compare the electromygraphical activity of shoulder girdle muscles in lowback pain patients and healthy subjects during arm flexion with and without load.
Methods: Tensubjects with chronic low back pain and ten age-matched control healthy subjects participated in this study. All participants were asked to perform arm flexion activities with and without load (with both dominant and nondominant sides) in a standing position. The outcome measures included electromygraphical activity of anterior and medial deltoid, infra and supra spinatus muscles for both groups. MANOVA and repeated measure statistical tests were used for between and within group comparisons. Alpha level was set at p˂0.05.
Results:The intensity of muscle activity in anterior and medial deltoid, infra spinatus and supra spinatus muscles of dominant upper limb in healthy group were 26.3±2.67, 17.01±2.02, 11.1±1.67, 12.40±2.34 percent of maximum voluntary isometric cotraction, respectively. These values for patients group were 27.90±3.78, 14.73±3.14, 16.48±2.37, and 18.19±3.31, respectively. There were not any significant diffrences between groups (p˃0.05). Load effect in dominant upper limb for the groups accounted for 132% and 136% increase in the total muscular activity.
Conclusion: Shoulder girdle muscle activity is similar in low back pain patients compred with the healthy subjects during arm flexion. It seems that low back pain didn't have any affect on shoulder muscular activiry; however, further studies are warranted.
Islamic Azad University, Hamedan Branch
Journal of Sport Biomechanics
2476-4906
2
3
2016
12
1
Comparison of Myoelectric Activity of a Selection of Upper Extremity Muscles while Doing Bench Press in Two Training Methods of TRX and Barbell Bench Press
51
60
FA
Ahmad Reza
Zibaei
Department of Physical Education and Sport Sciences, Islamic Azad University Central Tehran Branch, Tehran, Iran
Heydar
Sadeghi
Department of Physical Education and Sport Sciences, Islamic Azad University Central Tehran Branch, Tehran, Iran
Mahdi
Baghaeian
Department of Physical Education and Sport Sciences, Kharazmi University, Tehran, Iran
Objective: The aim of present research is to compare the myoelectric activity of some chosen upper extremity muscles while doing bench press in two training methods of TRX and barbell bench press.
Methods: Ten physically healthy students of physical education with experience in TRX participated in the study. Electromyography Bio Vision sixteen-channel and surface electrodes were used to calculate muscle activity of pectoralis major, anterior deltoeid, triceps brachii and trapezius. Data analysis of variance with repeated measures was used to assess the difference between the three states of the experiment at p<0/05.
Results: After performing the relative tests following results were obtained: the activity rate of dolly anterior muscle in TRX(b) method compared to barbell bench press 85% (P=0.015) and TRX(a) 66% decreased meaningfully (P=0.017). However, there were no meaningful difference, between barbell bench press and TRX(a) (P=0.65), the activity rate of pectoralis major muscles in barbell bench press increased by (P=0.000) as compared with 200% (P=0.000) for TRX(b). The activity rate of the triceps brachii in barbell bench press method increased by 185% as compared with TRX(b) (P=0.023). Compared to average ratings of trapezius muscle, it was found that TRX(a) would have the highest rating and the barbell bench press has the lowest and it was also observed that barbell bench press has less electrical activity compared to TRX(a) and TRX(b) methods.
Conclusion: Considering these results it can be maintained that TRX bench press resistance training can be an alternative and effective practice for barbell bench press because, given the results, it can be appreciated that TRX bench press, dips low in the trunk, can lead to muscle activity close to the level of muscle activity during the barbell bench press drill.