dynamic modeling

The purpose of this study was modeling some selected method of load carriage during sitting and arising, in order to introduce the best method to reduce energy consumption and risk of injury among troops.
In this research, ten subjects participate to determine the anatomical constraints, record the kinematic of motions and extract some parameters for modeling. Subsequently, the center of gravity position of four equipment for load carriage, including: Backpack, Double pack, Trunk vest and Double satchel, were determined and four different dynamic models of body and the load entered, were developed based on inverse dynamics equations by Lagrangian method. To calculate joint torque and mechanical energy, two dimensional models with four segments were run with kinematics information.
According to investigation results, mechanical energy consumption in Backpack method and hip torque in Double satchel method were lowest.
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 operation by Backpack method, according to its capabilities, is the best choice for carrying heavy and bulky equipment.

Finding the optimal techniques is one of the aims of sport biomechanics science. According to previous soccer kick studies، the pattern of optimal technique has been computing by analyzing the kinematic and kinetic parameters of elite soccer player. The purpose of this study was finding the optimal soccer kick pattern in forward swing phase to achieve a maximum speed shot. The solution approach which is suggested to produce the optimal technique is to use the mechanical modeling by applying the motion equations. This model has some advantages compared to experimental study such as changing the model parameters separately، low cost and run repeatedly the model. A two-dimensional four-link dynamic model is introduced and by applying the appropriate constraints، the genetic algorithm is used to achieve the optimal technique. The computed pattern was compared with six skill subject’s patterns that Acquired by cameras (240Hz). The results showed significant deference in joints angular displacement patterns between computed and subjects techniques. Also، the computed pattern velocity increased 62. 5 percent more than subject’s pattern and the computed pattern was similar to reported in previous studies. Therefore، the computed pattern is valid for human according to human body physiology and mechanics. Using the model in this study can create interaction between joint and segments and enhance Motion-Dependent Moment in distal segment and improve speed and quality of the kick. Therefore، it is important and necessary to enhance muscle strength and improve neuromuscular coordination. In a nutshell، this model is an apparatus which can available for trainers to teach optimal technique of soccer instep kick to athletes specifically.