# Development of an Estimation Formula to Evaluate Mission Motion Suitability of Military Jackets
## 1 Introduction  
The armed fighting vehicle (AFV) [1] is a tracked combat vehicle and a type of weapon system having specific functions in battle. In particular, the main battle tank (MBT) is a symbol of armored army forces and is designed with consideration for firepower, mobility, and protection [2]. The members of the main battle tank vary depending on the model, but third-generation main battle tanks in China, Russia, France, the United States, and Germany mainly consist of three or four crew members (commander, gunner, driver, and loader) [3]. The K1-series, Republic Of Korea's third-generation main battle tanks also have four crew members [4]. The mission efficiency of crew members regarding the operation of tracked vehicles has a significant impact on combat power [1]. Each crew member plays a different role, but they also perform common missions such as ammunition stowing, which is a high-intensity task [5]. However, the interior of the tracked vehicle is very narrow, and seats and protruding structures that are not ergonomic in design cause musculoskeletal discomfort for the tracked vehicle crew while performing missions [6; 7; 8]. Moreover, the vehicle crew reported discomfort while performing the mission motion because of their current uniform [9; 10; 11]. Uniforms worn during the mission should not interfere with performance. Therefore, the tracked vehicle crew's uniforms should be developed considering mission motion suitability [11]. Previous studies on the development of military uniforms have evaluated the motion suitability of clothing using general motion and mission motion [12; 13; 14; 15; 16]. The motion suitability of protective clothing mainly deals with the usability of the joints from an anatomical point of view [17]. All motions of joints can be described as flexion, extension, adduction, abduction, rotation, pronation, or supination [18; 19], and general motion for evaluating the motion suitability of the jackets includes the usability of joints of the cervical column(neck), lumbar vertebrae (trunk), shoulder, and elbow [11; 12; 13; 14; 15]. In particular, the shoulder joint is the joint with maximum movement among all the joints of the human body [19]; the usability of the shoulder joint is important in judging functional clothing [12]. On the contrary, the mission motion suitability evaluation includes consecutive motions; a number of studies have developed motion protocols to evaluate garment comfort and to test performance according to the type of clothing and the wearer's mission. A firefighter simulation protocol was developed to evaluate refighting operations [20]. Another study developed five simulation operation protocols to develop the ROK Navy summer uniform [21]. In addition, a training scenario assuming chemical accidents and terrorism through the analysis of the field crew activity was conceptualized [22]. Military combat uniforms were evaluated using the main combat training motions performed in combat training [14]. However, most of the training of a special group of tracked vehicle crew members is conducted inside and outside of the tracked vehicle, and their respective duties often require them to perform motions that differ from combat training motions usually performed by ordinary soldiers. Therefore, a mission motion protocol was developed for the evaluation of the tracked vehicle crew jacket [11]. However, because the clothing development goes through an iterative design process from preliminary investigation to the final product, following the mission motion protocol, every time an intermediate evaluation of a sample is conducted, it may be seen as a waste of time and materials. In particular, it is impossible to completely reproduce the internal and external environments of a tracked vehicle in order to evaluate the military uniforms of the tracked vehicle crew, and evaluation is limited due to the nature of military security.