Additional helmet and pack loading reduce situational awareness during the establishment of marksmanship posture

Abstract

The pickup of visual information is critical for controlling movement and maintaining situational awareness in dangerous situations. Altered coordination while wearing protective equipment may impact the likelihood of injury or death. This investigation examined the consequences of load magnitude and distribution on situational awareness, segmental coordination and head gaze in several protective equipment ensembles. Twelve soldiers stepped down onto force plates and were instructed to quickly and accurately identify visual information while establishing marksmanship posture in protective equipment. Time to discriminate visual information was extended when additional pack and helmet loads were added, with the small increase in helmet load having the largest effect. Greater head-leading and in-phase trunk-head coordination were found with lighter pack loads, while trunk-leading coordination increased and head gaze dynamics were more disrupted in heavier pack loads. Additional armour load in the vest had no consequences for Time to discriminate, coordination or head dynamics. This suggests that the addition of head borne load be carefully considered when integrating new technology and that up-armouring does not necessarily have negative consequences for marksmanship performance. Practitioner Summary: Understanding the trade-space between protection and reductions in task performance continue to challenge those developing personal protective equipment. These methods provide an approach that can help optimise equipment design and loading techniques by quantifying changes in task performance and the emergent coordination dynamics that underlie that performance.

Effect of Playing Position, Match Half, and Match Day on the Trunk Inclination, G-Forces, and Locomotor Efficiency Experienced by Elite Soccer Players in Match Play

“…The results showed trunk inclination values lower (i.e., more upright postures) than other team sports such as field hockey, in which the mean trunk inclination in match play was ~45° and little differences between the playing positions were observed (defenders: ~43.5°; midfielders: ~44.2°; strikers: ~46.4°) [ 10 ]. The trunk flexion position lets the players carry out soccer-specific movements (e.g., running, passing, or controlling the ball) but these actions may move the field of regard down and limit the visual exploration [ 10 , 16 ]. In addition, soccer is a team sport with continuous running actions, accelerations, decelerations, and changes of directions for each position [ 2 , 19 ], which induce constant trunk accelerations.…”

“…Then, the differences in the activity-profile from each position may explain why there were positional differences in G-forces in match play. In consequence, the development of position-specific training drills considering the trunk inclination and G-forces experienced by the players is necessary to prepare not only for the physical demands (e.g., training trunk flexion postures with constant G-forces, which may avoid low back pain) [ 12 ] but also for successful performance in the field of regard [ 10 , 16 ]. However, this consideration does not seem to be so important for the locomotor efficiency ratio since no positional differences were found, which confirms the results reported by a previous investigation [ 22 ].…”

“…For example, running at a controlled speed (e.g., 3.4 m/s) with an excessive upright posture has been associated with greater patellofemoral joint stress compared to running with forward trunk flexion [ 15 ]. In addition, the trunk inclination is not only related to the development of musculoskeletal injuries but it also may explain the performance in the field of regard [ 10 , 16 ]. Then, the trunk inclination may be considered as an important variable since soccer players usually play the ball with the feet and their ability to perform in the field of regard may be affected as well [ 10 ].…”

Kinematic Analysis of the Postural Demands in Professional Soccer Match Play Using Inertial Measurement Units

“…A recent investigation on field hockey players observed that these were half of a match in two trunk flexion zones (30°–40°: ~26% of total time and 40°–50°: ~26% of total time) [ 4 ]. This trunk inclination allowed the players to perform the sport-specific movements such as running with the ball or passing and controlling the ball, which may move the field of regard down [ 4 , 5 ]. In addition, the results showed that the playing position should be also considered when analyzing the postural demands.…”

“…Then, as in other team sports in which the ball, teammates, referees, or opposition players are continually in motion, it is suggested that the understanding of the postural demands met by the players when performing sports-specific skills would provide coaches and performance analysts with meaningful information about their performance in perception and action [ 4 ]. For example, the downward orientation of the head and the trunk may restrict the ability to perform in the field of regard [ 4 , 5 ]. However, soccer players usually play the ball with the feet, which may increase the trunk flexion and move the field of regard down [ 4 ].…”