Research Roundup 5.20.23


By Anna Woodring, MTI Strength and Conditioning Coach 

Effect of Armor and Carrying Load on Body Balance and Leg Muscle Function 

Published in the Journal of Gait and Posture. The purpose of this study was to examine how the weight and distribution of body armor and load carriage affect static body balance and leg muscle function. A group of seven male military students participated in a series of human performance tests, each with different weight distributions. Static body balance was evaluated by analyzing the trajectory of the center of plantar pressure and assessing the symmetry of weight distribution on the feet. Researchers loaded a ruck unevenly until they indicated a shift in foot pressure. Researchers utilized a foot pressure sensor mat to assess the changes on how the participants walked and stood under load. The mat would sense changes in patterns within the foot, which led to changes in balance. Leg muscle function was assessed by analyzing the peak electromyography amplitude of four specific leg muscles while the participants walked, indicating if participants changed their gait or if early fatigue was shown in lower body muscles. 

The findings of this study indicated that when the weight distribution of the load became uneven, surpassing an additional 9 kg, it negatively affected static body balance. This was evident from an increased sway of the center of plantar pressure and asymmetry in weight bearing on the feet. Specifically, adding weight on the non-dominant side of the body resulted in a greater hindrance to static balance. 

Looking at the small sample size of this study, I would want to test this myself to see if I experienced a change in leg fatigue or balance balance with an uneven load on my non-dominant side. I would be testing if an uneven load on my dominant side allowed for a smoother gait while walking and more stability in both the back and torso. If I experienced a noticeable difference I would utilize this approach if having to carry an uneven load. For most cases, this is not an issue as tactical athletes understand how to pack a ruck evenly. If uneven weight is carried it is seen primarily through something carried in the hands, which can be passed off from dominate to non-dominate and should be recommended. 

Effects of Sleep Extension on Cognitive/Motor Performance and Motivation in Military Tactical Athletes

Published in the Journal of Sleep Medicine. The deliberate increase in the usual duration of sleep, known as sleep extension, has demonstrated numerous advantageous outcomes for athletes. A recent comprehensive analysis of interventions to improve sleep and athletic performance found that extending sleep duration from eight hours to ten hours positively impacts subsequent performance. Consequently, sleep extension presents a potential strategy to maintain operational effectiveness in professions characterized by unique sleep circumstances and demanding work requirements. This study primarily aimed to examine the immediate impact of sleep extension on the cognitive/motor performance and motivation of ROTC students at the University of Maryland. The secondary objective was to assess whether the effects of sleep extension persisted and were still noticeable four days after participants reverted to their regular sleep patterns.

Following the implementation of sleep extension, notable variations emerged between the groups in terms of the average change in scores since the baseline assessment. The Psychomotor Vigilance Test, Trail Making Test, standing broad jump distance, and motivation levels for cognitive tasks exhibited significant disparities, with the extension group displaying a more substantial improvement in both performance and motivation. Moreover, even after participants returned to their regular sleep patterns, meaningful distinctions persisted between the groups, with the sleep extension group demonstrating superior enhancement in performance and motivation.

When seeking to enhance overall performance, this article suggests increasing sleep from eight hours to ten hours prior to an event. With a small sample size of college students this could be practical. However, many tactical events utilize sleep deprivation that is embedded within the training. Even while in garrison mornings typically start at 0600, meaning you would need to be asleep by 1900 to obtain ten hours of sleep. Sleep extension might only be practical for garrison yearly performance events, such as a physical fitness test. Practice like you play, if knowing you will not get much sleep before an event don’t get used to only performing with immense sleep. 

Applying Force Plate Technology to Inform Human Performance Programming in Tactical Populations

Published in the Journal of Applied Sciences. Force plate assessments, such as countermovement jumps and isometric mid-thigh pulls, are effective in evaluating and tracking physical capabilities by analyzing performances, including jump height, force, and power, as well as movement strategies such as asymmetries and durations. These assessments are highly suitable for accurately characterizing and monitoring an individual’s physical capabilities over time. While the physical demands and job requirements may differ among tactical populations, the significance of muscular strength and power remains consistently crucial across these environments. Many tactical populations experience high rates of musculoskeletal injuries, with the lower extremities, back, and shoulders being the most commonly affected areas. Initiatives for monitoring and profiling human performance should transition from injury prediction to assessing and improving potential risk factors associated with increased injury rates, such as muscular strength and power.

Conducting force plate testing annually offers valuable information regarding an individual’s neuromuscular performance capabilities, encompassing aspects such as strength, power, load carriage, and force absorption abilities. These performance scores can highlight areas of weakness that may require improvement to excel in tactically relevant tasks, particularly when considering the group as a whole.

This study is not practical for tactical units. This technology is expensive and is known to not be user friendly. This technology is trying to sell it self as more of a performance indicator for the tactical community, while it only presents data that shows if an athlete needs to cut back due to lack of recovery. Tactical units do not have the luxury that is provided for Force Plates target population which is collegiate and professional athletes. This population is capable of incorporating a deload week or a full recovery week. This means that while on paper, Force Plates look like a great idea, what is the benefit to finding out a tactical athlete might need to take three days off, when there are not three days to give? Determining and assessing an athletes strength, power, and speed can be done by easier and less expensive measures. This allows for assessments to be done at each individual unit, rather than by the one guy who knows how to work Force Plates. 

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