There is only limited data available regarding strength and endurance training adaptations to occupational physical performance during deployment. There is almost non-existing data available this type of test and exercises in military operations. Mbody smart shorts were used to measure training-induced acute neuromuscular responses to military specific test during a 6-month military operation in Middle East.
Results: Increased absolute and relative muscle activity in quadriceps and hamstring muscles during the military simulation test (MST) at the end of 6-month period. Combined strength and endurance training performed on average, three times per week during the deployment, likely increased the activation of the thigh muscles, and resulted in improved occupational performance of soldiers, assessed with MST.
The results were presented at the 5th International Congress on Soldiers’ Physical Performance (ICSPP) http://www.icspp2020.ca/. You can find the original presentation after registering to our Resources page here.
The study made in Finnish Defense Forces and University of Jyväskylä assessed acute training-induced changes in neuromuscular (electromyography; EMG) and metabolic (blood lactate, BLa) responses during a high-intensity military simulation test, performed in the beginning (PRE) and at the end (POST) of a six-month UN (crisis-management) operation. MST time shortened (145 ± 21 vs. 129 ± 16 s, −10 ± 7%, p < 0.001) during the operation. Normalized muscle activity increased from PRE to POST in the hamstring muscles by 87 ± 146% (116 ± 52 vs. 195 ± 139%EMGMVC, p < 0.001) and in the quadriceps by 54 ± 81% (26 ± 8 vs. 40 ± 20%EMGMVC, p < 0.001). In addition, higher acute BLa values were measured after MST during POST.
Changes in BLa and EMG suggested an increased neural input and metabolic rate during POST MST, likely leading to faster performance times at the end of the operation. High EMG values throughout the different phases of MST suggested that despite the anaerobic nature of the test, the soldiers were able to maintain their voluntary muscle activation level until the end of the test. This indicates only limited neural fatigue during the two-minute high-intensity military specific performance. While learning effect may explain some part of the improvement in the MST performance times, combined strength and endurance training three times per week may improve neuromuscular performance in occupationally relevant tasks.
49 soldiers of the test group of 81 were using Myontec Mbody (4ch version) smart shorts out-of-the lab, on the field, wearing full combat gear on top. First of a kind performance test in conflict area!
Article itself was published in International Journal of Environmental Research and Public Health on 30th December 2020. Read the abstract and the whole article https://www.mdpi.com/1660-4601/18/1/215
About the used sEMG technology
Traditionally, EMG measurements have been conducted in laboratory settings and using small bipolar electrodes, aiming to measure activity of a certain motor unit. This is challenging and requires precise determinations of measurement sites, especially, in longitudinal field studies. Even though the electrodes were carefully placed on the exact same anatomical positions, there were several pitfalls affecting the signal outcome such as conductivity issues related to possible changes in subcutaneous fat content, or amplitude cancellation, caused by differences in timing of action potentials, etc. During dynamic muscle contractions such as performing MST, both force output and body postures change and thus, there existed more confounding factors for the EMG analysis. For example, electrode shift during or between the measurements may lead to recording of different muscle fibers with different recruitment thresholds. To avoid these pitfalls, EMG amplitude was normalized to the respective MVC measurement. Furthermore, multiple electrodes, providing a more representative measure of muscle activity from a group of muscles, instead of a single motor unit, were used. As presented, this study used large area sEMG electrodes, which enabled quantification of the overall muscle activity of the quadriceps and hamstring muscle groups. The validity and reliability of textile. EMG measurement method has been tested against traditional laboratory-quality skin surface electrodes during static and dynamic activity.