Effect of Prolonged Military Exercises With High Load Carriage, on Neuromuscular Fatigue and Physiological/Biomechanical Responses

Study Overview
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Brief Summary
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Land military missions generally combine prolonged walking/moderate-pace-running and other physical actions such as creeping, jumping, shooting,… which are associated with the direct carrying of high to severe loads of equipment and supplies (20-30 to 50 kg) by soldiers. For an infantry section, typical intervention phases last about 20-24 h and combine variable intensity grades. Consequently, military mission characteristics are an interesting investigation field of human fatigue. Previous studies have investigated human neuromuscular alterations after prolonged normal locomotion exercises [Millet et al., 2004, 2009], thus the aim of this study is to characterize the neuromuscular determinants of fatigue induced by a 24-h Simulated Military Effort (SME) and a 4-h Military Road March (MM), both performed with high load carriage. Additionally, the consequences of fatigue on physiological and biomechanical parameters of locomotion will be investigated.

Conditions
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Healthy

Intervention / Treatment
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* Other: military equipment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: to be a male to have a VO2max > 45ml/min/kg (mean observed value in military subjects) to be aged from 30 to 45 to be recently retreated from National Army to be highly experienced in military efforts to be trained in exercises involving load carrying to benefit from a social security insurance Exclusion Criteria: All subjects with recent (< 3 month) bone, articular or muscle diseases. All subjects presenting a clinic sign of intolerance to testing procedures, especially subjects with knee, ankle, hip or back diseases. All subjects intolerant to muddy or wooded environment. All subjects presenting a clinic sign of intolerance to exercise, and particularly to running or walking while carrying a load All subjects involved at the same time in another medical research All subjects militarily active All subjects with cardiac or pulmonary identified and known diseases

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Military<br> | Other: military equipment<br>* Military exercise of 24 hours<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Central fatigue quantification based on voluntary and electrically-induced force measurement on activated muscle. |  | after a a military exercise of 24 hours | 
| Peripheral fatigue based on electrically-induced force measurement on the same muscle in relaxed condition. |  | after a a military exercise of 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxygen uptake, carbon-dioxide output, energetic-cost of locomotion and respiratory ratio, based on subject's gas exchanges. |  | after a a military exercise of 24 hours | 
| Lactatemia, based on subject's arterialized capillary blood samples analysis |  | after a a military exercise of 24 hours | 
| Muscular electrical activities, based on subject's surface EMG analysis |  | after a a military exercise of 24 hours | 
| Heart rate frequence |  | after a a military exercise of 24 hours | 
| Walking and running mechanics, measured by an instrumented treadmill |  | after a a military exercise of 24 hours | 
| Postural equilibration, measured by a piezo-dynamometric double platform |  | after a a military exercise of 24 hours | 
| Rate of perceived exertion, measured by the Borg scale ranging from 6 to 20 |  | after a a military exercise of 24 hours | 
| Perceived comfort, measured by a 10 cm visual analogic scale (VAS) |  | after a a military exercise of 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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military exercises, neuromuscular fatigue, physiological responses, biomechanical responses, simulated military effort, high load carriage, Healthy voluntary