Speed Marching in Military Boots: The Walk-To-Run Transition Speed and Vertical Ground Reaction Forces

Abstract

Background: Speed marching is the term for moving on foot, in which service members alternate marching and running to cover a certain distance in limited time. The standard load for speed marching is 25 kilograms, this includes a backpack, a tactical vest and rifle. When increasing walking speed, a person will switch from walking to running at a certain speed, this is called walk-to-run transition. The walkto-run transition speed for marching in military boots, with or without a rifle, is unknown. Marching and running are the source of many overuse injuries, the accumulation of impact forces plays a causal role. Research into alleviating the impact forces of military tasks, such as speed marching, is desirable. Research questions:1. What is the walk-to-run transition speed for marching in military boots, with standard 25 kg load, including a (practice) rifle? 2. What are the vertical ground reaction forces of marching and running at the speed of the walk-to-run transition? Methods: A one-time series of measurements on an instrumented treadmill, in a running laboratory, on twelve healthy military service members. Results:The walk-to-run transition speed averaged 7.4 km/h (SD 0.5 km/h). At 7.4 km/h, the maximum vertical ground reaction forces on the heel were less in running than in marching. The forces on the midfoot and forefoot were similar. Conclusion:The walk-to-run transition speed, measured in 12 healthy and experienced military service members during speed marching in boots, with 25 kg standard load and a (practice) rifle, is 7.4 km/h (SD 0.5 km/h). At the speed of walk-to-run transition, vertical ground reaction forces were lower in running than in marching in this particular population and activity.Recommendation: Switching from marching to running at a speed below the self-selected walk-to-run transition speed may reduce vertical ground reaction forces when marching with load in boots. Further research into the optimal transition speed from marching to running in military boots is warranted.