[abstract] USING THE NAVSTAR GLOBAL POSITIONING SYSTEM TO MEASURE SEAL COMBAT SWIMMER PERFORMANCE DURING FIELD RESEARCH

Abstract

INTRODUCTION: Evaluation of military performance in field settings is usually accomplished with measurements obtained before and after the training exercise. Changes in sample values are presumed to reflect the intervening experience. The subject's performance during the exercise is rarely observed. We used GPS technology to record changes in performance during training exercises. MATERIALS AND METHODS: Fifteen U.S. Navy SEALs participating in combat swimmer training exercises in either 63 F or 83 F water served as subjects. GPS receivers were programmed to collect and store a waypoint once a minute, placed in waterproof bags and attached to safety buoys towed by each dive pair during the training dives. SEAL Team training cadre provided a daily insertion and extraction point. Dive pairs then created a multiple leg dive profile to accomplish the mission. At the completion of each dive the data were downloaded to a laptop computer and displayed on digitized nautical charts. The charting software permitted the precise calculation of bearing and velocity of swimming, minute by minute. The obtained results were compared to the planned dive profile to obtain measures of accuracy. RESULTS: The planned dive profiles were over laid on the digitized charts and compared to the dive profiles swum. Differences between the planned and obtained dive profiles were calculated in degrees, distance, and time for each leg of the dive. Dive accuracy tended to be less precise in cold water, there were greater deviations from the planned leg bearings and the legs tended to be shorter. CONCLUSIONS: The GPS data collection and analysis system proved to be a reliable and accurate method for evaluating individual dive performance. The small sample size combined with relatively large individual variability resulted in T values that did not achieve statistical significance. This work was funded by Work Unit 603706N333.127.A0076 swimmer performance, global positioning system, performance training, SEALs