JMIR Publications

ABSTRACT

Background:

Service members volunteer for training and selection to serve in elite and specialized United States military units. Training is often psychologically and physically intense and is associated with high attrition rates. There is a need to graduate more service members without degrading performance standards. However, the mental and physical factors that predict success or failure in training are unknown, and thus it is difficult to target interventions.

Objective:

We sought to continuously quantify the mental and physical status of trainees of an elite United States military unit to identify novel predictors of success or failure in successive training classes performed on land and in water.

Methods:

Three consecutive classes of Marines and Sailors entering the first 25-day class of a specialized training course were provided with an Apple iPhone and Watch and a specially-designed mobile application. Baseline personality assessments and continuous daily measures of mental status, physical pain, heart rate, activity, sleep, hydration and nutrition were collected from the application and Watch data.

Results:

A total of 121 trainees were enrolled (100% male, age 22±4 years) and 64 (56%) successfully graduated (completed the course). Most training withdrawals (23%) occurred by day 7 (5.5± 3.4 days, range 1-22 days). Neither performance on physical training standards, such as hikes or aquatic training, or continuous measures of heart rate, work output, hydration, nutrition and sleep duration continuously predicted course completion. Throughout the 25-day course, trainees’ mean daily heart rate and work output was 112 ± 30 bpm (range 30-120 bpm), 10,510 ± 7,742 steps (range 1-34,978) and 1767.32 ± 64.46 Calories (range, 1-9133). Extraversion and positive affect personality traits and daily psychological profiles were associated with course completion; key psychological factors could predict withdrawals 1-2 days in advance (P=0.009).

Conclusions:

It is possible to gather accurate and continuous mental and physical status data during elite military training. Early predictors of trainee withdrawal can be identified that can provide an opportunity for intervention.