The effects aerobic fitness has on heart rate responses for a custody assistant recruit class performing a formation run

This study measured the heart rate (HR) responses to a formation run (group run completed along a set route) performed by higher fitness (HF), moderate fitness (MF), or lower fitness (LF) custody assistant (CA) recruits. Retrospective data from 26 recruits (12 males, 14 females) were analyzed. Prior to academy training, a YMCA step test was administered. Recruits were divided into three groups based on recovery HR: top 25% were HF; bottom 25% were LF; the rest were MF. Recruit HR was measured during a formation run completed at an ~11-minute mile· pace-1. HR zones were defined as: very light (< 57% of age-predicted maximum heart rate [HRmax]); light (57%-63% HRmax); moderate (64%-76% HRmax); vigorous (77%-95% HRmax); and very vigorous (> 95% HRmax). A one-way ANOVA, with Bonferroni post hoc, calculated between-group differences in time spent and percentage of total time in the HR zones during the run; effect sizes (d) were also calculated. HF recruits spent a significantly longer time and percentage of total time in the very light HR zone compared to the LF group (p ≤ 0.039; d = 1.20-1.35). There were no other significant between-group differences (p = 0.070-0.980). HF CA recruits spent more time in the very light training zone compared to the other groups (d = 0.92-1.35), which may not be optimal for aerobic adaptations. LF recruits spent more time in the vigorous-to-very vigorous HR zones (~45 minutes; 70% of the run). These recruits may potentially be working above their current capacity. Formation runs may not be the most efficient aerobic conditioning method for all CA recruits.