Cardiac-Autonomic Responses to In-Season Training Among Division-1 College Football Players

Abstract

Despite having to endure a rigorous in-season training schedule, research evaluating daily physiological recovery status markers among American football players is limited. The purpose of this study was to determine if recovery of cardiac-autonomic activity to resting values occurs between consecutive-day, in-season training sessions among college football players. Subjects (n = 29) were divided into groups based on position: receivers and defensive backs (SKILL, n = 10); running backs, linebackers and tight-ends (MID-SKILL, n = 11) and linemen (LINEMEN, n = 8). Resting heart rate (RHR) and the natural logarithm of the root-mean square of successive differences multiplied by twenty (LnRMSSD) were acquired at rest in the seated position prior to Tuesday and Wednesday training sessions and repeated over three weeks during the first month of the competitive season. A position × time interaction was observed for LnRMSSD (p = 0.04), but not for RHR (p = 0.33). No differences in LnRMSSD between days was observed for SKILL (Tuesday = 82.8 ± 9.3, Wednesday = 81.9 ± 8.7, p > 0.05). Small reductions in LnRMSSD were observed for MID-SKILL (Tuesday = 79.2 ± 9.4, Wednesday = 76.2 ± 9.5, p < 0.05) and LINEMEN (Tuesday = 79.4 ± 10.5, Wednesday = 74.5 ± 11.5, p < 0.05). The individually averaged changes in LnRMSSD from Tuesday to Wednesday were related to PlayerLoad (r = 0.46, p = 0.02) and body mass (r = -0.39, p = 0.04). Cardiac-parasympathetic activity did not return to resting values for LINEMEN or MID-SKILL prior to the next training session. Larger reductions in LnRMSSD tended to occur in players with greater body mass despite having performed lower workloads, though some individual variability was observed. These findings may have implications for how coaches and support staff address training and recovery interventions for players demonstrating inadequate cardiovascular recovery between sessions.

Heart Rate Variability in College Football Players throughout Preseason Camp in the Heat

“…3). This initial response to training is consistent with the between-position LnRMSSD responses observed during spring camp [18] and the early competitive period [33]. Possible explanations for the reduction in LnRMSSD among linemen have previously been discussed [18] and pertain to differences in aerobic fitness, body mass and composition, anaerobic workloads, and fluid losses between groups [12].…”

Association between Subjective Indicators of Recovery Status and Heart Rate Variability among Divison-1 Sprint-Swimmers

“…Despite a strong inverse relationship between RHR and LnRMSSD, LnRMSSD demonstrated stronger associations with ASRM at both the group and individual level. Previous investigations have demonstrated that ultra-short LnRMSSD was more sensitive than RHR for reflecting responses [ 3 ] and fitness changes [ 39 ] to training among team-sport athletes. Despite a greater sensitivity to training and perceptual responses, interpreting LnRMSSD in conjunction with RHR is still encouraged for other reasons, such as detecting parasympathetic saturation [ 10 ].…”

“…Resting heart rate variability (HRV) is considered a global marker of homeostasis [ 1 ] and is widely implemented as an indicator of training adaptation in the applied sports setting [ 2 , 3 , 4 , 5 , 6 ]. For example, HRV has been shown to reflect changes in performance [ 4 ] and training load [ 7 ] among competitive swimmers.…”

Daily Heart Rate Variability before and after Concussion in an American College Football Player

“…Player monitoring strategies and data analysis techniques in collegiate football are generally managed by performance staff. Microsensor-derived training load, subjective well-being, and ultra-short heart rate variability (HRV) represent a few of the measures currently being used by American college football teams in an effort to optimize player health and performance [1,2,3,4]. However, effective use of player monitoring tools such as HRV requires interpretation of the data in appropriate context given its sensitivity to a variety of physiological, psychological, and environmental factors [5].…”

“…Symptoms are poor indicators of neurological recovery, and standard clinical tests have been found inadequate for detection of subtle abnormalities that can persist beyond return to sport participation [10,11]. A number of published reports have established HRV as a reliable marker of autonomic dysregulation after SRC [10,12,13], potentially confounding interpretation of fatigue-induced alterations among collision-sport athletes [1,2,14,15,16]. Daily HRV averaged over a period of time (e.g., 1–2 weeks) reflects mean parasympathetic activity while its coefficient of variation (CV) reflects the magnitude of daily HRV fluctuations.…”