Abstract
Objectives: The objective of this study was to evaluate the impact rest time between games may have on injury rates as it pertains to overall incidence, injury location and player position. Methods: For this descriptive epidemiological study, data was obtained from official NFL gamebooks. In-game injuries were queried for all regular season games from all 32 teams over the course of four seasons (2013 to 2016). Only injuries which resulted in a stoppage of time during gameplay were included. Player position and injured body part were taken from the following week’s injury report. Rest periods between games were classified as short (4 days), regular (6-8 days), or long (10+ days) rest. Positions were categorized into Quarterback, Skill (wide receiver, running back and defensive backs), Lineman, and Other (fullback, linebacker and tightend). Overall observed injury rates, as well as injury rates specific to anatomic location and player position, were analyzed in correlation to different rest periods. Statistical significance was determined using the ANOVAprocedure of observed mean injuries per game. Pairwise analysis, through 2 sample T-test, was conducted to assess statistical significance between short, regular and long rest. Results: A total of 2,846 injuries were identified throughout the four seasons. ANOVA testing of all 3 cohorts taken together demonstrated a statistically significant difference between injuries/game between short, regular, and long rest (p = 0.012). With short rest, a mean of 1.26 injuries/game were observed (95% CI 1.046, 1.470), which was statistically significantly different when compared to the 1.53 observed injuries/game with regular rest (95% CI 1.463, 1.601; p = 0.029). Games with short rest were not found to be significantly different when compared to the 1.34 observed injuries/game associated with long rest (95% CI 1.186, 1.486; p = 0.555). Regarding player positions, only the Other cohort achieved statistically significantly less observed injuries/game with games played on Thursday compared to regular (p=0.0002) and long (p = 0.026). The quarterback position was the only position which sustained more injuries than expected with games played on Thursday compared to both regular and long rest; however, these results did not reach statistical significance (p = 0.09). No statistical difference was found regarding injury location in correlation to differences in rest periods. Conclusion: Our data suggests that there is a significant association between the amount of rest between games and observed injuries in the NFL. Interestingly, Thursday night games were found to have fewer injuries per game when compared to games played on regular rest. Subgroup analysis revealed fewer observed injuries with short rest for linebackers, fullbacks, and tightends. Although quarterbacks were observed to have more injuries than expected on short rest, this did not reach statistical significance. The results of this study do not support that less rest associated with Thursday night games leads to higher injury rates; however, quarterback injury rates may potentially be impacted with shortened rest. [Table: see text]