Sports health. November 20, 2021: 19417381211058458. doi: 10.1177 / 19417381211058458. Online ahead of print.
BACKGROUND: Non-traumatic deaths occur regularly in high school (HS) and college football athletes, primarily in obese linemen performing high-intensity exercise. A contributing factor to these deaths may be a mismatch between basic aerobic (cardiopulmonary) fitness and exercise regimens.
HYPOTHESIS: There is a wide range of aerobic capacity among HS and college football players. The Body Mass Index (BMI) is a safe and simple method for estimating basal aerobic capacity.
STUDY DESIGN: Retrospective cohort study.
LEVEL OF EVIDENCE: Level 3.
METHODS: A retrospective review was performed on 79 HS football athletes who had VO2 pic (mL kg-1Min-1) measured during the offseason. Multivariate regression analysis was used to determine whether the BMI (obesity, overweight and normal; kg / m2), position played (linemen vs. other), school year (freshmen vs. other), and / or race (African American vs. white) were risk factors for poor aerobic fitness. A separate cohort of 135 (48 HS; 87 academics) football athletes performed a 6-minute running test to determine speed (miles / min), extrapolate VO2Max, and calculate the benchmarks for the safe starting speeds suggested at the upper threshold (85% of maximum) for aerobic training based on BMI. The relationship between BMI and VO2 pic has been evaluated. Exercise regimes (speeds) from 2 public domain college football deaths were used to predict their VO2Max values.
RESULTS: Average VO2 pic (mL kg-1Min-1) was 38.5 Â± 8.6 (range 19.1-60.6); when grouped by BMI, low scores (2 pic was significantly lower among linemen (32.8 Â± 6.4; P = 0.007) compared to non-lineman (41.8 Â± 7.9) and obese players (according to BMI; 32.4; P = 0.019) compared to non-obese gamers (41.4 Â± 7.6), but did not differ by age, school year or race. Averages for speed (min / mile) and extrapolated VO2Max (mL kg-1Min-1) for the 6-minute run test by the BMI groups were both significantly different (P = 0.001) for normal (7.0 Â± 0.6; 51.1 Â± 2.6), overweight (7.6 Â± 0.8; 46.5 Â± 3.2) and obese (8.9 Â± 1.5; 36.8 Â± 5.9). There was a significant negative correlation (r = -0.551; P = 0.001; R2 = 0.304) between VO2 pic and BMI. Safe starting speed recommendations for running over a 1 mile range of 7.3 to 12.1 min / mile for BMIs of 20 to 40 kg / m2 for HS and collegiate athletes. For the 2 deaths (mean, BMI of 36.5 kg / m2) repetitive sprint speeds were 49% and 89% higher than our safe start speeds for their BMI.
CONCLUSION: A broad spectrum of basic aerobic fitness was noted among HS and college football players. Obese gamers and linemen had statistically lower basal aerobic fitness, a major risk factor for possible heat discomfort. BMI is an acceptable substitute for VO2 pic and can be used to develop safe training regimes without the need for maximum physical fitness testing, which may put the athlete at risk for a medical event.
CLINICAL RELEVANCE: Knowledge of BMI provides an estimate of baseline aerobic fitness and a basis for prescribing safe and individualized exercise regimens.
IDPM: 34806472 | DOI: 10.1177 / 19417381211058458