Effects of Cardiovascular Fitness and Body Composition on Maximal Core Temperature in Collegiate Football Players During Preseason.

McClelland, JM, Godek, SF, Chlad, PS, Feairheller, DL, and Morrison, KE. Effects of cardiovascular fitness and body composition on maximal core temperature in collegiate football players during preseason. J Strength Cond Res 32(6): 1662-1670, 2018-This study evaluated the effects of body mass index (BMI) and aerobic fitness (V[Combining Dot Above]O2max) on maximal core temperature values (Tcmax) in 17 National Collegiate Athletic Association Division III football players during preseason. The subjects included 9 backs (BKs) and 8 linemen (LM). V[Combining Dot Above]O2max testing was performed 1 week before preseason. Core temperature was monitored by ingestible sensor every 10 minutes during practices on day 4 (D1), day 5 (D2), day 7 (D3), and postacclimatization on day 14 (D4). Wet bulb globe temperature (WBGT) was recorded on each collection day. Independent, paired t-tests and Pearson's correlations were performed (α = 0.05). There were no significant correlations between V[Combining Dot Above]O2max and Tcmax on D1 (WBGT = 29.07° C) or D2 (WBGT = 30.93° C), but on D3 (WBGT = 31.39° C) there was a nonsignificant moderate negative correlation (r = -0.564, p = 0.090). There were no significant correlations between BMI and Tcmax on D1 or D2, but on D3 there was a nonsignificant moderate positive correlation (r = 0.596, p = 0.069). Paired t-tests revealed that overall Tcmax (D1-3) (38.56 ± 0.32° C) was statistically higher (p = 0.002) than D4 (38.16 ± 0.30° C). Independent t-tests between groups showed that the Tcmax values during preacclimatization (D1-D3) were significantly higher in LM (38.50 ± 0.37° C) than BKs (38.16 ± 0.35° C) (p = 0.007). V[Combining Dot Above]O2max was significantly lower (p = 0.006) in LM (36.89 ± 6.40 ml·kg·min) than BKs (47.44 ± 7.09 ml·kg·min), and BMI was significantly higher (p = 0.019) in LM (35.59 ± 4.00 kg·m) than BKs (28.68 ± 3.38 kg·m). The results of this study demonstrate that LM are significantly less fit than BKs and have a greater BMI. When WBGT was the highest on D3, the results suggest that those with lower V[Combining Dot Above]O2max and higher BMI experienced a higher Tcmax.