Dustin P. Joubert

Aquatic Treadmill Training Reduces Blood Pressure Reactivity to Physical Stress

PURPOSE Endurance exercise may reduce blood pressure and improve vasodilatory capacity, thereby blunting the hypertensive response to stress. Therefore, we sought to test the efficacy of a novel model of low-impact endurance training, the aquatic treadmill (ATM), to improve blood pressure (BP) parameters. METHODS Sixty sedentary adults were randomized to 12-wk of either ATM (n = 36 [19 males and 17 females], 41 ± 2 yr, 173.58 ± 1.58 cm, 93.19 ± 3.15 kg) or land-based treadmill (LTM, n = 24 [11 males, 13 females], 42 ± 2 yr, 170.39 ± 1.94 cm, 88.14 ± 3.6 kg) training, three sessions per week, progressing to 500 kcal per session, 85% VO2max. The maximal Bruce treadmill test protocol was performed before and after training with BP measured before, at the end of each stage, and for 5 min after exercise testing. Twelve subjects (five ATM and seven LTM) volunteered for biopsies of the vastus lateralis before and after training, and muscle samples were assessed for endothelial nitric oxide synthase content. Data collected during exercise testing were analyzed using group by training ANCOVA repeated across training, α = 0.05. RESULTS ATM but not LTM training significantly reduced resting diastolic BP (-3.2 mm Hg), exercise systolic BP (range 9-18.2 mm Hg lower for each exercise stage), diastolic BP (3.2-8.1 mm Hg), mean arterial pressure (4.8-8.3 mm Hg, lower than LTM posttraining), and pulse pressure (7.5-15 mm Hg) during stages of exercise stress and recovery (P < 0.05). In addition, an increase (+31%) in skeletal muscle endothelial nitric oxide synthase content after training (P < 0.05) occurred in only the ATM group. Body mass (-1.27 kg) and VO2max (+3.6 mL · kg(-1) · min(-1)) changes were significant for both groups (P < 0.001). CONCLUSION ATM training can reduce BP reactivity to physical stress.

A longitudinal study examining the effects of a season of American football on lipids and lipoproteins

BackgroundDyslipidemia is one factor cited for increased risk of cardiovascular disease (CVD) in American football players. However, American football players undergo physical conditioning which is known to influence lipids. This study examined if the physical activity of an American football season is associated with changes in lipids and if a relationship exists between lipids and body composition.MethodsFourteen division I freshmen American football players had blood drawn prior to summer training (T1), end of competition (T2), and end of spring training (T3). Samples were analyzed for total cholesterol (TCHL), HDL-C, LDL-C, and triglycerides (TG). Body composition was assessed via dual-x-ray absorptiometry. National Cholesterol Education Program (NCEP) lipid categorization was used to characterize participants. Pearson correlations were computed to determine relationships.ResultsBody mass increased T2 (p = 0.008) as a result of increase in fat mass (p = 0.005) and remained high despite a decrease T3. Lean mass did not differ significantly at any time. No significant time effects were observed for lipids measured. The number of participants presenting with risk factors attributed to dyslipidemia varied. By T3, no participant was categorized as “low” for HDL-C. TCHL was moderately correlated (r = 0.60) with fat mass at T1; whereas a moderate correlation (r = −0.57) was observed between BMI and HDL-C at T2. TG was strongly correlated with fat mass at each time point (T1, r = 0.83; T2, r = 0.94; T3, r = 0.70).ConclusionThe physical activity associated with a season of football results in little change in blood lipids and CVD risk. Further, TG are strongly related to fat mass. Future research should focus on examining the cause of dyslipidemia in American football players.

Does Ecg Predict Cardiac Hypertrophy In American-style Football Athletes?: 197 Board #34 June 1, 11: 00 AM - 12: 30 PM.

The accurate and cost effective identification of left ventricular (LV) hypertrophy is clinically relevant due to its association with cardiac mortality in the general population. PURPOSE: To determine if electrocardiographic (ECG) voltage criteria predicts LV mass measured with cardiac ultrasound in collegiate American-style football (ASF) players. METHODS: Over a 3-year period, standard resting, supine 12-lead ECG and echocardiographic (ECHO) procedures were performed on 76 collegiate ASF players first entering an NCAA Football Bowl Subdivision university as part of their preparticipation physical exams. Player demographics were: age=18±1 yr., height=186±7 cm, weight=100.1±22.0 kg, BMI=28.6±5.0 kg·m2, and BSA=2.24±0.25 m2. Linear regression was used to predict ECHO-derived LV mass and LV mass/BSA index from ECG precordial-lead voltage criteria [sum largest S (V1 or V2) + R (V5 or V6) ≥ 35 mm]. RESULTS: ECG voltage criteria did not significantly (p > 0.05) predict ECHO LV mass (LV mass = -0.12x + 216.94, r = 0.024, R2 = 0.0006), or LV mass/BSA index (LV mass/BSA = 0.3063x + 81.951, r = 0.17, R2 = 0.0244). CONCLUSION: ECG precordial lead voltage was not clinically useful in diagnosing ECHO-derived LV hypertrophy in our sample of first-year collegiate ASF players. We suggest that new and more accurate algorithms for evaluating LV hypertrophy in ASF athletes be explored, possibly using demographic, body habitus, cardiovascular, and other ECG criteria.