Steven E. Martin

Effects of Resistance, Endurance, and Concurrent Exercise on Training Outcomes in Men

UNLABELLED The specificity of training principle predicts that combining resistance and endurance training (concurrent training) could interfere with the maximum development of strength and endurance capacity that results from either type of training alone. PURPOSE To determine whether endurance and resistance training performed concurrently produces different performance and physiologic responses compared with each type of training alone. METHODS Untrained male volunteers were randomly assigned to one of three groups: endurance training (ET, N = 12); resistance training (RT, N = 13); and concurrent training (CT, N = 16). The following measurements were made on all subjects before and after 12 wk of training: weight, percent body fat, peak oxygen consumption (VO(2peak)), isokinetic peak torque and average power produced during single-leg flexion and extension at 60 and 180 degrees.s, one-repetition maximum (1RM) leg press, 1RM bench press, vertical jump height, and calculated jump power. RESULTS Weight and lean body mass (LBM) increased significantly in the RT and CT groups (P < 0.05). Percent body fat was significantly decreased in the ET and CT groups. VO(2peak) was significantly improved only in the ET group. Peak torque during flexion and extension at 180 degrees.s(-1) increased in the RT group. Improvements in 1RM leg press and bench press were significant in all groups, but were significantly greater in the RT and CT compared to the ET group. Jump power improved significantly only in the RT group, and no group showed a significant change in vertical jump height. CONCLUSIONS Concurrent training performed by young, healthy men does not interfere with strength development, but may hinder development of maximal aerobic capacity.

Electrocardiograms of collegiate football athletes.

The prevalence of electrocardiogram (ECG) abnormalities in American collegiate football athletes is virtually unknown.

Acute Exercise and Training Alter Blood Lipid and Lipoprotein Profiles Differently in Overweight and Obese Men and Women

Our purpose was to elucidate effects of acute exercise and training on blood lipids‐lipoproteins, and high‐sensitivity C‐reactive protein (hsCRP) in overweight/obese men (n = 10) and women (n = 8); age, BMI, body fat percentage, and VO2max were (mean ± SEM): 45 ± 2.5 years, 31.9 ± 1.4 kg·m−2, 41.1 ± 1.5%, and 25.2 ± 1.3 mlO2·kg−1·min−1. Before exercise training subjects performed an acute exercise session on a treadmill (70% VO2max, 400 kcal energy expenditure), followed by 12 weeks of endurance exercise training (land‐based or aquatic‐based treadmill): 3 sessions·week−1, progressing to 500 kcal·session−1 during which subjects maintained accustomed dietary habits. After training, the acute exercise session was repeated. Blood samples, obtained immediately before and 24 h after acute exercise sessions, were analyzed for serum lipids, lipoproteins, and hsCRP adjusted for plasma volume shifts. Exercise training increased VO2max (+3.67 mlO2·kg−1·min−1, P < 0.001) and reduced body weight (−2.7 kg, P < 0.01). Training increased high‐density lipoprotein (HDL) and HDL2b‐cholesterol (HDL‐C) concentrations (+3.7 and +2.4 mg·dl−1, P < 0.05) and particle numbers (+588 and +206 nmol·l−1, P < 0.05) in men. In women despite no change in total HDL‐C, subfractions shifted from HDL3‐C (−3.2, P < 0.01) to HDL2b‐C (+3.5, P < 0.05) and HDL2a‐C (+2.2 mg·dl−1, P < 0.05), with increased HDL2b particle number (+313 nmol·l−1, P < 0.05). Training reduced LDL3 concentration and particle number in women (−1.6 mg·dl−1 and −16 nmol·l−1, P < 0.05). Acute exercise reduced the total cholesterol (TC): HDL‐C ratio in men (−0.16, P < 0.01) and increased hsCRP in all subjects (+0.05 mg·dl−1, P < 0.05), regardless of training. Training did not affect acute exercise responses. Our data support the efficacy of endurance training, without dietary intervention, to elicit beneficial changes in blood lipids‐lipoproteins in obese men and women.

DEXA or BMI: clinical considerations for evaluating obesity in collegiate division I-A American football athletes.

Objective:To evaluate the relationship between body mass index (BMI) and %body fat (%Fat) in collegiate football athletes (FBA) compared with age-matched/gender-matched general population volunteers (comparison group, CG) and compare body composition and overweight/obese frequencies by BMI between FBA and CG. Design:Cross-sectional. Setting:Two Division I-A (D-IA) universities in Texas. Integrative Health Technologies (San Antonio, Texas) laboratory. Participants:Football athletes (n = 156, 20.0 ± 1.3 years, 185.6 ± 6.5cm, 103.3 ± 20.4 kg). Comparison group (n = 260, 21.5 ± 2.7 years, 179.0 ± 7.6 cm, 86.3 ± 20.9 kg). Statistical Analysis:Body mass index and bone densitrometry (DEXA) body composition were assessed. Regression was used to predict %Fat from BMI in CG and FBA. To compare %Fat, fat mass (FM), fat-free mass (FFM), and weight (WT) between CG, FBA, linemen, and non-linemen, 1 × 4 analysis of variance was used. Chi-square analysis was used to compare the frequency of BMI ≥25 between groups. Results:Body mass index differently predicted %Fat for CG (r2 = 0.643, SE = 6.258) and FBA (r2 =0.769, SE = 4.416). Body mass index cutoffs for overweight/obese corresponded to the following %Fat in each group [BMI ≥25 = 19.9% (CG) and 11.1% (FBA); BMI ≥30 = 27.3% (CG) and 20.2% (FBA)]. Football athletes had significantly higher WT, BMI, FFM, and frequency of BMI ≥25 with lower %Fat and FM than CG (&agr; < 0.05). Linemen had the highest WT, BMI, FFM, %Fat, and frequency of BMI ≥25. Conclusions:The relationship between BMI and %Fat differed between CG and FBA. Using current BMI thresholds for obesity in FBA may result in misleading inferences about health risk.

Predicting Football Players' Dual-Energy X-Ray Absorptiometry Body Composition Using Standard Anthropometric Measures

CONTEXT The recent increase in athlete size, particularly in football athletes of all levels, coupled with the increased health risk associated with obesity warrants continued monitoring of body composition from a health perspective in this population. Equations developed to predict percentage of body fat (%Fat) have been shown to be population specific and might not be accurate for football athletes. OBJECTIVE To develop multiple regression equations using standard anthropometric measurements to estimate dual-energy x-ray absorptiometry %Fat (DEXA%Fat) in collegiate football players. DESIGN Controlled laboratory study. PATIENTS AND OTHER PARTICIPANTS One hundred fifty-seven National Collegiate Athletic Association Division IA football athletes (age = 20 ± 1 years, height = 185.6 ± 6.5 cm, mass = 103.1 ± 20.4 kg, DEXA%Fat = 19.5 ± 9.1%) participated. MAIN OUTCOME MEASURE(S) Participants had the following measures: (1) body composition testing with dual-energy x-ray absorptiometry; (2) skinfold measurements in millimeters, including chest, triceps, subscapular, midaxillary, suprailiac, abdominal (SFAB), and thigh; and (3) standard circumference measurements in centimeters, including ankle, calf, thigh, hip (AHIP), waist, umbilical (AUMB), chest, wrist, forearm, arm, and neck. Regression analysis and fit statistics were used to determine the relationship between DEXA%Fat and each skinfold thickness, sum of all skinfold measures (SFSUM), and individual circumference measures. RESULTS Statistical analysis resulted in the development of 3 equations to predict DEXA%Fat: model 1, (0.178 · AHIP) + (0.097 · AUMB) + (0.089 · SFSUM) - 19.641; model 2, (0.193 · AHIP) + (0.133 · AUMB) + (0.371 · SFAB) - 23.0523; and model 3, (0.132 · SFSUM) + 3.530. The R(2) values were 0.94 for model 1, 0.93 for model 2, and 0.91 for model 3 (for all, P < .001). CONCLUSIONS The equations developed provide an accurate way to assess DEXA%Fat in collegiate football players using standard anthropometric measures so athletic trainers and coaches can monitor these athletes at increased health risk due to increased size.

Cardiovascular Risk Markers in Firefighters: A Longitudinal Study

The purpose of this study was to investigate the changes in cardiovascular risk factors for a group of firefighters (n=74) over a 6-year period. Subjects were full-time firefighters employed by a moderate-to-large municipality. Each subject was tested a minimum of 4 out of a possible 7 years (x=5.97) and underwent an assessment of body fat percentage (by underwater weighing), body weight, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and grip strength. Blood analysis was performed by a College of American Pathologists-accredited laboratory; grip strength was assessed using a handgrip dynamometer. Functional aerobic impairment was computed using age norms and a time-on-treadmill estimation of aerobic capacity (VO 2max ). A repeated measures analysis of variance was used to analyze the data. Results showed little significant change over time in cardiovascular risk markers. However, VO 2max was found to be below age-predicted averages, and body fat percentage was found to be significantly above age-predicted averages.

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.

Prediction Of The Total Energy Cost Of An Acute Bout Of Resistance Exercise In Young Men And Women: 1799

Int J Exerc Sci 2(1): S42, 2009. ACSM currently recommends resistance training (RT) for each major muscle group at least 2 times per week with a traditional repetition range of 8-12 per set. Because many investigators as well as fitness professionals consider kcal expenditure when creating training protocols, energy costs during both RT and aerobic training must be considered. PURPOSE: To develop a regression equation to predict kcal expenditure for a RT bout involving each major muscle group using VO2max, height, weight, lean body mass, fat mass, and total exercise volume (TV=sets*reps*wt) as independent variables. METHODS: Twelve subjects (7 men, 5 women, age 21-25 yrs) were tested using the standard Bruce treadmill protocol for VO2max, and strength tested to determine their 3-5 repetition max (RM) on Keiser® RT equipment 1 week prior to their experimental RT bout. Body composition was assessed using DEXA. For their experimental RT bout, a warm-up set followed by 2-3 sets of 8-12 reps at 60-70% predicted 1RM were performed for each exercise. Each set was started every two minutes. Exercises progressed in the following order: leg press, chest press, leg curl, lat pull, leg ext., triceps ext., biceps curl. Oxygen consumption was measured continuously throughout the RT bout using an automated metabolic cart. Multiple Linear Regression was used to determine the best model for prediction of kcal consumption. RESULTS: Mean kcal expenditure for the entire RT bout was 221.8±20.65 kcal (men = 272±36 & women = 150±16) with a mean kcal cost of 26.32-38.94 per exercise. Large muscle group/multi-joint exercises had the highest total kcal expenditures as expected. Collinearity diagnostics from the regression revealed that VO2max (L/min) and the square root of TV (TV0.5) were the only predictors needed in the model with all other variables being highly intercorrellated with VO2max (L/min), thus not adding significant improvement to the model. The prediction equation was (p<0.05, R2=0.86):

Short-term Changes In Ldl Density And Lipoprotein Particle Number In Trained Men After 3 Different Modes Of Exercise: 2868

Int J Exerc Sci 2(1): S40, 2009. PURPOSE: To determine the short-term changes in LDL density and lipoprotein particle number after three different modes of exercise in trained men. METHODS: Twenty seven subjects were randomly assigned to complete either (resistance [RE], endurance [EE], or combination resistance/endurance [CE]) exercise. Fasting blood samples were obtained 24 h before (baseline) and 24 h after exercise. The average group characteristics were as follows: [RE: n = 9, age = 22 + 1 yr,