Brad S. Lambert

Comparative efficacy of water and land treadmill training for overweight or obese adults.

PURPOSE No known previous research has been published to explore the efficacy of underwater treadmill (UTM) exercise training for the obese. Thus, the purpose of this study was to compare changes in physical fitness, body weight, and body composition in physically inactive, overweight, and obese adults after 12 wks of land treadmill (LTM) or UTM training. METHODS Fifty-seven physically inactive, overweight, and obese men (n = 25) and women (n = 32) participated in this investigation. The mean +/- SEM age, weight, body mass index (BMI), and V O2max upon entry were 44 +/- 2 yr, 90.5 +/- 2.4 kg, 30.5 +/- 0.7 kg.m, and 27.1 +/- 0.7 mL O2.kg.min, respectively. Subjects were randomly assigned to exercise three times per week for 12 wk on either LTM (n = 29) or UTM (n = 28) matched for intensity and volume. Session volume was progressively increased from 250 to 500 kcal per session by week 6 and remained at 500 kcal through week 12. Before and after training, V O2max was assessed by the Bruce treadmill protocol with open-circuit calorimetry, and body composition was assessed by dual-energy ray absorptiometry. Data were analyzed by a 2 (training) x 2 (exercise mode) x 2 (gender) ANOVA repeated across training (alpha = 0.05). RESULTS Training responses were not different between genders. After either UTM or LTM training, V O2max was significantly increased (+3.6 +/- 0.4 mL O2.kg.min), whereas body weight (-1.2 +/- 0.3 kg), BMI (-0.56 +/- 0.11 kg.m), body fat percentage (-1.3% +/- 1.3%), and fat mass (-1.1 +/- 0.3 kg) were significantly reduced (pooled means for UTM and LTM). Regional leg lean body mass (LBM) was significantly increased with both CTM and UTM (0.4 +/- 0.3 and 0.8 +/- 0.2 kg, respectively). An increase in total LBM approached significance with UTM training only (+0.6 +/- 0.3 kg, P = 0.0599). CONCLUSIONS UTM and LTM training are equally capable of improving aerobic fitness and body composition in physically inactive overweight individuals, but UTM training may induce increases in LBM.

Regulators of blood lipids and lipoproteins? PPARδ and AMPK, induced by exercise, are correlated with lipids and lipoproteins in overweight/obese men and women

PPARδ is a transcription factor regulating the expression of genes involved in oxidative metabolism, which may regulate blood cholesterols through transcription of oxidative and lipoprotein metabolism genes. To determine the association of skeletal muscle PPARδ content with blood lipids and lipoproteins before and following exercise, overweight and obese men (n = 9) and women (n = 7) were recruited; age, BMI, body fat percentage, and Vo(2max) were (means ± SE) 45 ± 2.5 yr, 31.9 ± 1.4 kg/m(-2), 41.1 ± 1.5%, and 26.0 ± 1.3 mLO(2)·kg(-1)·min(-1), respectively. Subjects performed 12 wk of endurance exercise training (3 sessions/wk, progressing to 500 kcal/session). To assess the acute exercise response, subjects performed a single exercise session on a treadmill (70% Vo(2max), 400 kcal energy expenditure) before and after training. Muscle and blood samples were obtained prior to any exercise and 24 h after each acute exercise session. Muscle was analyzed for protein content of PPARδ, PPARα, PGC-1α, AMPKα, and the oxidative and lipoprotein markers FAT/CD36, CPT I, COX-IV, LPL, F(1) ATPase, ABCAI, and LDL receptor. Blood was assessed for lipids and lipoproteins. Repeated-measures ANOVA revealed no influence of sex on measured outcomes. PPARδ, PGC-1α, FAT/CD36, and LPL content were enhanced following acute exercise, whereas PPARα, AMPKα, CPT I, and COX-IV content were enhanced only after exercise training. PPARδ content negatively correlated with total and LDL cholesterol concentrations primarily in the untrained condition (r ≤ -0.4946, P < 0.05), whereas AMPKα was positively correlated with HDL cholesterol concentrations regardless of exercise (r ≥ 0.5543, P < 0.05). Our findings demonstrate exercise-induced expression of skeletal muscle PPARs and their target proteins, and this expression is associated with improved blood lipids and lipoproteins in obese adults.

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.

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.

Anabolic responses to acute and chronic resistance exercise are enhanced when combined with aquatic treadmill exercise

Aquatic treadmill (ATM) running may simultaneously promote aerobic fitness and enhance muscle growth when combined with resistance training (RT) compared with land-treadmill (LTM) running. Therefore, we examined acute and chronic physiological responses to RT, concurrent RT-LTM, and concurrent RT-ATM. Forty-seven untrained volunteers (men: n = 23, 37 ± 11 yr, 29.6 ± 4.6 kg/m(2); women: n = 24, 38 ± 12 yr, 27.53 ± 6.4 kg/m(2)) from the general population were tested for V̇o2max, body composition, and strength before and after training. All groups performed 12 wk of RT (2 wk, 3 × 8-12 sets at 60 to approximately 80% 1-repetition maximum). The RT-LTM and RT-ATM groups also performed 12 wk of LTM or ATM training (2 wk immediately post-RT and 1 wk in isolation, 60-85% V̇o2max, 250-500 kcal/session). Additionally, 25 subjects volunteered for muscle biopsy prior to and 24 h post-acute exercise before and after training. Stable isotope labeling (70% (2)H2O, 3 ml/kg) was utilized to quantify 24 h post-exercise myofibrillar fractional synthesis rates (myoFSR). Mixed-model ANOVA revealed that RT-ATM but not RT-LTM training produced greater chronic increases in lean mass than RT alone (P < 0.05). RT-LTM training was found to elicit the greatest decreases in percent body fat (-2.79%, P < 0.05). In the untrained state, acute RT-ATM exercise elicited higher 24-h myoFSRs compared with RT (+5.68%/day, P < 0.01) and RT-LTM (+4.08%/day, P < 0.05). Concurrent RT-ATM exercise and training elicit greater skeletal muscle anabolism than RT alone or RT-LTM.

Reply to letter to the editor: to D2O or not to D2O? What are the reasons we D2O it at all?

to the editor: the estimation of protein synthesis has long been used as an outcome variable to better understand anabolic processes in skeletal muscle. Much of what we have learned about the regulation of muscle mass and protein metabolism has been a result of our ability to estimate synthesis

Patterns and Associations of Shoulder Motion, Strength, and Function in MARSOC Personnel Without History of Shoulder Injury

Introduction Military personnel are at an increased risk of shoulder injuries due to training and deployment demands, however, there is a lack of information on the tactical athletes upper extremity profile. Therefore, the purpose of this study was to examine shoulder musculoskeletal characteristics, including range of motion (ROM), strength, and function, and the relationships between these measures in Marine Corps Forces Special Operations Command (MARSOC) personnel without history of shoulder injury. Materials and Methods Participants included 195 full-duty male MARSOC personnel (age: 25.38 ± 2.85 yr; height: 1.79 ± 0.06 m, mass: 82.79 ± 7.88 kg) without history of shoulder injury. Measurements of ROM, strength, and function were obtained bilaterally. Shoulder internal rotation (IR) and external rotation (ER) ROM were summed to calculate total arc of motion (ARC). Shoulder IR and ER strength were assessed using an isokinetic dynamometer. Function was evaluated with an explosive push-up. Results MARSOC personnel present with significantly increased ER ROM, and decreased IR ROM and ARC in their dominant shoulder. They demonstrated greater IR strength and peak force during the explosive push-up on the dominant side but no bilateral differences in average or peak rate were found. Correlation analyses suggest a weak inverse relationship between strength and ARC (r = -0.15 to -0.24). Positive relationships between strength and function were identified except for dominant IR strength and push-up variables. Those with the greatest ARC demonstrated significantly weaker IR and ER strength compared to those with less motion. Conclusions MARSOC personnel demonstrate shoulder ROM and strength symmetry patterns similar to overhead athletes. Increased dominant shoulder strength does appear to translate to a bilateral functional performance, but overall performance may be limited by the weaker nondominant upper extremity. As ARC increases, IR and ER rotation strength decrease. Repetitive, increased loading of the dominant shoulder during functional movements and training may increase risk of chronic, overuse-type injuries, common to the military. Unilateral exercises and movement analysis should be incorporated to encourage proper development of bilateral shoulder strength, which may be particularly important in those with high ranges of ARC.

Epidemiological Analysis Of Injuries Occurring In Marine Corps Forces Special Operations Personnel: 3086 Board #151 June 3, 3: 30 PM - 5: 00 PM.

Special Operation Forces have been shown to sustain greater rates of musculoskeletal injuries than conventional forces. These injuries result in loss in deployable operators, which negatively impacts force readiness. In addition to Operators (OPs), Marine Corps Forces Special Operations Command (MARSOC) also utilizes Combat Support Personnel (CSP) to support OP missions. These CSP may also be at risk for sustaining similar injuries and mechanisms as OPs. PURPOSE: Describe injury epidemiology in MARSOC personnel and compare injury patterns between OPs and CSP. METHODS: A total of 141 MARSOC personnel (85 OPs, 56 CSP) completed an injury history questionnaire and described musculoskeletal injuries that occurred in the previous 12 months. Injury proportions were calculated for OPs and CSP. Proportions of injured subjects were compared between OPs and CSP using Fisher’s exact tests. RESULTS: A total of 43 injuries were reported within the previous 12 months, 25 of which were classified as preventable (15 in OPs, 10 in CSP). There were no statistically significant differences in the proportion of injured subjects between OPs and CSP. Preventable injuries were sustained by 14% of OPs and 16% of CSP. Both OPs and CSP sustained the majority of preventable injuries while performing lifting and running activities (27% and 40% for OPs and 40% and 50% for CSP, respectively). Also, the knee and lumbopelvic region were the most commonly reported location of preventable injuries for OPs (20% each) and CSP (30% each). The top three most common injury types were muscle strain, tendinopathy, and pain/spasm. CONCLUSION: Approximately 15% of MARSOC personnel experienced preventable injuries within 12 months prior to the questionnaire. Therefore, the force would significantly benefit from performance and injury prevention programs to mitigate preventable injuries and optimize force readiness. Because the majority of injuries were sustained during physical training there is a need to monitor training readiness to avoid overtraining and fatigue. Additionally, OPs and CSP seem to sustain similar injury patterns with similar mechanisms, suggesting CSP should also be included in injury prevention initiatives to optimize force readiness.

Epidemiological Analysis Of Injuries Occurring In Marine Corps Forces Special Operations Personnel: 3086 Board #151 June 3, 3

Special Operation Forces have been shown to sustain greater rates of musculoskeletal injuries than conventional forces. These injuries result in loss in deployable operators, which negatively impacts force readiness. In addition to Operators (OPs), Marine Corps Forces Special Operations Command (MARSOC) also utilizes Combat Support Personnel (CSP) to support OP missions. These CSP may also be at risk for sustaining similar injuries and mechanisms as OPs. PURPOSE: Describe injury epidemiology in MARSOC personnel and compare injury patterns between OPs and CSP. METHODS: A total of 141 MARSOC personnel (85 OPs, 56 CSP) completed an injury history questionnaire and described musculoskeletal injuries that occurred in the previous 12 months. Injury proportions were calculated for OPs and CSP. Proportions of injured subjects were compared between OPs and CSP using Fisher’s exact tests. RESULTS: A total of 43 injuries were reported within the previous 12 months, 25 of which were classified as preventable (15 in OPs, 10 in CSP). There were no statistically significant differences in the proportion of injured subjects between OPs and CSP. Preventable injuries were sustained by 14% of OPs and 16% of CSP. Both OPs and CSP sustained the majority of preventable injuries while performing lifting and running activities (27% and 40% for OPs and 40% and 50% for CSP, respectively). Also, the knee and lumbopelvic region were the most commonly reported location of preventable injuries for OPs (20% each) and CSP (30% each). The top three most common injury types were muscle strain, tendinopathy, and pain/spasm. CONCLUSION: Approximately 15% of MARSOC personnel experienced preventable injuries within 12 months prior to the questionnaire. Therefore, the force would significantly benefit from performance and injury prevention programs to mitigate preventable injuries and optimize force readiness. Because the majority of injuries were sustained during physical training there is a need to monitor training readiness to avoid overtraining and fatigue. Additionally, OPs and CSP seem to sustain similar injury patterns with similar mechanisms, suggesting CSP should also be included in injury prevention initiatives to optimize force readiness.