86 research outputs found
Vitamin D Deficiency in TAMU Female Basketball Players and Supplement Effectiveness
Purpose:
Vitamin D deficiency has been defined by the Institute of Medicine (IOM) as a level of serum 25-OH vitamin D less than 20 ng/mL. The Endocrine Society went on to further define vitamin D insufficiency as a level between 21 and 29 ng/mL. Research suggests that vitamin D deficiency could increase fracture risk in athletes, especially females who are naturally prone to deficiency.
Methods: Eight female athletes from the Texas A&M women’s basketball team
(21 ± 1yrs; 88 ± 18 kg; 179 ± 16.5cm; BMI 26 ± 3 kg/m2; black female) were identified to have low vitamin D blood levels in April of 2012. Each of these women was ordered to supplement with 50,000 IU of vitamin D2 1x/week. After 8 weeks, the subjects were again evaluated in July 2012. Body composition information was also attained via DEXA scan. For each subject, the change in blood vitamin D levels (final – initial) and bone mineral density (BMD) difference was calculated. Data were analyzed for frequency and for pre-post significance by dependent t-test, [α=0.05
Conclusions:
Vitamin D supplementation improved serum vitamin D levels significantly. 100% of the women were initially deficient in vitamin D. After intervention, 100% of the athletes were brought into the acceptable range as defined by the IOM (\u3e20 ng/mL), while 22.22% of the women improved to the standards to the standards of The Endocrine Society (\u3e 30ng/mL). The changes in pre-post vitamin D values were statistically significant after 8 weeks, while the BMD changes were not. Improvements in BMD may take longer than 8 weeks to become evident. Vitamin D assessment is critical to ensuring bone health and injury prevention in athletes, especially in black females
Resting and Post-Exercise Blood Pressure Response to Repeated Bouts of Aquatic Treadmill Exercise
Aerobic exercise is known to reduce resting blood pressure as well as induce and acute post-exercise hypotensive response. Purpose: Determine the effect of repeated bouts of aquatic treadmill exercise on consecutive days in physically untrained, pre-hypertensive men. Methods: Nine male subjects (SBP: 132 ± 8 mmHg; DBP: 79 ± 8 mmHG; 33 ± 8 years; 183 ± 7 cm; 103 ± 31 kg; 32 ± 10% Fat; 36 ± 7 ml·kg-1·min-1) participated in the study. All subjects completed an acute aquatic treadmill exercise session (60% VO2max; 300 kcal) on two consecutive days. Prior to each exercise session and following 10 minutes of seated rest, blood pressure and heart rate were automatically taken every 3 minutes for a total of 3 measurements. Following each exercise session, blood pressure and heart rate were measured automatically every 10-minutes from 20 to 60 minutes post while subjects were seated at rest. Pre-exercise and post-exercise measures were averaged. A dependent sample t-test was performed to compare the average values between the first (ATM1) and second (ATM2) exercise sessions. Results: Data are displayed in table below. Both pre-exercise and post-exercise systolic, diastolic, and mean arterial pressures were lower for ATM2. Conclusion: A single bout of ATM exercise resulted in reduced resting blood pressure 24-hours later. Furthermore, post-exercise blood pressure was lower following a second ATM exercise session. These data support both the efficacy of ATM exercise in regulating blood pressure and the cumulative benefit of repeated exercise bouts.
Pre-Exercise
Post-Exercise
SBP
DBP
MAP
HR
SBP
DBP
MAP
HR
ATM1
Avg
126
78
96
72
124
77
93
83
SD
11
7
7
11
12
7
8
10
ATM2
Avg
121
74
92
70
120
75
91
80
SD
11
7
7
11
10
8
7
13
T-Test
0.035
0.005
0.003
0.113
0.047
0.028
0.034
0.058
All values represent mean ± SD. p-values compare ATM1 vs. ATM
Prediction of Total Body and Regional Strength Using Dexa Body Composition Measurements
ABSTRACT Resistance training is a valuable exercise modality but few tools exist to aid practitioners in refining resistance exercise prescriptions. PURPOSE: To determine if a relationship exists between strength and selected body composition variables measured by DEXA; and if so, develop equations which predict total body and regional strength. METHODS: Sixty-eight subjects (Male n = 34, Age = 35±11.96yrs, Height = 181.54±6.76cm, Weight = 97.82±16.68kg, Body Fat = 31.24±8.12% | Female n = 34, Age = 37±12.6yrs, Height = 165.41±5.64cm, Weight = 80.55±18.48kg, Body Fat = 43.00±10.16%) underwent DEXA body composition testing and maximal strength testing utilizing Keiser® pneumatic resistance exercise equipment. Regional strength was assessed on seven different lifts: leg press, chest press, leg curl, lat pull-down, leg extension, triceps push-down, and biceps curl. The sum of the seven lifts was considered a measure of total body strength (TBS). Multiple linear regression (step-wise removal) was used to predict TBS and regional strength from: age, height (cm), weight (kg), lean mass (kg), fat mass (kg), and percent body fat. RESULTS: Height (cm) Weight (kg) Lean Mass (kg) Body Fat (%) Constant Correlation Coefficient SEE Total Strength -15.049 49.552 1657.592 R2 = .747 293.776 Leg Press -10.889 2.210 22.049 1291.683 R2 = .689 151.146 Chest Press -1.116 -0.658 4.974 101.797 R2 = .746 25.750 Leg Curl 3.583 -17.974 R2 = .678 30.461 Lat Pull-down -0.494 -0.796 4.917 48.997 R2 = .780 24.811 Leg Extension -0.684 4.261 -17.836 R2 = .662 31.388 Tri Push-down -2.968 7.385 -2.706 495.841 R2 = .564 73.997 Biceps Curl 0.291 1.233 -0.433 -51.421 R2 = .739 11.981 CONCLUSION: DEXA body composition measurements are correlated with, and are shown to be significant predictors of total body and regional strength. Data obtained from DEXA body composition measurements are a useful tool which may aid practitioners and the general public when maximal strength testing is ill-advised or impractical
Acute Blood Pressure Response to Aquatic and Land Treadmill Exercise
PURPOSE: To determine the acute blood pressure response of aquatic treadmill (AT) exercise compared to land treadmill (LT) exercise. METHODS: 11 Subjects (6 male; 23 ± 2 years; 70 ± 1 inches; 164 ± 32 pounds) completed 3 to 5, 5-minute graded exercise stages (~20, 26, 32 ml-1∙kg-1∙min-1 for stages 1, 2, and 3, respectively) up to 85% age predicted maximal heart rate on AT. Blood pressure (BP) was measured manually at the conclusion of each stage while subjects straddled the treadmill belt for 20-30 seconds. Heart rate (HR) and oxygen consumption (VO2) were measured continuously. Within 3-5 days, subjects completed an equivalent exercise bout on LT with stages matched for VO2. Resting BP and HR was measured with an automated BP cuff following 10 minutes of seated rest before exercise and every 3 minutes for 30 minutes during recovery. Pre-exercise BP was also measured manually following 5 minutes of standing on AT and LT immediately before exercise. A paired sample t-test was used to compare seated resting and pre-exercise standing measures between modes. Since all subjects completed at least 3 matched stages on each mode, a 3 (stage) x 2 (mode) ANOVA was used to analyze the dependent variables: VO2, HR, SBP, diastolic BP (DBP), mean BP (MAP), pulse pressure (PP), rate pressure product (RPP), and oxygen pulse (OP). SBP, DBP, MAP, and HR during seated recovery were analyzed by an 11 (time) x 2 (mode) ANOVA. All values presented as mean ± SE. RESULTS: Seated resting measures prior to exercise did not differ between modes. Pre-exercise standing SBP was greater (AT: 118 ± 9; LT: 113 ± 8; p = 0.05) and HR was lower (AT: 64 ± 10; LT: 77 ± 12; p \u3c 0.05) for AT relative to LT. During exercise, significant main effects for mode were found for DBP (AT: 65 ± 2; LT: 71 ± 2) and PP (AT: 81 ± 4; LT: 62 ± 4) with a trend toward significance in SBP (AT: 146 ± 4; LT: 135 ± 4; p = 0.057). Main effects for stage were significant for VO2, HR, RPP, and OP. No interactions were significant. During recovery, main effects for mode were observed only for HR (AT: 87 ± 1; LT: 78 ± 1), while there was a main effect for time for DBP, MAP, and HR. CONCLUSION: Hydrostatic pressure from AT increases exercise SBP and may lower HR
Pharmacological Inhibition of mTOR and ERK1/2 Resulted in Attenuated Protein Synthesis Rates in Differentiated C2C12 Myoblasts in a Similar Fashion to in vivo Rodent Studies.
Fractional protein synthesis rates have long been used as in indicator of acute alterations in the anabolic state of various tissues. Through the use of a number of stable and isotopic tracer methodologies, the measurement of fractional synthesis rates (FSR) in vivo has become a staple of skeletal muscle physiology. Through the application of a deuterium oxide tracer, this project sought to measure pharmacological perturbations in fractional synthesis rates in culture in differentiated C2C12 murine myotubes. PURPOSE: To assess myofibrillar protein FSR in differentiated C2C12 murine myotubes following pharmacological inhibition of rapamycin-sensitive (mTOR) or -insensitive (ERK1/2) pathways, and how signal transduction through these pathways impact FSR as compared to previous in vivo studies of pharmacological inhibition studies in skeletal muscle. METHODS: C2C12 murine myoblasts were cultured in collagen coated 6 well culture dishes, and grown to 60-70% confluency using a high glucose DMEM growth media (GM). Cultures were transitioned to a differentiation media (DM) upon reaching target confluency. DM was changed daily for 4 days to allow for complete differentiation to myotubes. Cultures were randomly assigned treatment conditions of cell control (CC), rapamycin inhibition (RAPA), ERK1/2 inhibition (ERK), and electrical stimulation (ESTIM). Cultures underwent treatment conditions for 24 hours with a 4% deuterium oxide GM supplement. Analysis was carried out using a gas chromatography mass spectrometer. RESULTS: Fractional rates of protein synthesis were significantly lower in the RAPA (p=0.028) and ERK (p=0.029) groups as compared to CC, with no differences between RAPA and ERK groups (p\u3e0.05). Although statistics were not applied to the ESTIM group due to low sample size, electrical pulse stimulation shows promise for the stimulation of FSR in cultured myotubes. CONCLUSION: Diminished FSR in both RAPA and ERK groups are consistent with previous findings from in vivo rodent studies. These results may indicate comparable alterations in skeletal muscle anabolic signaling in cell culture as well as in vivo rodent models. Further investigations into anabolic signaling mechanisms related to the control of protein synthesis are needed
Energy Expenditure Overestimation Bias in Elliptical Trainer Machine
Elliptical trainers are a common mode of aerobic exercise in recreationally active populations. Those with a weight loss goal might rely upon the energy expenditure (EE) estimation that many elliptical brands provide to keep track of calories (kcals) burned and make nutritional decisions. For this reason, it is important to evaluate the accuracy of the algorithms used by elliptical trainers to estimate EE. The purpose of this study was to compare EE estimates by a common brand of elliptical trainer to that measured using open circuit spirometry, at different combinations of resistance and pedal speed. Twenty subjects (10 male, 10 female; 34 ± 12 yr; 175.3 ± 10.7 cm; 77.1 ± 14.1 kg) consented to participate. Each completed three 15-min bouts of elliptical exercise on the same elliptical trainer, with at least 24 hr between exercise bouts. Pedal rates were held constant throughout each bout at 50, 60, or 70 RPM, and resistance was increased incrementally every 5 min from level 5 to 10 to 15. The different cadences were completed in a randomized order between participants. Expired gases were collected continuously throughout the 15 min. Heart rate, distance (mi), and EE from the elliptical readout were recorded every 1 min. RPE was collected twice per resistance level. A two-tailed paired samples t-test was used to compare elliptical EE to measured EE. A linear regression model was used to evaluate the ability of the elliptical EE to predict measured EE. Significance for all statistical measures was held at an alpha level of 0.05. The difference between EE estimates from the elliptical and measured VO2 was significant (p
Measured EE = 0.95*(Elliptical EE) – 3.161
In conclusion, the elliptical trainer used for this study demonstrated a bias to overestimate EE. This should be taken into account by health/fitness professionals using these estimations to program for clients. There may be some variation in the EE correction regression depending on elliptical model, and proper machine calibration should be ensured
Concurrent Resistance and Aquatic Treadmill Training Elicits Greater Lean Mass Gains than Resistance Training Alone.
PURPOSE: To examine the effects of combined aquatic treadmill training (ATM) and resistance training (RT) on body composition (Bcomp), strength, and VO2max following 12 wks of training compared to RT alone. METHODS: 5 healthy, sedentary men (32.6yr ±11, 187.5 cm ±4.9, 107.9 kg ±19.5) and 6 women (34.2 yrs ±14.3, 166.6 cm ±8.4, 78.6 kg ±19.69) were recruited and screened to assess VO2max (GXT), Bcomp (DEXA), and strength. During strength assessment, 1RMs were assessed in this order: leg press, chest press, leg curl, lat pull, leg ext, triceps push-down, biceps curl. Subjects were then randomized into 2 groups. Both groups (R = resistance training, CT = concurrent training) performed progressive RT for 12 wks (2/wk, 3 x 8-12 @ 60%1RM, ~1.5min rest int.). Following wk 6, 1RMs were reassessed and intensity was increased for wks 7-12 (3 x 4-8, beginning @ 75%1RM). Concurrently, the CT group performed 12 wks of progressive ATM (60→85%VO2max). VO2max was reassessed following wk 6. ATM occurred immediately following RT sessions and in isolation on a 3rd day during the wk. After training, baseline tests were again performed. A 2x3 factorial ANOVA w/ repeated measures for group (2) by time (3) was used to examine absolute and relative changes in body composition, strength, and VO2max
Prediction of the Total Energy Cost of an Acute Bout of Resistance Exercise in Young Men and Women
Prediction of the Total Energy Cost of an Acute Bout of Resistance Exercise in Young Men and Women
Brad S. Lambert†, Steven E. Martin‡, John S. Green‡ (FACSM), Aaron F. Carbuhn†, Stephen F. Crouse‡ (FACSM). Department of Health and Kinesiology, Texas A&M University, College Station, TX (Sponsor S.F. Crouse)
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\u3c0.05, R2=0.86):
Total kcal = (37.264*VO2max L/min) + (1.087*TV0.5) – 132.488
CONCLUSIONS: VO2max (L/min) and TV0.5 were found to be significant predictors of the energy cost of a RT bout involving each major muscle group. In regards to fitness, performance, and weight management, this equation may aid practitioners and young exercising adults in documenting kcal expenditure from resistance training
Predicting VO2max in Collegiate American-Style Football Athletes
Introduction: Maximal oxygen uptake (VO2max) is an important measurement for athletic performance. A common method of VO2max prediction is the Foster equation (MSSE, 1996). This equation produces accurate predictions in a normal population, however, significant difference has been noted between predicted and measured VO2max values when testing athletes. While other studies have produced new equations for athletes in general or even for soccer players, to our knowledge none have made one specifically for American-style football players. Purpose: The aim of this study is to develop an accurate VO2max prediction equation for collegiate American-style football athletes for testing on the treadmill with the standard Bruce protocol. Methods: Over 13 years, a total of 413 collegiate American football players (age: 18.5±1.15 yrs, height: 186.8±7.0 cm, weight 102.1±20.8 kg) were assessed for VO2max (Medical Graphics, Corp® Metabolic Cart) using the standard Bruce treadmill protocol. Linear regression analysis (JMP v. 12) determined which factor out of height, weight, or time spent on the test had a greater impact on VO2max. The linear regression analysis of the most significant factor against VO2max produced a prediction equation. Predicted VO2max was calculated using these data in both the Foster equation and this novel equation. Predicted values were compared to actual measured values with a t-test. α=0.05 for all statistical tests. Results: Of all the factors, time had the strongest relationship (p\u3c0.0001; r2=0.6464). The linear regression between VO2max and time produced a prediction equation: VO2max= -3.546 + 3.904(time in minutes). Both the Foster equation and this new equation were significantly and positively correlated with the actual VO2max values (Foster=0.805, New r=0.804). However, t-tests indicate that the Foster equation results were significantly different from the measured values (p=0.0007), and the new model’s results were not significantly different (p=1.0). Conclusion: The Foster equation is not a reliable predictor of VO2max as assessed on a treadmill in collegiate American-style football athletes. This new equation is more accurate to predict VO2max in this population
Chronic Changes In Serum IL-6 And TNF-α Following 12 Weeks of Concurrent Resistance And Aerobic Exercise Are Dependent On Exercise Mode And May Affect Adaptation
PURPOSE: To examine physiological responses to concurrent resistance and land treadmill training (RT-LTM) compared to concurrent resistance and aquatic treadmill training (RT-ATM) and the chronic effect of each on serum TNF-α and IL-6 (cytokines associated with chronic inflammation, CVD, and skeletal muscle metabolism). METHODS: Twenty-six untrained subjects (M: n=13, 98.6±17.1kg, 182.2±6.2cm, 34±11yrs, F: n=13, 78.9±14.0kg, 165.1±5.1cm, 38±11yrs) were screened to assess VO2max, body composition (DEXA), and strength (Lifts: leg press, chest press, leg curl, lat pull, leg ext, triceps push-down, biceps curl). Subjects were then randomized into 2 groups: RT-LTM (M=6, F=7), RT-ATM (M=7, F=6). Each performed progressive RT (2/wk, 3 x 8-12 @ 60%à ~80% 1RM) for 12 wks. Both groups also performed 12 wks of aerobic LTM or ATM (60à 85%VO2max) respectively. ATM or LTM occurred immediately following RT sessions and in isolation on a 3rd day during the wk. Kcal/session: Wk 1-6 = 250à 500 kcal/session, Wk 6-12 = 500 kcal/session. Blood samples were obtained in the rested state (\u3e72h after last exercise bout) before and after training. Serum TNF-α and IL-6 was analyzed using a multiplex assay kit (Luminex®, Millipore®). A 2x2 Mixed Model ANOVA w/ repeated measures was used to examine absolute and relative changes in the independent variables listed in the table. RESULTS:
INDEP. VAR.
Lean Mass (kg)
Fat Mass (kg)
%Body Fat (%)
VO2max (ml/kg/min)
Total Strength (lbs)
IL-6 (pg/dl)
TNF-α (pg/dl)
BASELINE MEASUREMENTS
RT-LTM
49.9 ± 3.7
35.9 ± 3.1
42.1 ± 2.5
29.9 ± 2.0
1457.4 ± 135.1
4.6 ± 1.6
7.1 ± 1.9
RT-ATM
53.1 ± 4.0
31.1 ± 2.8
37.0 ± 2.3
32.1 ± 1.6
1552.8 ± 145.9
4.6 ± 1.5
7.9 ± 1.5
POST TRAINING MEASUREMENTS
RT-LTM
51.0 ± 4.7â€
34.1 ± 2.7â€
40.1 ± 3.6â€
35.8 ± 2.9â€
1843.4 ± 201.1â€
7.1 ± 1.6â€
6.8 ± 0.5
RT-ATM
55.8 ± 4.6â€
30.3 ± 3.1
35.6 ± 2.4â€
35.8 ± 2.3â€
2193.6 ± 251.3â€
5.1 ± 2.7
6.6 ± 1.0â€
%∆ = Calculated From Each Individual Subjects Change From Baseline
RT-LTM
2.6% ± 1.4†,a
-6.5% ± 2.4†,a
-5.8% ± 1.8†,a
14.1% ± 2.3†,a
21.3% ± 1.1†,a
125.9% ± 36.6†,a
-1.8% ± 6.0a
RT-ATM
4.2% ± 0.9†,b
-2.1% ± 1.6b
-4.1% ± 1.5†,a
4.5% ± 3.0†,b
27.1% ± 1.7†,b
28.1% ± 34.7b
-13.0% ± 5.4†,b
Values are means ± SE. %Δ = Individual change from baseline. Like letters = not significantly different between groups, †=Significant change from baseline within group (α ≤ 0.05).
CONCLUSION: Chronic RT-LTM and RT-ATM training elicit different effects on markers of chronic inflammation which may be related to differing health and fitness outcomes observed between our groups
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