Theses/Dissertations - Health, Human Performance and Recreation

Permanent URI for this collectionhttps://hdl.handle.net/2104/9668

Browse

Now showing 1 - 20 of 91

Effects of hind limb unweighting on the expression of physiological markers of muscle atrophy and myofibrillar protein content in the soleus and extensor digitorum longus of Sprague-Dawley rats.
(2006-04-19T15:24:28Z) Vacanti, Anthony J.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The purpose of this study was to determine the effects of hind limb unweighting on the expression of physiological markers of muscle atrophy and myofibrillar protein content in the soleus (SOL) and extensor digitorum longus (EDL) of Sprague-Dawley rats. After the 2-week unweighting period, the rats (4 HU; 4 months old, 4 CON; 5 months old) were euthanized, EDL and SOL excised and sent to the Exercise and Biochemical Nutrition Laboratory at Baylor University. The samples were analyzed for myofibrillar protein content, MHC isoform mRNA expression, calpain1, 2 activities, and ubiquitin proteolytic enzymes E2, E3, Atrogin-1, RF-1. In HU a reduction in myofibrillar content was witnessed (49% SOL, 81% EDL). A significant main effect for group was observed (p = 0.047) indicating HU produced a significant reduction in myofibrillar protein content and changes in MHC mRNA expression. Calpain 1, 2 mRNA expression in HU EDL increased with significant interactions (p = 0.003) for calpain 1 mRNA. E3 mRNA witnessed a significant interaction (p = 0.037), and E2, atrogin-1, and RF-1, displayed no significant interactions (p > 0.05).
Effects of eight weeks of 6-OXO supplementation on serum hormone profiles and on serum and urinary clinical safety markers in resistance-trained males.
(2006-05-28T23:31:42Z) Rohle, Daniel A.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The purpose of this study was to determine the effects of 6-OXO, an aromatase inhibitor, in a dose dependent manner on serum hormone levels and clinical safety markers in resistance trained males. Sixteen healthy trained subjects, who participated in a resistance training protocol, had blood samples taken at weeks 0, 1, 3, 8, and 11. These samples were analyzed for total testosterone, free testosterone, DHT, estradiol, estriol, estrone, SHBG, LH, FSH, GH, and cortisol. There were no significant differences between groups (p>0.01). However, total testosterone concentration, free testosterone concentration, and DHT concentration increased over the course of the study (p=0.009). Measures of body composition did not change with supplementation (p>0.05). Safety markers were seen to not be adversely affected with ingestion of 6-OXO (p>0.01). 6-OXO supplementation appears to be safe and increases total testosterone, free testosterone, and DHT concentrations independent of the two different doses.
Analysis of exercise intensity and energy expenditure of women participating in the Curves exercise program.
(2006-07-30T19:49:16Z) Farris, Gregory D.; Kreider, Richard B., 1962-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The Curves program is designed to improve fitness. The purpose of this study was to identify exercise intensity, HR and energy expenditure in a group of women participating in the Curves program. Seventy-eight women (53.6 ± 7.09 yrs, 192.1 ± 30.43 pounds, 43.5 ± 4.52 % fat) performed the Curves workout on two occasions. Results show that mean HR was 119 ± 15 b/min which was equivalent to 79% max HR or 63 % HRR. Thirty-three women (52.7 ± 6.68 yrs, 193.1 ± 31.73 pounds, 1.8 ± 0.28 L/min VO2 max) performed the Curves 30-min workout on two occasions. Results show that the mean RER to perform the 30-min workout was 1.00 ± 0.07 and 0.98 ± 0.05 for the two sessions. Estimated caloric expenditure was 164.5 ± 25.19 kcals and 160.6 ± 28.36 kcals for the two sessions. Results indicate that the Curves program qualifies as moderate intensity exercise.
Acute effects of caloric intake and macronutrient type on body weight, body composition, resting energy expenditure, and total metabolic rate.
(2006-07-31T01:12:44Z) Thomas, Ashli.; Kreider, Richard B., 1962-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Obesity is a growing epidemic with no consensus regarding solutions. Thirty healthy overweight and obese female subjects (41.9 ± 12 years, 166 cm ± 7 cm, a 100.5 kg ± 19.6 kg, 46.0% ± 4.0% body fat, and BMI 37.4 ± 6.9) participated in the study. A 14-day dietary intervention examined acute effects of energy balance and macronutrient type on dietary intake, REE, body weight, body composition, and thyroid panel. Significant changes occurred in weight loss over time (p < 0.001); body fat mass over time (p < 0.001) and time x diet (p = 0.02); body fat percentage over time (p < 0.002) and time x diet (p = 0.023); REE over time (p = 0.03), and thyroid panel. Body weight continued to decrease during positive energy balance, yet metabolism rebounded. Results suggest energy balance has a greater overall effect on REE and weight loss than macronutrient type.
Effects of prophylactic supplementation of N-acetyl-cysteine and epigallocatechin gallate on markers of oxidative stress, inflammation and apoptosis after eccentric contraction-induced injury in untrained males.
(2007-02-07T18:58:56Z) Kerksick, Chad M.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The purpose of this study was the examine the effects of 14 days of prophylactic supplementation of N-acetyl-cysteine (NAC) and epigallocatechin gallate (EGCG) on changes in peak torque production, muscle soreness, muscle damage, oxidative stress, inflammation and apoptosis after a single damaging bout of eccentric muscle contractions. Thirty healthy, recreationally active males (20.0±1.8 years, 160±7.1cm, 167.4±37.3 kg) were randomized in a double-blind fashion to ingest daily either 1800 mg of NAC, 1,200 mg of EGCG, or 1,500 mg of glucomannan placebo (PLC) in a prophylactic fashion for 14 days. After supplementation, subjects completed one eccentric exercise bout (100 repetitions @ 30o•s-1) of the dominant knee extensors. Participants completed strength and soreness assessments while providing fasting blood samples and vastus lateralis muscle biopsies (no 72 h biopsy) before and after supplementation, as well as 6h, 24h, 48h and 72h post-exercise to assess changes in muscle damage, oxidative stress, inflammation, and apoptosis. Separate 3 x 6 repeated measures ANOVA with a probability level of 0.05 was used for the statistical analysis with LSD post-hoc comparisons for all significant interactions. Significant reductions in peak torque as well as increases in soreness and creatine kinase at 6 h post-ex were found in all groups. No changes (p > 0.05) were observed for the indicators of oxidative stress, serum superoxide dismutase, serum 8-isoprostane and muscle glutathione reductase, as well as the indicators of stress and inflammation, serum cortisol and tumor necrosis factor-alpha. For the apoptosis markers, significant increases (p < 0.05) in muscle levels of bax, bcl-2, caspase-3 enzyme activity and decreases in total DNA content were observed in all groups with no significant differences among groups, whereas no changes (p>0.05) were reported for cytochrome C. At all time points, PLC demonstrated greater caspase-3 enzyme activity and lower levels of total DNA content in comparison to either supplementation group. An eccentric bout of muscle contractions appears to significantly increases muscle damage and apoptosis with no changes in oxidative stress and inflammation. More research is needed to determine the impact supplementation with EGCG and NAC may have on changes related to apoptosis and eccentric exercise.
Effects of low- and high-intensity resistance exercise on skeletal muscle specific transcription factor activity and myosin heavy chain gene expression in males.
(2007-02-07T19:00:17Z) Wilborn, Colin D.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
A single bout of resistance training is capable of activating the expression of many diverse groups of genes including myosin heavy chain (MHC) isoforms and the myogenic regulatory factors (MRF). However, the role of exercise intensity in regards to the effects on transcription and protein synthesis are not well defined. Therefore, the purpose of this study was to investigate the effects of exercise intensity on MRF mRNA and protein and MHC mRNA isoforms. Thirteen male participants (21.5 ± 2.9 yrs, 86.1 ± 19.5 kg, 69.7 ± 2.7in) completed two bouts [low-intensity (LI = 65% 1-RM) and high-intensity (HI = 85% 1-RM)] of single-legged resistance exercise. The resistance exercise bout consisted of four sets of leg press and leg extension. Muscle biopsies were obtained from each leg immediately before exercise (PRE), and at 30 minutes (30MPST), 2 hours (2HRPST), and 6 hours (6HRPST) following each resistance exercise bout. Data were analyzed using RT-PCR for mRNA expression and ELISA for protein expression. Statistical analyses were performed by utilizing a 2 x 4 MANOVA (level of significance was set at p < 0.05). Results indicated that MHC I, IIb, and IIx all significantly increased in response to resistance exercise (p < 0.001). Furthermore, exercise intensity/volume played a role with LI high volume exercise stimulating a more positive response in MHC I (p < 0.001) and HI eliciting a greater response in MHC IIb and IIx (p < 0.001). In regards to the MRF, resistance exercise significantly increased the expression of Myogenin, Myf5, and MRF-4 mRNA (p < 0.05). Furthermore, LI high volume exercise stimulated a more positive response in MyoD, Myogenin, and Myf5 mRNA (p < 0.05), as well as MyoD, Myogenin, and MRF-4 protein (p < 0.05). MRF-4 protein significantly increased at 6HRPST over the baseline values (p < 0.05). Changes in MyoD and Myogenin mRNA were also found to be significantly correlated (p < 0.05) to changes in MHC I, IIa, IIb, and IIx mRNA. We can conclude from the findings of this study that both the MHC mRNA and MRF mRNA respond very quickly and positively in response to resistance exercise, in addition to LI high volume exercise eliciting a more positive response in most MRF mRNA and protein.
Effects of arachidonic acid supplementation on training adaptations in resistance-trained males.
(2007-02-09T22:16:18Z) Roberts, Michael D.; Kreider, Richard B., 1962-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The purpose of this study was to determine if 50 days of resistance training and arachidonic acid (AA) supplementation elicited changes in body composition, performance variables, hormonal/cytokine levels (i.e. prostaglandins, free and total testosterone, cortisol, and interleukin-6) and/or intramuscular markers [i.e. myosin heavy chain (MHC) I, -IIa, -IIx mRNA and protein levels] in resistance-trained males. Thirty-one subjects (22.1±5.0 yrs, 86.1±13.0 kg, 178.9±3.4 cm, 18.1±6.4 % body fat) were randomly assigned to a placebo (P: n=16; 1 g corn oil/day) or AA group (AA: n=15; 1 g AA/day) and were given supplemental protein in order attain an optimal protein intake of 2 g/kg/day while participating in a 2 d/wk upper body and 2 d/wk lower body resistance training regimen. Body composition, bench press one-repetition maximum (1-RM), leg press 1-RM and Wingate bike sprint tests were completed at 0, 25 and 50 days. Fasting blood was taken on days 0, 25, and 50 and muscle biopsies were taken from the vastus lateralis on days 0 and 50. Body composition, performance variables, hormonal levels and MHC mRNA and protein concentrations were analyzed by ANOVA with repeated measures while independent t-tests were used to assess changes in MHC mRNA expression. A significant increase was observed in Wingate relative peak power in the AA group (p=0.015). Statistical trends were found for PGE2 increases (p=0.06) and IL-6 decrements (p=0.07) in the AA group and a significant decrement in percent changes in MHC IIx mRNA expression was present in the AA group (p=0.015). Results suggest that AA supplementation in trained males may exert favorable alterations in training adaptations and fasting prostaglandin and IL-6 levels. However, additional research is needed to examine this hypothesis.
Self-selected intensity, repetitions, RPE and adherence of novice female weight lifters during 6-weeks of resistance training.
(2007-02-09T23:08:53Z) Faries, Mark.; Lutz, Rafer S.; Greenwood, Mike.; Frisch, Michael B.; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The purpose of this investigation was to determine what intensity novice female individuals would choose when allowed to self-select intensity when beginning a strength training program, the influence of efficacy beliefs and adherence. Fifty-three participants were randomly assigned to four groups based on weight type and instruction type and asked to record their self-selected intensities, repetitions and RPE in a public exercise facility for six-weeks. Results showed that the majority of participants exercised at an intensity that met commonly suggested guidelines (greater than or equal to 60% 1-RM) and that intensity did not differ between groups that received different instructions, although the potential for a one-repetition peak is discussed. Program attendance was not moderated by efficacy ratings. Lastly, significant correlations (at the 0.05 level) revealed that those with higher ratings of self-efficacy demonstrated greater adherence, while no significant correlation was found between the initial intensity chosen by individual participants and adherence.
Effects of low- and high-intensity single-leg resistance exercise on the mitogen-activated protein kinase ERK1/2 family signal transduction response in skeletal muscle of untrained males.
(2007-02-14T21:45:18Z) Taylor, Lemuel W.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Acute resistance exercise signals responses in the body to promote adaptations to the exercise stimulus. One key response during and following exercise is the role of signal transduction in the skeletal muscle (MAPK family) and its downstream effects on muscular adaptation. Therefore, the purpose of this study was to determine the differential response of a prominent signal transduction pathway following a high-(HI) and a low-intensity (LI) bout of acute resistance exercise. Participants completed a single-legged bout of HI (8-10 reps at 85% of 1-RM) and LI (18-20 reps at 65% of 1-RM) resistance exercise designed to reach muscular fatigue in a randomized, crossover design. Venous blood and muscle biopsies were taken at PRE, 30PST, 2HRPST, and 6HRPST for the two resistance exercise sessions (RES), with an additional blood draw occurring at POST time point. Serum analyses included cortisol, insulin, GH, IGF-1, and IGFBP-3. Muscle analyses included phosphorylated IGF-1R, MEK1, ERK1/2, and activated Elk-1. Statistical analyses utilized a 2X4 MANOVA for muscle and a 2X5 MANOVA for serum variables on delta responses (p>0.05). RES resulted significant increases in cortisol (p<0.001), GH (p<0.001), insulin (p<0.01), and IGFBP-3 (p<0.001) in serum, with the peak elevations occurring by 30MPST, with no significant differences observed between exercise intensities. RES resulted in significant increases in pIGF-1R (p<0.05), pMEK1 (p<0.001), pERK1/2 (p<0.001), and Elk-1(p<0.001) from baseline levels in muscle, with the peak activation by the 2HRPST time point. The LI RES resulted in a significant difference in pIGF-1R (p<0.05) and Elk-1 (p<0.05) activation. The results of this study indicate that acute RES of both HI and LI results in similar responses in the serum markers cortisol, insulin, GH, and IGFBP-3. The RES also up-regulated various levels of the ERK1/2 signal transduction pathway in skeletal muscle, with some beneficial responses observed in the LI group. Thus, these findings suggest that exercise intensity is not as important in up-regulating these anabolic and signaling mechanisms as once thought and that exercising to muscular fatigue may be a more important aspect of an acute exercise bout. Additionally, the effect of higher exercise volume may also have a positive effect on these responses.
An evaluation of the relationships between core stability, core strength, and running economy.
(2007-02-14T21:48:11Z) Gandy, Nicole J.; Greenwood, Mike.; Shim, Jaeho.; Stanford, Matthew S.; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Few studies have examined the relationship between core strength and core stability and running economy. Purpose: To evaluate the relationships between core strength, core stability, kinematic variables and running economy. Methodology: Twenty-three men (N = 7) and women (N = 16) participated. Over the course of four sessions subjects completed core strength and stability testing, a maximal aerobic capacity running test, and three tests for running economy. Results: There was no significant (P > 0.05) relationship between core strength and running economy. Three of the core stability tests were significantly related to oxygen consumption at each of the running intensities however, these relationships were moderate and positive in nature. Several kinematic variables were moderately related to core stability and strength, but did not show a significant relationship with running economy. Conclusions: These findings suggest a higher core performances did not relate to better running economy values.
The effects of active and passive recovery on blood lactate in collegiate female tennis players.
(2007-03-08T15:33:24Z) Coffer, Larry W.; Greenwood, Mike.; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Purpose: To examine the effects of active and passive recovery on lactate in females and to determine if a relationship exists between power and blood lactate concentration. Methods: Nine (9) female athletes performed two Wingate Power Tests. One test ended with passive recovery, the other ended with active recovery. Lactate was drawn during the recovery periods. From the Wingate Test, power indices were obtained. A t-test and an ANOVA were performed to evaluate differences in active and passive recovery and Pearson’s correlations were used to examine relationships between power and lactate values. Results: Active recovery significantly (p< 0.03) increased lactate removal compared to passive recovery. There were no significant correlations between lactate and power measures. Conclusions: Active recovery increases the rate of lactate removal in females; however, lactate measures are not correlated to the power measures from the Wingate Test.
Effects of 28 days of protein and amino acid supplementation and ankle immobilization on gastrocnemius muscle mass and strength and atrophy- and apoptosis-related gene expression in males.
(2008-06-11T11:43:18Z) Wismann, Jennifer.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Purpose: The primary purpose was to determine the extent to which the daily supplementation of protein and amino acids for 28-days in combination with ankle immobilization in humans attenuated decreases in: 1) gastrocnemius muscle mass, 2) plantar flexion strength, 3) and expression of genes associated with the ubiquitin proteolytic pathway (UPS) and calcium-activated proteolytic system (CAS). A secondary purpose was to assess the safety of 28-days of protein and amino acid ingestion by evaluating whole blood and serum clinical chemistry markers. Methods: Twenty male participants wore a lower-limb immobilization boot for 28 days, consumed either a protein and amino acid supplement or an isocaloric carbohydrate placebo twice daily, and underwent testing at days 0, 14, and 28. Each testing session included hemodynamic measurements, blood collection, body composition analysis, lower leg girth and skinfold measurement, strength measurement, dietary analysis, and gastrocnemius muscle biopsies. The muscle tissue was analyzed for mRNA expression of ubiquitin, 20S-HC2, 20S-HC3, E2, E3, atrogin-1, MuRF1, calpain 1, calpain 2, myostatin, TNF-α, and NF-κB. Results: Lower-leg girth decreased over time (p = 0.020), and increased the expression of several genetic variables, but there were no significant changes in the body composition or strength variables (p > 0.05). All UPS, CAS, cytokine, and myostatin degenerative markers showed a significant increase over time (p < 0.05). However, significant interactions only occurred for E2 (time x group, p < 0.001) and E3 (time x group x leg, p > 0.016). Conclusion: The study showed no difference between groups for any of the genetic proeolytic markers, but indicated that several of these markers were increased in the immobilized and control legs. These changes may indicate a link between the UPS and TNF-α and NF-κB. Additionally, the results also indicated that myosatin may play a role in muscle astrophy induced by immobilization, instead of only disease and fasting.
Effects of ingesting carbohydrate and branched-chain amino acids on markers of skeletal muscle protein synthesis of the insulin-PI3K-mTOR signal transduction pathways in response to a bout of heavy resistance exercise.
(2008-10-14T18:33:02Z) Ferreira, Maria Pontes.; Kreider, Richard B., 1962-; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Purpose: To determine if activity of the MAPK-ERK or PI3K-mTOR insulin signaling pathway is increased in response to an acute lower body resistance exercise (RE) bout and supplemental BCAA + CHO or CHO ingestion. Methods: 27 recreationally trained males (20.9 y; 81.8 kg) were randomly assigned to a group: BCAA (30 g) + CHO (350 g), CHO (350 g) or placebo CON. Participants performed 4 sets of leg press and extensions at 80% 1RM to failure. Supplements were ingested at 3 time points: 30 min prior to RE, and immediately pre- and post-RE. Venous blood was sampled at baseline (Pre); 30 min post-exercise; 2 h post-exercise, and 6 h post-exercise for serum glucose and insulin. Blood variables were transformed to percent change values and analyzed by a 3 x 4 repeated measures MANOVA. Muscle biopsies were obtained at baseline, 30 min post-exercise, 2 h post-exercise and 6 h post-exercise for ERK1/2, IRS, Akt/PKB, GSK, mTOR, 4E-BP1, and P70S6K. Skeletal muscle variables were transformed to percent change values and analyzed by 3 x 4 repeated measures MANOVA. Univariate ANOVAs were utilized as follow-up tests to the MANOVA for select variables. Results: MANOVA results demonstrate a significant group x time interaction for insulin and glucose (P<.05). Despite a nearly 3 fold-increase of insulin over fasting baseline measures in the CHO groups as compared to the placebo group, neither BCAA + CHO or CHO significantly increased any of the muscle variables. Univariate analysis demonstrated significant group x time interaction for Akt/PKB phosphorylation (p=0.039) suggestive of a group effect. The following muscle variables demonstrated by MANOVA a significant time effect: IRS (p=.054); Akt/PKB (p=0.011); ERK1/2 (p=0.026); p70S6K (p=0.038). A time trend for mTOR (p=0.089) was noted. No significant effects were found for GSK and 4E-BP above baseline or among groups. Summary: The results indicate that RE but not BCAA + CHO or CHO increased the phosphorylation status of IRS, AKT/PKB, p70S6K and ERK above baseline levels (p<.05) with trends for group x time interaction for Akt/PKB and trend for mTOR activation. Phosphorylation of GSK and 4E-BP was not influenced by the RE and supplementation protocol.
Effects of ingesting branched chain amino acids and carbohydrate on myostatin signaling and markers of myogenesis in response to a bout of heavy resistance exercise.
(2008-10-14T19:34:44Z) Li, Rui, 1972-; Kreider, Richard B., 1962-; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Purpose: To determine if co-ingestion of carbohydrate (CHO) with branchedchain amino acids (BCAA) or leucine (Leu) downregulates the myostatin signaling pathway and upregulates the makers of myogenesis to a extent greater than that which resistance exercise elicits alone; to explore a possible mechanism for a CHO-BCAA or CHO-Leu induced the modification of myostatin pathway and the activation of myogenesis. Methods: 31 males (22.5yrs; 81.1kg) were randomly assigned to 1 of 3 groups: CHO-BCAA (maltodextrin 1.5 g/kg/bw, BCAA 120mg/kg/bw), CHO-Leucine (maltodextrin 1.5 g/kg/bw, Leu 60mg/kg/bw) and CHO alone (maltodextrin 1.5 g/kg/bw). A control group ingesting placebo (450 ml Crystal Light®) was employed from the previous study using the same study design in the same lab. Subjects performed 4 sets of leg press and leg extension at 80% 1RM to failure. Supplementation was ingested at 3 time points: 30 minutes prior to RE, and immediately pre- and post-RE. Venous blood was sampled at baseline; 30min later, immediate postexercise, 30min post-exercise; 2hr post-exercise, and 6hr post-exercise for serum glucose, insulin, IGF-1, myostatin, myostatin propeptide, follistatin and FLRG. Muscle biopsies were sampled at baseline, and 30min post, 2hr post, and 6hr post-exercise for myostatin, ActRIIB, p21cip, p27kip, myoD, myf-5, myogenin and MRF-4 mRNA expression. Serum variables were expressed in delta values as percent change and analyzed via a 4 (group) × 6 (time points) repeated measures MANOVA. Muscle variables were analyzed as CT ratio for relative mRNA expression via a 4 (group) × 4 (time points) repeated measures MANOVA. Univariate ANOVAs (Bonferroni adjusted) were conducted as follow-up tests to the MANOVA. Post-hoc tests of the interaction effects demonstrated in the ANOVA were investigated via an independent sample T-test. Results: CHO-BCAA, CHO-Leu and CHO alone significantly increased blood glucose and serum insulin levels combined with resistance exercise. Either CHO-BCAA or CHO-Leu enhanced serum insulin to a greater extent compared with CHO alone, nonetheless no statistically significance indicated. None of the CHO-BCAA, CHO-Leu or CHO alone, compared with placebo, modified serum IGF-1, myostatin and its inhibitors. Regarding muscle samples, a univariate group × time interaction relative to myogenin mRNA expression indicated that the CHO-Leu group was significantly upregulated at the 6hr post time point in comparison with the Placebo group (p < .05). No group × time interactions were observed for the myostain signaling molecules and other myogenic regulatory factors except myogenin. Summary: CHO-Leu supplementation upregulated the myogenin mRNA expression in conjunction with resistance exercise at 6hr post-exercise. Co-ingestion of BCAA or Leu had no effect on the inhibition of myostatin signaling at pre- and post-translational level.
The effects of ingesting an anti-inflammatory nutritional supplement while participating in a resistance training program on indices of body composition and metabolic, cardiovascular, muscular, and hemodynamic function in overweight females.
(2008-10-15T12:12:32Z) Nassar, Erika Irene.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Sedentary, healthy, overweight women (n=40) participated in a full-body resistance training program 3 days/week. The study was performed in a randomized, double blind, placebo-controlled fashion. Participants followed a structured, energy-restricted, low glycemic diet. Participants ingested either a thermogenic/anti-inflammatory supplement a placebo supplement. Body composition, performance variables, serum lipid variables, inflammation markers, obesity markers, and GLUT-4 values were obtained at week 0 and after weeks 4 and 8. Data were analyzed by repeated measures MANOVA and are presented as means ± SD. GLUT- 4 values were analyzed by repeated measures ANOVA are presented as means ± SD. For body composition, there was a significant time main effect for body mass, BMI, and fat mass. Body mass reduction was significant between weeks 0 and 8 for both groups (p<0.001). BMI also had significant decreases in both groups between weeks 0 and 8 (p<0.001). Fat mass decreased significantly for both groups between weeks 0 and 8 (p=0.034). For performance variables, there was a significant time main effect for relative leg press and bench press strength. Relative leg press strength increased in both groups between weeks 0 and 8 (p<0.001). In addition, relative bench press strength increased in both groups between week 0 and 8 (p=0.000). For serum lipids, there was a significant time main effect for TCHOL, LDL, and HDL. TCHOL decreased between weeks 0 and 8 (p=0.004). LDL decreased between weeks 0 and 8 (p=0.048). HDL decreased between weeks 0 and 8 (p=0.009). Leptin concentrations decreased significantly between week 0 and 8 in (p=0.019). There was a significant time main effect for calories, carbohydrates, fat, and sugar intake. Caloric intake decreased significantly between week 0 and 8 (p<0.001). Fat intake decreased significantly between weeks 0 and 8 (p<0.001). Carbohydrate intake was reduced significantly between week 0 and 8 (p=0.001). Sugar intake also decreased for both group significantly between week 0 and 8 (p=0.004). Results indicate that a full body resistance training program, in combination with an energy-restricted, low glycemic diet promotes weight loss and strength gains. Acknowledgement: Supported by a research grant from Unigen Pharmaceuticals (Lacey, WA).
The effects of creatine monohydrate supplementation on creatine transporter activity and creatine metabolism in resistance trained males.
(2008-10-15T14:27:54Z) Moulton, Christopher J.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Creatine is a nutritional supplement that is used for its potential performance enhancing (ergogenic) benefits. It constitutes an important component of the immediate energy system, by which ATP is regenerated during intense physical activity. Oral creatine supplementation has been shown to provide numerous benefits, including increases in lean muscle mass, muscular strength, and enhanced performance in various athletic capacities. The creatine transporter is a transmembrane protein that mediates the entry of creatine from the circulation into the muscle cell. Little is understood about the importance of the creatine transporter in controlling the uptake and regulation of creatine within human skeletal muscle. This study attempts to characterize the specific variations in creatine receptor activity and concurrent creatine metabolism in human skeletal muscle in response to a regimen of oral creatine supplementation including a one week loading phase, a four week maintenance phase, and a four week washout phase. Supplementation induced significant increments in total body mass (p = 0.03) and lean body mass (p = 0.01). A moderate effect size (d = 0.51) was found for strength increase, which suggests that the study was underpowered to detect a significant difference in strength increase. There appeared to be no effect of supplementation on intramuscular creatine; however, these data were subject to large measurement error and are not likely accurate. There was no apparent effect on creatine transporter mRNA or creatine transporter content when measured after the loading phase, during and after the maintenance phase, and after the washout phase.
Effects of a multicomponent school-based intervention on health markers, body composition, physical fitness, and psychological measures in overweight and obese adolescent females.
(2008-11-18T21:52:10Z) Dove, Jacqueline Beckham.; Kreider, Richard B., 1962-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
The purpose of this study was to determine whether participation in a multicomponent school-based intervention using circuit-resistance training, dietary intervention and behavioral modification had an effect on health markers, body composition, physical fitness, and psychological measures for overweight/obese adolescent females. Forty-two overweight/obese adolescents participated in the 10-week program with assessments completed at 0, 10, and 22 weeks. Data were analyzed by ANOVA repeated measures analysis, with a level of significance set at p < 0.05, and presented as means ± SD from baseline. Statistically significant group x time interactions were observed for the following: body mass (CON 2.82% ± 2.7 vs. EXP 0.58% ± 2.5, p = 0.021) fat mass (CON 3.64% ± 5.9 vs. EXP -2.66% ± 5.7, p = 0.006), percent fat (CON 0.52% ± 4.69 vs. EXP -2.92% ± 4.44, p = 0.024), triglycerides (CON 44.78% ± 85.11 vs. EXP -9.56% ± 34.99, p = 0.002), HOMA-IR (CON 49.41% ± 69.65 vs. EXP 17.64% ± 66.76, p = 0.052), physical activity environmental factors (CON -6.92% ± 18.66 vs. EXP 9.96% ± 27.79, p = 0.039), fruit and vegetable con decisions (CON 31.71% ± 49.75 vs. EXP 3.41% ± 47.22, p = 0.043), and dietary protein intake (CON -3.28% ± 53.05 vs. EXP 8.15% ± 58.68, p = 0.025). Time significance represented an overall mean increase in body mass (1.6 % ± 3), lean mass (2.7% ± 4), bone mineral content (3.6% ± 5) and bone mineral density (3.4% ± 3). Follow-up testing was conducted with a subset of participants (n = 29), after three months. The participants’ revealed statistically significant group x time effects for the pediatric quality of life psychosocial health summary score (CON -23% ± 40 vs. EXP 25.3% ± 65, p = 0.039) and the PACE measurements of physical activity family support (CON -0.64% ± 24.4 vs. EXP 17.8% ± 19.3, p = 0.027). This research indicated that overweight/obese adolescent females can benefit from both standard physical education and a multicomponent program. However, the participants in the multicomponent program observed significantly greater improvements in body composition, triglycerides, and insulin sensitivity.
Effects of a high protein diet on weight loss, markers of health, and functional capacity in senior-aged females participating in the Curves® fitness program.
(2008-12-01T16:42:21Z) Galbreath, Melyn.; Kreider, Richard B., 1962-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Purpose: To determine the effectiveness of elderly females aged 60-75 years following the Curves fitness and weight loss program on body composition, markers of health, and functional capacity. Methods: 55 senior aged overweight females (66 ± 5 years; 79 ± 11 kg) were randomly assigned to one of three groups: High Protein diet + Exercise (HP); High Carbohydrate diet + Exercise (NCHO); or Exercise only (E). Participants were instructed to follow their respective nutrition plans and complete a supervised 30 minute Curves circuit resistance-training program three times a week. The participants underwent an array of tests at 0, 10 and 14 weeks. An analysis of variance (ANOVA) for repeated measures was used to analyze the data. Results: Subjects in the HP experiencing significantly greater weight loss (HP -4.8 ± 3.2%, NCHO -3.0 ± 2.9%, E -1.1 ± 2.3%, p=0.001), fat mass (HP -10.2 ± 5.9%, NCHO -5.7 ± 4.0% and E -2.7 ± 3.9%, p=0.001), and percent body fat (HP -6.3 ± 3.5%, NCHO -3.8 ± 3.4%, and E only -2.2 ± 3.6%). Improvements were also noted in an appetite regulating hormones leptin (HP -42.1 ± 21.3%, NCHO 43.4 ± 56.1% and E .80 ± 35.1%, p=0.000). No significant changes were observed in fat free mass or resting energy expenditure. All groups experienced improvements in strength, muscular endurance, aerobic capacity, and a number of markers of health. Summary: The Curves exercise and weight loss program is effective in senior aged females in promoting weight loss and favorable body composition changes. The greatest effects were seen in the HP group.
The effects of creatine ethyl ester supplementation combined with resistance training on body composition, muscle mass and performance, and intramuscular creatine uptake in males.
(2008-12-01T16:56:29Z) Spillane, Micheil Brian (Mike).; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Creatine monohydrate has become one of the most popular ingested nutritional supplements due to its potential enhancement of athletic performance. Creatine absorption from the serum into skeletal muscle occurs through the utilization of a membrane-spanning protein, CreaT1. Numerous creatine formulations have been developed primarily to maximize creatine absorption. Creatine ethyl ester (CEE) has been chemically modified by adding an ester group and is thought to increase creatine bio-availability by by-passing the CreaT1. This study examined how a seven week supplementation regimen with CEE affected body composition, muscle mass and performance, whole body creatine retention, as well physiological and molecular adaptations, associated with creatine uptake in nonresistance-trained males following a resistance-training program. Results demonstrated that CEE did not show any additional benefit to increases in muscle strength/performance or a significant increase in total muscle creatine when compared to creatine monohydrate or placebo. CEE supplementation did show a large increase in creatinine levels throughout the study.
Effects of concentric and eccentric muscle contractions on IL-6 signaling in human skeletal muscle and downstream regulation of HSP-72 gene expression : Is IL-6 signaling involved in exercise-induced cytoprotection?
(2009-04-01T16:08:10Z) Harvey, Travis.; Willoughby, Darryn Scott, 1963-; Health, Human Performance and Recreation.; Baylor University. Dept. of Health, Human Performance and Recreation.
Purpose: To determine the effects of concentric and eccentric muscle contractions on IL-6 signaling and its possible downstream regulation of HSP-72 expression in human skeletal muscle, and whether contraction-induced IL-6 expression may initiate a cytoprotective mechanism in the muscle by activating HSP-72 and HSP-27. Methods: Using a cross-over design, 10 recreationally active males (20.60 ± 2.80 yrs; 77.35 ± 12.79 kg) participated in 2 separate bouts of 10 sets of 10 unilateral isokinetic knee extensions at 30°/sec. Each subject performed one concentric (CON) and one eccentric (ECC) bout, with strength assessed 5 days prior to and at 24 and 48 hr after the bout. Muscle soreness and blood samples were sampled immediately before exercise (PRE), immediately post-exercise (POST), and at 2, 6, 24, and 48 hr after exercise for serum levels of CK, IL-6, IL-1β, and TNF-α. Muscle biopsies were obtained at PRE, POST, and at 2 and 6 hr post-exercise and assessed for protein levels of IL-6, HSP-72, HSP-27, NF-кB, p38 MAPK, STAT-1, and STAT-3 and for mRNA expression of IL-6, HSP-72, and HSP-27. Repeated measures MANOVA for isokinetic peak torque revealed a significant decrease in strength at 24 and 48 hr post-exercise. Repeated measures MANOVA on muscle soreness and CK located a significant (p ≤ 0.05) main effect for time for both variables, but not for contraction type. Repeated measures MANOVA for cytokine serum variables demonstrated no significant results. Repeated measures MANOVA for muscle variables demonstrated no significant main effect for contraction, though a significant main effect for time was located. Pairwise comparisons demonstrated a significant difference from immediately post-exercise to 6 hr post-exercise for HSP-27. Gene expression of muscle variables demonstrated no significant results. Conclusion: The CON and ECC bouts demonstrated muscle damage through significant elevations in CK and muscle fatigue through significantly decreased torque production at 24 and 48 hr post-exercise. However, the damage induced during the acute bouts appears to have been insufficient to produce systemic and intramuscular signaling of the IL-6 pathway and its associated factors. Further human research still needs to be conducted on this pathway with the factors investigated here, though other exercise intensities and modes should be considered.