[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to compare knee and hip joint kinematics previously associated with anterior knee pain and metabolic cost among treadmill running (TM), standard elliptical (SE), and lateral elliptical (LE) in healthy runners. Joint kinematics and metabolic parameters of sixteen runners were collected during all three modalities using motion capture and a metabolic system, respectively. Sagittal knee range of motion (ROM) was greater in LE (p < 0.001) and SE (p < 0.001) compared to TM. Frontal and transverse plane hip ROM were greater in LE compared to SE (p < 0.001) and TM (p < 0.001). Contralateral pelvic drop ROM was smaller in SE compared to TM (p = 0.002) and LE (p = 0.005). Similar oxygen consumption was found during LE and TM (p = 0.39) but LE (p < 0.001) and TM (p < 0.001) required greater oxygen consumption than SE. Although LE yields similar metabolic cost to TM and produces hip kinematics that may help strengthen hip abductors, greater knee flexion and abduction during LE may increase symptoms in runners with anterior knee pain. The findings suggest that research on the implications of elliptical exercise for injured runners is needed.
Journal of Applied Biomechanics 09/2015; Ahead of Press. DOI:10.1123/jab.2015-0110 · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Standard elliptical devices are a popular cross-training modality as they have similar metabolic cost as running with minimal lower extremity impact. A modified elliptical device produces lateral movement of the lower extremities and yields knee and hip joint motion that may have positive clinical implications for injured runners. Purpose Compare acute differences in joint kinematics and metabolic cost between treadmill running (TR), standard elliptical (SE), and lateral elliptical (LE) in runners. Methods 16 non-injured runners (8 men) completed ten minutes of randomized exercise on TR, SE and LE on separate days. 3D knee and hip joint kinematics for the right limb were collected using a motion capture system (Qualisys). Oxygen consumption (VO2; ml/kg/min) was collected using a metabolic system (Parvo Medics). Motion data were analyzed using Visual3D (C-Motion). One-way repeated measures ANOVA to assess exercise type main effects (p<0.05) and cohen’s d effect sizes (ES) to assess mean differences were used. Results The knee ROM were different in LE (69.2±9.4°; extension) compared to SE (32.4±6.5°; ES=4.70; extension) and TR (-17.9±3.2°; ES=12.81; flexion) and, different between SE and TR (ES=10.14). The transverse plane hip ROM were different in LE (-8.9±8.1°; ES=2.94; external rotation) and TR (-3.3±4.9°; ES=3.07; external rotation) compared to SE (8.0±2.2°; internal rotation) and different between LE and SE (ES=0.86). Frontal plane hip ROM were different in LE (-16.4±5.5°; ES=5.32; abduction) and SE (2.7±1.9°; ES=1.27; adduction) compared to TR (5.3±2.3°; adduction) and, different between LE and SE (ES=4.79). Contralateral pelvic drop ROM were greater in LE (-5.3±4.8°; ES=0.83) and TR (-5.7±1.9°; ES=1.71) compared to SE (-2.3±2.2°). Finally, VO2 were greater in both TR (36.9±4.4; ES=2.65) and LE (36.8±8.3; ES=1.70) compared to SE (26.1±4.0). Conclusions The LE yields joint motions that could have strengthening effects to help prevent knee and hip joint running injuries. However, greater pelvis drop in LE may have injurious consequences. The greater VO2 during LE suggests that LE may be more comparable to TR for metabolic activity than SE. The greater VO2 in LE may be due to greater frontal plane muscle control. Studies on chronic elliptical training effects are warranted in healthy and injured runners.
[Show abstract][Hide abstract] ABSTRACT: D-aspartic acid (DAA), nitrate, and vitamin D3 have received considerable attention in recent years for their potential health-enhancing properties. Using an open-label design, we evaluated the impact of a DAA/sodium nitrate/ vitamin D3 dietary supplement on blood testosterone and nitrate/nitrite, as well as subjective indicators of health, in middle-aged men.Methods: 10 overweight or obese men (mean age: 42 years) were assigned to ingest a DAA/sodium nitrate/ vitamin D3supplement (either one or two servings per day) for 28 days. Blood total and free testosterone and nitrate/nitrite was measured before and after 14 and 28 days of supplementation. Subjective assessment of to health indicators (e.g., energy level, libido) was included at each collection time.Results: Total and free testosterone increased on average 5-10%, which was not of statistical significance (p>0.05). The response was highly variable; some men failed to respond to treatment, while men with relatively low basal testosterone values experienced increases exceeding 20%. Plasma nitrate/nitrite was increased approximately 6-10 fold after treatment with the supplement, with a trend noted for a time effect (p=0.07). Men reported a significantly better feeling following supplement use, as evidenced by a time effect for both vitality (p=0.02) and libido (p=0.04), with a trend noted for increased energy level (p=0.08) and mental outlook and mood (p=0.10).Conclusion: Twenty-eight days of treatment with a DAA/sodium nitrate/ vitamin D3 dietary supplement increased blood nitrate/nitrite and improved subjective feelings of vitality and libido in middle-aged men. In selected men with low basal testosterone values, the supplement increased circulating levels of this hormone.
The Open Nutraceuticals Journal 03/2015; 8(1):43-48. DOI:10.2174/1876396001508010043
[Show abstract][Hide abstract] ABSTRACT: This paper provides an overview of the current literature and scientific evidence surrounding inorganic nitrate (NO3-) supplementation and its potential for improving human health and physical performance. As indicative of the ever-expanding organic and natural food consumer market, athletes and health enthusiasts alike are constantly searching for ingredient-specific "super foods" and dietary supplements capable of eliciting health and performance benefits. Evidence suggests that NO3- is the viable active component within beetroot juice (BRJ) and other vegetables, responsible for health-promoting and ergogenic effects. Indeed, multiple studies support NO3- supplementation as an effective method to improve exercise performance. NO3- supplementation (either as BRJ or sodium nitrate [NaNO3-]) has also demonstrated modest benefits pertaining to cardiovascular health, such as reducing blood pressure (BP), enhancing blood flow, and elevating the driving pressure of O2 in the microcirculation to areas of hypoxia or exercising tissue. These findings are important to cardiovascular medicine/exercise physiology and suggest a possible role for NO3- supplementation: (1) as a low-cost prevention and treatment intervention for patients suffering from blood flow disorders; and (2) an effective, natural ergogenic aid for athletes. Benefits have been noted following a single bolus, as well as daily supplementation of NO3-. While results are promising, additional research is needed to determine the impact of NO3- supplementation on anaerobic exercise performance, to identify principle relationships between isolated nitrate and other ingredients found in nitrate-rich vegetables (e.g., vitamin C, polyphenols, fatty acids, thiocyanate), to explore the specific dose-response relationships needed to elicit health and ergogenic benefits, to prolong the supplementation period beyond a relatively short period (i.e., >15 days), to determine if more robust effects can be observed with longer-term treatment, and to fully examine the safety of chronic NO3- supplementation, as this continues to be a concern of some.
[Show abstract][Hide abstract] ABSTRACT: Introduction
Aerobic exercise can reduce postprandial lipemia, and possibly oxidative stress, when performed prior to a lipid-rich meal.
To compare the impact of acute exercise on postprandial oxidative stress.
We compared aerobic and anaerobic exercise bouts of different intensities and durations on postprandial blood triglycerides (TAG), oxidative stress biomarkers (malondialdehyde, hydrogen peroxide, advanced oxidation protein products), and antioxidant status (trolox equivalent antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase). Twelve trained men (21–35 years) underwent four conditions: (1) No exercise rest; (2) 60-min aerobic exercise at 70 % heart rate reserve; (3) five 60-s sprints at 100 % max capacity; and (4) ten 15-s sprints at 200 % max capacity. All exercise bouts were performed on a cycle ergometer. A high-fat meal was consumed 1 h after exercise cessation. Blood samples were collected pre-meal and 2 and 4 h post-meal and analyzed for TAG, oxidative stress biomarkers, and antioxidant status.
No significant interaction or condition effects were noted for any variable (p > 0.05), with acute exercise having little to no effect on the magnitude of postprandial oxidative stress.
In a sample of healthy, well-trained men, neither aerobic nor anaerobic exercise attenuates postprandial oxidative stress in response to a high-fat meal.
[Show abstract][Hide abstract] ABSTRACT: Women have enhanced triglyceride (TAG) removal from the circulation following consumption of high-fat loads, potentially leading to decreased reactive oxygen and nitrogen species (RONS) generation. This may have implications related to long-term health outcomes. We examined the oxidative stress response to high-fat feeding between men and women to determine if women are less prone to postprandial oxidative stress as compared to men.
A total of 49 women (mean age: 31 ± 12 yrs) and 49 men (mean age: 27 ± 9 yrs) consumed a high-fat meal in the morning hours following a 10-12 hour overnight fast. Blood samples were collected before and at 2 and 4 hours after the meal. Samples were analyzed for TAG, various markers of oxidative stress (malondialdehyde [MDA], hydrogen peroxide [H2O2], Advanced Oxidation Protein Products [AOPP], nitrate/nitrite [NOx]), and Trolox-Equivalent Antioxidant Capacity (TEAC). Area under the curve (AUC) was calculated for each variable. Effect size calculations were performed using Cohen's d. Data from the total sample of 98 subjects were collected as a part of six previously conducted studies in our lab focused on postprandial oxidative stress, between 2007 and 2012.
AUC was higher for men compared to women for TAG (249.0 ± 21.5 vs. 145.0 ± 9.8 mg·dL(-1)·4 hr(-1); p < 0.0001; effect size = 0.89), MDA (2.7 ± 0.2 vs. 2.2 ± 0.1 μmol·L(-1)·4 hr(-1); p = 0.009; effect size = 0.47), H2O2 (29.9 ± 2.4 vs. 22.5 ± 1.6 μmol·L(-1)·4 hr(-1); p = 0.001; effect size = 0.55), AOPP (92.8 ± 6.9 vs. 56.4 ± 3.7 μmol·L(-1)·4 hr(-1); p < 0.0001; effect size = 1.38), and TEAC (1.7 ± 0.1 vs. 1.3 ± 0.0 mmol·L(-1)·4 hr(-1); p = 0.002; effect size = 0.91). No significant difference was noted for NOx (42.2 ± 4.6 vs. 38.3 ± 3.5 μmol·L(-1)·4 hr(-1) for men and women, respectively; p = 0.09; effect size = 0.17).
In the context of the current design, women experienced lower postprandial oxidative stress compared to men. Future work is needed to determine the potential health implications of lower postprandial oxidative stress in women.
[Show abstract][Hide abstract] ABSTRACT: Higenamine, also known as norcoclaurine, is an herbal constituent thought to act as a beta-2 adrenergic receptor agonist---possibly stimulating lipolysis. It was the purpose of this study to determine the impact of a higenamine-based dietary supplement on plasma free fatty acids and energy expenditure following acute oral ingestion.
Sixteen healthy subjects (8 men; 26.1 +/- 2.5 yrs; 8 women 22.4 +/- 3.1 yrs) ingested a dietary supplement containing a combination of higenamine, caffeine (270 mg), and yohimbe bark extract or a placebo, on two separate occasions in a double-blind, randomized, cross-over design, separated by 6--8 days. Blood samples were collected immediately before ingestion, and at 30, 60, 120, and 180 minutes post ingestion, and analyzed for plasma free fatty acids (FFA) and glycerol. Breath samples were collected at the same times for a measure of kilocalorie expenditure and respiratory exchange ratio (RER) using indirect calorimetry. Heart rate and blood pressure were recorded at all times. Data collection occurred in the morning following a 10 hour overnight fast.
A condition effect was noted for both FFA (p < 0.0001) and kilocalorie expenditure (p = 0.001), with values higher for supplement compared to placebo at 60, 120, and 180 minutes post ingestion. No statistically significant effects were noted for glycerol or RER (p > 0.05). A condition effect was noted for heart rate (p = 0.03) and systolic blood pressure (p < 0.0001), with values higher for supplement compared to placebo.
Ingestion of a higenamine-based dietary supplement stimulates lipolysis and energy expenditure, as evidenced by a significant increase in circulating FFA and kilocalorie expenditure. The same supplement results in a moderate increase in heart rate (~3 bpm) and systolic blood pressure (~12 mmHg), which is consistent with previous studies evaluating moderate doses of caffeine and yohimbine, suggesting that higenamine contributes little to the increase in these hemodynamic variables. These findings are in reference to young, healthy and active men and women.
Lipids in Health and Disease 10/2013; 12(1):148. DOI:10.1186/1476-511X-12-148 · 2.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 1,3-dimethylamylamine (DMAA) has been a component of dietary supplements and is also used within "party pills," often in conjunction with alcohol and other drugs. Ingestion of higher than recommended doses results in untoward effects including cerebral hemorrhage. To our knowledge, no studies have been conducted to determine both the pharmacokinetic profile and physiologic responses of DMAA.
Eight men reported to the lab in the morning following an overnight fast and received a single 25 mg oral dose of DMAA. Blood samples were collected before and through 24 hours post-DMAA ingestion and analyzed for plasma DMAA concentration using high-performance liquid chromatography--mass spectrometry. Resting heart rate, blood pressure, and body temperature was also measured.
One subject was excluded from the data analysis due to abnormal DMAA levels. Analysis of the remaining seven participants showed DMAA had an oral clearance of 20.02 +/- 5 L[bullet operator]hr-1, an oral volume of distribution of 236 +/- 38 L, and terminal half-life of 8.45 +/- 1.9 hr. Lag time, the delay in appearance of DMAA in the circulation following extravascular administration, varied among participants but averaged approximately 8 minutes (0.14 +/- 0.13 hr). The peak DMAA concentration for all subjects was observed within 3--5 hours following ingestion and was very similar across subjects, with a mean of ~70 ng[bullet operator]mL-1. Heart rate, blood pressure, and body temperature were largely unaffected by DMAA treatment.
These are the first data to characterize the oral pharmacokinetic profile of DMAA. These findings indicate a consistent pattern of increase across subjects with regards to peak DMAA concentration, with peak values approximately 15--30 times lower than those reported in case studies linking DMAA intake with adverse events. Finally, a single 25 mg dose of DMAA does not meaningfully impact resting heart rate, blood pressure, or body temperature.Trial registration: NCT01765933.
[Show abstract][Hide abstract] ABSTRACT: Background:
Strenuous, high-volume exercise is often associated with inflammation and joint pain. Cissus quadrangularis (CQ) has been reported to have anti-inflammatory activity. The purpose of our study was to determine the therapeutic effects of CQ supplementation in healthy, exercise-trained men with joint-specific pain.
Twenty-nine men between the ages of 20 and 46 years, who reportedly experienced chronic joint pain as a result of strenuous exercise, participated in our pilot study. All men received CQ 3200 mg daily for 8 weeks. Before and after the 8-week intervention period, subjects completed a questionnaire to determine their degree of joint pain (Western Ontario and McMaster Universities Index of Osteoarthritis [WOMAC]). Clinical measures (eg, heart rate, blood pressure, blood biomarkers) were also collected for each subject pre- (baseline) and post-intervention.
Subject ratings for multiple variables within the WOMAC Index improved (decreased) significantly (P < 0.05), with the subject mean total WOMAC score decreasing from 25.4 ± 2.4 to 17.4 ± 2.1 (~31%), pre- to post-intervention. No clinical measure was significantly impacted by use of CQ supplementation.
An 8-week course of supplementation with CQ reduced joint pain in a sample of 29 young, otherwise healthy, exercise-trained men. Additional study is needed to extend these findings, including comparison with a placebo-controlled cohort, and possibly, examining effects of CQ use in women and older adult subjects.
The Physician and sportsmedicine 09/2013; 41(3):29-35. DOI:10.3810/psm.2013.09.2021 · 1.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Daniel Fast involves dietary modification similar to a purified vegan diet. Although improvements in several health-specific biomarkers have been noted with this plan, the removal of animal products results in a significant reduction in both dietary protein and saturated fatty acid intake, which results in a loss of lean body mass and a reduction in HDL-cholesterol.
We assigned 29 men and women to either a traditional or modified Daniel Fast for 21 days and measured anthropometric and biochemical markers of health pre and post intervention. The modified Daniel Fast was otherwise identical to the traditional plan but included one serving per day of lean meat and dairy (skim milk), providing approximately 30 grams per day of additional protein.
Compared to baseline, both plans resulted in similar and significant improvements in blood lipids, as well as a reduction in inflammation.
Modification of dietary intake in accordance with either a traditional or modified Daniel Fast may improve risk factors for cardiovascular and metabolic disease.
Lipids in Health and Disease 07/2013; 12(1):114. DOI:10.1186/1476-511X-12-114 · 2.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Coffee has been reported to be rich in antioxidants, with both acute and chronic consumption leading to enhanced blood antioxidant capacity. High-fat feeding is known to result in excess production of reactive oxygen and nitrogen species, promoting a condition of postprandial oxidative stress.
We tested the hypothesis that coffee intake following a high-fat meal would attenuate the typical increase in blood oxidative stress during the acute postprandial period. On 3 different occasions, 16 men and women consumed a high-fat milk shake followed by either 16 ounces of caffeinated or decaffeinated coffee or bottled water. Blood samples were collected before and at 2 and 4 hours following intake of the milk shake and analyzed for triglycerides (TAG), malondialdehyde (MDA), hydrogen peroxide (H2O2), and Trolox equivalent antioxidant capacity (TEAC).
Values for TAG and MDA (P < 0.001), as well as for H2O2 (P < 0.001), increased significantly following milk shake consumption, with values higher at 4 hours compared with 2 hours post consumption for TAG and H2O2 (P < 0.05). TEAC was unaffected by the milk shake consumption. Coffee had no impact on TAG, MDA, H2O2, or TEAC, with no condition or interaction effects noted for any variable (P > 0.05).
Acute coffee consumption following a high-fat milk shake has no impact on postprandial oxidative stress.
Nutrition and Metabolic Insights 07/2013; 6:35-42. DOI:10.4137/NMI.S12215
[Show abstract][Hide abstract] ABSTRACT: The purposes of this study were to establish stability reliability of a measure of lower body anaerobic power, the Kansas Squat Test; (KST), and to compare the KST with the commonly used Wingate anaerobic test (WAnT) for lower body power. Fourteen resistance trained men (mean ± SD; age = 24.2 ± 3.6 yrs.) performed both the KST and the WAnT twice on separate occasions. The KST consisted of using an external dynamometer to measure mean repetition power while performing 15 repetitions of speed squats using 70% of 1 RM system mass (barbell + body mass), initiating each repetition at 6 second intervals. Repetition power, mean power for all 15 repetitions, and % fatigue for the KST were all reliable (intra-class correlation coefficient; ICC = 0.754 to 0.937; p < 0.05). There were no differences between tests for the mean power for all repetitions or relative fatigue (p<0.05), and no significant differences between tests for any individual repetition (test x repetition interaction, p<0.05). Although absolute values were different (p > 0.05), significant correlations were found between the KST and WAnT for mean (r = 0.752) and maximum (r = 0.775) test powers, but not for relative fatigue (r = 0.174). Lactate (HLa) responses were greater for the WAnT compared to the KST. These data indicate that the KST is reliable for resistance-trained men, and that measures of maximum and mean test powers for the KST are highly correlated to those values for the WAnT, but fatigue rates and HLa responses were not correlated. It appears that the KST is a lifting-specific anaerobic power and power endurance test that emphasizes phosphagen metabolism, and may be used to assess training induced changes in lower body power.
The Journal of Strength and Conditioning Research 07/2013; 28(3). DOI:10.1519/JSC.0b013e3182a0cb23 · 2.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Caffeine and 1,3-dimethylamylamine (DMAA) are widely used alone and in combination with dietary supplements. No investigation has determined the safety profile of chronic intake of caffeine or DMAA, alone or in combination, within the same study design. A total of 50 young and healthy men completed 12 weeks of daily supplementation with either a placebo (n = 11), caffeine at 250 mg day(-1) (n = 14), DMAA at 50 mg day(-1) (n = 13), or caffeine at 250 mg day(-1) + DMAA at 50 mg day(-1) (n = 12). Before and after 6 and 12 weeks of supplementation, the following variables were measured: body mass/composition, resting respiratory rate, blood pressure, 12-lead electrocardiogram, urinalysis, complete blood count, metabolic panel, lipid panel, and oxidative stress, inflammatory, and cardiac biomarkers. No interaction effects were noted for any variable (p > 0.05), with little change occurring across time for subjects in any of the four conditions. With the exception of urinary pH (p = 0.05; Pre (6.5 ± 0.1) higher than week 6 (6.1 ± 0.1)) and blood CO(2) (p = 0.02; week 12 (25.9 ± 0.3 mmol L(-1)) higher than week 6 (24.8 ± 0.3 mmol L(-1))), no time effect was noted for any other variable (p > 0.05). These data indicate that 12 weeks of daily supplementation with caffeine and DMAA, alone or in combination, does not result in a statistically significant change in any of the measured outcome variables.