Publications by authors named "Jody L Clasey"

33 Publications

Predictors of Arterial Stiffness in Law Enforcement Officers.

Int J Environ Res Public Health 2021 09 28;18(19). Epub 2021 Sep 28.

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA.

Background: Compare arterial stiffness among law enforcement officers (LEOs) versus general population normative values and identify predictors of arterial stiffness in LEOs.

Methods: Seventy male LEOs (age: 24-54 years) completed body composition, blood pressures, physical activity level, and carotid-femoral pulse wave velocity (cfPWV) measurements. T-tests and regression analyses were utilized to compare LEO data to normative data and predict cfPWV, respectively.

Results: Compared to similar age strata within the general population, cfPWV was lower among LEO's under 30-years (mean difference = -0.6 m·s), but higher among LEOs 50-55-years (mean difference = 1.1 m·s). Utilizing regression, age, relative body fat, and diastolic blood pressure explained the greatest variance in LEO's cfPWV (adj. R = 0.56, < 0.001).

Conclusion: This investigation demonstrated that arterial stiffness may progress more rapidly in LEOs and LEOs' relative body fat and blood pressure may primarily affect arterial stiffness and risk of CVD.
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http://dx.doi.org/10.3390/ijerph181910190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8508055PMC
September 2021

Impact of Pediatric Obesity on Diurnal Blood Pressure Assessment and Cardiovascular Risk Markers.

Front Pediatr 2021 4;9:596142. Epub 2021 Mar 4.

Division of Pediatric Nephrology, Department of Pediatrics, University of Kentucky, Lexington, KY, United States.

The prevalence of hypertension is increasing particularly among obese children and adolescents. Obese children and adolescents with hypertension are likely to remain hypertensive as they reach adulthood and hypertension is linked to an increased risk for cardiovascular disease. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has become one of the most important tools in diagnosing hypertension in children and adolescents and circadian patterns of blood pressure may be important disease-risk predictors. A retrospective chart review was conducted in patients aged 6-21 years who underwent 24-h ABPM at Kentucky Children's Hospital (KCH) from August 2012 through June 2017. Exclusion criteria included conditions that could affect blood pressure including chronic kidney disease and other renal abnormalities, congenital heart disease, cancer, and thyroid disease. Subjects were categorized by body mass index into normal (below 85th percentile), overweight (85th-95th percentile), stage I obesity (95th-119th percentile), stage II obesity (120th-139th) and stage III obesity (>140th). Non-dipping was defined as a nocturnal BP reduction of <10%. Two hundred and sixty-three patients (156 male patients) were included in the analysis, of whom 70 were normal weight, 33 overweight, 55 stage I obesity, 53 stage II, and 52 stage III obesity. Although there was no significant difference between normal weight and obese groups for prevalence of hypertension, there was a greater prevalence of SBP non-dipping in obese patients as BMI increased ( = 0.008). Furthermore, non-dippers had a significantly elevated LVMI as well as abnormal lab values for uric acid, blood lipid panel, creatinine, and TSH ( < 0.05). These findings demonstrate that obese children and adolescents constitute a large proportion of hypertensive children and adolescents and the severity of pediatric obesity is associated with nocturnal BP non-dipping. Additionally, obesity in children is linked to several cardiovascular risk factors including left ventricular hypertrophy, dyslipidemia, and elevated uric acid levels. Further studies utilizing ABPM measures on risk stratification in this very high-risk population are warranted.
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http://dx.doi.org/10.3389/fped.2021.596142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7969716PMC
March 2021

Circadian rhythm phase shifts caused by timed exercise vary with chronotype.

JCI Insight 2020 02 13;5(3). Epub 2020 Feb 13.

Center for Clinical and Translational Science.

BACKGROUNDThe circadian system entrains behavioral and physiological rhythms to environmental cycles, and modern lifestyles disrupt this entrainment. We investigated a timed exercise intervention to phase shift the internal circadian rhythm.METHODSIn 52 young, sedentary adults, dim light melatonin onset (DLMO) was measured before and after 5 days of morning (10 hours after DLMO; n = 26) or evening (20 hours after DLMO; n = 26) exercise. Phase shifts were calculated as the difference in DLMO before and after exercise.RESULTSMorning exercise induced phase advance shifts (0.62 ± 0.18 hours) that were significantly greater than phase shifts from evening exercise (-0.02 ± 0.18 hours; P = 0.01). Chronotype also influenced the effect of timed exercise. For later chronotypes, both morning and evening exercise induced phase advances (0.54 ± 0.29 hours and 0.46 ±0.25 hours, respectively). In contrast, earlier chronotypes had phase advances from morning exercise (0.49 ± 0.25 hours) but had phase delays from evening exercise (-0.41 ± 0.29 hours).CONCLUSIONLate chronotypes - those who experience the most severe circadian misalignment - may benefit from phase advances induced by exercise in the morning or evening, but evening exercise may exacerbate circadian misalignment in early chronotypes. Thus, personalized exercise timing prescription, based on chronotype, could alleviate circadian misalignment in young adults.TRIAL REGISTRATIONTrial registration can be found at www.clinicaltrials.gov (NCT04097886).FUNDINGFunding was supplied by NIH grants UL1TR001998 and TL1TR001997, the Barnstable Brown Diabetes and Obesity Center, the Pediatric Exercise Physiology Laboratory Endowment, the Arvle and Ellen Turner Thacker Research Fund, and the University of Kentucky.
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http://dx.doi.org/10.1172/jci.insight.134270DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098792PMC
February 2020

The Effect of Personal Protective Equipment on Firefighter Occupational Performance.

J Strength Cond Res 2020 Aug;34(8):2165-2172

Departments of Kinesiology and Health Promotion; and.

Lesniak, AY, Bergstrom, HC, Clasey, JL, Stromberg, AJ, and Abel, MG. The effect of personal protective equipment on firefighter occupational performance. J Strength Cond Res 34(8): 2165-2172, 2020-The purpose of this study was to evaluate the effects of load carriage (LC) and LC plus respirator use (LC + self-contained breathing apparatus [SCBA]) on firefighters' work capacity to enhance our understanding of occupational demands. Twenty-one male structural firefighter recruits (age: 28.6 ± 4.3 years; height: 178.6 ± 7.2 cm; body mass: 94.1 ± 15.4 kg; body fat: 22.9 ± 6.1%) participated. Occupational performance was assessed by time to complete a simulated fire ground test (SFGT). After 2 familiarization trials, recruits performed the following SFGT conditions in a randomized order: PT (physical training clothes), LC only, and LC + SCBA. To describe within-group differences between SFGT conditions, relative difference scores were calculated as follows: % difference = ([experimental trial outcome - PT trial outcome]/PT trial outcome) × 100. Statistical differences between conditions were assessed with repeated-measures analysis of variance. The level of significance was set p < 0.01. Time to complete the LC + SCBA trial (345.9 ± 43.7 seconds; p < 0.001) and LC-only trial (331.2 ± 39.3 seconds; p < 0.001) were significantly greater than the PT trial (241.0 ± 33.3 seconds). Post-SFGT rating of perceived exertion was higher in the LC + SCBA trial (6.7 ± 1.7) and LC trial (6.4 ± 1.5) compared with the PT trial (4.7 ± 1.8; p < 0.001). Heart rate and lactate measures were similar across conditions (p = 0.488; p = 0.287). Personal protective equipment (PPE) significantly decreases the work capacity and increases the perceived effort of occupational tasks. Thus, these findings describe the additional physical demands produced by PPE and indicate that performance of firefighting tasks in an unloaded condition does not reflect work capacity in a bona fide condition.
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http://dx.doi.org/10.1519/JSC.0000000000003384DOI Listing
August 2020

Optimism and Pain Interference in Aging Women.

Ann Behav Med 2020 02;54(3):202-212

Department of Psychology, University of Kentucky, Lexington, KY, USA.

Background: Pain interferes with people's daily lives and often limits the extent to which they can pursue goals and engage in activities that promote well-being. However, people vary in how much interference they experience at a given level of pain.

Purpose: The present study tested how optimism affects and is affected by pain interference and goal-directed activity among older women.

Methods: Every 3 months for 2 years, community-dwelling middle- and older-age women (N = 199) completed online daily diaries at home for a 7 day period, in which they reported their daily pain, pain interference, and goal-directed activity. Optimism was measured at the start and end of the study. Multilevel models tested the between- and within-person relationships among pain, optimism, and pain interference or goal-directed activity. Linear regression predicted change in optimism over 2 years from pain interference and goal-directed activity.

Results: Pain best predicted pain interference and optimism best predicted goal-directed activity. There were subtle interactions between optimism and pain-predicting interference and goal-directed activity. Accumulated goal-directed activity and pain interference across the study predicted longitudinal changes in optimism, with higher activity and lower pain interference predicting increased optimism over 2 years.

Conclusions: Optimism may play a protective role in disruptions caused by pain on a day-to-day basis, leading to increased goal-directed activity and possibly decreased pain interference. In turn, less interference and more goal-directed activity feed forward into increased optimism, resulting in a virtuous cycle that enhances optimism and well-being among older women.
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http://dx.doi.org/10.1093/abm/kaz040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7309584PMC
February 2020

Low-Load vs. High-Load Resistance Training to Failure on One Repetition Maximum Strength and Body Composition in Untrained Women.

J Strength Cond Res 2019 Jul;33(7):1737-1744

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky.

Dinyer, TK, Byrd, MT, Garver, MJ, Rickard, AJ, Miller, WM, Burns, S, Clasey, JL, and Bergstrom, HC. Low-load vs. high-load resistance training to failure on one repetition maximum strength and body composition in untrained women. J Strength Cond Res 33(7): 1737-1744, 2019-This study examined the effects of resistance training (RT) to failure at low and high loads on one repetition maximum (1RM) strength and body composition (bone- and fat-free mass [BFFM] and percent body fat [%BF]) in untrained women. Twenty-three untrained women (age: 21.2 ± 2.2 years; height: 167.1 ± 5.7 cm; body mass: 62.3 ± 16.2 kg) completed a 12-week RT to failure intervention at a low (30% 1RM) (n = 11) or high (80% 1RM) (n = 12) load. On weeks 1, 5, and 12, subjects completed 1RM testing for 4 different exercises (leg extension [LE], seated military press [SMP], leg curl [LC], and lat pull down [LPD]) and a dual-energy x-ray absorptiometry scan to assess body composition. During weeks 2-4 and 6-7, the subjects completed 2 sets to failure for each exercise. During weeks 8-11, the subjects completed 3 sets to failure for each exercise. The 1RM strength increased from week 1 to week 5 (LE: 18 ± 16%; SMP: 9 ± 11%; LC: 12 ± 22%; LPD: 13 ± 9%), week 1 to week 12 (LE: 32 ± 24%; SMP: 17 ± 14%; LC: 23 ± 26%; LPD: 25 ± 13%), and week 5 to week 12 (LE: 11 ± 9%; SMP: 7 ± 9%; LC: 10 ± 7%; LPD: 11 ± 11%) in each exercise, with no significant differences between groups. There were no significant changes in BFFM (p = 0.241) or %BF (p = 0.740) for either group. Resistance training to failure at 30% 1RM and 80% 1RM resulted in similar increases in 1RM strength, but no change in BFFM or %BF. Untrained women can increase 1RM strength during RT at low and high loads, if repetitions are taken to failure.
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http://dx.doi.org/10.1519/JSC.0000000000003194DOI Listing
July 2019

Non-fasting High-Density Lipoprotein Is Associated With White Matter Microstructure in Healthy Older Adults.

Front Aging Neurosci 2019 7;11:100. Epub 2019 May 7.

Neuroscience Department, University of Kentucky, Lexington, KY, United States.

A growing body of evidence indicates that biomarkers of cardiovascular risk may be related to cerebral health. However, little is known about the role that non-fasting lipoproteins play in assessing age-related declines in a cerebral biomarker sensitive to vascular compromise, white matter (WM) microstructure. High-density lipoprotein cholesterol (HDL-C) is atheroprotective and low-density lipoprotein cholesterol (LDL-C) is a major atherogenic lipoprotein. This study explored the relationships between non-fasting levels of cholesterol and WM microstructure in healthy older adults. A voxelwise and region of interest approach was used to determine the relationship between cholesterol and fractional anisotropy (FA). Participants included 87 older adults between the ages of 59 and 77 (mean age = 65.5 years, SD = 3.9). Results indicated that higher HDL-C was associated with higher FA in diffuse regions of the brain when controlling for age, sex, and body mass index (BMI). HDL-C was also positively associated with FA in the corpus callosum and fornix. No relationship was observed between LDL-C and FA. Findings suggest that a modifiable lifestyle variable associated with cardiovascular health may help to preserve cerebral WM.
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http://dx.doi.org/10.3389/fnagi.2019.00100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6513892PMC
May 2019

Human Body Composition and Immunity: Visceral Adipose Tissue Produces IL-15 and Muscle Strength Inversely Correlates with NK Cell Function in Elderly Humans.

Front Immunol 2018 6;9:440. Epub 2018 Mar 6.

Department of Pathology and Laboratory Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States.

Natural killer (NK) lymphocyte-mediated cytotoxicity and cytokine secretion control infections and cancers, but these crucial activities decline with age. NK cell development, homeostasis, and function require IL-15 and its chaperone, IL-15 receptor alpha (IL-15Rα). Macrophages and dendritic cells (DC) are major sources of these proteins. We had previously postulated that additional IL-15 and IL-15Rα is made by skeletal muscle and adipose tissue. These sources may be important in aging, when IL-15-producing immune cells decline. NK cells circulate through adipose tissue, where they may be exposed to local IL-15. The objectives of this work were to determine (1) if human muscle, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) are sources of IL-15 and IL-15 Rα, and (2) whether any of these tissues correlate with NK cell activity in elderly humans. We first investigated IL-15 and IL-15Rα RNA expression in paired muscle and SAT biopsies from healthy human subjects. Both tissues expressed these transcripts, but IL-15Rα RNA levels were higher in SAT than in skeletal muscle. We also investigated tissue obtained from surgeries and found that SAT and VAT expressed equivalent amounts of IL-15 and IL-15Rα RNA, respectively. Furthermore, stromal vascular fraction cells expressed more IL-15 RNA than did adipocytes. To test if these findings related to circulating IL-15 protein and NK cell function, we tested 50 healthy adults aged > 70 years old. Plasma IL-15 levels significantly correlated with abdominal VAT mass in the entire cohort and in non-obese subjects. However, plasma IL-15 levels did not correlate with skeletal muscle cross-sectional area and correlated inversely with muscle strength. Plasma IL-15 did correlate with NK cell cytotoxic granule exocytosis and with CCL4 (MIP-1β) production in response to NKp46-crosslinking. Additionally, NK cell responses to K562 leukemia cells correlated inversely with muscle strength. With aging, immune function declines while infections, cancers, and deaths increase. We propose that VAT-derived IL-15 and IL-15Rα is a compensatory NK cell support mechanism in elderly humans.
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http://dx.doi.org/10.3389/fimmu.2018.00440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5845694PMC
June 2019

Examination of Resistance Settings Based on Body Weight for the 3-Minute All-Out Critical Power Test.

Int J Exerc Sci 2018;11(4):585-597. Epub 2018 Jan 1.

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA.

There are conflicting suggestions regarding the most valid resistance (3-5% of body weight) to use for the critical power (CP) 3-min all-out (CP) test to estimate CP and anaerobic work capacity (AWC). The purpose of this study was to determine if the CP and AWC estimates from the CP test were affected by the percentage of body weight used to set the resistance on a Monark cycle ergometer. Ten recreationally trained participants (mean ± SD: Age: 22.2 ± 2.2 yrs.) completed the CP test at resistances of 4.5% (CP) and 3% (CP) of body weight to determine the CP and AWC. There were no significant differences between the CP (167 ± 34 W) and CP (156 ± 36 W) estimates. The AWC (5.6 ± 2.5 kJ) estimates were significantly lower than the AWC (9.0 ± 4.0 kJ). The CP and AWC estimates from the CP were consistent with values reported in the literature, however, the AWC estimate from the CP was lower than typically reported. These findings suggested that a resistance set at 3% of body weight for the CP test may be too low to accurately estimate AWC, but 3% and 4.5% resulted in the same estimation of CP. Thus, the principal finding of this study was that a resistance of 4.5% of body weight for CP in recreationally trained participants resulted in more accurate estimates of AWC, compared to a resistance of 3%, and supports the use of 4.5% body weight resistance to measure both CP and AWC.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5841676PMC
January 2018

Contributions of Lower-Body Strength Parameters to Critical Power and Anaerobic Work Capacity.

J Strength Cond Res 2021 Jan;35(1):97-101

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky; and.

Abstract: Byrd, MT, Wallace, BJ, Clasey, JL, and Bergstrom, HC. Contributions of lower-body strength parameters to critical power and anaerobic work capacity. J Strength Cond Res 35(1): 97-101, 2021-This study examined the contribution of lower-body strength and isokinetic peak torque measures to the prediction of critical power (CP) and anaerobic work capacity (AWC). Fourteen recreationally trained males (mean ± SD age: 22.4 ± 2.5 years; height: 177.9 ± 7.7 cm; body mass: 84.2 ± 12.4 kg) with anaerobic training experience participated in this study. The lower-body strength measures included 1 repetition max bilateral back squat (BSq), isokinetic peak torque at 30°·s-1 [PT30], and isokinetic peak torque at 240°·s-1 [PT240] of the dominant leg. The CP and AWC were determined from the 3-minute all-out CP cycle ergometer test (CP3MT), with the resistance set at 4.5% of the total body mass. The CP was defined as the mean power output over the final 30 seconds of the test, and the AWC was calculated using the equation, AWC = 150 seconds (P150 - CP), where P150 equals the mean power output for the first 150 seconds. Stepwise regression analyses indicated that only BSq contributed significantly to the prediction of AWC (AWC = 0.0527 [BSq] + 8.094 [standard error of estimate = 2.151 kJ; p = 0.012]), with a correlation of r2 = 0.423. None of the strength parameters significantly predicted CP. These findings indicated that BSq strength accounted for 42% of the variance in AWC, but lower-body strength was not related to CP. The current results indirectly support the unique metabolic characteristics of both CP and AWC in providing separate measures of an individual's aerobic and anaerobic capabilities, respectively.
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http://dx.doi.org/10.1519/JSC.0000000000002555DOI Listing
January 2021

Examination of a Multi-ingredient Preworkout Supplement on Total Volume of Resistance Exercise and Subsequent Strength and Power Performance.

J Strength Cond Res 2018 Jun;32(6):1479-1490

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky.

Bergstrom, HC, Byrd, MT, Wallace, BJ, and Clasey, JL. Examination of a multi-ingredient preworkout supplement on total volume of resistance exercise and subsequent strength and power performance. J Strength Cond Res 32(6): 1479-1490, 2018-This study examined the acute effects of a multi-ingredient preworkout supplement on (a) total-, lower-, and upper-body volume of resistance exercise and (b) the subsequent lower-body strength (isokinetic leg extension and flexion), lower-body power (vertical jump [VJ] height), upper-body power (bench throw velocity [BTv]), and cycle ergometry performance (critical power and anaerobic work capacity). Twelve men completed baseline strength and power measures before 2 experimental visits, supplement (SUP) and placebo (PL). The experimental visits involved a fatiguing cycling protocol 30 minutes after ingestion of the SUP or PL and 15 minutes before the beginning of the resistance exercise protocol, which consisted of 4 upper-body and 4 lower-body resistance exercises performed for 4 sets to failure at 75% 1 repetition maximum. The exercise volume for the total, lower, and upper body was assessed. The VJ height and BTv were measured immediately after the resistance exercise. Postexercise isokinetic leg extension and flexion strength was measured 15 minutes after the completion of a second cycling protocol. There was a 9% increase in the total-body volume of exercise and a 14% increase in lower-body volume of exercise for the SUP compared with the PL, with no effect on exercise volume for the upper body between the SUP and PL. The increased lower-body volume for the SUP did not result in greater lower-body strength and power performance decrements after exhaustive exercise, compared with the PL. These findings suggested the potential for the SUP to increase resistance exercise volume, primarily related to an increased lower-body volume of exercise.
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http://dx.doi.org/10.1519/JSC.0000000000002480DOI Listing
June 2018

Arm crank ergometry improves cardiovascular disease risk factors and community mobility independent of body composition in high motor complete spinal cord injury.

J Spinal Cord Med 2019 05 15;42(3):272-280. Epub 2018 Jan 15.

b Department of Physical Medicine and Rehabilitation , Pennsylvania State University College of Medicine , Hershey , Pennsylvania.

Objective: Evaluate the effect of aerobic exercise using arm crank ergometry (ACE) in high motor complete (ISNCSCI A/B) spinal cord injury (SCI) as primarily related to cardiovascular disease (CVD) risk factors and functional mobility and secondarily to body composition and metabolic profiles.

Design: Longitudinal interventional study at an academic medical center.

Methods: Ten previously untrained participants (M8/F2, Age 36.7 y ± 10.1, BMI 24.5 ± 6.0) with high motor complete SCI (C7-T5) underwent ACE exercise training 30 minutes/day × 3 days/week for 10 weeks at 70% VO.

Outcome Measures: Primary outcome measures were pre- and post-intervention changes in markers of cardiovascular fitness (graded exercise testing (GXT): VO, VO, respiratory quotient [RQ], GXT time, peak power, and energy expenditure [EE]) and community mobility (time to traverse a 100ft-5° ramp, and 12-minute WC propulsion test). Secondary outcome measures were changes in body composition and metabolic profiles (fasting and area under the curve for glucose and insulin, homeostasis model assessment [HOMA] for %β-cell activity [%β], %insulin sensitivity [%S], and insulin resistance [IR], and Matsuda Index [ISI]).

Results: Resting VO, relative VO, absolute VO, peak power, RQ, 12-minute WC propulsion, fasting insulin, fasting G:I ratio, HOMA-%S, and HOMA-IR all significantly improved following intervention (P < 0.05). There were no changes in body composition (P>0.05).

Conclusions: Ten weeks of ACE at 70% VO in high motor complete SCI improves aerobic capacity, community mobility, and metabolic profiles independent of changes in body composition.
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http://dx.doi.org/10.1080/10790268.2017.1412562DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6522950PMC
May 2019

Recovery Responses to Maximal Exercise in Healthy-Weight Children and Children With Obesity.

Res Q Exerc Sport 2018 Mar 20;89(1):38-46. Epub 2017 Dec 20.

a University of Kentucky.

Purpose: The purpose of this study was to examine differences in heart rate recovery (HRRec) and oxygen consumption recovery (VO recovery) between young healthy-weight children and children with obesity following a maximal volitional graded exercise test (GXTmax).

Method: Twenty healthy-weight children and 13 children with obesity completed body composition testing and performed a GXTmax. Immediately after the GXTmax, HRRec and VO recovery were measured each minute for 5 consecutive minutes.

Results: There were no statistically significant group differences in HRRec for the 5 min following maximal exercise, Wilks's Lambda = .885, F(4, 28) = 0.911, p = .471, between the healthy-weight children and children with obesity despite statistically significant differences in body fat percentage (BF%; healthy-weight children, 18.5 ± 6.1%; children with obesity, 41.1 ± 6.9%, p < .001) and aerobic capacity relative to body mass (VO peak; healthy-weight children, 46.8 ± 8.2 mL/kg/min; children with obesity, 31.9 ± 4.7 mL/kg/min, p < .001). There were statistically significant differences in VO recovery for the 5 min following exercise, Wilks's Lambda = .676, F(4, 26) = 3.117, p = .032. There were no statistically significant correlations between HRRec and body mass index (BMI), BF%, VOpeak, or physical activity.

Conclusions: In a healthy pediatric population, obesity alone does not seem to significantly impact HRRec, and because HRRec was not related to obesity status, BMI, or BF%, it should not be used as the sole indicator of aerobic capacity or health status in children. Using more than one recovery variable (i.e., HRRec and VO recovery) may provide greater insight into cardiorespiratory fitness in this population.
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http://dx.doi.org/10.1080/02701367.2017.1407492DOI Listing
March 2018

Endothelial Function Is Associated with White Matter Microstructure and Executive Function in Older Adults.

Front Aging Neurosci 2017 2;9:255. Epub 2017 Aug 2.

Magnetic Resonance Imaging and Spectroscopy Center, University of KentuckyLexington, KY, United States.

Age-related declines in endothelial function can lead to cognitive decline. However, little is known about the relationships between endothelial function and specific neurocognitive functions. This study explored the relationship between measures of endothelial function (reactive hyperemia index; RHI), white matter (WM) health (fractional anisotropy, FA, and WM hyperintensity volume, WMH), and executive function (Trail Making Test (TMT); Trail B - Trail A). Participants were 36 older adults between the ages of 59 and 69 (mean age = 63.89 years, SD = 2.94). WMH volume showed no relationship with RHI or executive function. However, there was a positive relationship between RHI and FA in the genu and body of the corpus callosum. In addition, higher RHI and FA were each associated with better executive task performance. Tractography was used to localize the WM tracts associated with RHI to specific portions of cortex. Results indicated that the RHI-FA relationship observed in the corpus callosum primarily involved tracts interconnecting frontal regions, including the superior frontal gyrus (SFG) and frontopolar cortex, linked with executive function. These findings suggest that superior endothelial function may help to attenuate age-related declines in WM microstructure in portions of the corpus callosum that interconnect prefrontal brain regions involved in executive function.
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http://dx.doi.org/10.3389/fnagi.2017.00255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5539079PMC
August 2017

Contributions of Body-Composition Characteristics to Critical Power and Anaerobic Work Capacity.

Int J Sports Physiol Perform 2018 Feb 14;13(2):189-193. Epub 2018 Feb 14.

Critical power (CP) and anaerobic work capacity (AWC) from the CP test represent distinct parameters related to metabolic characteristics of the whole body and active muscle tissue, respectively.

Purpose: To examine the contribution of whole-body composition characteristics and local lean mass to further elucidate the differences in metabolic characteristics between CP and AWC as they relate to whole body and local factors.

Methods: Fifteen anaerobically trained men were assessed for whole-body (% body fat and mineral-free lean mass [LBM]) and local mineral-free thigh lean mass (TLM) composition characteristics. CP and AWC were determined from the 3-min all-out CP test. Statistical analyses included Pearson product-moment correlations and stepwise multiple-regression analyses (P ≤ .05).

Results: Only LBM contributed significantly to the prediction of CP (CP = 2.3 [LBM] + 56.7 [r = .346, standard error of the estimate (SEE) = 31.4 W, P = .021]), and only TLM to AWC (AWC = 0.8 [TLM] + 3.7 [r = .479, SEE = 2.2 kJ, P = .004]).

Conclusions: The aerobic component (CP) of the CP test was most closely related to LBM, and the anaerobic component (AWC) was more closely related to the TLM. These findings support the theory that CP and AWC are separate measures of whole-body metabolic capabilities and the energy stores in the activated local muscle groups, respectively. Thus, training programs to improve CP and AWC should be designed to include resistance-training exercises to increase whole-body LBM and local TLM.
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http://dx.doi.org/10.1123/ijspp.2016-0810DOI Listing
February 2018

Arterial hemodynamics are impaired at rest and following acute exercise in overweight young men.

Vasc Med 2016 12 28;21(6):497-505. Epub 2016 Sep 28.

Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA

Higher body mass index (BMI) is associated with greater cardiovascular disease (CVD) risk, in part due to aortic stiffening assessed by carotid-femoral pulse wave velocity (cfPWV). Importantly, greater cardiorespiratory fitness (CRF; VO) decreases CVD risk, and is associated with reductions in aortic stiffness. We tested the hypothesis that young adult overweight (OW, n=17) compared with healthy-weight (HW, n=17) men will have greater resting aortic stiffness, reduced CRF and an impaired post-exercise hemodynamic response. Resting cfPWV was greater in OW versus HW individuals (5.81 ± 0.13 vs 4.81 ± 0.12 m/sec, p<0.05). Relative CRF (VO; mL/kg/min) was lower in OW compared with HW individuals (49.4 ± 1.3 vs 57.6 ± 1.0 mL/kg/min, p<0.05), and was inversely related with cfPWV (p<0.05). However, CRF as absolute VO (L/min) was not different between groups and there was no relation between cfPWV and absolute VO (L/min), indicating reduced relative CRF in OW men is due to greater body mass. Following the maximal treadmill exercise test, cfPWV was greater in OW compared with HW subjects from rest to 60 minutes post-exercise (p<0.05). Compared with HW, OW individuals had higher systolic blood pressure (main effect, p<0.05) and diastolic blood pressure was selectively increased for up to 60 minutes following exercise (p<0.05). Overweight individuals had an attenuated post-exercise decrease in mean arterial pressure (p<0.05). Collectively, these results indicate that young, apparently healthy, OW men have greater resting aortic stiffening and an impaired post-exercise hemodynamic response.
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http://dx.doi.org/10.1177/1358863X16666692DOI Listing
December 2016

Body Composition and Bone Mineral Density in Patients With Heart Failure.

West J Nurs Res 2017 04 11;39(4):582-599. Epub 2016 Jul 11.

2 University of Kentucky College of Nursing, Lexington, KY, USA.

The purpose of this study was to examine associations among bone mineral density, osteopenia/osteoporosis, body mass index (BMI), and body composition in patients with heart failure (HF). A total of 119 patients (age = 61 ± 12 years, 65% male) underwent dual-energy X-ray absorptiometry scans to determine bone mineral density and body composition. In multivariable linear regressions, BMI, relative skeletal muscle index (RSMI), and mineral-free lean mass were positively associated with total body bone mineral density. Mineral-free lean mass was most strongly associated with bone mineral density (β = .398). In multivariable logistic regressions, higher BMI, RSMI, and mineral-free lean mass were associated with lower odds for osteopenia/osteoporosis. Fat mass was not associated with total body bone mineral density or osteopenia/osteoporosis. These results suggest that muscle mass may be the important component of body mass associated with bone mineral density in patients with HF.
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http://dx.doi.org/10.1177/0193945916658885DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5225244PMC
April 2017

Frontal plane kinematics of the hip during running: Are they related to hip anatomy and strength?

Gait Posture 2015 Oct 19;42(4):505-10. Epub 2015 Aug 19.

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA. Electronic address:

Excessive hip adduction has been associated with a number of lower extremity overuse running injuries. The excessive motion has been suggested to be the result of reduced strength of the hip abductor musculature. Hip anatomical alignment has been postulated to influence hip abduction (HABD) strength and thus may impact hip adduction during running. The purpose of this study was to investigate the relationship between hip anatomy, HABD strength, and frontal plane kinematics during running. Peak isometric HABD strength, 3D lower extremity kinematics during running, femoral neck-shaft angle (NSA), and pelvis width-femur length (PW-FL) ratio were recorded for 25 female subjects. Pearson correlations (p<0.05) were performed between variables. A fair relationship was observed between femoral NSA and HABD strength (r=-0.47, p=0.02) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and hip adduction during running. None of the anatomical measurements, NSA or PW-FL, were associated with hip adduction during running. Deviations in the femoral NSA have a limited ability to influence peak isometric hip abduction strength or frontal plane hip kinematics during running. Hip abduction strength does also not appear to be linked with changes in hip kinematics. These findings in healthy individuals question whether excessive hip adduction typically seen in female runners with overuse injuries is caused by deviations in hip abduction strength or anatomical structure.
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http://dx.doi.org/10.1016/j.gaitpost.2015.07.064DOI Listing
October 2015

Relationship of Physical Fitness Measures vs. Occupational Physical Ability in Campus Law Enforcement Officers.

J Strength Cond Res 2015 Aug;29(8):2340-50

1Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky; and 2School of Human Services, University of Cincinnati, Cincinnati, Ohio.

Law enforcement officers (LEOs) on university campuses are required to perform a variety of physical occupational tasks. Identifying which physical fitness characteristics are associated with these occupational tasks will assist in the development of appropriate exercise programs and physical fitness assessments. Therefore, the purpose of this study was to identify physical fitness and demographic characteristics that were correlated with occupational tasks commonly performed by campus LEOs. The occupational assessment was conducted using an Officer Physical Ability Test (OPAT), which simulated a foot chase of a suspect. Sixteen male LEOs (age: 33.1 ± 8.7 years; body mass: 87.2 ± 11.2 kg; height: 179.0 ± 7.9 cm) performed the OPAT. A battery of physical fitness tests were used to assess aerobic capacity, muscular endurance, strength, power, flexibility, agility, and body composition. Bivariate correlations were performed to identify significant (p ≤ 0.05) correlations between physical fitness characteristics and OPAT time. The officers' age was significantly correlated to the majority of OPAT tasks, physical fitness, and anthropometric assessments. Therefore, partial correlations were used to control for the confounding effects of age. After controlling for the officers' age, the overall OPAT time was significantly correlated with agility (r = 0.57) and aerobic endurance (r = -0.65). Furthermore, push-up, curl-up, body mass, waist circumference, and abdominal circumference were significantly correlated to individual OPAT tasks. In conclusion, exercise programs and fitness assessments should be used for campus LEOs that address a variety of physical fitness characteristics associated with occupational performance. In addition, exercise programs should focus on body composition management and fitness for older LEOs.
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http://dx.doi.org/10.1519/JSC.0000000000000863DOI Listing
August 2015

Physical activity, and not fat mass is a primary predictor of circadian parameters in young men.

Chronobiol Int 2015 23;32(6):832-41. Epub 2015 Jun 23.

Department of Kinesiology and Health Promotion and.

Circadian rhythms are ≈24 h oscillations in physiology and behavior, and disruptions have been shown to have negative effects on health. Wrist skin temperature has been used by several groups as a valid method of assessing circadian rhythms in humans. We tested the hypothesis that circadian temperature amplitude (TempAmp) and stability (TempStab) would significantly differ among groups of healthy young men of varying adiposities, and that we could identify physiological and behavioral measures that were significantly associated with these temperature parameters. Wrist skin temperatures taken at 10 min intervals for 7 consecutive days were determined in 18 optimal (OGroup), 20 fair (FGroup) and 21 poor (PGroup) %Fat grouped young men and subsequently analyzed using available validated software. Body composition, cardiorespiratory fitness, actigraphy, daily nutritional and sleep data, and fasting lipid, insulin and glucose concentration measures were also determined. Significant changes in TempAmp and TempStab parameters in subjects with a single metabolic syndrome (MetS) risk factor compared to those with no MetS factors was observed. In addition, stepwise multivariate regression analyses showed that 50% of the variance in TempAmp was explained by actigraphy (mean steps taken per day; MSTPD), cardiorespiratory fitness, and late night eating per week (#LNE); and 57% in TempStab by MSTPD, time spent in moderate-to-vigorous activity per day, fat mass, and #LNE. Overwhelmingly, physical activity was the most important measure associated with the differences in circadian rhythm parameters. Further research is warranted to determine the effects of increasing the amount and timing of physical activity on the status of the circadian system in a variety of populations.
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http://dx.doi.org/10.3109/07420528.2015.1043011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4550083PMC
April 2016

Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.

Neuroimage 2016 05 30;131:126-32. Epub 2015 May 30.

Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA; Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY 40536, USA. Electronic address:

A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness.
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http://dx.doi.org/10.1016/j.neuroimage.2015.05.063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5029275PMC
May 2016

The effect of a novel tactical training program on physical fitness and occupational performance in firefighters.

J Strength Cond Res 2015 Mar;29(3):578-88

1Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky; 2Athletic Training Education Program School of Human Services, University of Cincinnati, Cincinnati, Ohio; and 3Department of Gerontology, University of Kentucky, Lexington, Kentucky.

Structural firefighting is a dangerous and physically demanding profession. Thus, it is critical that firefighters exercise regularly to maintain optimal physical fitness levels. However, little is known about optimal training methods for firefighters, and exercise equipment is often not available to on-duty firefighters. Therefore, the purpose of this study was to determine the effect of a novel supervised on-duty physical training program on the physical fitness and occupational performance of structural firefighters. Twenty professional male firefighters were divided into a supervised exercise group (SEG; n = 11) and a control group (CG; n = 9). The SEG participated in a 12-week circuit training intervention. The SEG exercised for 1 hour on 2 d·wk. At baseline and after the intervention, subjects performed a battery of physical fitness tests and a simulated fire ground test (SFGT). At baseline, there were no significant differences (p = 0.822) in the completion rate of the SFGT in the SEG (82%) vs. the CG (78%). After the intervention, a significantly greater proportion of the firefighters in the SEG completed the SFGT compared with the CG (SEG = 100% vs. CG = 56%; p < 0.013). In addition, the SEG demonstrated significant improvements in body mass, fat mass, and body mass index (p ≤ 0.05). The findings of this study indicate that training with firefighter equipment improved occupational performance and anthropometric outcomes in incumbent firefighters. Furthermore, implementing a supervised exercise program using firefighter equipment can be done so in a safe and feasible manner.
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http://dx.doi.org/10.1519/JSC.0000000000000663DOI Listing
March 2015

Cardiorespiratory fitness is positively correlated with cerebral white matter integrity in healthy seniors.

Neuroimage 2012 Jan 19;59(2):1514-23. Epub 2011 Aug 19.

Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA.

High cardiorespiratory fitness (CRF) is an important protective factor reducing the risk of cardiac-related disability and mortality. Recent research suggests that high CRF also has protective effects on the brain's macrostructure and functional response. However, little is known about the potential relationship between CRF and the brain's white matter (WM) microstructure. This study explored the relationship between a comprehensive measure of CRF (VO(2) peak, total time on treadmill, and 1-minute heart rate recovery) and multiple diffusion tensor imaging measures of WM integrity. Participants were 26 healthy community dwelling seniors between the ages of 60 and 69 (mean=64.79 years, SD=2.8). Results indicated a positive correlation between comprehensive CRF and fractional anisotropy (FA) in a large portion of the corpus callosum. Both VO(2) peak and total time on treadmill contributed significantly to explaining the variance in mean FA in this region. The CRF-FA relationship observed in the corpus callosum was primarily characterized by a negative correlation between CRF and radial diffusivity in the absence of CRF correlations with either axial diffusivity or mean diffusivity. Tractography results demonstrated that portions of the corpus callosum associated with CRF primarily involved those interconnecting frontal regions associated with high-level motor planning. These results suggest that high CRF may attenuate age-related myelin declines in portions of the corpus callosum that interconnect homologous premotor cortex regions involved in motor planning.
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http://dx.doi.org/10.1016/j.neuroimage.2011.08.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3230672PMC
January 2012

A new BIA equation estimating the body composition of young children.

Obesity (Silver Spring) 2011 Sep 16;19(9):1813-7. Epub 2011 Jun 16.

Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky, USA.

Bioelectric impedance analyses (BIA) provides a valid and reliable measure of body composition in field, clinical, and research settings if standard protocol procedures are followed, and population-specific equations are available and utilized. The objective of this study was to create and cross-validate a new BIA body composition equation with representative healthy weight (HW), overweight (OW), and obese (OB) young children. Participants were 436 children who were 5-11 years of age. Dual-energy absorptiometry fat-free mass (FFM) was used as the criterion measure and a single frequency tetra-polar BIA device was used to create the new BIA equation. The new BIA equation explained 95.2% of the variance in FFM with no statistical shrinkage upon cross-validation. The use of this equation may help to identify effective intervention strategies to prevent or combat childhood obesity, and may assist in additional conditions or treatments where information concerning body composition measures would provide greater accuracy and sensitivity measures for preventing or combating disease.
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http://dx.doi.org/10.1038/oby.2011.158DOI Listing
September 2011

The assessment of physical activity and nutrition in home schooled versus public schooled children.

Pediatr Exerc Sci 2010 Feb;22(1):44-59

Dept. of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40536-0219, USA.

The purpose of this study was to descriptively compare the physical activity and dietary intake of public school (PSC) versus home schooled children (HSC). Potential parental and home influences were also examined. Thirty six matched pairs of public school-home school children aged 7-11 years participated in this study. Each participant wore an activity monitor and recorded their dietary intake concurrently for seven consecutive days. PSC had significantly more total and weekday steps, and spent more time in moderate-to-vigorous physical activity compared with HSC. There were no differences in dietary intake between the two groups. These results suggest differences in physical activity between PSC and HSC and encourage further study of public and home school environments, in relation to the obesity epidemic.
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http://dx.doi.org/10.1123/pes.22.1.44DOI Listing
February 2010

The relation between mild leg-length inequality and able-bodied gait asymmetry.

J Sports Sci Med 2010 1;9(4):572-9. Epub 2010 Dec 1.

Department of Exercise Sciences, Brigham Young University.

The causes of able-bodied gait asymmetries are unclear. Mild (< 3 cm) leg-length inequality (LLI) may be one cause of these asymmetries; however, this idea has not been thoroughly investigated. The purpose of this study was to investigate the nature of the relationship between LLI and able-bodied gait asymmetries. We hypothesized that subjects (n = 26) with relatively large LLI, quantified radiographically, would display less symmetrical gait than subjects with relatively small LLI. Gait asymmetries for joint kinematics and joint kinetics were determined using standard gait analysis procedures. Symmetry coefficients were used to quantify bilateral gait symmetry for sagittal-plane hip, knee, and ankle joint angles, moments, and powers. A Pearson product-moment correlation coefficient (r) was used to evaluate the relationship between LLI and the aforementioned symmetry coefficients. Also, these symmetry coefficients were compared between subjects with relatively small LLI (LLI < 1 cm; n = 19) and relatively large LLI (LLI ≥ 1 cm; n = 7). Statistically significant relationships were observed between LLI and the symmetry coefficient for knee joint moment (r = -0.48) and power (r = -0.51), and ankle joint moment (r = -0.41) and power (r = -0.42). Similarly, subjects with relatively large LLI exhibited significantly lower symmetry coefficients for knee joint moment (p = 0.40) and power (p = 0.35), and ankle joint moment (p = 0.40) and power (p = 0.22) than subjects with relatively small LLI. Degree of bilateral symmetry for knee and ankle joint kinetics appears to be related to LLI in able- bodied gait. This finding supports the idea that LLI is one cause of able-bodied gait asymmetries. Other factors, however, are also likely to contribute to these gait asymmetries; these may include other morphological asymmetries as well as asymmetrical neuromuscular input to the lower limb muscles. Key pointsModerate negative relationships were observed between mild limb-length inequality and gait symmetry for knee and ankle moment and power.Subjects with relatively large mild limb-length inequality (between 1.0 and 2.3 cm) exhibited significantly less symmetrical gait for knee and ankle joint moment and power than subjects with relatively small mild limb-length inequality (< 1 cm).These results indicate that the degree of symmetry for knee and ankle joint kinetics appears to be related to mild limb-length inequality in able-bodied gait.These results further our understanding of normal human walking and provide important background information for future studies on gait pathology associated with mild limb-length inequality.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761822PMC
October 2013

Glucagon-like peptide 1 and pancreatic polypeptide responses to feeding in normal weight and overweight children.

J Pediatr Endocrinol Metab 2009 Jun;22(6):493-500

Department of Pediatrics, University of Kentucky, Lexington, KY, USA.

Background: Glucagon-like peptide 1 (GLP-1) and pancreatic polypeptide (PP) are intestinal hormones that are involved in the post-prandial satiety response. We sought to assess meal-related changes in these hormones in young children and determine whether differences exist between normal weight (NW) and overweight (OW) children.

Methods: Seven to 11-year-old healthy NW (n=20) and OW (n=12) volunteers were given a standardized breakfast and lunch following an overnight fast and had measurements of GLP-1 and PP over 9 hours. We characterized whether GLP-1 and PP changed from the pre-prandial to the post-prandial state and whether the serum levels corresponded to reported appetite.

Results: GLP-1 did not increase after eating, did not decline prior to the next meal, and did not correspond to satiety ratings in either group. PP increased post-prandially in OW children after both breakfast and lunch, but in the NW group PP only increased after breakfast. PP levels did not decline in either group as the next meal approached.

Conclusions: In our study of school-age children, feeding had little effect on GLP-1 secretion and a variable effect on serum PP levels. Observed differences in the GLP-1 and PP responses between the NW and OW groups do not suggest there is an intrinsic abnormality in their secretion that causes weight gain.
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http://dx.doi.org/10.1515/jpem.2009.22.6.493DOI Listing
June 2009

Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial.

Ann Intern Med 2008 Nov;149(9):601-11

University of Virginia, Charlottesville, Virginia 22908, USA.

Background: Growth hormone secretion and muscle mass decline from midpuberty throughout life, culminating in sarcopenia, frailty, decreased function, and loss of independence. The decline of growth hormone in the development of sarcopenia is one of many factors, and its etiologic role needs to be demonstrated.

Objective: To determine whether MK-677, an oral ghrelin mimetic, increases growth hormone secretion into the young-adult range without serious adverse effects, prevents the decline of fat-free mass, and decreases abdominal visceral fat in healthy older adults.

Design: 2-year, double-blind, randomized, placebo-controlled, modified-crossover clinical trial.

Setting: General clinical research center study performed at a university hospital.

Participants: 65 healthy adults (men, women receiving hormone replacement therapy, and women not receiving hormone replacement therapy) ranging from 60 to 81 years of age.

Intervention: Oral administration of MK-677, 25 mg, or placebo once daily.

Measurements: Growth hormone and insulin-like growth factor I levels. Fat-free mass and abdominal visceral fat were the primary end points after 1 year of treatment. Other end points were body weight, fat mass, insulin sensitivity, lipid and cortisol levels, bone mineral density, limb lean and fat mass, isokinetic strength, function, and quality of life. All end points were assessed at baseline and every 6 months.

Results: Daily administration of MK-677 significantly increased growth hormone and insulin-like growth factor I levels to those of healthy young adults without serious adverse effects. Mean fat-free mass decreased in the placebo group but increased in the MK-677 group (change, -0.5 kg [95% CI, -1.1 to 0.2 kg] vs. 1.1 kg [CI, 0.7 to 1.5 kg], respectively; P < 0.001), as did body cell mass, as reflected by intracellular water (change, -1.0 kg [CI, -2.1 to 0.2 kg] vs. 0.8 kg [CI, -0.1 to 1.6 kg], respectively; P = 0.021). No significant differences were observed in abdominal visceral fat or total fat mass; however, the average increase in limb fat was greater in the MK-677 group than the placebo group (1.1 kg vs. 0.24 kg; P = 0.001). Body weight increased 0.8 kg (CI, -0.3 to 1.8 kg) in the placebo group and 2.7 kg (CI, 2.0 to 3.5 kg) in the MK-677 group (P = 0.003). Fasting blood glucose level increased an average of 0.3 mmol/L (5 mg/dL) in the MK-677 group (P = 0.015), and insulin sensitivity decreased. The most frequent side effects were an increase in appetite that subsided in a few months and transient, mild lower-extremity edema and muscle pain. Low-density lipoprotein cholesterol levels decreased in the MK-677 group relative to baseline values (change, -0.14 mmol/L [CI, -0.27 to -0.01 mmol/L]; -5.4 mg/dL [CI, -10.4 to -0.4 mg/dL]; P = 0.026); no differences between groups were observed in total or high-density lipoprotein cholesterol levels. Cortisol levels increased 47 nmol/L (CI, 28 to 71 nmol/L (1.7 microg/dL [CI, 1.0 to 2.6 microg/dL]) in MK-677 recipients (P = 0.020). Changes in bone mineral density consistent with increased bone remodeling occurred in MK-677 recipients. Increased fat-free mass did not result in changes in strength or function. Two-year exploratory analyses confirmed the 1-year results.

Limitation: Study power (duration and participant number) was insufficient to evaluate functional end points in healthy elderly persons.

Conclusion: Over 12 months, the ghrelin mimetic MK-677 enhanced pulsatile growth hormone secretion, significantly increased fat-free mass, and was generally well tolerated. Long-term functional and, ultimately, pharmacoeconomic, studies in elderly persons are indicated.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2757071PMC
http://dx.doi.org/10.7326/0003-4819-149-9-200811040-00003DOI Listing
November 2008

Meal-related changes in ghrelin, peptide YY, and appetite in normal weight and overweight children.

Obesity (Silver Spring) 2008 Mar 24;16(3):547-52. Epub 2008 Jan 24.

Department of Pediatrics, Division of Endocrinology, University of Kentucky, Lexington, KY, USA.

Objective: Ghrelin and peptide YY (PYY) are two gut hormones that have effects on appetite. Our objectives were to characterize the patterns of secretion of these hormones in response to feeding in school-age children and determine whether there were differences between normal weight (NW) and overweight (OW) subjects.

Methods And Procedures: This was a cross-sectional study at one tertiary care center. Subjects were 7- to 11-year-old healthy NW and OW volunteers recruited from local advertisements. Following an overnight fast, the subjects were given a standardized breakfast and lunch and had nine hourly blood samples for total ghrelin and total PYY. We assessed whether ghrelin and PYY levels changed from the preprandial to postprandial state and corresponded to reported hunger/satiety.

Results: Hunger ratings were similar between the two groups throughout the study period. Ghrelin was not suppressed after eating, did not rise prior to the next meal, and did not correspond to hunger ratings in either group. PYY increased postprandially and decreased preprandially in the NW group, but OW children exhibited this pattern for only part of the day. PYY levels incompletely corresponded to reported satiety in the OW group.

Discussion: Mixed meal consumption had little effect on ghrelin secretion and a variable effect on PYY secretion in young children in our study. Differences that were observed between the groups do not suggest that an abnormality in their secretion contributes to the development of obesity.
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http://dx.doi.org/10.1038/oby.2007.129DOI Listing
March 2008

A comparison of hydrostatic weighing and air displacement plethysmography in adults with spinal cord injury.

Arch Phys Med Rehabil 2005 Nov;86(11):2106-13

Department of Kinesiology and Health Promotion, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40506-0219, USA.

Objectives: To compare (1) total body volume (V(b)) and density (D(b)) measurements obtained by hydrostatic weighing (HW) and air displacement plethysmography (ADP) in adults with spinal cord injury (SCI); (2) measured and predicted thoracic gas volume (V(TG)); and (3) differences in percentage of fat measurements using ADP-obtained D(b) and HW-obtained D(b) measures that were interchanged in a 4-compartment body composition model (4-comp %fat).

Design: Twenty adults with SCI underwent ADP and V(TG), and HW testing. In a subgroup (n=13) of subjects, 4-comp %fat procedures were computed.

Setting: Research laboratories in a university setting.

Participants: Twenty adults with SCI below the T3 vertebrae and motor complete paraplegia.

Interventions: Not applicable.

Main Outcome Measures: Statistical analyses, including determination of group mean differences, shared variance, total error, and 95% confidence intervals.

Results: The 2 methods yielded small yet significantly different V(b) and D(b). The groups' mean V(TG) did not differ significantly, but the large relative differences indicated an unacceptable amount of individual error. When the 4-comp %fat measurements were compared, there was a trend toward significant differences (P=.08).

Conclusions: ADP is a valid alternative method of determining the V(b) and D(b) in adults with SCI; however, the predicted V(TG) should be used with caution.
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http://dx.doi.org/10.1016/j.apmr.2005.06.013DOI Listing
November 2005
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