Browsing by Author "Wingo, Jonathan E."

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    Acute Effect of Lower-Body Vibration as a Recovery Method After Fatiguing Exercise
    Nepocatych, Svetlana; Balilionis, Gytis; Katica, Charlie P.; Wingo, Jonathan E.; Bishop, Philip A.; University of Alabama Tuscaloosa
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    Anxiety and affective responses to acute bouts of moderate intensity exercise (walking): effects of varying durations
    (University of Alabama Libraries, 2015) Geary, Colleen Louise; Richardson, Mark T.; University of Alabama Tuscaloosa
    Anxiety affects approximately 40 million American adults each year (Kessler, Chiu, Demler, and Walters, 2005; National Institute of Mental Health [NIMH], 2009). However, the dose-response research investigating the antianxiety and affective benefits of acute bouts of exercise indicates that multiple dose-response issues remain unresolved. The purpose of this study was to investigate the anxiolytic and affective responses following an acute bout of moderate intensity walking of different durations (30, 10 and 5 minutes) on a moderately fit, non-clinically anxious population. This study also sought to test the duration of effect by assessing post-exercise responses immediately and at 20 and 40 minutes post-exercise. This is the first study to include the analysis of four specific covariates (trait anxiety, fitness level, enjoyment of activity, and sex) when examining psychological responses to walking. One of the main findings of the current investigation was that a main effect of time was observed for the majority of variables. While some measures showed favorable (anxiety, tense arousal, calmness, tension, tranquility, physical exhaustion, affective valence, and revitalization) other measures ultimately showed unfavorable (positive affect, perceived activation, energetic arousal, energy, and positive engagement) responses following the cessation of exercise. Secondly, although several measures were affected by exercise duration (tranquility, physical exhaustion, and affective valence), the majority were not. Finally, of the four covariates, only fitness (positive affect, energetic arousal, and energy) and sex (positive affect, revitalization, energy, and calmness) influenced the exercise-affect relationship.
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    Barriers to exercise/physical activity for adolescents in rural west Alabama
    (University of Alabama Libraries, 2016) Cox, Melissa; Richardson, Mark T.; University of Alabama Tuscaloosa
    Regular physical activity (PA) in childhood and adolescence improves strength and endurance, helps build healthy bones and muscles, helps control weight, reduces anxiety and stress, increases self-esteem, and may improve blood pressure and cholesterol levels. The American College of Sports Medicine (ACSM) shows PA trends among adolescents (defined as 13 – 18 yrs.) decrease such that the majority of adolescents are not participating in sufficient activity to meet recommended guidelines. Cardiovascular Disease (CVD) risk factors that are present in adolescence have a tendency to track into adulthood. Youth who are overweight tend to have a higher prevalence of CVD risk factors than their normal weight peers. Rural adolescents may not be engaging in PA as often as their urban counterparts due to barriers of their rural lifestyle. Many rural communities are characterized by vast distances, low socioeconomic status, transportation challenges, and low public funding levels for facilities, programs, and other public amenities. Rural residency, especially in the southern U.S. has been associated with low levels of PA. The rural population is very unique in that they have specific barriers to PA. These may be social, financial, transportation, personal (i.e. lack of time, resources, caregiver responsibilities) or environmental factors (i.e., transportation, inadequate programs, lack of facilities). The purpose of this study was to extend previous findings by surveying a large sample of rural Alabama adolescents regarding barriers to PA and surveying parents and school administrators in this regard as well. Also, this study evaluated the effect that age, race/ethnicity, gender, and SES have on barriers to PA. This study did indeed demonstrate several demographic differences concerning barriers to PA. Additionally, it demonstrated several differences between students, parents, and administrators regarding perceived barriers to PA. Finally, this study provided additional data concerning common barriers to PA reported in the literature. Gender and SES differences were found to be the two covariates that were barriers to exercise and PA in rural West Alabama adolescents.
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    Beverage choice impact on hydration and performance for the recreational athlete
    (University of Alabama Libraries, 2010) O'Neal, Eric Kyle; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Three studies examined hydration and performance for recreational exercisers (REC). Three beverages (flavored caloric (CE) and non-caloric (NCE) electrolyte-containing sport drinks and water (W)) were served to male (n = 24) and female (n = 14) REC in a counter-balanced order during 1-h of moderate intensity cycling (mean ± SD heart rate = 146 ± 4 beats/min) in an environment of 25° C wet bulb globe temperature. The volume of beverage served was equal to sweat loss measured (mean ± SE = 834 ± 59 mL) in a familiarization trial with no fluid intake during exercise. No differences (p > .05) among beverages were found in: performance (peak and mean power) during a set of three Wingate Anaerobic Tests completed after cycling, perceived exertion, or mood states among beverages. After exercise in the familiarization trial with no fluid intake, participants drank ad libitum for 30 min with all beverages available. Consumption volume among beverages did not differ (p > .05). Participants reported that replacing 100% of sweat loss was an appropriate volume and did not result in stomach discomfort for the majority of individuals in fluid intake during exercise sessions. Total intake in the familiarization session when fluids were consumed in recovery only (mean ± SD, 971 ± 375 mL) was less (p < .001) than when consumed during both exercise and recovery (W (1,415 ± 560 mL,), NCE (1,244 ± 538 mL, p < .001), and CE (1,196 ± 444 mL), and W was greater than CE (p = .01)). The survey found decreased performance (69%) and heat-illness (45%) believed to be related to dehydration among runners was very common. Almost all (94%) of participants (n = 276) reported drinking during outdoor runs in warm weather. Faster higher volume runners believed that consuming sport beverages would result in improved performance and better hydration than water. For REC exercising for ~1 h, replacing sweat loss during exercise and drinking ad libitum afterwards, should result in a fluid intake level that will return body mass close to pre-exercise level, be tolerable, and result in no decrease in performance when W or CE are used instead of CE.
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    Cardiovascular and themoregulatory responses to ice slurry ingestion during heat stress
    (University of Alabama Libraries, 2015) Ng, Jason; Wingo, Jonathan E.; University of Alabama Tuscaloosa
    Fluid ingestion has been reported to influence cardiovascular and thermoregulatory function, thereby affecting exercise performance. It remains unclear whether ice slurry ingestion during exercise results in similar effects. Three experiments examined thermal-, cardiovascular-, and exercise-related responses to ice slurry ingestion. In the first study, participants in firefighter protective clothing walked at ~7 METs in 35 °C while ingesting carbohydrate-electrolyte beverages as a tepid fluid, cold fluid, and ice slurry in a counterbalanced repeated measures study design. When ingested in large quantities and during uncompensable heat stress, ice slurry ingestion mitigated physiological strain by attenuating the rise in heart rate and rectal temperature. In a second study, cardiovascular drift (CV drift) was measured during 45 min of cycling at 60% maximal oxygen uptake (V̇O2max) in 35 °C, immediately followed by measurement of V̇O2max. Participants ingested fluid and ice slurry during two counterbalanced trials of exercise. CV drift was attenuated with ice slurry ingestion but V̇O2max was unaffected. In a third study, participants ingested ice slurry or cold fluid ad libitum while cycling at 50% maximal workload in 35 °C, immediately followed by a 15-min time trial during which participants completed as much work as possible. Compared to the fluid treatment, participants consumed half as much ice slurry, but total work completed during the time trial was not different. In conclusion, ice slurry ingestion blunts physiological strain during conditions in which evaporative heat loss is impaired, such as when wearing occlusive coverings. Furthermore, ice slurry ingestion attenuates the magnitude of CV drift during exercise in the heat, but this does not blunt the decrease in V̇O2max associated with exercise in hot conditions. Lastly, a smaller quantity of ice slurry is voluntarily ingested compared to cold fluid during prolonged submaximal exercise in the heat, but this does not differentially affect exercise performance.
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    Cardiovascular drift and maximal oxygen uptake during heat stress in women
    (University of Alabama Libraries, 2019) Stone, Tori; Wingo, Jonathan E.; University of Alabama Tuscaloosa
    During prolonged constant-rate exercise, heart rate and stroke volume progressively increase and decrease, respectively, characterizing cardiovascular (CV) drift. CV drift is greater when driven by hyperthermia and generally results in proportional decreases in maximal oxygen uptake (V̇O2max). Less is known about CV drift and decrements in V̇O2max in women because nearly all studies on this topic focused on men. This dissertation determined the effects of hormonal status, fitness level, and sudomotor function on CV drift and V̇O2max in women. In 3 separate studies, CV drift was measured during 45 min of cycling in 35 °C, immediately followed by measurement of V̇O2max. V̇O2max also was measured after 15 min in a separate trial to assess changes in V̇O2max over the same time interval that CV drift occurred. Study 1 compared follicular (FP) and luteal phases (LP) of the menstrual cycle during exercise at 60% V̇O2max. Resting and exercise core temperatures (Tre) were higher in LP, but increases during exercise (ΔTre) were similar to FP, so the CV drift/V̇O2max relationship was not modulated by phase. Study 2 compared high-fit (HI) and low-fit (LO) women during exercise at 60% V̇O2max (REL) and 500 W of metabolic heat production (FIXED). During REL, heat production and ΔTre were significantly greater in HI versus LO, as were magnitudes of CV drift and decrements in V̇O2max. During FIXED, heat production, ΔTre, CV drift, and V̇O2max were similar between groups. Study 3 compared women to men during exercise at 500 W of metabolic heat production. For women, sweating plateaued and accelerated ΔTre compared to men, but differences in CV drift and V̇O2max were not statistically discernible between sexes. In conclusion, the relationship between CV drift and V̇O2max during heat stress does not change across the menstrual cycle and is not affected by fitness level, independent of metabolic heat production. The relationship is similar between men and women during 45 min of exercise at the same, relatively high load.
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    Cardiovascular Drift is Related to Reduced Maximal Oxygen Uptake During Heat Stress
    Wingo, Jonathan E.; Lafrenz, Andrew J.; Ganio, Matthew S.; Edwards, Gaylen L.; Cureton, Kirk J.; University of Alabama Tuscaloosa
    Introduction/Purpose: This study investigated whether the progressive rise in heart rate (HR) and fall in stroke volume (SV) during prolonged, constant-rate, moderate-intensity exercise (cardiovascular drift, CVdrift) in a hot environment is associated with a reduction in VO2max. Methods: CVdrift was measured in nine male cyclists between 15 and 45 min of cycling at 60% VO2max in 35degreesC that was immediately followed by measurement of VO2max. VO2max also was measured after 15 min of cycling on a separate day, so that any change in VO2max between 15 and 45 min could be associated with the CVdrift that occurred during that time interval. This protocol was performed under one condition in which fluid was ingested and there was no significant body weight change (0.3 +/- 0.4%), and under another in which no fluid was ingested and dehydration occurred (2.5 +/- 1%, P < 0.05). Results: Fluid ingestion did not affect CVdrift or change in VO2max. A 12% increase in HR (151 +/- 9 vs 169 +/- 10 bpm, P < 0.05) and 16% decrease in SV (120 +/- 12 vs 101 +/- 10 mL(.)beat(-1), P < 0.05) between 15 and 45 min was accompanied by a 19% decrease in VO2max (4.4 +/- 0.6 vs 3.6 +/- 0.4 L(.)min(-1), P < 0.05) despite attainment of a higher maximal HR (P < 0.05) at 45 min (194 +/- 5 bpm) vs 15 min (191 +/- 5 bpm). Submaximal VO2 increased only slightly over time, but %VO2max increased from 63 +/- 5% at 15 min to 78 +/- 8% at 45 min (P < 0.05). Conclusion: We conclude CVdrift during 45 min of exercise in the heat is associated with decreased VO2max and increased relative metabolic intensity. The results support the validity of using changes in HR to reflect changes in relative metabolic intensity during prolonged exercise in a hot environment in which CVdrift occurs.
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    Clothing fabric effects on physiological and comfort responses
    (University of Alabama Libraries, 2011) Balilionis, Gytis; Bishop, Phillip A.; University of Alabama Tuscaloosa
    During exercise and in hot environments, the main cooling mechanism is through sweat evaporation. However, clothing can disrupt evaporation, which leads to decreased performance and in some cases can lead to heat illness. New fabrics and designs have been introduced with the purpose of improving thermoregulatory properties. One of those innovations is a channeled synthetic fabric. The first of three studies evaluated the effects of a channeled synthetic and synthetic t-shirts under a ballistic vest on physiological and comfort responses during exercise in a hot environment. Eight participants, in counterbalanced order, completed two simulated "industrial" protocols for three hours. The overall (0 - 180 min) change in rectal temperature was significantly (p = 0.04) lower with channeled synthetic shirt compared to a synthetic shirt. Additionally, overall change in thermal comfort (p = 0.05), sweating sensation (p = 0.06), and heart rate (p = 0.07) were, or tended to be more favorable throughout exercise with channeled synthetic compared to synthetic shirt. We also examined the effects of channeled synthetic shirt and synthetic cycling shirt effects on thermoregulation, thermal comfort, and heart rate. Eight participants attempted a 30-km cycling time trial. Results indicated significantly (p = 0.04, n = 8) smaller increase in rectal temperature from baseline to 15th km (first dropout) with the channeled synthetic shirt compared to cycling shirt. Also, the change in thermal comfort was significantly (n = 5, p = 0.03) lower with channeled shirt compared to cycling shirt from baseline to 30th km. A third study examined channeled compression shorts, compression shorts, and cycling shorts effects on thermoregulation, heart rate, and thermal comfort response during 30-km cycling trial in hot a environment. Eight participants completed a 25-km cycling trial. Results revealed no significant main effect for rectal or skin temperatures, heart rate, and thermal comfort between the three different types of shorts (n = 8, p > 0.05). In conclusion, wearing a channeled synthetic shirt provided better thermoregulatory or thermal comfort responses compared to synthetic shirt in two studies. Channeled compression shorts did not improve thermoregulatory or thermal comfort responses compared to cycling and compression shorts.
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    Combined Facial Heating and Inhalation of Hot Air Do Not Alter Thermoeffector Responses in Humans
    Wingo, Jonathan E.; Low, David A.; Keller, David M.; Kimura, Kenichi; Crandall, Craig G.; University of Alabama Tuscaloosa
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    Consensus Recommendations on Training and Competing in the Heat
    Racinais, Sebastian; Alonso, Juan-Manuel; Coutts, Aaron J.; Flouris, Andreas D.; Girard, Olivier; González-Alonso, Jose; Hausswirth, Christophe; Jay, Ollie; Lee, Jason K. W.; Mitchell, Nigel; Nassis, George P.; Nybo, Lars; Pluim, Babette M.; Roelands, Bart; Sawka, Mike N.; Wingo, Jonathan E.; Périard, Julien D.; University of Alabama Tuscaloosa
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    Effect of elevated local temperature on cutaneous vasoconstrictor responsiveness in humans
    (American Physiological Society, 2009-02-01) Wingo, Jonathan E.; Low, David A.; Keller, David M.; Brothers, R. Matthew; Shibasaki, Manabu; Crandall, Craig G.; University of Texas System; University of Texas Southwestern Medical Center Dallas; Nara Womens University; University of Alabama Tuscaloosa
    Wingo JE, Low DA, Keller DM, Brothers RM, Shibasaki M, Crandall CG. Effect of elevated local temperature on cutaneous vasoconstrictor responsiveness in humans. J Appl Physiol 106: 571-575, 2009. First published December 4, 2008; doi: 10.1152/japplphysiol.91249.2008.-Cutaneous vascular conductance (CVC) increases in response to local skin heating. Although attenuation of vasoconstrictor responsiveness due to local heating has been demonstrated, the mechanism(s) responsible for this attenuation remains unclear. Nitric oxide has been shown to at least partially contribute to this response, but other mechanisms also may be involved. The purpose of this study was to test the hypothesis that local heating diminishes cutaneous vasoconstrictor responsiveness through a nitric oxide-independent mechanism by altering postsynaptic reactivity to norepinephrine. A follow-up protocol tested the hypothesis that local heating attenuates the presynaptic release of neurotransmitters that cause vasoconstriction, also via non-nitric oxide mechanisms. In protocol I, CVC was assessed in eight subjects during administration of increasing doses of norepinephrine (via intradermal microdialysis) at adjacent sites separately heated to 34 degrees C and 40 degrees C. In protocol II, which was identical to, but separate from, protocol I, CVC was assessed in seven subjects during administration of increasing doses of tyramine, which causes release of neurotransmitters from adrenergic nerves. At each site for both protocols, nitric oxide synthesis was inhibited (via microdialysis administration of N-G-nitro-L-arginine methyl ester) and flow was matched (via microdialysis administration of adenosine); therefore, temperature was the only variable that differed between the sites. For both protocols, nonlinear regression analysis revealed no difference (P > 0.05) in the effective drug concentration causing 50% of the vasoconstrictor response. Minimum CVC [6.3 +/- 2.0 and 9.0 +/- 4.0% of peak CVC (mean +/- SD) for protocol 1 and 19.3 +/- 9.3 and 20.5 +/- 11.9% of peak CVC for protocol II at 34 degrees C and 40 degrees C sites, respectively] was not different between sites. Independent of nitric oxide, local skin heating to 40 degrees C does not attenuate adrenergically mediated cutaneous vasoconstriction through pre- or postsynaptic mechanisms.
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    Effect of intermittent cooling on baseball pitching and catching
    (University of Alabama Libraries, 2012) Bishop, Stacy Howard; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Cryotherapy has been shown to be an effective method for reducing edema and inflammation, decreasing pain in acute injury, and is being studied as an aid in recovery. The traditional recovery treatment between innings for pitchers and catchers is to rest in the dugout. In this study, pitchers (n = 8) threw two simulated games separated by 5-7 days for recovery. Participants were given 4 min of intermittent arm and shoulder cooling treatment (AC) or no cooling (NC) in between each of 5-simulated innings. Pitchers that received NC had a significant decrease in velocity over the 5 innings (4%); by contrast, pitchers that received AC maintained pitching velocity (p = 0.04) (all-innings mean velocity 31.2 ± 2.1 m*s−1 versus 30.6 ± 2.2 m*s−1). Average pitch speed in the 4th inning and 5th inning was significantly faster for AC (31.3 ± 2 m*s−1 and 31.3 ± 2 m*s−1) compared to NC (30 ± 2 m*s−1 and 30.4 ± 2 m*s−1, p= 0.04), respectively. Additionally, AC resulted in significantly lower perceived exertion (RPE) (p = 0.01) and improved perceived recovery (PRS) (p = 0.01) compared to NC in a temperate environment. In catchers (n = 6), torso cooling (TC) resulted in a significantly lower RPE (p = 0.01) and improved PRS (p = 0.01) compared to NC. Significantly lower mean recovery HR was seen during the TC treatment compared to NC in the 5th (84 ± 8 vs. 90 ± 9 bpm, p = 0.04), 7th (84 ± 3 vs. 92 ±7 bpm, p = 0.02), and 9th (85 ± 7 vs. 93 ± 5 bpm, p = 0.01) innings. Increase in rectal temperature was smaller in TC compared to NC (0.58 ± 0.20 ºC vs. 0.98 ± 0.20 ºC, p = 0.01). Working HR was significantly lower at the end of the TC when compared to NC (108 ± 16 vs. 120 ± 19 bpm, p = 0.02). Cryotherapy improved recovery during baseball pitching and catching, attenuated a decrease in pitching velocity as well as attenuated core temperature increases in catchers.
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    Effect of whole-body vibration on acute recovery after fatiguing exercise
    (University of Alabama Libraries, 2011) Nepocatych, Svetlana; Bishop, Phillip A.; University of Alabama Tuscaloosa
    High-intensity intermittent or resistance activity for a short period of time causes an increased break down of energy stores and accumulation of metabolic by-products. Increased metabolic disturbances may lead to decreased muscle contractile function which eventually will lead to muscle fatigue. Sufficient recovery time is needed for optimal competitive performance and optimizing the ability to tolerate high-intensity, various lengths and duration training loads. There are a number of recovery modalities available that have been used between training sessions, pre- and post- training, and between competitions. In order to evaluate vibration as a recovery aid that contributes to improved performance, three studies were conducted. The first study evaluated the effects of whole-body vibration (WBV) and WBV plus cooling on lower-body peak and mean anaerobic performance, leg volume, perceived recovery, and muscle soreness. The second study evaluated the effects of WBV and upper-body vibration (UBV) on upper-body performance, perceived recovery and muscle soreness, and the third study evaluated the effect of WBV on sprint performance, leg volume and perceived recovery. Healthy and physically active male and female volunteers participated in the studies. In a repeated measures, counterbalanced design, participants completed fatiguing exercise, each recovery treatment and performance test. As indicated by the group mean data, results of the first study suggested possible psychological but not performance enhancing benefits after the use of WBV and WBVC as a recovery method. The findings of the second study suggest no psychological or physiological benefits using WBV and UBV as a recovery modality. The results of the third study suggest no benefits for WBV in enhancing recovery or sprint performance. However, while actual recovery was not enhanced, perceived recovery was better after WBV compared to no vibration. Even though actual recovery or performance was not enhanced by the addition of WBV to the recovery, psychological perception of better recovery may be of some benefit for training or competition. It appears that acute exposure to WBV does not enhance performance under the conditions of this study.
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    Effect of Work-To-Rest Cycles on Cardiovascular Drift and Maximal Oxygen Uptake During Heat Stress
    (University of Alabama Libraries, 2020) Mulholland, Anne; Wingo, Jonathan E.; University of Alabama Tuscaloosa
    Cardiovascular (CV) strain, indexed as CV drift—a progressive increase in heart rate (HR) and decrease in stroke volume (SV) during prolonged exercise—is exacerbated by environmental heat stress and is accompanied by a decrease in maximal work capacity (V?O2max). To attenuate CV strain, work:rest ratios have been recommended by the National Institute for Occupational Safety and Health (NIOSH). Whether these guidelines sufficiently mitigate CV drift and preserve V?O2max is unknown. PURPOSE: To test the hypothesis that during moderate work (201-300 kcal/h) in hot conditions [indoor wet-bulb globe temperature (WBGTin)=29 °C] utilizing the recommended 45:15 work:rest ratio, CV drift will ‘accumulate’ over time, and the magnitude of accumulated CV drift will be proportional to decrements in V?O2max after 120 min. METHODS: Eight subjects [5 women; (mean±SD) age=25±5 y; body mass=74.8±11.6 kg; V?O2max=42.9±5.6 mL/kg/min] completed 3 sessions on different days. The first visit involved measurement of V?O2max (WBGTin=18.1±1.2 °C). The following 2 experimental trials were counterbalanced (WBGTin=29.0±0.6 °C). Moderate work was achieved by 2.5 min of arm curls (4.5 kg at 20/min) and 20 min of walking (V?O2=1.0–1.1 L/min) on a treadmill, repeated once for a total of 45 min of work, and then followed by 15 min of seated rest. HR and SV were measured at 15 and 45 min of each work bout to evaluate CV drift. The 120-min trial consisted of 2 full work-rest cycles followed by measurement of V?O2max; the 15-min trial replicated the first 15 min of the 120-min visit followed by measurement of V?O2max and was necessary to measure V?O2max before CV drift occurred. RESULTS: CV drift accumulated between 15 and 105 min: HR increased 16.7% (18±9 bpm, P=0.004) and SV decreased 16.9% (-12.3±5.9 mL, P=0.003), but V?O2max was not affected after 2 full work-rest cycles (P=0.14). Core body temperature increased by 0.5±0.2 °C (P=0.006) over 2 h. CONCLUSION: Although CV drift occurred after two 45:15 work:rest cycles, V?O2max was unaffected. Work capacity is preserved during 2 hours of work in the heat with rest cycles patterned like those in this study, but CV and thermal strain persist unabated.
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    Effects of bunker gear temperature and different work rates on micro-E and heat stress
    (University of Alabama Libraries, 2015) Hornsby, Jared Heath; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Wearing protective clothing (PC) such as firefighter bunker gear leads to increased heat strain. Bunker gear has multiple layers which creates a heat sink during the first several minutes after donning, potentially providing some amount of cooling of the micro-environment (micro-E) around the skin. Furthermore, predicting heat strain at various work rates while wearing PC is important for determining work tolerance limits. The purpose of these studies was to determine the effect of a COLD (< 0 °C) bunker gear on rectal temperature (T_re ) and micro-E at a steady-state exercise intensity and to begin creating a regression model to predict micro-E temperature and relative humidity under bunker gear based on work rate. Studies I and II utilized a repeated-measures randomized experimental design, which consists of 4 trials (LO, MOD, HI (HOT), and HI (COLD)). Human volunteers wore bunker gear for 30 min while oxygen uptake (V̇O_2), heart rate, perceptive measures (ratings of perceived exertion, thermal sensation, sweating sensation, and clothing comfort), T_re, skin temperature, and micro-E (temperature and relative humidity at the anterior and posterior portion of the jacket and pants) were measured. A repeated measures MANOVA with a Bonferroni post hoc analysis was used to evaluate: the physiological measures; while the Friedman's Test was performed with a Wilcoxon Signed Rank Test on all perceptual measures. The COLD bunker gear did not significantly alleviate heat strain when compared to HOT bunker gear. Additionally we low, moderate and high intensities of work in ~ 29 °C macro-E WBGT did not differentially affect micro-E WBGT under bunker gear, and these data were used to derive models of micro-E from macro-E. Further data is needed to cross-validate the derived micro-E WBGT model predicted from macro-E WBGT and work rate.
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    The effects of interval walking on caloric expenditure
    (University of Alabama Libraries, 2015) Mitchell, Jermaine B.; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Purpose: As obesity rates continue to rise in physically inactive individuals, modified training methods should be explored to address exercise adherence. The purposes of the proposed studies were to evaluate the effectiveness of interval walking, intermittent interval walking, and self-paced intermittent interval walking on oxygen uptake (⩒O_2) and excess post- exercise oxygen consumption (EPOC). Methods: In Study I and Study II participants completed a 30-min continuous walking protocol at a low-moderate intensity. Each protocol in these studies incorporated the same volume [90 metabolic equivalent-minutes (MET-min)] of exercise. Study I consisted of two interval walking protocols of cycled high-moderate and low-moderate intensities of 30-s work bouts and active recovery bouts of 60 and 120 s and total durations of 24-min-24-s (protocol 1) and 26-min-20-s (protocol 2). Study II consisted of three 10-min intermittent walking bouts of low-moderate intensities, three 8-min-40-s interval walking bouts of 30-s work bouts and active recovery bouts of 120 s, and three 8-min interval walking protocols of 30-s work bouts and active recovery bouts of 60 s. Study III assessed oxygen uptake before, during, and after continuous, intermittent, and intermittent interval walking of a self-regulated moderate RPE range (RPE 12-13), each totaling 30 min. Intermittent walking consisted of three 10-min bouts of walking and intermittent interval walking consisted of cycled 30-s high-moderate:120-s low-moderate intensity walking. Results: Study I: ⩒O_2 during interval walking was higher (p < 0.05) than during continuous walking; however, EPOC differed only between continuous walking and interval walking protocol 1 (p < 0.05). Study II: Compared to continuous walking, intermittent walking and both intermittent interval walking protocols elicited higher (p < 0.05) cumulative ⩒O_2 during exercise, and cumulative total 20-min EPOC values were higher as well (p < 0.05). Study III: Compared to continuous walking, both self-paced intermittent and intermittent interval walking protocols elicited higher cumulative ⩒O_2 during exercise periods and higher cumulative total 20-min EPOC values (all p < 0.05). Conclusion: These results indicate that moderate-intensity interval and intermittent interval walking protocols elicited higher exercise ⩒O_2 and EPOC compared with continuous walking of the same volume (90 MET-min) or duration (30 min).
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    Evaluation of HRV as a predictor of response to a modified physical training program in ROTC cadets
    (University of Alabama Libraries, 2016) Allen, Kimberly Elizabeth; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Continually enhancing military personnel training is essential in order to prepare soldiers to perform optimally. The soldier’s ability to perform may be closely associated with baseline autonomic nervous system activity, indicated by heart rate variability (HRV). Variability in heart rate may be related to results on the Army Physical Fitness Test (APFT). PURPOSE: The purpose of this study was to determine if ROTC cadets’ APFT scores would improve following a novel 8-week training program, if performance on the APFT was related to baseline HRV, and if training adaptations in APFT performance were related to changes in HRV. METHODS: Twenty ROTC cadets (age 20 ± 1 yr) were evaluated on APFT at baseline, 4 and 8-weeks. A subset of 13 cadets completed HRV recordings using a validated smartphone application immediately upon awakening. The initial 3-days of HRV recordings served as baseline HRV. A subset of 8 cadets recorded HRV after the 4th week APFT through the end of the 8th week. An average of 3 readings at the beginning and end determined ΔHRV, and week 4 and 8 scores were subtracted to get ΔAPFT. RESULTS: APFT scores significantly improved in all fitness measures over the 8-week training program. Baseline HRV was moderately correlated with performance in each event, except for push-ups. Change in HRV and change in APFT scores from week 4 to week 8 was not significantly correlated. CONCLUSION: A periodized, progressive overload program significantly improved APFT scores. A trend towards moderate to strong correlations were found between performance tests and HRV, though they were not all significant in this sample size.
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    Evaluation of selected field and laboratory measures of body composition
    (University of Alabama Libraries, 2016) Nickerson, Brett Stephen; Esco, Michael R.; Bishop, Phillip A.; University of Alabama Tuscaloosa
    The four-compartment (4C) model is a laboratory method that is a valid method for the assessment of body composition. Three experiments were performed to 1) determine the validity of selected bioimpedance equations with the 4C model, 2) determine the impact of predicted vs. simultaneous residual lung volume (RLV) during underwater weighing (UWW) on the 4C model, and 3) develop a new body fat prediction equation. In the first study, subjects had body fat percentage (BF%) and fat-free mass (FFM) predicted from four bioelectrical impedance equations and compared to the 4C model. Three equations produced a significant mean difference, while another was non-significant. However, all four equations had a small standard error of the estimate (SEE) and fairly narrow limits of agreement. In a second study, RLV was measured simultaneously and predicted when determining UWW and 4C model BF%. The mean differences for UWW BF% was significant when comparing predicted vs. simultaneous RLV, but non-significant when the body density values derived via UWW were incorporated in the 4C model. The error was lower when using RLV prediction equations for determining BF% via the 4C model than UWW. In a third study the variables sex, body mass index (BMI), sum of combined handgrip strength, and vigorous physical activity was utilized in a regression equation to predict 4C model BF%. The new BF% equation, previous BMI-based BF% equations and skinfolds were compared to the 4C model. The new equation and BMI-based equations had significantly different BF% values and provided large 95% limits of agreement. Similarly, skinfolds had a significant mean difference, but the SEE was 3.7%, leading to the recommendation of skinfolds over the new equation and BMI-based equations. In conclusion, BIA equations can be used in the field, but practitioners should consider the tendency of the equations to over-predict BF% and under-predict FFM. Furthermore, the prediction of RLV can be used for the UWW procedure when determining 4C model BF%, but should not be used for UWW BF% alone. Lastly, the new BF% equation and BMI-based equations did not compare favorably with 4C model and the use of skinfolds is recommended.
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    Exploring the utility of unobtrusive methods of acquiring heart rate variability at rest and following exercise
    (University of Alabama Libraries, 2018) Dobbs, Ward; Esco, Michael R.; Fedewa, Michael V.; University of Alabama Tuscaloosa
    Use heart rate variability (HRV) for monitoring cardio-autonomic perturbations in response to physical stimuli has increased in popularity and demand. However, the utility of measures of HRV to reflect acute changes in muscle recovery from exercise is controversial. As criterion short-term HRV recordings are performed with a gold standard electrocardiogram (ECG), less obtrusive methods have been developed for improved practicality of HRV measures. Three studies were performed to investigate the accuracy of less obtrusive methods for acquiring HRV and the utility of HRV for tracking changes in muscular performance recovery. The first study involved a systematic review and meta-analysis on the accuracy of portable devices for acquiring HRV. Twenty-three studies yielded 301 effects and revealed that HRV measures acquired from portable devices differed from those obtained from ECG (ES=0.23, 95% CI: 0.05, 0.42), although this effect was small and highly heterogeneous (I2=78.6%, 95% CI: 76.2%, 80.7%). Moderator analysis revealed that HRV metric (p<0.001), position (p=0.033), and biological sex (β=0.45, 95% CI: 0.30, 0.61; p<0.001), but not portable device, modulated the degree of absolute error. Within metric, absolute error was significantly higher when expressed as SDNN (ES=0.44) compared to any other metric but was no longer significantly different after a sensitivity analysis removed outliers. Likewise, the error associated with the tilt/recovery position was significantly higher than any other position and remained significantly different without outliers in the model. In the second study, the time course in recovery between criterion short-term HRV measures and acute muscular performance 72 hours following an exhaustive bout of resistance training was investigated. All HRV metrics had a significant interaction with muscular performance (performance) over time (p < .01) indicating change scores in performance and HRV following the physiological stressor were not parallel and did not track. Mean change scores in all HRV metrics significantly differed from performance across time (p < .05), except the standard deviation of all normal-to-normal R-R intervals (SDNN), low frequency power (LF), and the standard deviation of long-term HRV from the Poincaré plot (SD2) at the 0.5-hr mark, and high frequency power (HF) at the 24-hr time point. Furthermore, repeated measures correlation analysis indicated a lack of intra-individual association between the change in performance and HRV over time (all < .45). In the third study, the agreement between ultra-short and criterion short-term HRV measures surrounding a bout of exhaustive resistance training was investigated. Results displayed the highest levels of agreement from the log-transformed (ln) root mean square of successive R-R differences (lnRMSSD) [LOA = -0.91– 0.69, ICC = .91, p = .082, ES = 0.15] and the standard deviation of the points through the width of the plot (lnSD1) [LOA = -0.90 – 0.72, ICC = .91, p = .156, ES = 0.13] compared to all other metrics.