The purpose of this study was to examine the validity of a Garmin device for estimating heart rate, energy expenditure, and step count during incremental treadmill exercise. Eighteen physically active males (n = 12; mean ± SD age = 22.8 ± 4.7 years; body mass = 83.8 ± 13.4 kg) and females (n = 6; 24.2 ± 5.6 years; 65.2 ± 9.6 kg) completed an incremental treadmill test with the Garmin Vivoactive 4 and criterion methods measuring heart rate, energy expenditure, and step count. Mean absolute percent error (MAPE) and Bland–Altman plots were used to assess accuracy. Acceptable accuracy was defined as MAPE < 5% for heart rate and <10% for energy expenditure and step count. MAPE (±SD) values were 13.0 (±10.1), 19.1 (±15.0), and 4.6 (±5.3)% for heart rate, energy expenditure, and step count, respectively. The Bland–Altman regression analyses illustrated proportional bias was present for heart rate (r = 0.591, p < 0.001) and step count (r = 0.516, p = 0.028), but not energy expenditure (r = 0.351, p = 0.153). These findings indicated that the Garmin Vivoactive 4 provided acceptable accuracy for step count but unacceptable accuracy for heart rate and energy expenditure during incremental treadmill exercise.

The primary purpose of this study was to examine the acute effects of a multi-ingredient preworkout supplement (MIPS) on isometric, concentric, and eccentric peak torque and electromyographic (EMG) responses of the leg extensors during a fatiguing isokinetic protocol. Thirteen male subjects (mean age ± SD = 22.9 ± 2.2 years) were assigned in crossover fashion to ingest an MIPS or placebo before an isokinetic protocol that consisted of 30 maximal, concentric and eccentric muscle actions with EMG signals recorded from the vastus lateralis, rectus femoris, and vastus medialis muscles. Immediately before (PRE) and after (POST) the isokinetic fatigue protocol, subjects were assessed for isometric peak torque. The MIPS condition resulted in greater isometric (205 ± 48 vs. 185 ± 44 N·m, p = 0.04) and concentric (121 ± 34 vs. 103 ± 27 N·m, p = 0.015) torque values versus placebo (collapsed across time). For eccentric peak torque as well as EMG amplitude and frequency values, there were no significant (p > 0.05) interactions or main effects for each condition. These findings indicated that acute ingestion of the MIPS enhanced isometric and concentric peak torque of the leg extensors, which was not explained by changes in the EMG signal.

Physical function is regarded as the cornerstone of healthy aging, and exercise is an important determinant of healthy aging. This study examined the feasibility and physiological (heart rate, blood pressure, blood lactate, and rate of perceived exertion) and psychological (enjoyment) response resulting from an acute progressive sled-push (SLP) exercise session using the novel XPO Sled Trainer in older adults and compared that with walking (WKC) condition. The exercise session comprised six exercise bouts at 75%, 85%, 100% (2×), and 125% (2×) of normal velocity with a 2-min rest between bouts. Thirty-six older adults were randomly allocated into either the SLP or WKC conditions. No adverse events were observed during the exercise session, and all participants completed the exercise protocol as prescribed. One-third of the participants in the SLP group reported minimal body discomfort. Significantly higher responses were observed for all physiological variables as the intensity of the exercise increased in the SLP group compared with the WKC group ( p < .001). The SLP group presented a decline in enjoyment as the intensity of the exercise increased (during), but similar enjoyment level than the WKC group for the overall exercise session ( p = .711). Our findings support the viability and safety of SLP exercise using the XPO Sled Trainer in older adults. Such exercise demonstrated an intensity-driven modality that may have potential to elucidate positive adaptations in the cardiovascular system of older adults with acceptable levels of enjoyment.

Estrogen influences thermoregulation of the human body. Accompanied by the loss of estrogen, the onset of menopause can cause disruptive vasomotor symptoms (VMS). VMS present intense physical and psychological discomfort for woman including a sudden feeling of warmth spreading through the upper body, a flushed appearance, rapid heartbeat, perspiration, and anxiety. As much as 80% of menopausal females report hot flushes daily for up to 10 years of their life. Previous research explores treatment options to reduce VMS, but few studies look for activity levels and intensity to predict severity of VMS. PURPOSE: The purpose of this study was to investigate the associations between physical activity levels and the severity of hot flushes in menopausal and post-menopausal females. METHODS:101 females ages 41-79 (mean = 57 ± 8.09) were recruited on social media and local fitness studios to complete an online survey. Females were included in this project if they were in any phase of menopause transition or post-menopausal. The questionnaire required subjects to rate 12 different menopausal symptoms on a 5-category Likert Scale ranging from none to very severe. The participants were asked to recall their activity levels in minutes per week and to categorize their minutes in intensities. Subjects self-reported their exercise intensity as vigorous, moderate, or low physical activity. Subjects’ total activity minutes was categorized into quartiles in SPSS and subjects were grouped as low total activity, moderate total activity, high total activity, and very high total activity. Pearson Correlation coefficient was used to investigate relationships between volume of exercise, intensity of exercise, and severity of hot flushes. RESULTS: We found a statistically significant positive relationship between very high volume of moderate activity and severity of hot flushes. (r = 0.526, p = 0.007). CONCLUSION: These findings demonstrate that a very high volume of moderate exercise weekly may contribute to a greater severity of VMS for menopausal females. The practical implications of this study can influence exercise recommendations for menopausal females.

The ergogenic effects of caffeine supplementation on repeated-sprint ability (RSA) have produced equivocal results. This study aimed to examine the effects of 200 mg of caffeine during repeated-sprint running on heart rate (HR), rating of perceived exertion (RPE), blood lactate (BLa) concentration, and sprint time (ST). Thirty-two individuals (males: n = 17, females: n = 15; age: 22 ± 1 years) participated in the study. The study followed a double-blind, randomized, placebo-controlled, crossover design, in which each participant ingested 200 mg of caffeine or placebo on separate visits 60 minutes prior to repeated-sprinting exercise. The repeated-sprint protocol consisted of three sets of six maximal-effort 30-meter sprints with 20 seconds and 5 minutes of active recovery in between sprints and sets, respectively. During each set, HR, RPE, BLa, and ST were recorded. Caffeine supplementation did not significantly (set 1: p = 0.535; set 2: p = 0.602; set 3: p = 0.189) impact HR during exercise. Similarly, RPE was not statistically (p = 0.052) altered between conditions during any of the sprint sets. The caffeine trials elicited greater BLa values after all three sets compared to the placebo trials (p < 0.001). Moreover, the caffeine trials demonstrated significantly reduced total STs during all sets compared to the placebo trials (p < 0.001). Thus, our findings suggested that 200 mg of caffeine supplementation elicited an increase in RSA in young, healthy non-athletes. These findings are accompanied by a blunted perceived exertion relative to an increase in exercise intensity during repeated-sprint exercise.

The aging process is characterized by a chronic, low-grade pro-inflammatory state that may contribute to age-related conditions such as Alzheimer’s Disease (AD). Recent frameworks suggest monocyte phenotypes play key roles in the aging immune response that may exacerbate AD pathology and contribute to cognitive decline. Lifestyle behaviors, such as aerobic exercise training, can be neuroprotective and immunoprotective but the relationships between monocyte phenotypes, cardiorespiratory fitness, and cognitive function are poorly understood.PURPOSE:To explore the associations between monocyte phenotypes, cardiorespiratory fitness (VO2max), and performance in a hippocampal-dependent pattern separation task. METHODS:Active older adults (70 ± 6.7y, n = 24) were recruited for this study. Baseline VO2max was obtained via graded exercise test and pattern separation performance with a previously validated computerized test. Following a 12 h fast, Peripheral blood mononuclear cells (PBMCs) were isolated via Ficoll-gradient and immunostained with cell surface markers CD14 and CD16 to sort monocytes via flow cytometry. Spearman’s rank-order correlations (rs) were employed to determine the associations between monocyte phenotypes, VO2max, and cognitive outcomes. A multiple linear regression analysis was used to determine the association between monocyte polarization and outcomes of interest. RESULTS:No significant associations were found between classical (rs = -0.09, p > .05), intermediate (rs = 0.18, p > .05), or non-classical (rs = 0.10, p > .05) monocytes and pattern separation performance. Classical monocytes showed a direct correlation with VO2max (rs = 0.26, p = .01) while intermediate (rs = -0.18, p = .01) and non-classical (rs = -0.24, p = .01) monocytes showed inverse correlations with VO2max. A multiple regression model predicting VO2max from all monocyte phenotypes, controlling for age and sex, was significant (F(5,18) = 9.38, p = <.001, R2 = 0.64); follow-up contrasts indicated only intermediate monocytes were a significant predictor of VO2max (t(18) = -2.25, p = 0.03).CONCLUSIONS:Our results suggest pro-inflammatory monocyte phenotypes may negatively relate to VO2max in active older adults, but monocyte phenotypes did not relate to cognitive outcomes.

Body composition quantification in football athletics is an important tool for developing training programs and monitoring athlete progress for optimal performance. Fat free mass (FFM) and fat mass (FM) are common assessed body composition parameters that have been associated with optimal performance and increased risk for injury. However, most research has only investigated the body composition changes in collegiate football players during the off-season. PURPOSE: To investigate changes in body composition variables in Division I collegiate football players throughout one collegiate season in two groups of athletes (traveling team (TT) and the development team (DT)). METHODS: Seventy-seven football players (Mean ± SD; age = 20.6 ± 2.2 years TT; 18.3 ± 2.2 years DT) participated in in this study (TT = 46, DT = 31). Multi-frequency bioelectrical impedance analysis was used to asses FFM, FM, body weight, skeletal muscle mass (SMM), BMI, and FMpercentage. Within each group, participants were divided into sub-groups based on their positions (Big, Mid, and Skill) and all participants followed the strength training plan developed and implemented by the Director of Sports Performance for Football. A three-way repeated measures ANOVA was used to test for differences between team, position, and measurement time. Follow-up pairwise comparisons were calculated for significant main effects or interactions. All analysis was conducted with an alpha level of 0.05. RESULTS: Within the TT, a statistically significant interaction between time and weight was observed (MD = -3.201 lbs., p = 0.001; TTPre 233.4 ± 42.4, TTpost 230.1 ± 43.3) and between time and BMI (MD = -0.528, p = 0.002; TTPre 30.1 ± 4.4, TTpost 29.5 ± 4.7). Conversely on the DT, there was a statistically significant interaction between time and FFM (MD = 3.244 lbs., p = 0.001; DTPre 184.7 ± 24.1, DTpost 187.8 ± 24.7) and between time and SMM (MD = 2.293 lbs., p = 0.0001; DTPre 106.6 ± 14.1, DTpost 108.9 ± 14.4). There were no significant differences between the TT and DT. CONCLUSION: The findings of the present study suggest that a effective in-season training programs can negate the decreases in FFM and increases in FM typically observed in the active players on the TT during the competitive season and assist in increasing FFM and SMM in the DT players.

PURPOSE: This study examined the association among body fat percentage (%BF) measured using bioelectrical impedance analysis and various physiological and fitness markers in a sample of physically-inactive adults. METHODS: Thirty-nine healthy adults (Mean ± SD; age = 22 ± 2.2 years; height = 1.7 ± 0.1 meters; body mass = 75.5 ± 16.9 kg; body mass index = 26.4 ± 5.4 kg/m2; 24 females) participated in this study. Participants completed a collection of physiological and fitness assessments in a single visit in a laboratory research setting that last approximately two hours. Body composition was assessed using a multi-frequency bioelectrical impedance analysis. Physiological markers included: heart rate variability (HRV), resting heart rate (RHR), and heart rate recovery (HRR). Fitness variables included: time to exhaustion (TTE), and maximal oxygen uptake (VO 2max). HRV and RHR were measured using a Polar Bluetooth heart rate monitor and valid cellphone application. TTE, HR and HRR were assessed using a submaximal Bruce graded exercise protocol, and VO 2max was estimated based on age, body mass index, and time at completion. Data were analyzed using Pearson r correlation along with 95% Confidence Intervals, and the coefficients were interpreted as small (0.1), moderate (0.3), and large (0.5). RESULTS: We observed negative significant correlations (large in magnitude) between %BF and TTE (r = -.68 [-0.82; -0.46]; p < 0.01) and VO 2max (r = -.84 [-0.91; -0.72]; p < 0.01). All other correlation analysis (RHR (r = 0.05 [-0.26; 0.36]; p = 0.756), HRV (r = -0.15 [-0.44; 0.17]; p = 0.365), HRR (r = -0.11 [-0.41; 0.21]; p = 0.498)), were not statistically significant. CONCLUSION: The findings of the present study indicated that higher levels of body fat in physically-inactive college-aged adults were associated with poorer exercise performance and estimated aerobic capacity, but not selected variables pertaining to resting and recovery heart rate. Health professionals can use this information to better inform individuals of the potential health risk associated with poor aerobic capacity and excessive body fat.

Obesity and sedentary behavior are major concerns in the United States. It has been observed that Americans who watch more television are at greater risk of becoming obese and have lower health-related fitness markers. Most literature, however, has not focused on college-aged adults. PURPOSE: The purpose of this study was to examine the association between daily screen time viewing (proxy of sedentary behavior) and health-related fitness markers in college-aged adults. METHODS: A total of one hundred and forty one college-aged subjects (mean age ± SD= 22.9 ± 2.6 years; percent body fat= 22.9 ± 10.3%) were separated into four groups in accordance to reported screen time (very low viewing time, low viewing time, moderate viewing time, and high viewing time) and participated in two data collection (screening & exercise) sessions. In the screening session, subjects completed an informed consent form, inclusion criteria form, screen time survey, and body composition assessment through a bioelectrical impedance analysis device. Seven days later, participants returned to complete a countermovement jump assessment of lower body anaerobic power and an aerobic capacity PACER test to assess cardiorespiratory fitness. RESULTS: Spearman rank-order correlation coefficient tests showed a significant positive correlation (p = 0.032, r = 0.352) between daily time spent watching television and vertical jump displacement for the very low viewing time group. A significant positive correlation (p = 0.022, r=0.402) between daily time spent watching television and PACER laps was found in the very low viewing time group as well as a significant negative correlation (p = 0.49, r = -0.340) in the high viewing group. However, there were no statistically significant associations between daily time spent watching television and percent body fat. A one-way ANOVA showed a statistically significant difference (p < 0.05) for viewing time groups. A Tukey post hoc analysis showed statistically significant differences (p < 0.001) between all viewing time groups. CONCLUSION: Lower amounts of daily television viewing in college-aged adults was associated with greater lower body power production and greater cardiorespiratory fitness. Higher amounts of daily television viewing were associated with decreased cardiorespiratory fitness.

The purpose of this study was to evaluate the validity of whole body percent fat (%BF) and segmental fat-free mass (FFM) using multi-frequency bioelectrical impedance analysis (MF-BIA) and dual-energy x-ray absorptiometry (DEXA) in college-aged adults. Sixty-two participants male (n = 32) and female (n = 30) completed MF-BIA and DEXA measurements following established pre-test guidelines. %BF and segmental FFM (right arm, left arm, trunk, right leg, and left leg) were collected and analyzed. The MF-BIA significantly (p < 0.05) underestimated %BF for all participants, females, and males compared to DEXA. In addition, MF-BIA significantly (p < 0.05) underestimated FFM in the arms and legs in all participants and males with the exception of the left arm in all subjects while significantly overestimating FFM in the trunk. In females, the MF-BIA overestimated FFM in the arms and trunk while significantly (p < 0.05) underestimating FFM in the legs. Difference plots also indicated that the underestimation of FFM from MF-BIA in the arms and legs increased as the amount of FFM increased. Thus, our findings suggested that the MF-BIA may not be accurate for measuring whole %BF and segmental FFM in the college-aged population.

PURPOSE: To investigate changes in shooting performance of law enforcement officers under varying levels of stress. This study determined how increasing levels of stress from operating a firearm on static targets changed when participants were subjected to simulated life threatening situations. METHODS: Thirteen law enforcement officers completed three trials of hangun shooting trials using a battery-operated laser marking pistol. Trial one included a modified course from the Illinois State Firearms Qualification Course of Fire. Officers completed two separate simulation trials separated by 48 hrs (SIMCON1, SIMCON2). , Each officer engaged in dangerous encounters with virtual suspects using a TI Simulator (TI Training, Golden, Colorado) requiring each officer to draw his weapon and fire against an armed assailant. Heart rate, blood pressure, salivary cortisol, and shooting performance data were collected throughout the courses of fire. RESULTS: Compared with the qualification course of fire (99.23% hit rate of intended target), there was a statistically significant reduction p < .001 in percentage of shots hit during both SIMCON1 (hit rate 47.48%) and SIMCON2 (hit rate 50.13%) conflicts. Compared to trial 1 mean heart rate increased 16.46 BPM and 19.7 BPM and systolic blood pressure 18.77 mm Hg and 23.08 mm Hg respectively for SIMCON1 and SIMCON2 trials. Although a significant physiological effect was noted following both SIMCON trials, it did not statistically correlate with poor marksmanship performance. CONCLUSIONS: Future research should collect physiological variables such as heart rate and blood pressure when the officers are on duty. This real-life situation would likely heighten the physiological responses versus that of simulated setting used in this study. It may provide better insight how real-life scenarios may negatively affect marksmanship performance.

Physiological systems exhibit high levels of complexity characterized by non-linearity and persistent fractal correlations (low levels corresponding to states such as disease, injury, and fatigue) and has become recognized as a defining feature of healthy physiological functioning. Neuromuscular complexity is affected by fatigue and intensity of contractions, although no study has investigated the effect of contraction type on complexity. PURPOSE: The purpose of this study was to investigate the effect of contraction type on neuromuscular complexity. METHODS: Twelve collegiate-aged resistance-trained females (21 ± 1 years, 63.3 ± 7.4 kg) were recruited to visit the laboratory on two occasions, the first for familiarization purposes. In session two, participants performed three maximal knee extensor contractions on an isokinetic dynamometer for each contraction type [concentric (CON), eccentric (ECC), and isometric (ISO)] in random order. Relative knee angle was standardized to 120° during ISO contractions. Angular speed was standardized to 30°∙s-1 and range of motion to 90° (90° - 180° at full extension) during CON and ECC contractions. Each contraction lasted three seconds with three seconds rest between contractions. Electromyographic (EMG) signals were recorded from the vastus lateralis using a bipolar electrode configuration. Sample entropy (SE), a unitless measure of statistical irregularity was used as an index of physiological complexity. A one-way repeated measures ANOVA was performed to investigate differences in EMG SE among contraction types. Alpha level was set to 0.05. RESULTS: Contraction type was observed to have a significant effect on EMG SE (F(2,22) = 7.212, p = 0.004). Specifically, CON contractions (1.671 ± 0.193) displayed significantly greater EMG SE than ECC (1.497 ± 0.321, p = 0.017) and ISO (1.569 ± 0.223, p = 0.028) contractions. CONCLUSION: These findings indicated that neuromuscular complexity is contraction-type dependent, being significantly higher during CON than ECC and ISO contractions. In addition, there exists no generally accepted framework to explain the underlying factors regulating complexity and thus, further investigation may provide valuable insight into these potential mechanisms.

Caffeine is one of the most widely used drugs in the world due to its benefits of increasing mental and physical capabilities. Caffeine also is commonly used as an ergogenic aid when performing repeated-sprint activity (RSA). PURPOSE: The purpose of this study is to examine the effects of 200 mg of caffeine during RSA on heart rate (HR), rating of perceived exertion (RPE), blood lactate concentration (BLa), and sprint time (ST). METHODS: Thirty-two students (Age: 22.19 ± 2.29 years) participated in the study. The study followed a randomized crossover design, in which each participant ingested either 200 mg of caffeine or placebo 45 minutes prior to sprinting. The sprinting protocol consisted of three sets of six maximal-effort 30-meter sprints. Each sprint covered a 15-meter distance between the starting and the secondary marker, such that each subject sprinted down to the secondary and back to the starting. Each of the sprints in a set were separated by a total of 20 seconds of active recovery. Following each set, HR, BLa, ST, and RPE were recorded. RESULTS: The caffeine trials were not significantly different than the placebo for HR and RPE. However, for RPE, there was a main effect for time [F(3,93) = 292.810, p < 0.001]. The caffeine trials (Resting: 1.30 ± 0.52 mmol/L; Set 1: 11:33 ± 2.38 mmol/L; Set 2: 13.26 ± 3.02 mmol/L; Set 3: 13.67 ± 2.49 mmol/L) elicited increased BLa compared to the placebo (Resting: 1.37 ± 0.53 mmol/L; Set 1: 9.24 ± 2.43 mmol/L; Set 2: 11.46 ± 2.87 mmol/L; Set 3: 11.83 ± 2.55 mmol/L). The caffeine trials (Set 1: 6.78 ± 0.58 secs; Set 2: 6.81 ± 0.55 secs; Set 3: 6.85 ± 0.57 secs) also produced a decreased average ST compared to the placebo (Set 1: 7.00 ± 0.64 secs; Set 2: 7.02 ± 0.62 secs; Set 3: 7.12 ± 0.63 secs). For the average ST, there were significant main effects for condition [F(1,31) = 36.839, p < 0.001] and time [F(2,62) = 5.806, p = 0.006]. CONCLUSION: Caffeine supplementation of 200 mg elicits an increase in RSA in college-aged non-athletes.

VALIDITY OF WHOLE AND REGIONAL BODY COMPOSITION TESTING DEVICES Rachel N. Tauber, M.S. Ed. Department of Kinesiology and Physical Education Northern Illinois University, 2018 Peter J. Chomentowski III, Thesis Director Obesity has increased exponentially within the last three decades and is now widely recognized as one of today’s leading health threats due to it being a risk factor for diseases such as type 2 diabetes, cardiovascular disease, and hypertension. In recent years, there have been advances in technology such as bioelectrical impedance analysis (BIA), dual-energy X-ray absorptiometry (DEXA), and air-displacement plethysmography that have been used to categorize individuals into percent fat categories. However, there are still concerns with the validity of these devices. PURPOSE: The purpose of this study was to analyze the validity of the InBody 520, BodPod, and Hologic DEXA against hydrostatic weighing. METHODS: 32 male and 30 female subjects performed body composition testing using the InBody 520, BodPod, Hologic DEXA, and hydrostatic weighing. RESULTS: The constant error values and mean values for percent body fat were the highest among the DEXA compared to the InBody and BodPod. The InBody showed a non-significant relationship (p=0.11, p=0.47, and p=0.26) between constant error values and percent body fat values for hydrostatic weighing for females, males, and all subjects respectively. The BodPod showed a significant negative relationship (p=0.04 and p<0.01) between constant error values and percent body fat from hydrostatic weighing but a non-significant negative relationship (p=0.16) for males. The DEXA showed a significant positive relationship (p <0.01 and p=0.05) between constant error and percent body fat for hydrostatic weighing for males and all subjects respectively. CONCLUSION: The BodPod underestimated individuals with less fat mass and overestimated individuals with more fat mass. The Hologic DEXA consistently overestimated percent fat in all individuals.

The purpose of the present study was to examine the validity and reliability of the handheld Nova Max Plus blood glucose monitor during an oral glucose tolerance test and 60-minute bout of exercise. Thirty subjects (mean age +/- SD=22.3 +/- 1.9 years; body mass=77.6 +/- 14.2 kg) volunteered for an oral glucose tolerance test or a 60-minute treadmill test. Blood glucose concentrations were measured from the fingertip at six time points during both tests. The reference method of blood glucose analysis was the Yellow Springs Instruments (YSI) 2300. Our results indicated that the blood glucose values provided by the Nova Max Plus were significantly (p<.05) greater than the YSI 2300 at all-time points of the oral glucose tolerance test and treadmill test. In addition, the Nova Max Plus exhibited an overall mean absolute relative deviation (+/- SD) of 9.0 (+/- 7.0) and did not meet the 95% accuracy requirements of ISO 15197:2013. The Bland-Altman plot for constant error (YSI 2300 - Nova Max Plus) versus the reference method (YSI 2300) indicated an average negative bias (-8.2 mg.dL(-1)) that increased (r=-0.23) at higher blood glucose values. Intra-device reliability analyses for the Nova Max Plus demonstrated the ICC was R=0.99 and CV=3.0%, with no mean differences between the test and retest values. These findings suggested that the Nova Max Plus provided highly reliable, yet inaccurate blood glucose values compared to the YSI 2300 during the dynamic conditions associated with an oral glucose tolerance test and exercise.

Objective: To determine if hip fracture patients would have smaller cross-sectional area (CSA) and lower radiological attenuation (suggesting greater fat infiltration) in all trunk muscles as compared to older adults without hip fractures. Design: Cross-sectional analysis of computed tomography (CT) scans. Setting: Clinical imaging facility. Participants: Forty-one white participants (19 men, 22 women) from the Baltimore Hip Studies seventh cohort at 2 months postfracture were compared to 693 white participants (424 men, 269 women) from the Health, Aging and Body Composition (Health ABC) study at the year 6 visit (N=734). Intervention: Not applicable. Main Outcome Measures: Trunk muscle CSA and attenuation values were obtained from a single 10-mm, axial CT scan completed at the L4-L5 disc space in each participant. Results: The hip fracture cohort had significantly smaller CSA for all trunk muscles (range: 12.1%-38% smaller) compared to the Health ABC cohort (P<.01), with the exception of the rectus abdominus muscle in men (P= .12). But, hip fracture patients, particularly female patients, had higher attenuation levels (lower intramuscular fat) in all trunk muscles (P<.0001). Conclusions: Findings are consistent with atrophy of the trunk muscles in the hip fracture population without a high level of intramuscular fat. Future work should evaluate the role of trunk muscle composition in the functional recovery of older adults after hip fracture. (C) 2018 by the American Congress of Rehabilitation Medicine

A number of fatigue thresholds have been developed to describe fatigue-induced changes in various physiological factors including muscle activation, blood lactate, and gas exchange. These fatigue thresholds, however, may correspond to different exercise intensities depending on the variable from which they were derived as well as their underlying mechanisms. PURPOSE: The purpose of the present study was to examine the relationships and compare power outputs among fatigue thresholds derived from neuromuscular, metabolic, and ventilatory parameters. METHODS: Fifteen college-aged males (mean age ± SD = 22.1 ± 1.7 years, 78.0 ± 9.4 kg, 176.5 ± 5.6 cm) volunteered to perform an incremental test to exhaustion on an electronically-braked cycle ergometer for determination of their physical working capacity at the fatigue threshold (PWCFT), lactate threshold (LT), ventilatory threshold (VT), and gas exchange threshold (GET). The incremental test involved recording electromyographic (EMG) signals from the vastus lateralis as well as measurements of blood lactate from the fingertip and gas exchange using open circuit spirometry. RESULTS: The results of the one-way ANOVA with repeated measures and follow-up paired samples t-tests indicated that the LT (132 ± 14 W) occurred at a significantly (P < 0.05) lower power output than the PWCFT (153 ± 33 W), GET (155 ± 33 W), and VT (177 ± 27 W). In addition, the VT occurred at a higher output than the LT, PWCFT, and GET, whereas there was no difference in power outputs between the PWCFT and GET. Furthermore, there were no significant inter-correlations among any of the fatigue thresholds (r = -0.03 - 0.35), except between the GET and VT (r = 0.70). CONCLUSIONS: Based on the significant mean differences in power outputs and non-significant correlations, the findings of the present study indicated there were no relationships among indicators of fatigue identified through changes in muscle activation (PWCFT), blood lactate (LT), and measurements of gas exchange (VT and GET). These findings suggested there is a dissociation among the exercise intensities associated with the PWCFT, LT, VT, and GET, and thus, each originate from separate physiological mechanisms.

PURPOSE: This study investigated how high-intensity interval training (HIIT) at altitude (ALT) versus sea level (SL) with and without supplemental oxygen recovery (SRO2) affected cardiac function and skeletal muscle %O2 saturation (SMO2). METHODS: Eight cyclists aged 42.4 ± 7.7 (HT: 68.9 ± 4.6; WT: 177.9 ± 26.6; Body Fat: 19.3% ± 7.5%; VO2 max L/min 4.38 ± 1.01) performed a baseline cycling VO2max test and four treatment trials (TRA - ALTHIIT/SRO2; TRB - SLHIIT/SLrecovery; TRC - ALTHIIT/ SLrecovery; TRD - steady-state (SS) cycling). Each HIIT work period (n=3) was 75s with 120s recovery at 75% and 50% of VO2max, respectively. For TRD, subjects cycled at a workload equal to the mean O2 uptake equal of TRB (Control-Trial). O2 uptake was measured using a breath X breath metabolic cart for VO2 max and TRB. Cardiac function (HR, Cardiac Output (Q), Stroke Volume (SV)) was assessed using impedance cardiography. SMO2 was measured in the vastus-intermedius quadricep muscles using Moxy NIR devices. Data was analyzed using a w/in repeated measures design (Treatment (4) X 3 HIIT/Recovery Periods). RESULTS: Despite identical workloads, HR was significantly lower during SS cycling compared to the HIIT trials by 7.6% (SS: 118.0 ± 3.4; Mean HIIT TR HRs: 127.0 ± 3.7, p=0.002). ALTHIIT/SRO2 (TRA: 141.8 ± 9.2) showed a lower SV by 8.4% compared to the ALTHIIT/SLrecovery trial (TRC: 154.3 ± 9.2). Q was significantly lower during the HIITw/SRO2 (TRA:17.7 ± 1.1) compared to SLHIIT/SLrecovery & ALTHIIT/SLrecovery (TRB: 19.8 ± 1.1; TRC:19.8 ± 1.1) by 12% (P=0.04). SMO2 data showed a trend for ALTHIIT/SRO2 & SS cycling to have higher SMO2 values compared to the both HIIT trials without SRO2 (p=0.09). During recovery, ALTHIIT/SRO2 showed improved HR recovery 5.2% (p=0.01), increased SMO2 re- saturation rate 12.6% (p=0.01), and lowered Q 11.9% (p=0.01) compared to the altitude-sea level recovery trial. CONCLUSION: These results suggested that supplemental O2 recovery lowered cardiac demand (Q) at the same HIIT workload by maintaining HIIT SMO2 better by enhancing the overall recovery process. Supported by a grant from LiveO2 and Exercising Nutritionally, LLC