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Functional Electrical Stimulation of the Soleus Increases Ankle Mechanics with a Modest Increase in Metabolic Rate during Walking in Young and Older Adults
Get PDFBetter mobility improves older adult health, independence, and quality of life. Unfortunately, walking performance declines with advanced age, as older adults expend 10-25% more metabolic energy during walking compared to young adults. This age-related increase in metabolic energy expenditure is partly because older adults characteristically produce less ankle mechanics during walking compared to young adults, in turn compensating with increased hip mechanics (distal-to-proximal redistribution). Such mechanical changes may be attenuated using functional electrical stimulation (FES) to enhance ankle extensors. Stimulating ankle extensors during walking likely increases joint output and underlying muscle metabolism, with concomitant reductions in hip mechanics. If so, the attenuated distal-to-proximal redistribution in leg joint mechanics may offset the metabolic increase of stimulated muscles. PURPOSE: The purpose of this study was to determine whether FES to bilateral soleus muscles during walking attenuates the age-related distal-to-proximal redistribution in joint mechanics without increasing metabolic rate. METHODS: Twenty adults participated (10 young: 21 ± 2 yrs; 10 older: 77 ± 5 yrs). Participants walked on the treadmill at 1.25 m/s for familiarization, baseline, and FES trials. Each trial lasted 5-min with a 5-min seated rest preceding each trial. FES was applied over the soleus when the respective leg’s propulsive ground reaction force was \u3e 10% body weight. We recorded ground reaction forces, motion capture data, and metabolic power during walking. We conducted a two-way repeated measures ANOVA to test the effects of walking trial and age group on dependent variables. RESULTS: There was no interaction between walking trial and age group on any dependent variable (all ≥ 0.129). Peak ankle moments and mechanical power were both greater during walking with FES vs. Baseline (FES: 1.37 ± 0.23 Nm/kg, Baseline: 1.32 ± 0.23 Nm/kg, p=0.004; FES: 2.36 ± 0.45 W/kg, Baseline: 2.17 ± 0.47 W/kg, p=0.004). Peak hip moments and power did not differ between FES and Baseline (FES: 0.66 ± 0.44 Nm/kg, Baseline: 0.70 ± 0.44 Nm/kg, p=0.208; FES: 0.92 ± 0.21 W/kg, Baseline: 0.95 ± 0.23 W/kg, p=0.138). Due to the greater stimulated ankle mechanical output and minimal changes to hip mechanics, walking with FES required 3% more net metabolic power vs. Baseline (FES: 3.11 ± 0.54 W/kg, Baseline: 3.01 ± 0.58 W/kg, p=0.04). CONCLUSION: FES increases ankle mechanics and metabolic rate during walking in young and older adults. Our findings support the notion that older adults can physically walk with more youthful ankle mechanics, but aging neural strategies contribute to proximal redistribution in joint mechanics. Follow-up studies will evaluate the potential for FES to increase the corticospinal excitability of older adult leg muscles and to restore more youthful walking mechanics
Examining the Relationship Between Competition Stress and Performance in Collegiate Rodeo Bronc Riders Through Salivary Cortisol and Heart Rate
Get PDFCompetition stress significantly impacts the performance of athletes across various sports. Despite its unique demands, stress in rodeo athletes remains underexplored, largely due to the sport\u27s nomadic and individualistic nature and its prior lack of mainstream attention. While comparisons can be drawn between the intermittent structure of rodeo and mainstream sports like baseball or football, the recent surge in rodeo\u27s popularity has increased interest in optimizing athlete performance. PUROSE: The aim of this study was to identify and compare salivary cortisol concentration (SCC) and physical workloads experienced by riders and horses in practice and competition settings. Additionally, the study aims to determine the relationship between SCC and performance outcomes. METHODS: Collegiate rodeo athletes (bareback riders n=3; saddle bronc riders n=4) from McNeese State University were recruited. Salivary cortisol, heart rate (HR), and VO2 max levels were measured. Saliva samples were collected via oral swab from riders 20 minutes before and after a scheduled practice, a mock competition, and a Bruce treadmill protocol VO2 max test. Riders rode the same horse for both practice and mock competition rides; and there were 3 weeks between tests. Salivary cortisol was analyzed via Immunoassay kit (Salimetrics) with 4.6% intra-assay CV and 6.0% inter-assay CV. Statistical analysis included generalized linear model to determine the relationship between variables across tests. RESULTS: No statistically significant differences in mean SCC were observed in riders pre-practice (0.189±0.059 µg/dL), post-practice (0.482±0.057 µg/dL), pre-VO2 max (0.361±0.068 µg/dL), post-VO2 max (0.302±0.068 µg/dL) or pre-competition (0.512±0.062 µg/dL) (p \u3e 0.05). However, SCC was higher post-competition than any other time points (1.956±0.057 µg/dL; p \u3c 0.05) and was negatively correlated with total score (y=77.187±2.023 – 3.088±0.566SCC; r2=0.881; p=0.005). Mean rider HR was higher during competition (161.5±0.289bpm) than practice (154.7±0.267bpm) (p=0.007). CONCLUSION: Post-competition SCC was significantly higher than post-VO2 max, suggesting that the elevated SCC is likely influenced by heightened psychological stress rather than solely the physical demands of the sport. The negative correlation between SCC and performance score highlights the potential impact of competition stress on outcomes. Further research on strategies to control psychological stress in rodeo athletes could lead to enhanced performance and better management of competition-related challenges
Visceral Adipose Tissue – A Comparative Analysis of DXA and Bioelectrical Impedance Analysis
Get PDFVisceral adipose tissue (VAT), defined as the abdominal fat surrounding intraabdominal organs including the stomach, kidneys, and intestines, can be directly linked to the development of metabolic syndrome and increased mortality. CT and MRI are currently regarded as the most reliable modalities for estimating VAT area, however bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) have emerged as more convenient and cost-friendly alternatives for obtaining VAT and other body composition values. PURPOSE: This study compared VAT areas gathered via DXA and BIA in a population of mostly Hispanic individuals, to assess the reliability and association of both modalities to body fat percentage (PBF). METHODS: 47 adults, aged 18+, were assessed for total body composition with the Lunar iDXA (GE Healthcare, Madison WI) and BIA via the InBody 770 (InBody, Seoul, South Korea). Participants were instructed to arrive hydrated, with manufacturer suggested clothing, for testing after a minimum 4-hour fast and abstain from exercise for the previous 12 hours. Hydration was assessed before testing using a urine refractometer with an acceptable range between 1.004-1.029. Participants repeated the testing protocol on a separate day within a two-week period for reliability measures. Coefficient of variation percent (CV%) and least significant change at 95% (LSC) were used for reliability, Pearson correlations were used to assess the relationship between VAT and PBF, and paired samples t-tests compared VAT area between DXA and BIA. Statistical analyses were conducted using SPSS v28 (IBM Corporation, New York, USA) and alpha was set at 0.05. RESULTS: DXA VAT area values had higher CV% (28.24%, LSC= 99.4) than BIA (7.36%, LSC= 8.3). PBF and VAT area obtained with the InBody were strongly correlated (r=0.847, p\u3c.001). PBF and VAT with DXA showed moderate correlation (0.466, pp\u3c0.001) as were both VAT measures (0.785, p\u3c0.001). CONCLUSION: DXA and BIA, albeit more indirectly, may provide reliable indicators regarding patterns of VAT area accrual with increases in PBF. InBody resulted in VAT values with less variation, making it a more cost-friendly, user-friendly, and accessible option for regular use in individuals seeking information and guidance on potential consequences of central obesity patterns
Agreement between Two Systems for Measuring Vertical Jump Height
Get PDFMeasuring vertical jump is considered one of the standardized test used to determine athletic performance. The Vertec is considered the gold standardized test for vertical jump where this equipment is hard to obtain and typically expensive. However easily mobile, more accessible, and less expensive equipment such as the Jawku has yet to be explored on its reliability and validity in vertical jump heights. PURPOSE: To determine if new technological equipment (Jawku) is a valid measurement of vertical jump height. METHODS: Forty participants (Age= 23.4±4.4 yrs, height= 66.8±3.7 in, weight= 164.5±36.4 lbs, shoe size= 9.2±1.6 US) were measured for reach height on the Vertec and performed a familiarization countermovement (CM) and non-countermovement (NCM) jump. Participants then jumped a total of six trials (alternating CM and NCM) where both the Vertec and the Jawku measured jump heights simultaneously. A factorial ANOVA was used to assess significant differences between jumps. Pairwise error was controlled through the Bonferroni techniques. Alpha was set at .05 for all tests. RESULTS: There was no significant difference in counter movement jump height between Jawku (13.7±3.3 in) and Vertec (14.3±4.6 in), p=.604, nor in non-counter movement between Jawku (12.9±2.8 in) and Vertec (13.3±4.5 in), p=1.0. Agreement was similar for both devices in each condition CONCLUSION: Although there was 13.7% absolute error in CM and 16.2% in NCM, there were no significant differences in both the jump heights for both the Jawku and Vertec. Caution should be used when relying on Jawku for precision results.
This project was supported in part by the A&M-SA Office of Research
Force & Accuracy for an Ipsilateral vs Contralateral Stance in a Cornhole Throw
Get PDFMany people have played cornhole before, whether it be at college or for fun at family events. Everyone has a method of playing, but does the stance affect accuracy and force? PURPOSE: This study was to find out if a contralateral stance is more accurate than an ipsilateral stance. We also wanted to test whether an ipsilateral stance had more muscle activation than a contralateral stance. METHODS: For this study, we tested a total of 10 participants all ranging from ages 18-26 both male and female. We then placed EMGs on each participant\u27s bicep, tricep, and anterior deltoid muscles on their right arm. After attaching the EMGs to the participant they then were told to stand ipsilaterally or contralaterally to throw 4 cornhole bags at the cornhole board from 27 feet. When all 4 throws were completed, we gathered the data from the EMG readings as well as the placement of the cornhole bags on, off, or inside the hole of the board to measure accuracy. Once the results were gathered, we then had them stand in the opposite stance and repeat. RESULTS: The force for the contralateral step averaged out to be 0.207. The ipsilateral step force averaged out to be 0.195. Yet the force for the ipsilateral step tricep is significantly higher than the contralateral step tricep. That said, the numbers were similar. The bicep is 0.110 for ipsilateral and 0.125 for contralateral. The deltoids are significantly higher than the bicep and tricep readings: 0.422 for the ipsilateral step and 0.453 for the contralateral step. The accuracy for each step was also recorded during this time. Three options were decided for every throw: Off the board, On the board, and in the hole. These were also assigned numbers, off the board being 0, on the board being 0.5, and in the hole being 1. With these numbers, the first throws gave an average of 0.05 for ipsilateral and 0.15 for contralateral. The second throw averages 0.20 for ipsilateral and 0.25 for contralateral. The third throw gave an average of 0.25 for ipsilateral and 0.40 for contralateral. Finally, the last throw gave 0.15 for both ipsilateral and contralateral. The most prevalent score was Off the board (0) for both steps. The average score for ipsilateral is 0.16 and the contralateral average is 0.24. CONCLUSION: The results we recorded proved one of our hypotheses correct. That hypothesis being that the contralateral step was more accurate than the ipsilateral step by .08 or 8%. Our other hypothesis was rejected which predicted that the ipsilateral stance was going to produce more force than the contralateral stance. The ipsilateral stance had an average muscle activation of .195 and the contralateral had an average of .207 when using the EMGs. With our results we found that contralateral stance is more accurate and has more muscle activation than the ipsilateral stance
Acute Effects of an Investigational Pre-Workout Supplement on Mood and Safety in Resistance Trained Males: A Proof-of-Concept, Randomized, Controlled, Crossover Study
Get PDFCaffeine-containing multi-ingredient pre-workout supplements (MIPS), marketed as improving physical performance acutely, are a particularly popular category within sports nutrition and yet finished products are rarely clinically evaluated. PURPOSE: The purpose of this randomized, controlled, crossover study was to examine the acute effects of an investigational MIPS formula when used by experienced resistance trained consumers of high-stimulant MIPS. METHODS: Eighteen (n=18) US military veteran, adult males (40.6 ± 1.7 yrs; 90.2 ± 2.2 kg; 28.7 ± 0.6 BMI; mean ± SEM) completed familiarization and 2 randomly assigned and counter-balanced lab visits, separated by 5±1 days between visits. Resting heartrate (HR), blood pressure (SBP & DBP), rate pressure product (RPP = HR x SBP), and Profile of Mood States 2nd Ed. Adult Short Form (POMS) was assessed prior to (PreTRX) and 50-min after (PostTRX) consuming 16 fl ozs H2O (positive control; CTL) or H20+MIPS (C4A; Nutrabolt; Austin, TX). Hemodynamic safety response was also assessed immediately post-exercise testing (PostEX; ~130 mins after consuming treatment). Adverse events (AEs) questionnaire was completed at the end of each lab visit. Exercise performance presented separately. RESULTS: There were no within or between treatment differences (p\u3e0.05) for POMS “Total Mood Disturbance”. C4A reduced fatigue (FA; “Fatigue-Inertia”) and increased “Tension-Anxiety” (TA) from PreTRx to PostTRx [FA: -6.2% (p=0.0119); TA: +14.3% (p=0.0052)] and when compared to CTL at PostTRx [FA: -13.6% (p=0.0190); TA: +16.7% (p=0.0118)]. PreTRx to PostTRx HR was unchanged (p\u3e0.05) by C4A, and there were no differences (p\u3e0.05) in HR between C4A vs CTL at PostTRx and PostEX. C4A increased PreTRx to PostTRx SBP and DBP by 8.3 ± 1.7 mmHg and 4.2 ± 1.7 mmHg, respectively, and these effects by time were significant (ppp\u3e0.05) for PostTRx to PostEX SBP for either condition. PostTRx to PostEX DBP was unchanged by CTL, whereas C4A promoted a PostTRx to PostEX decrease in DBP (-4.8%; pp\u3e0.05) were observed for RPP between C4A and CTL. Beta-alanine induced paresthesia was observed in 61% of subjects in response to C4A vs CTL (p=0.001). No other significant differences (p≥0.25) were observed for AEs between conditions. CONCLUSION: This pre-market proof of concept study suggests that acute use of C4A poses no undue cardiovascular or safety risk when used by experienced resistance trainers that regularly consume caffeine-containing MIPS
The Effect of a Short-Term Antibiotic Cycle on Blood Biomarkers in Adults with Overweight and Obesity
Get PDFIt has been demonstrated in previous literature that early-life antibiotic exposure may contribute to metabolic dysfunction related to the development of overweight and obesity later in life. More recent studies suggest an additional relationship between antibiotic exposure beyond early life and obesity, as well as insulin resistance. However, there are a limited number of studies reporting the effects of short-term antibiotic exposure on insulin resistance and other blood biomarkers. PURPOSE: This study investigates the effects of short-term antibiotic exposure on insulin resistance and other blood biomarkers. METHODS: This study is part of a larger ongoing investigation examining the effects of a synbiotic on the gut microbiome in adults with overweight and obesity (BMI: 25.0-40.0 kg/m²). Prior to starting the synbiotic supplement, participants underwent a short antibiotic cycle (3 days) with a therapeutic dose of vancomycin (500 mg taken every eight hours). At the first visit, before taking the antibiotic, participants came to the lab for a 12-hour fasted blood sample. Within 12–24 hours of completing the 3-day antibiotic regimen, participants returned to the lab for an additional 12-hour fasted blood sample. The pre- and post-antibiotic blood samples were sent to an offsite laboratory for the analysis of blood glucose, insulin, and hemoglobin A1C (HbA1C) concentrations. RESULTS: A two-tailed Student’s t-test was conducted to determine differences in blood biomarkers before and after the short antibiotic cycle. No significant differences were observed in blood glucose or HbA1C concentrations. However, blood insulin concentrations significantly increased by 1.3 μU/mL (p = 0.02). CONCLUSION: The significant acute increase in blood insulin concentration is consistent with our understanding of the effects of chronic antibiotic use. A decrease in insulin sensitivity leads to increased circulating insulin concentrations. Relating these results to the larger study, the use of an antibiotic may help clear the gut of harmful bacteria in individuals preparing to take a synbiotic supplement for gut health. However, this benefit may come at the cost of increased blood insulin concentrations. Further results from the larger study will be needed to assess the potential benefits of synbiotic consumption following a short course of antibiotic use
Examining the Relationship Between Sprinting, Drop Jump, and Vertical Jump Flight Times in Collegiate Track Athletes
Get PDFINTRODUCTION: Flight time during sprints, drop jumps, and vertical jumps is commonly used to evaluate athletic performance and neuromuscular function. While all three metrics reflect rapid force production, their relationships across different athletic movements remain unclear. PURPOSE: This study aimed to investigate the correlations between sprint step flight time, bilateral drop jump flight time, and bilateral vertical jump flight time in male and female Division I collegiate track athletes. METHODS: A group of 33 collegiate track athletes (males = 14, females = 19) who compete in sprinting, hurdles, or jumping events performed three drop jumps, three vertical jumps, three 30m fly sprints. During the drop and vertical jumps, force plates were used to measure jump performance, including flight time. Sprint kinematics, including step flight time, were measured using photoelectric cells. The average flight times from the three trials of each test were calculated. Flight time during jumps was defined as the duration from the moment that the vertical ground reaction force reached zero to the moment that vertical force deviated from zero upon landing. Spearman rank correlations were conducted to examine the relationships between sprint step flight time and drop jump flight time, as well as sprint step flight time and vertical jump flight time. RESULTS: There were no significant correlation between sprint step flight time and drop jump flight time (Spearman r = -0.092, p = 0.611), or sprint step flight time and vertical jump flight time (Spearman r = -0.047, p = 0.797). CONCLUSION: The results suggest that drop jump flight time, vertical jump flight time, and sprinting flight time are not related in this sample of athletes. While drop jump and vertical jump performance has been associated with sprint performance, it appears that these associations are not specific to flight time parameters. Although flight time is an important factor sprinting and jumping, the flight times of these movements do not appear to be associated with one another
Effects of a Sprint Post-Activation Performance Enhancement Stimulus on Discus Throw Performance in Collegiate Division I Throwers: A Pilot Study
Get PDFInternational Journal of Exercise Science 18(3): 251-262, 2025. No study has determined the impact a sprinting potentiating stimulus has on discus throwing performance in collegiate throwers. To test the hypothesis, that compared to a dynamic warm-up alone (DyWU), a dynamic warm-up with a multi-set sprinting potentiating stimulus (DyWU+SPR) would enhance discus throw performance. 12 NCAA Division I thrower athletes (18-25 year) randomly completed two sessions separated by at least 48 hours. One session involved a standardized dynamic warm-up (DyWU) and the other session involved a DyWU with multiple sets of a sprinting post-activation performance enhancement (PAPE) stimulus (DyWU+SPR), with both sessions followed by three trials of competition discus throws. A two-way ANOVA (warm-up x timepoint) with repeated measures was used for analyses, p \u3c 0.05. There were no significant (p\u3e0.05) differences between DyWU alone versus DyWU+SPR stimulus for discus throw distances at 8 min. (35.7±5.4 vs 35.0±5.5 meters, respectively; d = -0.12, trivial), 11 min. (34.8±4.5 vs 35.6±5.0 meters, respectively; d = 0.18, trivial), 14 min. (37.5±4.5 vs 36.7±4.9 meters, respectively; d = -0.19, trivial), or best throw attempt (36.2±5.1 vs 36.6±5.0 meters, respectively; d = 0.07, trivial). Within the parameters of this study, there were no differences in discus throw performance with DyWU+SPR compared to a DyWU alone in NCAA Division I throwers. Coaches, athletes, and practitioners should be aware that these results do not support the use of multiple sets of a sprinting PAPE stimulus beyond a dynamic warm-up alone to enhance discus throw performance in collegiate throwers
Perceived Changes in Physical Activity, Sedentary Behavior, and Stress During the Pandemic Predict Current Levels of These Same Variables
Get PDFInternational Journal of Exercise Science 18(4): 306-315, 2025. The COVID-19 pandemic and its associated restrictions placed on daily life may have negatively impacted overall physical and psychological health as well as health behaviors such as decreased physical activity and increased sedentary behavior. It is important to understand if these potential changes during the pandemic may be predictive of current health behaviors where pandemic-related restrictions are no longer being implemented. This study aimed to assess the relationships between perceived changes in physical activity, sitting, and stress during the COVID-19 pandemic to current measures of these same variables. In April 2022, participants (N = 208) completed a survey in which they indicated perceived changes in physical activity, sitting, and stress during the pandemic. Participants then self-reported their current total physical activity, daily sitting, and anxiety. Multiple Pearson correlation analyses were performed to assess the relationships between perceived measures of physical activity, sitting, and stress during the pandemic to current measures of these same variables. Greater perceived inactivity (i.e., reduced physical activity) during the pandemic was associated with lower current total physical activity (r = -0.28, p \u3c 0.001) and greater daily sitting (r = 0.19, p = 0.007). Greater perceived sitting during the pandemic was associated with lower current total physical activity (r = -0.26, p \u3c 0.001). Lastly, greater perceived stress during the pandemic was associated with greater current anxiety (r = 0.35, p \u3c 0.001). This suggests that individuals who perceived negative health-related changes during the pandemic may still be impacted by persisting effects