Case Study: Effect of Surgical Metal Implant on Single Frequency Bioelectrical Impedance Measures of an Athlete

This case study examined the influence of a surgical metal implant on the bioelectrical impedance analysis (BIA) readings of an athlete. Single‐frequency BIA using a tetrapolar electrode configuration was applied to both the right and left sides of a 23‐year‐old female jumper who had an 8 × 345 mm titanium alloy nail implanted in her left tibia. The metal implant reduced BIA resistance and reactance on the implanted side by 27 and 6 ohms, respectively. This reduction in impedance resulted in a 0.4 kg–1.9 kg increase in the estimate of fat‐free mass (FFM) depending on the prediction formula used. There was a concomitant decrease in the estimate of body fat percentage (%BF) with the underestimation ranging from 0.6% to 2.7% BF depending on the prediction formula. A metal implant of substantial size can alter the BIA reading. Technicians should apply BIA to the opposite side of the body when athletes present with a surgical implant in a limb

LDEF data: Comparisons with existing models

The relationship between the observed cratering impact damage on the Long Duration Exposure Facility (LDEF) versus the existing models for both the natural environment of micrometeoroids and the man-made debris was investigated. Experimental data was provided by several LDEF Principal Investigators, Meteoroid and Debris Special Investigation Group (M&D SIG) members, and by the Kennedy Space Center Analysis Team (KSC A-Team) members. These data were collected from various aluminum materials around the LDEF satellite. A PC (personal computer) computer program, SPENV, was written which incorporates the existing models of the Low Earth Orbit (LEO) environment. This program calculates the expected number of impacts per unit area as functions of altitude, orbital inclination, time in orbit, and direction of the spacecraft surface relative to the velocity vector, for both micrometeoroids and man-made debris. Since both particle models are couched in terms of impact fluxes versus impactor particle size, and much of the LDEF data is in the form of crater production rates, scaling laws have been used to relate the two. Also many hydrodynamic impact computer simulations were conducted, using CTH, of various impact events, that identified certain modes of response, including simple metallic target cratering, perforations and delamination effects of coatings

Effects of Ambient Particulate Matter on Aerobic Exercise Performance

Background/Objective: Wintertime thermal inversions in narrow mountain valleys create a ceiling effect, increasing concentration of small particulate matter (PM2.5). Despite potential health risks, many people continue to exercise outdoors in thermal inversions. This study measured the effects of ambient PM2.5 exposure associated with a typical thermal inversion on exercise performance, pulmonary function, and biological markers of inflammation. Methods: Healthy, active adults (5 males, 11 females) performed two cycle ergometer time trials outdoors in a counterbalanced design: 1) low ambient PM2.5 concentrations (/m3 ), and 2) an air quality index (AQI) ranking of “yellow.” Variables of interest were exercise performance, exhaled nitric oxide (eNO), c-reactive protein (CRP), forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1). Results: Despite a significant difference in mean PM2.5 concentration of 9.3 ± 3.0 mg/m3 between trials (p \u3c .001), there was no significant difference (p = .424) in the distance covered during low PM2.5 conditions (9.9 ± 1.7 km) compared to high PM2.5 conditions (10.1 ± 1.5 km). There were no clinically significant differences across time or between trials for eNO, CRP, FVC, or FEV1. Additionally, there were no dose-response relationships (p \u3e .05) for PM2.5 concentration and the measured variables. Conclusion: An acute bout of vigorous exercise during an AQI of “yellow” did not diminish exercise performance in healthy adults, nor did it have a negative effect on pulmonary function or biological health markers. These variables might not be sensitive to small changes from acute, mild PM2.5 exposur

ASEA Redox Supplement Fails to Improve Aerobic Capacity and Ventilatory Threshold: A Double-Blind, Placebo-Controlled Study

The ASEA redox cell signaling supplement beverage has been commercially available for the past decade. Despite the market longevity of this supplement, athletic sponsorship, and anecdotal ergogenic claims, there is no independent, peer-reviewed research on its efficacy. The purpose of this study was to determine if ASEA improves aerobic capacity (VO2 max) and/or ventilatory threshold (VT) of physically active subjects. Eleven (6 females, 5 males) young adults (21.9 ± 3.9 yrs) performed 3 VO2 max tests: (a) baseline; (b) after 2 wks of supplementing with ASEA; and (c) after 2 wks of taking a placebo in a cross-over design. The treatment order was randomized and double-blind. The subjects consumed 4 oz∙d-1 (118 mL∙d -1) of the ASEA treatment according to the manufacturer’s recommendations. The subjects’ VO2 max values at baseline (55.0 ± 8.6 mL·kg-1 ·min-1), placebo (53.6 ± 9.1 mL·kg-1 ·min-1), and ASEA (53.7 ± 10.1 mL·kg-1 ·min-1) were not significantly different (P=0.172). Similarly, absolute VO2 max (P=0.436), time to reach VO2 max (P=0.955), VT as a percentage of VO2 max (P=0.678), and maximal heart rate (P=0.410) were not significantly different between trials. Contrary to the manufacturer’s claims, ASEA did not improve the aerobic performance of young, fit adults who supplemented with the product daily for 2 wks

Reliability of the Wingate Anaerobic Test with Ice Hockey Players on the Velotron Cycle Ergometer

Purpose: This study evaluated the test-retest reliability of the Wingate Anaerobic Test (WAnT) performed on a Velotron electromagnetically-braked cycle ergometer (EE) for power-trained athletes and assessed whether a familiarization trial was necessary to achieve high test-retest reliability. Methods: Twenty-one male ice hockey players (age 23.5 ± 4.7 yrs, mass 86.3 ± 16.6 kg, height 180.9 ± 7.4 cm) from a collegiate club team (Club = 10) and a recreational league (Rec = 11) performed three, 30-sec WAnTs within 2 weeks, and with at least 24 hours between visits. Mean power, anaerobic capacity, peak power, anaerobic power, maximum RPM, and fatigue index were assessed. Resistance was 8.5% of the participant’s body weight. Results: The effect of time on power output was moderated (p \u3c .001, ηp2 = .24) such that a significant increase was observed after a practice trial, but not between subsequent trials for the Club players; no practice effect was observed among Rec players. Extremely high reliability was found between trials after excluding the practice trial (ICC1,1 \u3e .89). The Club players achieved higher outputs despite no significant differences in body size or age compared to the Rec League players. Conclusion: Ice hockey players performing the 30-sec WAnT on the Velotron EE had highly reliable data, and using a familiarization trial is recommended to increase reliability and achieve higher power outputs. Lastly, because WAnT results from EE and mechanically-braked ergometers cannot be compared, normative tables for EE results need to be created

Damage areas on selected LDEF aluminum surfaces

With the U.S. about to embark on a new space age, the effects of the space environment on a spacecraft during its mission lifetime become more relevant. Included among these potential effects are degradation and erosion due to micrometeoroid and debris impacts, atomic oxygen and ultraviolet light exposure as well as material alteration from thermal cycling, and electron and proton exposure. This paper focuses on the effects caused by micrometeoroid and debris impacts on several LDEF aluminum plates from four different bay locations: C-12, C-10, C-01, and E-09. Each plate was coated with either a white, black, or gray thermal paint. Since the plates were located at different orientations on the satellite, their responses to the hypervelocity impacts varied. Crater morphologies range from a series of craters, spall zones, domes, spaces, and rings to simple craters with little or no spall zones. In addition, each of these crater morphologies is associated with varying damage areas, which appear to be related to their respective bay locations and thus exposure angles. More than 5% of the exposed surface area examined was damaged by impact cratering and its coincident effects (i.e., spallation, delamination and blow-off). Thus, results from this analysis may be significant for mission and spacecraft planners and designers

ACUTE EFFECTS OF ANTAGONIST STRETCHING ON JUMP HEIGHT, TORQUE, AND ELECTROMYOGRAPHY OF AGONIST MUSCULATURE

Although there has been substantial research on the acute effects of static stretching on subsequent force and power development, the outcome after stretching of the antagonist musculature has not been examined. The purpose of this study was to investigate the effects of static stretching of antagonist musculature on multiple strength and power measures. Sixteen trained men were tested for vertical jump height and isokinetic peak torque production during knee extension at 60°.s (SlowKE) and 300°.s (FastKE). Electromyography was recorded for the vastus lateralis and the biceps femoris muscles during isokinetic knee extension. Subjects performed these tests in a randomized counterbalanced order with and without prior stretching of the antagonist musculature. Paired samples t-tests indicated significantly greater torque production during the FastKE when preceded by stretching of the antagonist musculature vs. the nonstretch trial (102.2 vs. 93.5 N.m; p = 0.032). For SlowKE, torque production was not significantly different between the trials (176.7 vs. 162.9 N.m; p = 0.086). Vertical jump height (59.8 vs. 58.6 cm; p = 0.011) and power (8571 vs. 8487 W; p = 0.005) were significantly higher after the stretching trial vs. the nonstretching trial. Electromyography responses were similar between the trials. These results suggest that static stretching of the antagonist hamstrings before high-speed isokinetic knee extension increases the torque production. Furthermore, stretching the hip flexors (emphasis on single-joint hip flexors) and dorsiflexors, the antagonists of the hip extensors and plantarflexors, may enhance jump height and power, although the effect sizes were small

Cognitive and psychomotor responses to high-altitude exposure in sea level and high-altitude residents of Ecuador

Background High-altitude inhabitants have cardiovascular and respiratory adaptations that are advantageous for high-altitude living, but they may have impaired cognitive function. This study evaluated the influence of altitude of residence on cognitive and psychomotor function upon acute exposure to very high altitude. Findings Ecuadorians (31 residing at 0–1,500 m [LOW], 78 from 1,501–3,000 m [MOD], and 23 living \u3e3,000 m [HIGH]) were tested upon their arrival to a hut at 4,860 m on Mount Chimborazo. Cognitive/psychomotor measurements included a go-no-go test (responding to a non-visual stimulus), a verbal fluency test (verbalizing a series of words specific to a particular category), and a hand movement test (rapidly repeating a series of hand positions). Mean differences between the three altitude groups on these cognitive/psychomotor tests were evaluated with one-way ANOVA. There were no significant differences (p = 0.168) between LOW, MOD, and HIGH for the verbal fluency test. However, the go-no-go test was significantly lower (p \u3c 0.001) in the HIGH group (8.8 ± 1.40 correct responses) than the LOW (9.8 ± 0.61) or MOD (9.8 ± 0.55) groups, and both MOD (97.9 ± 31.2) and HIGH (83.5 ± 26.7) groups completed fewer correct hand movements than the LOW (136.6 ± 37.9) subjects (p \u3c 0.001). Conclusions Based on this field study, high-altitude residents appear to have some impaired cognitive function suggesting the possibility of maladaptation to long-term exposure to hypobaric hypoxia

Comparison of A-mode and B-mode Ultrasound for Measurement of Subcutaneous Fat

With lower-cost devices and technologic advancements, ultrasound has been undergoing a resurgence as a method to measure subcutaneous adipose tissue. We aimed to determine whether a low-cost, 2.5-MHz amplitude (A-mode) ultrasound, designed specifically for body composition assessment, could produce subcutaneous fat thickness measurements comparable to an expensive, 12-MHz brightness (B-mode) device. Fat thickness was measured on 40 participants (20 female, 20 male; 29.7 ± 11.1 y of age; body mass index 24.9 ± 4.5 kg/m2) at 7 sites (chest, subscapula, mid-axilla, triceps, abdomen, suprailiac and thigh) with both devices. Intraclass correlations exceeded 0.75 at all measurement sites. Mean differences in fat thickness were not significantly different (p \u3e 0.05) and within ± 1.0 mm. Variability between devices was greatest at the abdomen, the site with the greatest thickness. The low-cost, low-resolution A-mode ultrasound provides subcutaneous fat thickness measurements similar to the more expensive, high-resolution B-mode ultrasound

Measured Thoracic Gas Volume Versus Two Predictions

Body composition, or one’s fat mass relative to total mass, is important to a person’s health and physical performance. One method to measure body composition is the Bod Pod air displacement plethysmograph. To determine body volume from the Bod Pod, thoracic gas volume (TGV), or the volume of air in the lungs during a normal breath, must be measured or predicted. PURPOSE: The intent of this study was to compare measured TGV to two predictions: one from the Bod Pod (TGVBP) that makes assumptions about functional residual capacity and tidal volume, and one from a recent publication (TGVDucharme) that relies on measures of height and body mass rather than lung volumes. METHODS: Bod Pod data from university club sport athletes participating in a larger study were used. TGV was measured following the Bod Pod manufacturer’s instructions. Comparisons of mean data were made between the measured test and the two predictions with a one-way repeated-measures ANOVA. Individual error scores were evaluated with Bland-Altman plots. RESULTS: Data from 26 club sport athletes (18 male, 8 female) revealed a statistically significant difference (p = .001) between the three TGV measures. The measured TGV (4.108 ± 0.850 L) and TGVDucharme (4.092 ± 0.655 L) were not significantly different from one another (p = .851), but TGVBP (3.724 ± 0.409 L) significantly underestimated the measured TGV (p = .002) and Ducharme’s prediction (p \u3c .001). A clear bias exists for TGVBP (r = -0.799, p \u3c .001), such that the Bod Pod prediction overestimates athletes with a small TGV (\u3c 3.3 L) and underestimates athletes with a large TGV (\u3e 3.3 L). The bias for TGVDucharme is statistically significant (r = -0.460, p = .018), but much smaller than the bias from the Bod Pod prediction. CONCLUSION: When possible, measure TGV. If TGV must be predicted, use the Ducharme prediction rather than the TGV prediction from the Bod Pod