The Impact of Early Morning Training Sessions on Total Sleep Time in Collegiate Athletes

International Journal of Exercise Science 15(6): 423-433, 2022. Early morning training sessions may affect sleep quantity in athletes. The purpose of this study is to examine differences in total sleep time of collegiate athletes on nights prior to early morning training sessions relative to non-training nights. Wristwatch monitors equipped with photoplethysmography and accelerometer technology were worn by 18 NCAA Division III collegiate athletes (Age: 20.1 ± 1.6 years, Height: 1.81 ± 0.02 m, Body Mass: 91.2 ± 6.5 kg, Body Fat %: 20.8 ± 1.6%) during a two-week period of training to monitor total sleep times. Athletes recorded time in and out of bed using a sleep diary, anxiety levels due to having to wake up in the morning, and perceived recovery status (PRS) upon waking the next day. The data were divided into: nights before non-training days (NT) and Training days (TD). Data were analyzed using univariate analysis. All athletes obtained significantly less total sleep on nights before TD relative to NT (NT: 8:15 ± 1:03 vs. TD: 6:08 ± 0:59 hh:mm; p \u3c 0.05). There was a positive relationship between total sleep time and recovery status (p \u3c 0.01). Anxiety scores were inversely related to total sleep time (p \u3c 0.01). Next-day recovery status was inversely related to anxiety scores (p \u3c 0.001). College athletes obtained significantly less total sleep time on nights before early morning training sessions (\u3c 0700) during the off-season, regardless of sex and sport. Coaches should consider later training sessions or promote optimal sleep quantity in order to minimize the risks associated to early morning training sessions

Body Composition Estimation in Youth Athletes: Agreement Between Two-Component Methods

Body composition techniques such as skinfold measurements, air displacement plethysmography, and underwater weighing are commonly performed in athletic populations, particularly in youth athletes who may not have access to other laboratory methods. However, little is known whether such body composition estimates can be directly compared across techniques. PURPOSE: To determine the agreement between common two-component (2C) body composition techniques. METHODS: 90 youth athletes (Males: 39; Females: 51; Age: 18.2 ± 2.4 years; Height: 172.0 ± 9.9 cm; Body Mass: 69.0 ± 12.5 kg; Underwater Weighing [UWW] Body Fat Percentage [%BF]: 20.2 ± 7.0%) participated in this study. 2C estimates of %BF were determined via UWW, air displacement plethysmography (ADP), and 7-site skinfold (SKF) using the applicable Jackson-Pollock equation. Body mass was measured via calibrated scale. Agreement between methods was quantified using Lin’s concordance correlation coefficients (CCC). Estimates of body fat percentage were also compared between techniques using paired samples t-tests (α \u3c 0.05) and equivalence testing, with the threshold of equivalence set at ± 2% body fat. RESULTS: Mean ± SD %BF estimates were 20.2 ± 7.0% (UWW), 18.7 ± 7.3% (ADP), and 16.1 ± 7.2% (SKF). Mean differences between methods were 1.6% [95% CI: 0.8, 2.3] for UWW vs. ADP, 4.1% [95% CI: 3.4, 4.8] for UWW vs. SKF, and 2.6% [95% CI: 1.9, 3.2] for ADP vs. SKF. Paired-samples t-tests revealed significant differences between %BF estimates for each comparison. Likewise, no methods were found to be equivalent, based on a ± 2% BF equivalence range. CCC values were 0.855 for UWW vs. ADP, 0.759 for UWW vs. SKF, and 0.844 for ADP vs. SKF. CONCLUSION: This study suggests limited agreement between 2C %BF estimates derived from three common assessment techniques. Hypothesis testing revealed significant differences between methods, and the magnitude of these differences resulted in non-equivalence at ± 2% BF. Based on these results, it appears that direct comparisons between 2C %BF estimates from these different techniques should be avoided if possible. Though the magnitude of the differences between techniques may be acceptable in certain contexts, coaches and clinicians should strive to utilize the same assessment methodology when examining and comparing body composition results across time

Assessment of Youth Athlete Body Composition using Bioimpedance Techniques as Compared to a Three-Compartment Model

Body composition is believed to contribute to success in many sports. For this reason, assessment of body composition with various devices is commonly performed. The agreement between devices warrants exploration, particularly in groups with limited data, such as youth athletes. PURPOSE: To determine the agreement between a 3-compartment model (3C) and bioelectrical impedance analysis (BIA) devices for assessing body composition in youth athletes. METHODS: The body composition of 90 youth athletes was evaluated (51 F, 39 M; age: 18.2±2.4 y; body mass: 69.0±12.5 kg; height: 172.0±9.9 cm; BMI: 23.2±3.2 kg/m2, BF%: 19.7±6.9%). 3C values were produced using body volume from an underwater weighing system, body water from bioimpedance spectroscopy (ImpediMed SFB7), and body mass from a calibrated scale. Additionally, three BIA techniques were performed: a consumer-grade standing hand-to-foot analyzer (InBody H2ON; BIAINBODY), a consumer-grade standing foot-to-foot analyzer (Tanita BF-680W; BIATANITA), and a laboratory-grade supine hand-to-foot analyzer (RJL Quantum IV; BIARJL). Bioimpedance from BIARJL was inserted into the Matias FFM equation for athletes. BIA BF% and FFM values were compared to 3C values using paired t-tests, Pearson correlations, and the standard error of the estimate (SEE). RESULTS: 3C BF% estimates did not differ from BIAINBODY (-0.9%, 95% CI: -2.1, 0.2) or BIARJL (0.2%, 95% CI: -0.8, 1.2%). However, BF% was underestimated by BIATANITA relative to 3C (-2.7%, 95% CI: -4.1, -1.2). All BIA BF% estimates were significantly correlated with 3C (r: 0.59 to 0.73; R2: 0.35 to 0.53, pINBODY (0.8 kg, 95% CI: -0.1, 1.6) or BIARJL (0.1 kg, 95% CI: -0.6, 0.9). However, FFM was overestimated by BIATANITA relative to 3C (1.8 kg, 95% CI: 0.7, 2.8). All BIA FFM estimates were significantly correlated with 3C (r: 0.92 to 0.97; R2: 0.85 to 0.93, pCONCLUSION: This study demonstrated potentially acceptable agreement between 3C BF% and FFM estimates and those from BIAINBODY and BIARJL, with the athlete-specific equation used with BIARJL demonstrating the best performance. In contrast, the consumer-grade foot-to-foot analyzer underestimated BF% and overestimated FFM. These findings may help inform practical and accurate body composition estimation in youth athletes

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Examining Changes in Shoulder Strength, Lower Body Power, and Body Composition among Collegiate Baseball Players after Completion of a Summer Baseball League Season

The strength of the shoulder musculature involved with internal rotation and arm extension plays an important role in the overhead throwing motion for baseball athletes, both for throwing-related performance and injury risk. The maintenance of shoulder strength is a high priority for baseball athletes throughout a season; however, little is known in regards to the expected changes in strength throughout a season. To examine pre-post changes in shoulder strength, lower body power, and body composition among collegiate baseball players after the completion of a summer baseball league season. Amateur baseball players (n = 12; age: 20.9 ± 1.0 years.; height: 181.6 ± 5.6 cm; body mass: 86.4 ± 11.1 kg; BMI: 26.0 ± 2.6 kg/m2) participated in the current study. Pre- and post-competitive season, the participants completed shoulder strength assessments and body composition and countermovement vertical jump (CMJ) tests. An upper-body isometric test (athletic shoulder [ASH] test) was used to evaluate shoulder strength for each arm. Each subject completed maximal isometric contractions for both the throwing and non-throwing arms at four separate angles of abduction (180°, ‘I’; 135°, ‘Y’; 90°, ‘T’; and −180°, ‘A’) while lying in a prone position. For shoulder strength, the primary dependent variable of interest was a composite measure that represented the average of the forces produced across all four positions of the ASH test (I, Y, T, A). For the ASH test composite measure, there was a trend toward a significant arm-by-time interaction effect (p = 0.08), as shoulder strength decreased by 9.03% for the throwing arm (ES = 0.72; 95% CI = [−0.27, −0.01]), compared to only 2.03% for the non-throwing arm (ES = 0.15; 95% CI = [−0.16, 0.09]), over the course of the season. The main effects of time (p = 0.16) and arm (p = 0.58) were not significant for the ASH test composite measure. There was no relationship between lower body power and throwing arm strength at baseline (r = 0.20, p = 0.56), and only a non-significant weak relationship at post-test (r = 0.28, p = 0.41). Throughout a season, baseball players may experience reductions in shoulder strength of the throwing arm with minimal changes in shoulder strength in the non-throwing arm