"Distance mapping" and the 3-D structure of BB +30 3639

BD +30 3639 is a member of a group of uncommon planetary nebula with Wolf-Rayet central star and higher expansion velocities in [O III] than in [N II] lines. Images and high-resolution spectra from the literature are used in order to construct a 3-D model of the nebula using the morpho-kinematic code SHAPE. We find that two homologous expansion laws are needed for the [N II] and [O III] shell. We conclude that the internal velocity field of BD +30 3639 decreases with the distance from the central star at least between the [O III] and [N II] shells. A cylindrical velocity component is used to replicate the high-speed bipolar collimated outflows. We also present a new kinematic analysis technique called "distance mapping". It uses the observed proper motion vectors and the 3-D velocity field to generate maps that can be used as a constraint to the morpho-kinematic modeling with SHAPE as well as improve the accuracy for distance determination. It is applied to BD+30 3639 using 178 internal proper motion vectors from Li et al. (2002) and our 3-D velocity field to determine a distance of 1.52 \pm 0.21 kpc. Finally, we find evidence for an interaction between the eastern part of nebula and the ambient H2 molecular gas.Comment: 11 pages, 12 figures, 1 table, Accepted to MNRA

Countermovement Jump Inter-Limb Asymmetries in Collegiate Basketball Players

The purpose of the present study was to establish the intrasession and intersession reliability of variables obtained from a force plate that was used to quantitate lower extremity inter-limb asymmetry during the bilateral countermovement jump (CMJ). Secondarily, a comparison was performed to determine the influence of the jump protocol CMJ with or without an arm swing (CMJ AS and CMJ NAS, respectively) on inter-limb asymmetries. Twenty-two collegiate basketball players performed three CMJ AS and three CMJ NAS on dual force platforms during two separate testing sessions. A majority of variables met the acceptable criterion of intersession and intrasession relative reliability (ICC > 0.700), while fewer than half met standards established for absolute reliability (CV < 10%). CMJ protocol appeared to influence asymmetries; Concentric Impulse-100 ms, Eccentric Braking Rate of Force Development, Eccentric Deceleration, and Force at Zero velocity were significantly di erent between jumping conditions (CMJAS versus CMJ NAS; p < 0.05). The present data establish the reliability and smallest worthwhile change of inter-limb asymmetries during the CMJ, while also identifying the influence of CMJ protocol on inter-limb asymmetries, which can be useful to practitioners and clinicians in order to e ectively monitor changes associated with performance, injury risk, and return-to-play strategies.Open Access fees paid for in whole or in part by the University of Oklahoma LibrariesYe

The Influence of Countermovement Jump Protocol on Reactive Strength Index Modified and Flight Time: Contraction Time in Collegiate Basketball Players

The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSIMod) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSIMod and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSIMod was calculated by the flight-time (RSIModFT) and impulse-momentum methods (RSIModIMP). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (p < 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSIModFT, RSIModIMP, and FT:CT during both the CMJAS (r ≥ 0.864, p < 0.001) and CMJNAS (r ≥ 0.960, p < 0.001). These findings identify an increase in RSIMod or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSIMod or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.Conflicts of Interest The authors declare no conflict of interest. Funding This research received no external funding.Ye

Associations Between Two Athlete Monitoring Systems Used to Quantify External Training Loads in Basketball Players

Monitoring external training load (eTL) has become popular for team sport for managing fatigue, optimizing performance, and guiding return-to-play protocols. During indoor sports, eTL can be measured via inertial measurement units (IMU) or indoor positioning systems (IPS). Though each device provides unique information, the relationships between devices has not been examined. Therefore, the purpose of this study was to assess the association of eTL between an IMU and IPS used to monitor eTL in team sport. Retrospective analyses were performed on 13 elite male National Collegiate Athletic Association (NCAA) Division I basketball players (age: 20.2 ± 1.2 years, height: 201.1 ± 7.6 cm, mass: 96.8 ± 8.8 kg) from three practices during the off-season training phase. A one-way analysis of variance was used to test differences in eTL across practices. Pearson’s correlation examined the association between the Distance traveled during practice captured by IPS compared to PlayerLoad (PL), PlayerLoad per Minute (PL/Min), 2-Dimensional PlayerLoad (PL2D), 1-Dimensional PlayerLoad Forward (PL1D-FWD), Side (PL1D-SIDE), and Up (PL1D-UP) captured from the IMU. Regression analyses were performed to predict PL from Distance traveled. The eTL characteristics during Practice 1: PL = 420.4 ± 102.9, PL/min = 5.8 ± 1.4, Distance = 1645.9 ± 377.0 m; Practice 2: PL = 472.8 ± 109.5, PL/min = 5.1 ± 1.2, Distance = 1940.0 ± 436.3 m; Practice 3: PL = 295.1 ± 57.8, PL/min = 5.3 ± 1.0, Distance = 1198.2 ± 219.2 m. Significant (p ≤ 0.05) differences were observed in PL, PL2D, PL1D-FWD, PL1D-SIDE, PL1D-UP, and Distance across practices. Significant correlations (p ≤ 0.001) existed between Distance and PL parameters (Practice 1: r = 0.799–0.891; Practice 2: r = 0.819–0.972; and Practice 3: 0.761–0.891). Predictive models using Distance traveled accounted for 73.5–89.7% of the variance in PL. Significant relationships and predictive capacities exists between systems. Nonetheless, each system also appears to capture unique information that may still be useful to performance practitioners regarding the understanding of eTL.Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

Monitoring External Training Loads and Neuromuscular Performance for Division I Basketball Players over the Preseason

Limited research has paralleled concomitant changes in external training load (eTL) and countermovement jump (CMJ) performance. Therefore, this investigation characterized eTL and CMJ performance changes across preseason training in Division 1 male collegiate basketball athletes, while examining the influence of position (Guard vs. Forward/Center) and scholarship status (Scholarship = S vs. Walk-on = WO). During 22 practices, eTL was monitored in 14 male athletes, with weekly CMJs performed to quantify neuromuscular performance (Jump Height [JH], Flight Time:Contraction Time [FT:CT], Reactive Strength Index Modified [RSIMod ]). PlayerLoad per minute was significantly higher during W1 and W2 (5.4 ± 1.3au and 5.3 ± 1.2au, respectively; p < 0.05) compared to subsequent weeks, but no additional differences in eTL parameters across time were observed. Scholarship athletes displayed greater PlayerLoad (S = 777.1 ± 35.6, WO = 530.1 ± 56.20; Inertial Movement Analysis (IMA) IMA_High (S = 70.9 ± 15.2, WO = 41.3 ± 15.2); IMA_Medium (S = 159.9 ± 30.7, WO = 92.7 ± 30.6); and IMA_Low (S = 700.6 ± 105.1, WO = 405 ± 105.0;) (p < 0.05), with no observed differences in eTL by position. Moderate decreases in FT:CT and RSIMod paralleled increased eTL. Significant increases in practice intensity (W1 and W2) did not impact CMJ performance, suggesting athletes could cope with the prescribed training loads. However, moderate perturbations in FT:CT and RSIMod paralleled the weeks with intensified training. Cumulatively, scholarship status appears to influence eTL while player position does not.The authors would like to thank Mr. Brady Brown and Mr. Keldon Peak for their assistance with this project. Additionally, the authors thank the Basketball Programs at the University of Oklahoma for their continued support of research directed at enhancing athlete performance, while also improving overall student-athlete welfare. Finally, the authors would also like to thank all of the student-athletes that graciously volunteered their time to enroll and participate in this study. The experiments comply with the current laws of the country in which they were performed. The authors have no conflict of interest to declare. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

3-D ionization structure (in stereoscopic view) of Planetary Nebulae: the case of NGC 1501

Long-slit echellograms of the high excitation planetary nebula NGC1501, reduced according to the methodology developed by Sabbadin et al. (2000a, b), allowed us to obtain the ``true'' distribution of the ionized gas in the eight nebular slices covered by the spectroscopic slit. A 3-D rendering procedure is described and applied, which assembles the tomographic maps and rebuilds the spatial structure. The images of NGC 1501, as seen in 12 directions separated by 15 deg, form a series of stereoscopic pairs giving surprising 3-D views in as many directions. The main nebula consists of an almost oblate ellipsoid of moderate ellipticity (a=44 arcsec, a/b=1.02, a/c=1.11), brighter in the equatorial belt, deformed by several bumps, and embedded in a quite homogeneous, inwards extended cocoon. Some reliability tests are applied to the rebuilt nebula; the radial matter profile, the small scale density fluctuations and the 2-D (morphology) - 3-D (structure) correlation are presented and analysed. The wide applications of the 3-D reconstruction to the morphology, physical conditions, ionization parameters and evolutionary status of expanding nebulae in general (planetary nebulae, nova and supernova remnants, shells around Population I Wolf-Rayet stars, nebulae ejected by symbiotic stars, bubbles surrounding early spectral type main sequence stars etc.) are introduced.Comment: 12 pages + 11 (gif) figures. Accepted for publication in A&A. A postscript file with figs. can be retrieved at http://panoramix.pd.astro.it/~sabbadi

Does Footwear Influence Countermovement Jump Parameters Used to Assess Performance in Collegiate Basketball Players?

Background: The countermovement jump (CMJ) is used to monitor short- and long-term changes in neuromuscular performance, where practically relevant alteration may be subtle, requiring detailed and consistent testing protocols to limit error and allow detection of meaningful change. Collegiate basketball players often wear different types of footwear depending upon the training activity, potentially influencing CMJ performance outcomes. Objective: This study evaluated the influence of footwear on key CMJ variables used for routine performance assessments in a cohort of 11 NCAA women’s collegiate basketball players. Method: In a cross-over repeated measures study design, players performed three CMJs in Basketball-, Training-(Trainers), and Olympic Weightlifting (WL) shoes, in a randomized order during one testing session. One-way repeated measures analyses of variance (p ≤ .05) and effect sizes (Cohen’s d) were used to discern differences in CMJ variables among shoe conditions. Results: WL demonstrated greater Eccentric Mean Force (p ≤ .014, d ≥ 0.03) and lower Flight Time:Contraction Time (p ≤ .029, d ≥ 0.31), Jump Height (p ≤ .040, d ≥ 0.32), and Reactive Strength Index-Modified (p ≤ .032, d ≥ 0.40) than both Basketball and Trainers. Additionally, WL exhibited lower Concentric Mean Force (p = .018, d = 0.19), Concentric Mean Power (p = .008, d = 0.29), Eccentric Peak Force (p = .050, d = 0.19), and Flight Time (p = .036, d = 0.31) compared to Trainer. No significant differences and only trivial effects appeared between Basketball and Trainers (p > 0.05, d < 0.1). Conclusion: These findings suggest footwear significantly influences CMJ performance. WL shoes appear to negatively impact CMJ performance; however, Basketball and Trainers appear to exert negligible effects that should allow clinicians and practitioners to feel confident about measurement and data quality when performing short- and long-term CMJ measurements in either Basketball or Trainers