Seasonal Change in Countermovement Jump Performance in NCAA Women’s Golfers

Background of Study: The countermovement vertical jump (CMJ) task has been reported to have positive associations with golf-specific performance variables. Additionally, the CMJ is commonly used to assess neuromuscular fatigue in athletic populations. Objective: Thus, this investigation sought to examine the changes in CMJ performance throughout a competitive season in NCAA collegiate women’s golfers. Methods: Using a longitudinal study design, six collegiate women golfers completed three sessions (pre, mid, and post) of CMJ testing during the spring competition period. During each testing session, two successful jump trials were collected using a portable force platform sampling at 1000 Hz. During each trial, an arm swing was restricted by the use of a dowel placed across the upper back. A one-way repeated measures analysis of variance was used to determine if differences were present between testing sessions. Results: Propulsive net impulse significantly increased from pre to mid (p 0.05) and pre to post (p 0.05). No other variables showed a statistically significant change over the duration of the study, though moderate effect size increases were in countermovement depth from pre to mid-testing (0.73) and jump height from pre to post-testing (0.72). Conclusions: These findings support previous findings of an increase in vertical jump performance over the course of a season in collegiate golfers, though strategies for maximal performance may shift

Impact of hydration status on electromyography and ratings of perceived exertion during the vertical jump

Copyright (c) the author(s). This is an open access article under CC BY license (https://creativecommons.org/licenses/by/4.0/) Background: The vertical jumping task is commonly used to assess lower-body power output in athletic populations, in addition to being commonly used to during investigations of hydration and anaerobic performance. Changes in neuromuscular function during a hypohydrated state have been proposed as a potential mechanism to decreases in anaerobic performance. Objectives: The primary purpose of this investigation was to examine the impact of hydration state on electromyography during the vertical jumping task. Methods: Twenty recreationally trained males were tested in three hydration conditions (hypohydrated, euhydrated, and control). Testing included maximal voluntary contractions of the vastus lateralis, vastus medialis, semitendinosus and medial gastrocnemius. Participants performed three maximal countermovement and squat jumps respectively for a total of six jumps in each condition. Both mean muscle activity and percentage of maximal voluntary contraction were calculated across the propulsive phase of each jump. Additionally, measures of RPE and the use of a mood rating scale were used as subjective measures. Results: No differences were seen in mean muscle activity and percentage of MVC in either of the jumping conditions (p \u3e 0.05). Significant differences were seen with higher ratings of perceived exertion as well as lower levels of mood ratings after the hypohydrated condition (p = 0.02 and p = 0.048 respectively). Conclusions: Decrements seen in vertical jump performance during a hypohydrated state appear to be caused from changes other than neuromuscular function and muscle activity. Differences in subjective measures may provide insight into changes in motivational levels and potentially impacting performance

Impact of Hydration Status On Electromyography and Ratings of Perceived Exertion During the Vertical Jump

Background: The vertical jumping task is commonly used to assess lower-body power output in athletic populations, in addition to being commonly used to during investigations of hydration and anaerobic performance. Changes in neuromuscular function during a hypohydrated state have been proposed as a potential mechanism to decreases in anaerobic performance. Objectives: The primary purpose of this investigation was to examine the impact of hydration state on electromyography during the vertical jumping task. Methods: Twenty recreationally trained males were tested in three hydration conditions (hypohydrated, euhydrated, and control). Testing included maximal voluntary contractions of the vastus lateralis, vastus medialis, semitendinosus and medial gastrocnemius. Participants performed three maximal countermovement and squat jumps respectively for a total of six jumps in each condition. Both mean muscle activity and percentage of maximal voluntary contraction were calculated across the propulsive phase of each jump. Additionally, measures of RPE and the use of a mood rating scale were used as subjective measures. Results: No differences were seen in mean muscle activity and percentage of MVC in either of the jumping conditions (p \u3e 0.05). Significant differences were seen with higher ratings of perceived exertion as well as lower levels of mood ratings after the hypohydrated condition (p = 0.02 and p = 0.048 respectively). Conclusions: Decrements seen in vertical jump performance during a hypohydrated state appear to be caused from changes other than neuromuscular function and muscle activity. Differences in subjective measures may provide insight into changes in motivational levels and potentially impacting performance

Impact of Hydration Status on Jump Performance in Recreationally Trained Males

International Journal of Exercise Science 13(4): 826-836, 2020. The vertical jump is commonly used as a means of evaluating athlete readiness. Athletes have been shown to arrive to training and competition in a hypohydrated state. Thus, this investigation sought to examine the impact of hydration status on both countermovement (CMJ) and squat jump (SJ) performance. Twenty-five recreationally trained males completed three CMJ and SJ in a euhydrated, hypohydrated and control condition. Conditions were separated by a minimum of 24 hours. Hydration status was assessed using urine specific gravity. Jump performance was evaluated using both kinematic and kinetic data obtained from a force platform. A repeated-measures ANOVA was performed for each variable of interest in both the CMJ and SJ. CMJ peak and mean force values were significantly greater in the euhydrated condition compared to the hypohydrated condition (p \u3c 0.05), with no differences between the control condition and either experimental condition. SJ showed reductions in jump height, peak and mean velocity, peak and mean power and impulse from control and euhydrated conditions (p \u3c 0.05). The findings of this investigation show that when performing jump testing, specifically SJ, that hydration status of the individual may impact commonly used variables to assess the readiness of the individual for a given day

Differences in Falls and Recovery From a Slip Based On an Individual\u27s Lower Extremity Corrective Response

Background: Slips and falls account for high rates of injury and mortality in multiple populations. The corrective responses during the slip perturbation have been well documented. However, when a fall results from a slip, it is unclear which of these responses were inadequate. Objective: The purpose of this study was to examine differences in lower extremity corrective responses of the slip recovery response between individuals who fall and those who recover. Methodology: Sixty-four participants completed this study (32 males & 32 females). Participant’s gait kinematics and kinetics were collected during normal gait (NG) and an unexpected slip (US). A prediction equation for slip outcome and slip severity were created using a binary logistic regression model. Results: Our findings show an increased time to peak hip extension (OR = 1.006, CI: 1.000-1.011) and ankle dorsiflexion (OR = 1.005, CI: 1.001-1.009) moments increased the odds of falling, while the average ankle moment was negatively associated with falling (OR = 0.001, CI: 0.001-0.005). Conclusions: Rapid lower extremity corrective responses appear critical in arresting the slip and preventing a fall. While there are various strategies for slip recovery, our findings suggest that the primary recovery mechanism at the slipping hip may play a vital role in preventing the fall

Differences in falls and recovery from a slip based on an individual’s lower extremity corrective response

Copyright (c) the author(s). This is an open access article under CC BY license (https://creativecommons.org/licenses/by/4.0/) Background: Slips and falls account for high rates of injury and mortality in multiple populations. The corrective responses during the slip perturbation have been well documented. However, when a fall results from a slip, it is unclear which of these responses were inadequate. Objective: The purpose of this study was to examine differences in lower extremity corrective responses of the slip recovery response between individuals who fall and those who recover. Methodology: Sixty-four participants completed this study (32 males & 32 females). Participant’s gait kinematics and kinetics were collected during normal gait (NG) and an unexpected slip (US). A prediction equation for slip outcome and slip severity were created using a binary logistic regression model. Results: Our findings show an increased time to peak hip extension (OR = 1.006, CI: 1.000-1.011) and ankle dorsiflexion (OR = 1.005, CI: 1.001-1.009) moments increased the odds of falling, while the average ankle moment was negatively associated with falling (OR = 0.001, CI: 0.001-0.005). Conclusions: Rapid lower extremity corrective responses appear critical in arresting the slip and preventing a fall. While there are various strategies for slip recovery, our findings suggest that the primary recovery mechanism at the slipping hip may play a vital role in preventing the fall

Distant Cluster Hunting I: A Comparison Between the Optical and X-ray Luminosity Functions from an Optical/X-ray Survey

We present a comparison of X-ray and optical luminosities and luminosity functions of cluster candidates from a joint optical/X-ray survey, the ROSAT Optical X-Ray Survey. Completely independent X-ray and optical catalogs of 23 ROSAT fields (4.8 deg2) were created by a matched-filter optical algorithm and by a wavelet technique in the X-ray. We directly compare the results of the optical and X-ray selection techniques. The matched-filter technique detected 74% (26 out of 35) of the most reliable cluster candidates in the X-ray-selected sample; the remainder could be either constellations of X-ray point sources or z>1 clusters. The matched-filter technique identified approximately 3 times the number of candidates (152 candidates) found in the X-ray survey of nearly the same sky (57 candidates). While the estimated optical and X-ray luminosities of clusters of galaxies are correlated, the intrinsic scatter in this relationship is very large. We can reproduce the number and distribution of optical clusters with a model defined by the X-ray luminosity function and by an LX Lambda cl relation if H0=75 km s-1 Mpc-1 and if the LX Lambda cl relation is steeper than the expected LX Lambda 2cl. On statistical grounds, a bimodal distribution of X-ray luminous and X-ray faint clusters is unnecessary to explain our observations. Follow-up work is required to confirm whether the clusters without bright X-ray counterparts are simply X-ray faint for their optical luminosity because of their low mass or youth or are a distinct population of clusters that do not, for some reason, have dense intracluster media. We suspect that these optical clusters are low-mass systems, with correspondingly low X-ray temperatures and luminosities, or that they are not yet completely virialized systems.Comment: 11 pages, 3 figures. ApJ Letters publishe

Distant Cluster Hunting II: A comparison of X-ray and optical cluster detection techniques and catalogs from the ROX Survey

We present and analyze the optical and X-ray catalogs of moderate-redshift cluster candidates from the ROSAT Optical X-ray Survey, or ROXS. The survey covers 4.8 square degrees (23 ROSAT PSPC pointings). The cross-correlated cluster catalogs were constructed by comparing two independent catalogs extracted from the optical and X-ray bandpasses, using a matched filter technique for the optical data and a wavelet technique for the X-ray data. We cross-id cluster candidates in each catalog. In Paper II we present the cluster catalogs and a numerical simulation of ROXS. We also present color-magnitude plots for several cluster candidates, and examine the prominence of the red sequence in each. We find that the X-ray clusters analyzed in this way do not all have a prominent red sequence. We conclude that while the red sequence may be distinct for massive, virialized clusters, it may be less so for lower-mass clusters at even moderate redshifts. Multiple, complementary methods of selecting and defining clusters may be essential, particularly at high redshift where all methods run into completeness limits, incomplete understanding of physical evolution, and projection effects.Comment: 68 pages, 18 figures ApJ, in pres

BMP9 Mutations Cause a Vascular-Anomaly Syndrome with Phenotypic Overlap with Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), the most common inherited vascular disorder, is caused by mutations in genes involved in the transforming growth factor beta (TGF-β) signaling pathway (ENG, ACVRL1, and SMAD4). Yet, approximately 15% of individuals with clinical features of HHT do not have mutations in these genes, suggesting that there are undiscovered mutations in other genes for HHT and possibly vascular disorders with overlapping phenotypes. The genetic etiology for 191 unrelated individuals clinically suspected to have HHT was investigated with the use of exome and Sanger sequencing; these individuals had no mutations in ENG, ACVRL1, and SMAD4. Mutations in BMP9 (also known as GDF2) were identified in three unrelated probands. These three individuals had epistaxis and dermal lesions that were described as telangiectases but whose location and appearance resembled lesions described in some individuals with RASA1-related disorders (capillary malformation-arteriovenous malformation syndrome). Analyses of the variant proteins suggested that mutations negatively affect protein processing and/or function, and a bmp9-deficient zebrafish model demonstrated that BMP9 is involved in angiogenesis. These data confirm a genetic cause of a vascular-anomaly syndrome that has phenotypic overlap with HHT

Evaluation Research and Institutional Pressures: Challenges in Public-Nonprofit Contracting

This article examines the connection between program evaluation research and decision-making by public managers. Drawing on neo-institutional theory, a framework is presented for diagnosing the pressures and conditions that lead alternatively toward or away the rational use of evaluation research. Three cases of public-nonprofit contracting for the delivery of major programs are presented to clarify the way coercive, mimetic, and normative pressures interfere with a sound connection being made between research and implementation. The article concludes by considering how public managers can respond to the isomorphic pressures in their environment that make it hard to act on data relating to program performance.This publication is Hauser Center Working Paper No. 23. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers