Tag: statistics

Biochem Cell Biol. 2023 Aug 28. doi: 10.1139/bcb-2023-0156. Online ahead of print.

ABSTRACT

Cerebral Microbleeds (CMBs) in the brain are the essential indicators of critical brain disorders such as dementia and ischemic stroke. Generally, CMBs are detected manually by experts which is an exhaustive task with limited productivity. Since, CMBs have complex morphological nature, so manual detection is prone to errors. This paper presents a machine learning-based automated Cerebral Microbleeds detection technique in the brain SWI scans based on statistical feature extraction and classification. The proposed method consists of three steps: 1. Removal of the skull and extraction of the brain 2. Thresholding for the extraction of initial candidates 3. Extracting features and applying classification models such as random forest and naïve bayes classifiers for the detection of true positive cerebral microbleeds. The proposed technique is validated on a dataset consisting of 20 subjects. The dataset is divided into training data which consists of 14 subjects with 104 microbleeds and testing data which consists of 6 subjects with 63 microbleeds. We were able to 85.7% sensitivity using the random forest classifier with 4.2 false positives per CMB and the naive bayes classifier achieved 90.5% sensitivity with 5.5 false positives per CMB. The proposed technique outperformed many state-of-the-art methods proposed in previous studies.

PMID:37639730 | DOI:10.1139/bcb-2023-0156

Ann Intern Med. 2023 Aug 29. doi: 10.7326/M23-0069. Online ahead of print.

ABSTRACT

BACKGROUND: Firearm injuries are a public health crisis in the United States.

OBJECTIVE: To examine the incidence and factors associated with recurrent firearm injuries and death among patients presenting with an acute (index), nonfatal firearm injury.

DESIGN: Multicenter, observational, cohort study.

SETTING: Four adult and pediatric level I trauma hospitals in St. Louis, Missouri, 2010 to 2019.

PARTICIPANTS: Consecutive adult and pediatric patients (n = 9553) presenting to a participating hospital with a nonfatal acute firearm injury.

MEASUREMENTS: Data on firearm-injured patient demographics, hospital and diagnostic information, health insurance status, and death were collected from the St. Louis Region-Wide Hospital-Based Violence Intervention Program Data Repository. The Centers for Disease Control and Prevention (CDC) Social Vulnerability Index was used to characterize the social vulnerability of the census tracts of patients’ residences. Analysis included descriptive statistics and time-to-event analyses estimating the probability of experiencing a recurrent firearm injury.

RESULTS: We identified 10 293 acutely firearm-injured patients of whom 9553 survived the injury and comprised the analytic sample. Over a median follow-up of 3.5 years (IQR, 1.5 to 6.4 years), 1155 patients experienced a recurrent firearm injury including 5 firearm suicides and 149 fatal firearm injuries. Persons experiencing recurrent firearm injury were young (25.3 ± 9.5 years), predominantly male (93%), Black (96%), and uninsured (50%), and resided in high social vulnerability regions (65%). The estimated risk for firearm reinjury was 7% at 1 year and 17% at 8 years.

LIMITATIONS: Limited data on comorbidities and patient-level social determinants of health. Inability to account for recurrent injuries presenting to nonstudy hospitals.

CONCLUSION: Recurrent injury and death are frequent among survivors of firearm injury, particularly among patients from socially vulnerable areas. Our findings highlight the need for interventions to prevent recurrence.

PRIMARY FUNDING SOURCE: Emergency Medicine Foundation-AFFIRM and Missouri Foundation for Health.

PMID:37639717 | DOI:10.7326/M23-0069

Cyberpsychol Behav Soc Netw. 2023 Aug 28. doi: 10.1089/cyber.2022.0108. Online ahead of print.

ABSTRACT

The advent of short video apps like Douyin has greatly popularized the practice of sharing travel experiences in the form of live-streaming or prerecorded videos. With the breakout of COVID-19, the feasibility and appeal of physical travel were substantially undermined such that people now become increasingly dependent on watching short videos as a means of consuming travel-related content. This revolutionary change in the landscape of destination marketing is reshaping the tourism industry, which calls for research efforts of both scholars and practitioners. Our study aimed to investigate how two major characteristics of tourism-themed short videos, namely, level of novelty and camera angle, influence viewers’ behavioral intentions toward actually visiting the places, with the incorporation of several relevant psychological mediators, including immersion, positive surprise, spatial presence, and perceptual realism. A 2 (low- vs. high-level novelty) × 2 (first- vs. third-person view) factorial experiment was designed and conducted. Statistical analysis based on a sample of 480 participants suggested that the perception of positive surprise increased with the level of novelty contained in the videos, which was positively associated with viewers’ visit intentions in an indirect manner. Moreover, compared to the third-person view, employing the first-person view to film sites and scenes produced a greater sense of immersion, which in turn stimulated interest in taking a tour. This study contributes to the growing body of research in digital travel and telepresence.

PMID:37639706 | DOI:10.1089/cyber.2022.0108

J Strength Cond Res. 2023 Aug 25. doi: 10.1519/JSC.0000000000004560. Online ahead of print.

ABSTRACT

McGrath, R, FitzSimmons, S, Andrew, S, Black, K, Bradley, A, Christensen, BK, Collins, K, Klawitter, L, Kieser, J, Langford, M, Orr, M, and Hackney, KJ. Prevalence and trends of weakness among middle-aged and older adults in the United States. J Strength Cond Res XX(X): 000-000, 2023-Muscle weakness, which is often determined with low handgrip strength (HGS), is associated with several adverse health conditions; however, the prevalence and trends of weakness in the United States is not well-understood. We sought to estimate the prevalence and trends of weakness in Americans aged at least 50 years. The total unweighted analytic sample included 22,895 Americans from the 2006-2016 waves of the Health and Retirement Study. Handgrip strength was measured with a handgrip dynamometer. Men with weakness were below at least one of the absolute or normalized (body mass, body mass index) cut points: <35.5 kg, <0.45 kg/kg, <1.05 kg/kg/m2. The presence of any weakness in women was also identified as being below one of the absolute or normalized HGS cut points: <20.0 kg, <0.34 kg/kg, or <0.79 kg/kg/m2. There was an increasing trend in the prevalence of any weakness over time (p < 0.001). The prevalence of weakness was 45.1% (95% confidence interval [CI]: 44.0-46.0) in the 2006-2008 waves and 52.6% (CI: 51.5-53.7) in the 2014-2016 waves. Weakness prevalence was higher for older (≥65 years) Americans (64.2%; CI: 62.8-65.5) compared with middle-aged (50-64 years) Americans (42.2%; CI: 40.6-43.8) in the 2014-2016 waves. Moreover, the prevalence of weakness in the 2014-2016 waves was generally higher in women (54.5%; CI: 53.1-55.9) than in men (50.4%; CI: 48.7-52.0). Differences existed in weakness prevalence across races and ethnicities. The findings from our investigation suggest that the prevalence of weakness is overall pronounced and increasing in Americans. Efforts for mitigating and better operationalizing weakness will elevate in importance as our older American population grows.

PMID:37639680 | DOI:10.1519/JSC.0000000000004560

J Strength Cond Res. 2023 Aug 25. doi: 10.1519/JSC.0000000000004552. Online ahead of print.

ABSTRACT

Askow, AT, Jennings, W, Jagim, AR, Fields, JB, Beaudoin, RG, Sanchez, GM, Weeks, JE, Oliver, JM, and Jones, MT. Athlete external load measures across a competitive season in high school basketball. J Strength Cond Res XX(X): 000-000, 2023-The purpose of this retrospective analysis was to quantify in-season external load and to determine if relationships existed between load metrics and basketball performance. Eleven male high school varsity basketball athletes (n = 11; mass 80.5 ± 9.6 kg, height 190.2 ± 9.4 cm, age 17.6 ± 0.7 years) were monitored across a season. PlayerLoad (PL), PL per minute (PL·min-1), total jumps, and explosive movements (EMs) were quantified using a commercially available local positioning unit. Basketball-specific performance metrics, including points scored, points allowed, point differentials, and shooting percentages for each quarter and game, were compiled. Data were analyzed using repeated-measure analysis of variance to evaluate differences in load by starting status, session type, game outcome, and game type. Pearson’s correlation coefficients were used to assess relationships between load metrics and basketball performance. Statistical significance was set at p < 0.05. The mean values across 23 games for PL, PL·min-1, total jumps, and EMs were 457 ± 104 AU, 10.9 ± 1.6 AU, 42.6 ± 9.6, and 46.7 ± 7.2, respectively. Relationships were observed (p < 0.05) between PL and points scored (r = 0.38) and free throw percentage (r = 0.21). Further relationships were observed between PL·min-1 and free throw shooting percentage (r = -0.27), and between points scored and total jumps (r = 0.28), and EMs (r = 0.26). Notable differences in game demands were observed for playing status. Meaningful differences in measures of external load were observed between each quarter of play, with the highest measures evident in quarters 1 and 3. Guards and forwards experienced minimal differences in external load during gameplay, and game outcome did not result in differences. Higher point totals corresponded with higher PL, total jumps, and EM.

PMID:37639668 | DOI:10.1519/JSC.0000000000004552

J Strength Cond Res. 2023 Aug 25. doi: 10.1519/JSC.0000000000004546. Online ahead of print.

ABSTRACT

Gillen, ZM. Percentile rankings and position differences for absolute and allometrically scaled performance measures from the National Football League scouting combine. J Strength Cond Res XX(X): 000-000, 2023-This study aimed to provide percentile rankings for absolute and allometrically scaled performance measures for National Football League (NFL) Scouting Combine subjects and determine if allometric scaling affected position-specific differences in performance measures. Subjects included American football players (n = 3,015) who participated in the NFL Scouting Combines between 2015 and 2019. Subjects were divided into position groups: defensive backs (DBs, n = 562), defensive linemen (DL, n = 498), linebackers (LBs, n = 395), offensive linemen (OL, n = 505), running backs (RBs, n = 303), tight ends (TEs, n = 165), quarterbacks (QBs, n = 165), and wide receivers (WRs, n = 422). Performance measures included 40-yd dash time (with 10- and 20-yd split times), bench press repetitions to failure, vertical jump height, broad jump distance, pro-agility time, and L-cone drill time. Descriptive statistics were computed for all performance metrics and allometrically scaled performance metrics. One-way analyses of variance tested for position group differences for absolute and allometrically scaled performance measures. Percentile rankings for absolute and allometrically scaled performance measures were determined. Position-specific differences for absolute performance measures indicated that DB and WR tended to be faster, jump higher and further, and have greater change-of-direction capabilities compared with LB, QB, RB, and TE, who scored better in these respects than OL and DL. Allometric scaling revealed that DL, LB, RB, and TE tended to have superior performance than DB and WR, with QB and OL having the poorest performance. This study provides percentile rankings and the equation and parameters by which coaches and practitioners may allometrically scale data for evaluations of normalized performance measures from the NFL Scouting Combine.

PMID:37639664 | DOI:10.1519/JSC.0000000000004546

J Strength Cond Res. 2023 Aug 25. doi: 10.1519/JSC.0000000000004518. Online ahead of print.

ABSTRACT

Wizenberg, AM, Gonzalez-Rojas, D, Rivera, PM, Proppe, CE, Laurel, KP, Stout, JR, Fukuda, DH, Billaut, F, Keller, JL, and Hill, EC. Acute effects of continuous and intermittent blood flow restriction on sprint interval performance and muscle oxygen responses. J Strength Cond Res XX(X): 000-000, 2023-This investigation aimed to examine the acute effects of continuous and intermittent blood flow restriction (CBFR and IBFR, respectively) during sprint interval training (SIT) on muscle oxygenation, sprint performance, and ratings of perceived exertion (RPE). Fifteen men (22.6 ± 2.4 years; 176 ± 6.3 cm; 80.0 ± 12.6 kg) completed in random order a SIT session with CBFR, IBFR (applied during rest), and no blood flow restriction (NoBFR). Each SIT session consisted of two 30-second all-out sprint tests separated by 2 minutes. Peak power (PP), total work (TW), sprint decrement score (Sdec), RPE, and muscle oxygenation were measured during each sprint. A p value ≤0.05 was considered statistically significant. PP decreased to a greater extent from sprint 1 to sprint 2 during CBFR (25.5 ± 11.9%) and IBFR (23.4 ± 9.3%) compared with NoBFR (13.4 ± 8.6%). TW was reduced similarly (17,835.6 ± 966.2 to 12,687.2 ± 675.2 J) from sprint 1 to sprint 2 for all 3 conditions, but TW was lower (collapsed across time) for CBFR (14,320.7 ± 769.1 J) than IBFR (15,548.0 ± 840.5 J) and NoBFR (15,915.4 ± 771.5 J). There were no differences in Sdec (84.3 ± 1.7%, 86.1 ± 1.5%, and 87.2 ± 1.1% for CBFR, IBFR, and NoBFR, respectively) or RPE, which increased from sprint 1 (8.5 ± 0.3) to sprint 2 (9.7 ± 0.1). Collective muscle oxygenation responses increased across time and were similar among conditions, whereas increases in deoxy[heme] and total[heme] were greatest for CBFR. Applying BFR during SIT induced greater decrements in PP, and CBFR resulted in greater decrements in work across repeated sprints. The larger increases in deoxy[heme] and total[heme] for CBFR suggested it may induce greater metabolite accumulation than IBFR and NoBFR when combined with SIT.

PMID:37639655 | DOI:10.1519/JSC.0000000000004518

J Strength Cond Res. 2023 Aug 25. doi: 10.1519/JSC.0000000000004564. Online ahead of print.

ABSTRACT

Burke, BI, Carroll, KM, Travis, SK, Stone, ME, and Stone, MH. Two days versus four days of training cessation following a step-taper in powerlifters. J Strength Cond Res XX(X): 000-000, 2023-Tapering and training cessation are methods of training load management aimed at optimizing athlete preparedness leading into competition. Such practices are often used by strength sport athletes such as powerlifters (i.e., athletes who compete in the back squat [BS], bench press [BP], and deadlift [DL]). The purpose of this study was to compare the differences in maximal strength, subjective recovery and stress state, and body composition alterations in strength athletes undergoing a 1-week step-taper followed by either a 2-day (2D) or 4-day (4D) period of training cessation. Twelve powerlifters (22.3 ± 2.1 yrs; 92.1 ± 20.4 kg; 174.8 ± 7.5 cm) completed a 6-week training protocol aimed at peaking 1 repetition maximum (1RM) strength on BS, BP, and DL. Body composition, subjective recovery and stress state, and 1RM on BS, BP, and DL were assessed before an overreach week (T1) and after the periods of training cessation (T2) for each group. Alpha criterion was set at p ≤ 0.05. There were significant increases in BP (p = 0.032, g = 0.10), powerlifting total (p = 0.014, g = 0.11), and DOTS score (p = 0.006, g = 0.12) after 2D of cessation. However, after 4D of cessation, significant increases were only observed in DL (p = 0.019, g = 0.11) along with significant decreases in BP (p = 0.003, g = -0.13). There were no statistically significant changes in any other variable for either group indicating that BS, psychometric, and body composition data were maintained between T1 and T2. The results of this study support the use of 1-week step-tapers, followed by a short period of training cessation (2-4D) to maintain or improve maximal strength performance.

PMID:37639652 | DOI:10.1519/JSC.0000000000004564

J Clin Oncol. 2023 Aug 28:JCO2300617. doi: 10.1200/JCO.23.00617. Online ahead of print.

ABSTRACT

PURPOSE: The surrogacy of biochemical recurrence (BCR) for overall survival (OS) in localized prostate cancer remains controversial. Herein, we evaluate the surrogacy of BCR using different surrogacy analytic methods.

MATERIALS AND METHODS: Individual patient data from 11 trials evaluating radiotherapy dose escalation, androgen deprivation therapy (ADT) use, and ADT prolongation were obtained. Surrogate candidacy was assessed using the Prentice criteria (including landmark analyses) and the two-stage meta-analytic approach (estimating Kendall’s tau and the R²). Biochemical recurrence-free survival (BCRFS, time from random assignment to BCR or any death) and time to BCR (TTBCR, time from random assignment to BCR or cancer-specific deaths censoring for noncancer-related deaths) were assessed.

RESULTS: Overall, 10,741 patients were included. Dose escalation, addition of short-term ADT, and prolongation of ADT duration significantly improved BCR (hazard ratio [HR], 0.71 [95% CI, 0.63 to 0.79]; HR, 0.53 [95% CI, 0.48 to 0.59]; and HR, 0.54 [95% CI, 0.48 to 0.61], respectively). Adding short-term ADT (HR, 0.91 [95% CI, 0.84 to 0.99]) and prolonging ADT (HR, 0.86 [95% CI, 0.78 to 0.94]) significantly improved OS, whereas dose escalation did not (HR, 0.98 [95% CI, 0.87 to 1.11]). BCR at 48 months was associated with inferior OS in all three groups (HR, 2.46 [95% CI, 2.08 to 2.92]; HR, 1.51 [95% CI, 1.35 to 1.70]; and HR, 2.31 [95% CI, 2.04 to 2.61], respectively). However, after adjusting for BCR at 48 months, there was no significant treatment effect on OS (HR, 1.10 [95% CI, 0.96 to 1.27]; HR, 0.96 [95% CI, 0.87 to 1.06] and 1.00 [95% CI, 0.90 to 1.12], respectively). The patient-level correlation (Kendall’s tau) for BCRFS and OS ranged between 0.59 and 0.69, and that for TTBCR and OS ranged between 0.23 and 0.41. The R² values for trial-level correlation of the treatment effect on BCRFS and TTBCR with that on OS were 0.563 and 0.160, respectively.

CONCLUSION: BCRFS and TTBCR are prognostic but failed to satisfy all surrogacy criteria. Strength of correlation was greater when noncancer-related deaths were considered events.

PMID:37639648 | DOI:10.1200/JCO.23.00617

J Strength Cond Res. 2023 Aug 25. doi: 10.1519/JSC.0000000000004505. Online ahead of print.

ABSTRACT

Donahue, PT, Peel, SA, Rush, M, McInnis, AK, Littlefield, T, Calci, C, and Brutofsky, T. Examining countermovement jump strategies between women’s NCAA division I sports. J Strength Cond Res XX(X): 000-000, 2023-The purpose of this study was to examine countermovement vertical jump performance among female athletes who rely heavily on vertical jump performance within their given sport. Forty-five female athletes representing 3 teams (basketball, volleyball, and beach volleyball) competing at the NCAA Division I level completed 2 maximal effort countermovement jumps (CMJ) using a portable force platform. A 1-way analysis of variance was used to compare groups across each variable. Statistically significant differences were found between the groups regarding propulsive duration and time to takeoff with basketball showing the shortest time and beach volleyball having the longest times (p < 0.05). In addition, differences were seen in countermovement depth and mean propulsive force between the groups with basketball displaying the smallest countermovement and highest force (p < 0.05). No differences were seen in jump height and reactive strength index modified. Greater force and shorter durations in basketball athletes versus the low force and long durations in the beach volleyball athletes suggest that sporting backgrounds play a large role in how the CMJ is performed. This information can aid strength and conditioning practitioners in the design of training programs that are sport specific to the strategies used by the athlete.

PMID:37639644 | DOI:10.1519/JSC.0000000000004505