Citations

Abstract VanZile, AW, Jones, DD, McHugh, LJ, Clickovich, GL, Morales, MA, Reimschisel, RK, Widenhoefer, TL, Baughman, JT, Urquidi, MD, Conner, DJ, Dobbs, WC, Jagim, AR, Luedke, JA, and Almonroeder, TG. Examining countermovement jump performance and dynamic balance among male high school athletes with varying levels of sports specialization. J Strength Cond Res 39(11): 1163–1168, 2025—Specializing at a young age may limit an athlete's motor development, since focusing on a single sport potentially exposes athletes to less variety of movements and neuromuscular demands. However, there are few studies examining the association between sport specialization and movement performance/control. The purpose of this study was to compare countermovement jump performance and dynamic balance among high school athletes of varying levels of sports specialization. 110 male high school athletes completed countermovement jump testing and the Y-Balance Test (YBT). Ground reaction forces were recorded during countermovement jumps and used to derive peak force, peak velocity, peak power, jump height, and the modified reactive strength index. Y-Balance Test composite scores were calculated to assess dynamic balance across multiple directions, for the dominant and non-dominant limbs. Athletes were grouped into high ( n = 46), moderate ( n = 39), and low ( n = 25) specialization groups based on their sport participation habits. There were no between-group differences for any of the countermovement jump metrics ( p > 0.05). For the YBT composite scores, there was not a group-by-limb interaction effect ( p = 0.28); however, there was a main effect of group ( p = 0.03). Post hoc tests indicated that the high specialization group exhibited lower YBT composite scores compared to the moderate specialization group ( p = 0.01) and a trend toward lower scores compared to the low specialization group ( p = 0.05). In general, highly specialized male athletes exhibited poorer dynamic balance compared to less specialized athletes.

Abstract Witte, BC, Schouten, TC, Westphal, JA, VanZile, AW, Jones, DD, Widenhoefer, TL, Dobbs, WC, Jagim, AR, Luedke, JA, and Almonroeder, TG. The modified reactive strength index is a valid measure of lower-body explosiveness in male and female high school athletes. J Strength Cond Res 38(8): 1428–1432, 2024—The modified reactive strength index (mRSI) is a commonly used metric to quantify lower-body explosiveness during countermovement jump (CMJ) performance. However, few studies have attempted to examine its validity as a measure of explosiveness, particularly among high school athletes. The purpose of this study was to examine the validity of the mRSI as a measure of lower-body explosiveness among a relatively large sample of male and female high school athletes from various sports. As part of this study, male ( n = 132) and female ( n = 43) high school athletes performed CMJs, while ground reaction forces were recorded using a force platform. The vertical ground reaction force data collected during the CMJs were used to derive the following variables: peak force (PF), peak power, time to PF, time to take-off, peak rate of force development, and the mRSI. Principal component analysis was applied and reduced these variables into 2 components related to “force” and “speed.” The mRSI loaded on both the force (loading = 0.82) and speed (loading = −0.46) components, indicating that it incorporates elements of both force and speed, although it loaded more strongly on the force component than the speed component. The observed pattern of cross-loading suggests that the mRSI is generally a valid measure of lower-body explosiveness for male and female high school athletes.

AbstractBackgroundHuman factors research has suggested benefits of consistent teams yet no surgical team consistency measures have been established for teamwork improvement initiatives.MethodsRetrospective analysis was conducted of teams performing consecutive elective procedures of unilateral primary total knee and hip replacement between June 2008 and May 2010 at a large tertiary medical center. Surgeons who performed fewer than 50 cases of the procedures during the study period were excluded. A team was defined as consistent when its nurse and surgical technologist members were both among the three most frequent working with the surgeon during the study period. Odds ratios for prolonged operative time (in the longest quartile), prolonged hospital stay (longer than median), and 30‐day all‐cause readmissions were adjusted for patient characteristics (sex, age, comorbidity, American Society of Anesthesiology status), surgery characteristics (procedures, time of day), and surgeons.ResultsInconsistent teams performed 61 % of the 1,923 cases with eight surgeons, each of which worked with a median of 43.5 (range, 28–58) nurses and 29 (range, 13–47) technologists. Inconsistent teams were associated with higher likelihood of prolonged operative time [odds ratio 1.52, 95 % confidence interval (CI) 1.20–1.91], higher likelihood of prolonged hospital stay (odds ratio 1.51, 95 % CI 1.23–1.86), and more readmissions (adjusted odds ratio 1.42, 95 % CI 1.07–1.89).ConclusionsTeam consistency was an independent predictor of prolonged operative time, prolonged hospital stay, and 30‐day hospital readmission in elective, primary, unilateral total knee, and hip replacement procedures, after adjusting for patient and surgery characteristics and surgeons.

Purpose For nearly two decades, multiple retrospective reports, small prospective studies, and meta-analyses have arrived at conflicting results regarding the value of timing surgical intervention for breast cancer on the basis of menstrual cycle phase. We present the results of a multi–cooperative group, prospective, observational trial of menstrual cycle phase and outcome after breast cancer surgery, led by the North Central Cancer Treatment Group (NCCTG) in collaboration with the National Surgical Adjuvant Breast and Bowel Project (NSABP) and the International Breast Cancer Study Group (IBCSG). Patients and Methods Premenopausal women age 18 to 55 years, who were interviewed for menstrual history and who were surgically treated for stages I to II breast cancer, had serum drawn within 1 day of surgery for estradiol, progesterone, and luteinizing hormone levels. Menstrual history and hormone levels were used to determine menstrual phase: luteal, follicular, and other. Disease-free survival (DFS) and overall survival (OS) rates were determined by Kaplan-Meier method and were compared by using the log-rank test and Cox proportional hazard modeling. Results Of 1,118 women initially enrolled, 834 women comprised the study cohort: 230 (28%) in luteal phase; 363 (44%) in follicular phase; and 241 grouped as other. During a median follow-up of 6.6 years, and in analysis that accounted for nodal disease, estrogen receptor status, adjuvant radiation therapy or chemotherapy, neither DFS nor OS differed with respect to menstrual phase. The 5-year DFS rates were 82.7%, 82.1%, and 79.2% for follicular, luteal, or other phases, respectively. Corresponding OS survival rates were 91.9%, 92.2%, and 91.8%, respectively. Conclusion When menstrual cycle phases were strictly defined, neither DFS nor OS differed between women who underwent surgery during the follicular phase versus the luteal phase. Nearly 30% of the patients did not meet criteria for either follicular- or luteal-phase categories.