Running throughout Middle-Age Keeps Old Adult-Born Neurons Wired.

Exercise may prevent or delay aging-related memory loss and neurodegeneration. In rodents, running increases the number of adult-born neurons in the dentate gyrus (DG) of the hippocampus, in association with improved synaptic plasticity and memory function. However, it is unclear whether adult-born neurons remain fully integrated into the hippocampal network during aging and whether long-term running affects their connectivity. To address this issue, we labeled proliferating DG neural progenitor cells with retrovirus expressing the avian TVA receptor in two-month-old sedentary and running male C57Bl/6 mice. More than six months later, we injected EnvA-pseudotyped rabies virus into the DG as a monosynaptic retrograde tracer, to selectively infect TVA expressing "old" new neurons. We identified and quantified the direct afferent inputs to these adult-born neurons within the hippocampus and (sub)cortical areas. Here, we show that long-term running substantially modifies the network of the neurons generated in young adult mice, upon middle-age. Exercise increases input from hippocampal interneurons onto "old" adult-born neurons, which may play a role in reducing aging-related hippocampal hyperexcitability. In addition, running prevents the loss of adult-born neuron innervation from perirhinal cortex, and increases input from subiculum and entorhinal cortex, brain areas that are essential for contextual and spatial memory. Thus, long-term running maintains the wiring of "old" new neurons, born during early adulthood, within a network that is important for memory function during aging.

Impact of Preceding Workload on Team Performance in Collegiate Men's Ice Hockey.

ABSTRACT: Neeld, KL, Peterson, BJ, Dietz, CC, Cappaert, TA, and Alvar, BA. Impact of preceding workload on team performance in collegiate men's ice hockey. J Strength Cond Res 35(8): 2272-2278, 2021-Although the workload-injury relationship has received ample research attention, the relationship between prior workload and performance in team sport remains poorly understood. The purpose of this study was to determine if preceding workloads influence competition performance in men's ice hockey. On-ice workload data were collected from all players on a NCAA Division I men's ice hockey team for 2 consecutive seasons. Training and match workloads were characterized using 7 variables (player load, skating load, explosive efforts, high force strides, player load·min-1, skating load·min-1, and average stride force·lb-1). Team performance was calculated as the difference between the subject and opposing teams' shots on goal. Nine separate ANCOVAs were performed to assess the effect of workload across quartiles of 5 different time spans (1,3,5,7 and 28 days), and low, typical, and high zones of 4 time ratios (1/28, 3/28, 5/28, and 7/28) days) on team shot differential, accounting for season quarter and rank differential between the subject and opposing team. Alpha was set a priori to 0.05. Of all workload measures included in each analysis, only 7-day high force strides (p < 0.01, eta2 = 0.72), and 7-day player load·min-1 (p < 0.05, eta2 = 0.50) had a significant effect on shot differential. Measures of skating intensity in the week preceding competition have the largest impact on team performance. These results can be used by performance coaches to examine tests of speed, power, strength, and conditioning to identify potential limiting factors to high-intensity skating, design training programs with specific need-based emphases, and make recommendations for weekly management of high-intensity skating loads.

Reliability of Triaxial Accelerometry for Measuring Load in Men's Collegiate Ice Hockey.

Van Iterson, EH, Fitzgerald, JS, Dietz, CC, Snyder, EM, and Peterson, BJ. Reliability of triaxial accelerometry for measuring load in men's collegiate ice hockey. J Strength Cond Res 31(5): 1305-1312, 2017-Wearable microsensor technology incorporating triaxial accelerometry is used to quantify an index of mechanical stress associated with sport-specific movements termed PlayerLoad. The test-retest reliability of PlayerLoad in the environmental setting of ice hockey is unknown. The primary aim of this study was to quantify the test-retest reliability of PlayerLoad in ice hockey players during performance of tasks simulating game conditions. Division I collegiate male ice hockey players (N = 8) wore Catapult Optimeye S5 monitors during repeat performance of 9 ice hockey tasks simulating game conditions. Ordered ice hockey tasks during repeated bouts included acceleration (forward or backward), 60% top-speed, top-speed (forward or backward), repeated shift circuit, ice coasting, slap shot, and bench sitting. Coefficient of variation (CV), intraclass correlation coefficient (ICC), and minimum difference (MD) were used to assess PlayerLoad reliability. Test-retest CVs and ICCs of PlayerLoad were as follows: 8.6% and 0.54 for forward acceleration, 13.8% and 0.78 for backward acceleration, 2.2% and 0.96 for 60% top-speed, 7.5% and 0.79 for forward top-speed, 2.8% and 0.96 for backward top-speed, 26.6% and 0.95 for repeated shift test, 3.9% and 0.68 for slap shot, 3.7% and 0.98 for coasting, and 4.1% and 0.98 for bench sitting, respectively. Raw differences between bouts were not significant for ice hockey tasks (p > 0.05). For each task, between-bout raw differences were lower vs. MD: 0.06 vs. 0.35 (forward acceleration), 0.07 vs. 0.36 (backward acceleration), 0.00 vs. 0.06 (60% top-speed), 0.03 vs. 0.20 (forward top-speed), 0.02 vs. 0.09 (backward top-speed), 0.18 vs. 0.64 (repeated shift test), 0.02 vs. 0.10 (slap shot), 0.00 vs. 0.10 (coasting), and 0.01 vs. 0.11 (bench sitting), respectively. These data suggest that PlayerLoad demonstrates moderate-to-large test-retest reliability in the environmental setting of male Division I collegiate ice hockey. Without previously testing reliability, these data are important as PlayerLoad is routinely quantified in male collegiate ice hockey to assess on ice physical activity.

Drivers of healthcare costs associated with the episode of care for surgical aortic valve replacement versus transcatheter aortic valve implantation.

OBJECTIVE: Transcatheter aortic valve implantation (TAVI) is generally more expensive than surgical aortic valve replacement (SAVR) due to the high cost of the device. Our objective was to understand the patient and procedural drivers of cumulative healthcare costs during the index hospitalisation for these procedures. DESIGN: All patients undergoing TAVI, isolated SAVR or combined SAVR+coronary artery bypass grafting (CABG) at 7 hospitals in Ontario, Canada were identified during the fiscal year 2012-2013. Data were obtained from a prospective registry. Cumulative healthcare costs during the episode of care were determined using microcosting. To identify drivers of healthcare costs, multivariable hierarchical generalised linear models with a logarithmic link and γ distribution were developed for TAVI, SAVR and SAVR+CABG separately. RESULTS: Our cohort consisted of 1310 patients with aortic stenosis, of whom 585 underwent isolated SAVR, 518 had SAVR+CABG and 207 underwent TAVI. The median costs for the index hospitalisation for isolated SAVR were $21 811 (IQR $18 148-$30 498), while those for SAVR+CABG were $27 256 (IQR $21 741-$39 000), compared with $42 742 (IQR $37 295-$56 196) for TAVI. For SAVR, the major patient-level drivers of costs were age >75 years, renal dysfunction and active endocarditis. For TAVI, chronic lung disease was a major patient-level driver. Procedural drivers of cost for TAVI included a non-transfemoral approach. A prolonged intensive care unit stay was associated with increased costs for all procedures. CONCLUSIONS: We found wide variation in healthcare costs for SAVR compared with TAVI, with different patient-level drivers as well as potentially modifiable procedural factors. These highlight areas of further study to optimise healthcare delivery.

Off-Ice Anaerobic Power Does Not Predict On-Ice Repeated Shift Performance in Hockey.

Peterson, BJ, Fitzgerald, JS, Dietz, CC, Ziegler, KS, Baker, SE, and Snyder, EM. Off-ice anaerobic power does not predict on-ice repeated shift performance in hockey. J Strength Cond Res 30(9): 2375-2381, 2016-Anaerobic power is a significant predictor of acceleration and top speed in team sport athletes. Historically, these findings have been applied to ice hockey although recent research has brought their validity for this sport into question. As ice hockey emphasizes the ability to repeatedly produce power, single bout anaerobic power tests should be examined to determine their ability to predict on-ice performance. We tested whether conventional off-ice anaerobic power tests could predict on-ice acceleration, top speed, and repeated shift performance. Forty-five hockey players, aged 18-24 years, completed anthropometric, off-ice, and on-ice tests. Anthropometric and off-ice testing included height, weight, body composition, vertical jump, and Wingate tests. On-ice testing consisted of acceleration, top speed, and repeated shift fatigue tests. Vertical jump (VJ) (r = -0.42; r = -0.58), Wingate relative peak power (WRPP) (r = -0.32; r = -0.43), and relative mean power (WRMP) (r = -0.34; r = -0.48) were significantly correlated (p ≤ 0.05) to on-ice acceleration and top speed, respectively. Conversely, none of the off-ice tests correlated with on-ice repeated shift performance, as measured by first gate, second gate, or total course fatigue; VJ (r = 0.06; r = 0.13; r = 0.09), WRPP (r = 0.06; r = 0.14; r = 0.10), or WRMP (r = -0.10; r = -0.01; r = -0.01). Although conventional off-ice anaerobic power tests predict single bout on-ice acceleration and top speed, they neither predict the repeated shift ability of the player, nor are good markers for performance in ice hockey.

Association Between Vitamin D Status and Maximal-Intensity Exercise Performance in Junior and Collegiate Hockey Players.

Recent evidence suggests that athletes are at risk for poor vitamin D status. This study used a cross-sectional design to investigate the strength of association between 25-hydroxyvitamin D (25(OH)D) concentration and measures of maximal-intensity exercise performance in competitive hockey players. Fifty-three collegiate and junior male ice hockey players training near Minneapolis, MN (44.9° N latitude) participated in the study during the off-season (May 16-June 28). Circulating 25(OH)D concentration, grip strength, vertical jump performance, and power production during the Wingate Anaerobic Test (WAnT) were evaluated. Despite no athletes with 25(OH)D concentration indicative of deficiency (<20 ng·mL), positive bivariate correlations were detected between vitamin D status, relative grip strength (p = 0.024), and peak power during the WAnT (p = 0.035). Only for relative grip strength (p = 0.043), did 25(OH)D concentration predict performance after adjusting for level of play, fat-free mass, fat mass, and self-reported total physical activity in sequential linear regression. Vitamin D status was positively associated with starting gradient (p = 0.020) during the squat jump, with higher concentrations associated with increased rate of force development in the initial portion of the jump. Interventional trials should investigate the impact of vitamin D supplementation on maximal-intensity exercise performance outcomes and rate of force development in large samples of vitamin D-deficient athletes while controlling for training exposure. Our data indicate that if vitamin D status is causally related to maximal-intensity exercise performance in athletes, the effect size is likely small.

Division I Hockey Players Generate More Power Than Division III Players During on- and Off-Ice Performance Tests.

Current research has found anthropometric and physiological characteristics of hockey players that are correlated to performance. These characteristics, however, have never been examined to see whether significant differences exist between on- and off-ice performance markers at different levels of play; Division I, Elite Junior, and Division III. The purpose of this study was to examine the differences that may exist between these characteristics in Division I (24), Elite Junior (10), and Division III hockey (11) players. Forty-five (age: 18-24 years) hockey players completed anthropometric, on-ice, and off-ice tests to ascertain average measures for each division of play. On-ice testing was conducted in full hockey gear and consisted of acceleration, top-speed, and on-ice repeated shift test (RST). Off-ice tests included vertical jump, Wingate, grip strength, and a graded exercise test performed on a skating treadmill to ascertain their (Equation is included in full-text article.). Division I players had significantly lower body fat than their Division III peers (p = 0.004). Division I players also scored significantly better on measures of anaerobic power; vertical jump (p = 0.001), Wingate peak power (p = 0.05), grip strength (p = 0.008), top speed (p = 0.001), and fastest RST course time (p = 0.001) than their Division III counterparts. There was no significant difference between Division I and Elite Junior players for any on- or off-ice performance variable. The results of this study indicate that performance differences between Division I and Division III hockey players seem to be primarily because of the rate of force production.

Vitamin D status is associated with adiposity in male ice hockey players.

UNLABELLED: The prevalence of insufficient vitamin D status is of concern and may negatively affect health and physical performance. PURPOSE: The purpose of this study was twofold, as follows: to assess the prevalence of 25-hydroxyvitamin D (25(OH)D) insufficiency among young hockey players and evaluate the association between 25(OH)D concentration and fat mass (FM) after adjusting for covariates. METHODS: Data were collected for 53 junior and collegiate ice hockey players residing near Minneapolis, MN (44.9° N) during the off-season (May 16 to June 28). Liquid chromatography-tandem mass spectrometry was used to assess 25(OH)D concentration, and hydrostatic weighing was used to determine FM. Dietary intake and endogenous synthesis of vitamin D were evaluated via a questionnaire. RESULTS: Twenty (37.7%) athletes possessed insufficient 25(OH)D concentrations (<32 ng·mL(-1)). Log-transformed 25(OH)D concentration was inversely associated with FM in the athletes (r = -0.52, n = 51, P = 0.001). After controlling for measured covariates using sequential linear regression, the adjusted R2 change value indicated that 8.1% of the variability in (log of) 25(OH)D concentration was predicted by FM (P = 0.005). CONCLUSIONS: The findings of this study demonstrate an inverse association between FM and vitamin D status after adjusting for environmental, dietary, and anthropometric predictors in a sample population of athletes. Athletes with higher levels of adiposity may be at increased risk of poor vitamin D status.

Vitamin D status and V[combining dot above]O2peak during a skate treadmill graded exercise test in competitive ice hockey players.

Vitamin D status has been associated with cardiorespiratory fitness (CRF) in cross-sectional investigations in the general population. Data characterizing the association between 25-hydroxyvitamin D (25(OH)D) concentration and CRF in athletes are lacking. Junior and collegiate ice hockey players were recruited from the Minneapolis, MN (44.9° N), area during the off-season period (May 16-June 28). The purpose of this study was to examine the cross-sectional association between 25(OH)D concentration and CRF in a sample population of competitive ice hockey players. Circulating 25(OH)D level was assessed from a capillary blood sample analyzed using liquid chromatography-tandem mass spectrometry. V[Combining Dot Above]O2peak during a skate treadmill graded exercise test (GXT) was used to assess CRF. Data on both 25(OH)D concentration and V[Combining Dot Above]O2peak were available for 52 athletes. Insufficient 25(OH)D concentrations were found in 37.7% of the athletes (<32 ng·ml). Vitamin D status was not significantly associated with any physiological or physical parameter during the skate treadmill GXT.