Journal of Strength and Conditioning Research最新文献

{"title":"Twice a Day Lacrosse Training in Temperate Conditions Results in a Negative 24-Hour Sodium Balance in Male and Female University Lacrosse Players.","authors":"Heather Z Macrae, Kirsty M Reynolds, Thomas G Cable, Asya Barutcu, Emily J Hansell, Stephen A Mears, Katharine L Midwood, Callum Mould, Mark P Funnell, Vicky L Goosey-Tolfrey, Lewis J James","doi":"10.1519/JSC.0000000000005164","DOIUrl":"10.1519/JSC.0000000000005164","url":null,"abstract":"<p><strong>Abstract: </strong>Macrae, HZ, Reynolds, KM, Cable, TG, Barutcu, A, Hansell, EJ, Mears, SA, Midwood, KL, Mould, C, Funnell, MP, Goosey-Tolfrey, VL, and James, LJ. Twice a day lacrosse training in temperate conditions results in a negative 24-hour sodium balance in male and female university lacrosse players. J Strength Cond Res 39(9): e1091-e1098, 2025-This study measured 24-hour fluid and sodium balance in 27 university lacrosse players (13 males, 14 females; 21 ± 1 years). For 24 hours, participants maintained their usual fluid and food intake, completed a weighed food diary, and collected all urine produced. Participants completed 2 bouts of 1.5 hours (males) or 2 hours (females) lacrosse training (16.0 ± 3.9°C, 62.3 ± 11.7% relative humidity) separated by 2-2.5 hours rest. Nude body mass was measured at baseline (0 hour), 24 hours later, before and after training, and corrected for food/fluid consumed and urine/feces produced during training to determine sweat losses. A sweat patch was applied (scapula) and analyzed for sweat sodium concentration. Data are mean ± standard deviation or median (Q1-Q3), p < 0.05. Sodium balance at 24 hours was negative for both male (-0.76 ± 1.31 g) and female (-0.47 ± 0.70 g) players but was not different between sexes ( p = 0.350). Body mass at 0 hour and 24 hours was not different for male (79.99 ± 10.02 kg vs 79.69 ± 10.15 kg) or female (65.68 ± 10.17 kg vs 65.82 ± 10.21 kg; both p > 0.05) players. Sweat rates were relatively low and not different between male (0.39 ± 0.23 L/h) and female (0.33 ± 0.18 L/h; p = 0.286) players. There was no difference in sweat sodium concentration (male players: 27 (23-28) mmol/L; female players: 27 (23-31) mmol/L; p = 0.786). Ad libitum drinking, combined with low sweat rates, generally prevented dehydration accruing to a level that might impair performance. Sodium balance deficit was small (∼0.61 g) but may require investigation to understand whether daily deficits accumulate.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e1091-e1098"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Squat Training, Jump Training, and Their Combination on Jump and Sprint Performance of Team Sports Athletes: A Systematic Review With Meta-Analysis.","authors":"Paul Ulloa-Sánchez, Rohit K Thapa, Jessenia Hernández-Elizondo, Andrew Sortwell, Rodrigo Ramirez-Campillo","doi":"10.1519/JSC.0000000000005161","DOIUrl":"10.1519/JSC.0000000000005161","url":null,"abstract":"","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"996-1012"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability of Time Spent Near V̇ o2 max During 2 Cycling Interval Training Sessions: The Effect of V̇ o2 max Criteria.","authors":"João A G Raimundo, Artur F Tramontin, Eduardo C Martins, Fernando K Borszcz, Tiago Turnes, Rafael A de Aguiar, Fabrizio Caputo","doi":"10.1519/JSC.0000000000005154","DOIUrl":"10.1519/JSC.0000000000005154","url":null,"abstract":"<p><strong>Abstract: </strong>Raimundo, JAG, Tramontin, AF, Martins, EC, Borszcz, FK, Turnes, T, de Aguiar, RA, and Caputo, F. Reliability of time spent near V̇ o2 max during 2 cycling interval training sessions: the effect of V̇ o2 max criteria. J Strength Cond Res 39(9): e1067-e1074, 2025-This study aimed to determine the reliability of the time spent near V̇ o2 max (tV̇ o2 max) during 2 work-matched cycling interval trainings and to compare tV̇ o2 max reliability using different V̇ o2 max criteria. Fifteen healthy males participated in this cross-sectional and crossover study. The participants performed on different days, an incremental ramp test followed by a V̇ o2 max verification test, and a test-retest model to analyze tV̇ o2 max during 2 distinct work-matched interval training sessions. The interval training protocols comprised 5 × 2-minute efforts with 1-minute recovery (HIIT 2min:1min ) or 10 × 1-minute efforts with 30-second recovery (HIIT 1min:30s ) at 85% of the incremental peak power output, both followed by a V̇o 2 max verification test. Times sustained above 90 and 95% (t95V̇ o2 max) of V̇ o2 max were analyzed and were compared based on 3 different criteria: (a) V̇ o2 max from incremental and verification test (V̇ o2 max INC-VER ); (b) V̇ o2 max from the verification test on the training day (V̇ o2 max DAY ); and (c) mean V̇ o2 max from V̇ o2 max INC-VER and V̇ o2 max DAY . There were no significant differences in test-retest tV̇ o2 max; the only exception was t95V̇ o2 max during HIIT 1min:30s assessed by V̇ o2 max INC-VER . The typical error of measurement and coefficient of variation ranged from 28 to 61 seconds and 19%-35% for HIIT 2min:1min , and from 21 to 66 seconds and 36%-72% for HIIT 1min:30s . V̇ o2 max INC-VER reduced tV̇ o2 max coefficient of variation compared with V̇ o2 max DAY for HIIT 2min:1min , but not for HIIT 1min:30s . Despite similar test-retest, tV̇ o2 max exhibited low reliability, with no improvement when a V̇ o2 max verification test was included on the training day.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e1067-e1074"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Novel Method for Assessing Load-Velocity Profiles With a Motorized Resistance Device in the Sit-to-Stand Test in Older Adults.","authors":"Daniel Jiménez-Lupión, Ignacio Chirosa-Ríos, Rodrigo Lizama-Pérez, Luis Chirosa-Ríos, Daniel Jerez-Mayorga","doi":"10.1519/JSC.0000000000005173","DOIUrl":"10.1519/JSC.0000000000005173","url":null,"abstract":"<p><strong>Abstract: </strong>Jiménez-Lupión, D, Chirosa-Ríos, I, Lizama-Pérez, R, Chirosa-Ríos, L, and Jerez-Mayorga, D. A novel method for assessing load-velocity profiles with a motorized resistance device in the sit-to-stand test in older adults. J Strength Cond Res 39(9): e1112-e1118, 2025-The load-velocity (L-V) relationship correlates external load and lifting velocity, and the 2-point method for determining this relationship has become a reliable way to assess muscle mechanical capacities. This assessment could prove highly valuable in geriatrics and aging research because it helps identify early declines in muscle strength and power. Functional Electromechanical Dynamometry (FEMD) enables load, velocity, and power measurements during multijoint tasks, like the sit-to-stand (STS) test, facilitating comprehensive muscle function assessment in older adults. This study aimed to evaluate the test-retest reliability and concurrent validity of the 2-point method for determining the L-V relationship using FEMD during loaded STS tasks. Thirty healthy subjects (23 women, 7 men; mean age 61 ± 9.33 years; mean body mass 70.5 ± 14.7 kg; mean height 1.59 ± 0.07 m) participated. They performed unloaded and loaded 5-STS tasks with FEMD. Mean velocities from all loads were used to calculate individual L-V relationships. The absolute reliability demonstrated acceptable repeatability for L 0 (i.e., load at zero velocity) (coefficient of variation [CV]: 9.97%; intraclass correlation coefficient [ICC]: 0.94), V 0 (i.e., velocity at zero load) (CV: 5.70%; ICC: 0.95), and A line (i.e., the area under the L-V relationship line) (CV: 7.60%; ICC: 0.98) with a CV < 10% in all cases. Regarding the concurrent validity of A line variable with respect to mean mechanical power, a high correlation was observed ( r = 0.82; p = < 0.001). This study confirms the reliability and validity of the 2-point method using FEMD for assessing L-V relationships and muscle power during 5-STS in older adults.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e1112-e1118"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comparison of Maximal Push-Up and Bench Press Performance and Their Prediction Based on Load-Velocity Relationships.","authors":"Roland van den Tillaar, Hallvard N Falch, Stian Larsen","doi":"10.1519/JSC.0000000000005160","DOIUrl":"10.1519/JSC.0000000000005160","url":null,"abstract":"<p><strong>Abstract: </strong>van den Tillaar, R, Falch, HN, and Larsen, S. A comparison of maximal push-up and bench press performance and their prediction based on load-velocity relationships. J Strength Cond Res 39(9): 919-923, 2025-This study aimed to compare maximal push-up and bench press performance, and their prediction based on the load-velocity relationships. Eleven resistance-trained men (age 25.3 ± 4.0 years, body mass 84.2 ± 6.1 kg, and body height 1.80 ± 0.06 m) performed push-ups and bench presses with 4 different loads randomly. Push-ups were performed with and without a 10-20-30 kg weight vest. Bench press was performed with similar weights as in the push-ups, followed by finding 1RM in each exercise. A linear encoder measured barbell and push-up velocities during the exercises, and force plates were used to measure the average force on the arms during the push-ups. A load-velocity relationship was established between the load and velocity for the push-up and bench press per subject and the equation used to establish a predicted 1RM. The main findings of this study demonstrate that 1RM for push-ups was significantly higher than with bench press (112.4 ± 18.9 vs. 106.4 ± 20.4 kg); meanwhile, there were no differences in the predicted 1RM. Furthermore, an extremely strong association was observed between the actual 1RM loads performed with the push-up and bench press ( r = 0.92). Even with different load-velocity relationships for the 2 exercises, it was possible to predict a cross-over 1RM between them, which was not significantly different from the actual 1RM loads. For coaches and athletes, this method is an easy, cost, and time-effective option for standard 1RM bench press testing to predict maximal upper body strength.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"919-923"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Change of Direction Density: A Novel Consideration of Consecutive Changes of Direction in Elite Youth Soccer.","authors":"Oliver J Morgan, Barry Drust, Jack David Ade, Mark A Robinson","doi":"10.1519/JSC.0000000000005145","DOIUrl":"10.1519/JSC.0000000000005145","url":null,"abstract":"<p><strong>Abstract: </strong>Morgan, OJ, Drust, B, Ade, JD, and Robinson, MA. Change of direction density: A novel consideration of consecutive changes of direction in elite youth soccer. J Strength Cond Res 39(8): e1010-e1016, 2025-This study aimed to characterize change of directions (CODs) based on density (number of CODs within 10 seconds), locomotor activity (walk, jog, stride, and sprint), and movement direction pre- and post-COD (forwards, sideways, and backwards), relative to playing position. In total, 24 elite male English Premier League academy soccer players (mean ± SD ; age: 19.0 ± 1.9 years, height: 179.9 ± 7.0 cm and body mass: 71.9 ± 6.4 kg) were individually filmed during 10 competitive matches. In total, 7,399 CODs were observed. Level of significance was p ≤ 0.05. An average of 84 ± 23 multiple COD events per player, per game occurred with no significant difference between position. Six CODs within 10 seconds were the average maximum density across positions (1.4 ± 1.2), with 9 CODs within 10 seconds being the maximum observed. Overall, 94% of multiple COD events were 2, 3, and 4 CODs within 10 seconds collectively, and were each performed significantly more than all other density categories (5-9 CODs in 10 seconds) ( p < 0.001). Jogging and striding pre- and post-COD were the most common locomotor activities ( p < 0.05). Change of directions were rarely surrounded by sprinting (1.4 ± 1.4) with <1% of total CODs with a sprint (pre and post) with approximately half of CODs (53%) occurring in a forward movement pre- and post-COD. Change of directions seem to be performed as multiple events, in multiple directions, at mostly submaximal locomotor activities, with some positional differences for movement direction and locomotor activity pre- and post-COD. These data provide valuable guidance for practitioners for testing, conditioning, and rehabilitating soccer players.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e1010-e1016"},"PeriodicalIF":2.5,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Nordic Hamstring Exercise Set Configuration on Eccentric Hamstring Strength Changes in Youth Female Athletes.","authors":"Thibaut Bounias, Greg Henry, Ramnath Goswami, Jason Moran, David G Behm, Benjamin Drury","doi":"10.1519/JSC.0000000000005139","DOIUrl":"10.1519/JSC.0000000000005139","url":null,"abstract":"<p><strong>Abstract: </strong>Bounias, T, Henry, G, Goswami, R, Moran, J, Behm, DG, and Drury, B. Effects of Nordic hamstring exercise set configuration on eccentric hamstring strength changes in youth female athletes. J Strength Cond Res 39(8): 829-836, 2025-Anterior cruciate ligament injury poses a significant risk in youth female athletes. The Nordic hamstring exercise (NHE) can improve eccentric hamstring strength (EHS), a key factor related to anterior cruciate ligament injury risk, yet limited research exists in this population. This study compared 2 NHE set configurations-traditional sets (TS) and rest redistribution (RR)-on EHS in youth female athletes. Subjects (age: 13.93 ± 1.58 years; body mass: 48.95 kg ± 11.15 kg; percentage of predicted adult height: 96.50% ± 4.30%) were randomly assigned to TS ( n = 17) or RR ( n = 18) groups. Both groups performed a 6-week NHE program, increasing weekly volume from 6 to 18 repetitions. Pretests and post-tests assessed EHS changes using the NordBord and isokinetic testing at 60°·s -1 and 180°·s -1 , assessing peak torque (PT), angle of peak torque (°PT), and torque at 20°, 40°, 60°, and 80° of knee flexion. Both TS and RR significantly increased NordBord EHS ( g = 0.34-0.98). Isokinetic data at 60°·s -1 and 180°·s -1 revealed significant small increases in PT and torque at 40°, 60°, and 80° ( g = 0.22-0.46). Yet, no changes were observed in torque at 20° ( g = 0.01-0.23) and the °PT increased ( g = 0.33-0.83). No between-group differences were observed for any measure. These findings suggest that TS or RR set configurations can effectively enhance EHS in youth female athletes. However, to target EHS at longer muscle lengths, practitioners should include additional exercises beyond the NHE.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"829-836"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144258226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sleep Duration and Sleep Quality as Season-Long Predictors of Ratings of Perceived Exertion and Psychological Well-Being in Female Soccer Athletes.","authors":"John William Long, Matthew Gonzalez, John Farrell, Maria Elena Carmargo, Kelly Cheever","doi":"10.1519/JSC.0000000000005166","DOIUrl":"10.1519/JSC.0000000000005166","url":null,"abstract":"<p><strong>Abstract: </strong>Long, JW, Gonzalez, M, Farrell, J, Carmargo, ME, and Cheever, K. Sleep duration and sleep quality as season-long predictors of ratings of perceived exertion and psychological well-being in female soccer athletes. J Strength Cond Res 39(9): 973-981, 2025-Sleep's effect on physiologic and psychological well-being has been examined through cross-sectional studies, but research is limited on the longitudinal impact sleep has on well-being in collegiate athletes. Thus, the purpose of this study was to explore daily fluctuations in subjective measures of psychological wellness and physiologic stress (soreness, rating of perceived exertion [RPE]) across a competitive soccer season, and the extent to which sleep duration and quality modify daily measures of wellness. Twenty female collegiate soccer players underwent daily measures of psychological well-being (mental stress, mental fatigue, anxiety, and depression), physical stress (active time, total distance, GPS load, soreness, and RPE), and sleep (duration and quality) across a 120-day competitive season. Generalized linear mixed-effects models with a zero-inflation component were used to examine the effects of sleep duration and quality on measures of physiologic and psychological stress. Sleep duration was a predictor of RPE and anxiety, and there was an interaction between sleep duration and the day of the soccer season affecting RPE, anxiety, and soreness ( p < 0.05). Sleep quality was a predictor of anxiety, mental stress, and RPE ( p < 0.05). Significant interactions were observed between sleep quality and the day of the soccer season affecting soreness, anxiety, mental fatigue, and mental stress (all p < 0.05). Findings suggest sleep duration and sleep quality are protective of measures of psychological well-being, with increasingly protective effects across a competitive soccer season. These findings have utility in helping to maximize both student athlete performance and wellness.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"973-981"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neuromuscular Profiles of Female Collegiate Athletes: Variations in Countermovement Jump Metrics Across 8 NCAA Division I Sports.","authors":"William J Kraemer, Emaly A Vatne, Catherine Saenz, Paul C Jones, Tyler J Carpenter, Daniel A Cencer, Kevin E Enchelmeyer, Kyle R Pulvermacher, Clare K Quebedeaux, Matthew R Vatne, Joshua A Hagen","doi":"10.1519/JSC.0000000000005170","DOIUrl":"10.1519/JSC.0000000000005170","url":null,"abstract":"<p><strong>Abstract: </strong>Kraemer, WJ, Vatne, EA, Saenz, C, Jones, PC, Carpenter, TJ, Cencer, DA Jr, Enchelmeyer, KE, Pulvermacher, KR, Quebedeaux, CK, Vatne, MR, and Hagen, JA. Neuromuscular profiles of female collegiate athletes: variations in countermovement jump metrics across 8 NCAA Division I sports. J Strength Cond Res 39(9): 952-958, 2025-This study investigated countermovement jump (CMJ) performance metrics among National Collegiate Athletic Association Division I female athletes in 8 sports. The purpose of this study was to assess sport-specific variations in CMJ metrics to inform targeted training. A total of 169 athletes from basketball, field hockey, gymnastics, ice hockey, lacrosse, soccer, swimming, and volleyball were included. Athletes completed 3 CMJ trials with metrics recorded from the best trial, including jump height, average and peak propulsive power, modified reactive strength index, relative peak braking power, and relative peak landing force. Data were analyzed using 1-way analysis of variance with significance at p ≤ 0.05. Significant differences were observed across sports. Ice hockey athletes showed significantly higher jump height, peak propulsive power, and relative braking power compared with athletes in lacrosse, swimming, and field hockey. Findings suggest that athletes in explosive sports like ice hockey demonstrate superior CMJ performance, potentially due to high demands for rapid acceleration and deceleration in competition. These results can guide strength and conditioning coaches to tailor training programs to the specific neuromuscular demands of each sport, enhancing performance and reducing injury risks.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"952-958"},"PeriodicalIF":3.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144266489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron Supplementation After Blood Donation Expedites Hematological Recovery but Does Not Influence Exercise Performance.","authors":"Tyler B Judd, Keely A Shaw, Joel R Krentz, Philip D Chilibeck","doi":"10.1519/JSC.0000000000005082","DOIUrl":"10.1519/JSC.0000000000005082","url":null,"abstract":"<p><strong>Abstract: </strong>Judd, TB, Shaw, KA, Krentz, JR, and Chilibeck, PD. Iron supplementation after blood donation expedites hematological recovery but does not influence exercise performance. J Strength Cond Res 39(6): 660-665, 2025-While the impact of blood donation on hemoglobin and exercise performance and the timeline for recovery is well studied, the role of iron supplementation in expediting recovery of performance is unknown. The objective of this research was to assess the effectiveness of oral iron supplementation in enhancing recovery of hemoglobin, hematocrit, and exercise performance after blood donation. Hemoglobin, hematocrit, and 5-km time trial performance were assessed in 10 moderately active subjects (6 men, 4 women; age = 34.0 ± 7.6 years, body mass = 74.4 ± 12.5 kg, V̇ o2 peak = 50.5 ± 6.0 ml·kg -1 ·min -1 ) before blood donation, the day after, and at weekly intervals for 5 weeks after donation. Before donation, individuals were stratified by sex and randomly assigned to supplement with 60 mg of elemental iron (3 men, 2 women) or placebo (3 men, 2 women) for 5 weeks. Significance was as accepted at p < 0.05. Time trial performance was decreased the day after donation by 6.7% ( p < 0.001) and returned to baseline levels by 1 week after blood donation with no difference between groups. Hemoglobin concentration decreased by 1.6 g·dl -1 after blood donation ( p < 0.01) with no difference between groups and failed to return to baseline after 5 weeks in either group. Hematocrit decreased by 4.0 and 3.1% in the iron and placebo groups, respectively, the day after donation compared with baseline ( p < 0.001). By week 4, hematocrit in the iron group was no longer different from baseline ( p = 1.0) but did not return to baseline values by week 5 in those supplementing with placebo ( p < 0.05). Iron supplementation may enhance hematological recovery after blood donation but does not influence recovery of endurance performance.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"660-665"},"PeriodicalIF":3.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}