Journal of Strength and Conditioning Research最新文献

{"title":"Maximum Isometric Hip Adduction Squeeze and Abduction Press Strength Values in Men's Rugby Union Players at Select Timepoints Throughout a Competitive Season.","authors":"Ciaran O' Connor, Martin Mc Intyre, Eamonn Delahunt, Kristian Thorborg","doi":"10.1519/JSC.0000000000005014","DOIUrl":"10.1519/JSC.0000000000005014","url":null,"abstract":"<p><strong>Abstract: </strong>O' Connor, C, Mc Intyre, M, Delahunt, E, and Thorborg, K. Maximum isometric hip adduction squeeze and abduction press strength values in men's rugby union players at select timepoints throughout a competitive season. J Strength Cond Res 39(4): e569-e580, 2025-The purpose of this research was to report hip adduction and abduction strength values in men's rugby union players at select timepoints throughout a competitive season and to examine if differences exist between time of season and hip-testing positions. This cross-sectional repeated measures study design consisted of 15 male rugby union players competing at senior club level. Maximum isometric hip adduction and abduction strength were measured using a ForceFrame in 3 testing positions at specific timepoints: start of preseason (T1), start of competitive season (T2), mid-season period 1 (T3), and mid-season period 2 (T4). At group level, hip adduction strength (N·kg -1 ) increased from T1 to T2 in all testing positions, with significant increases observed in the 0° hip-flexion short-lever position ( p = 0.048), and 45° hip-flexion position ( p = 0.032). No significant changes occurred in hip abduction strength (N·kg -1 ). Hip adduction:abduction strength ratio increased from T1 to T2, with a significant increase observed in the 0° hip-flexion short-lever position ( p = 0.008). At individual level, large variations from baseline strength (N·kg -1 ) were observed between timepoints for hip adduction strength, abduction strength, and adduction:abduction strength ratio. In conclusion, the present study shows increases in hip adduction strength and hip adduction:abduction strength ratio from the start of preseason to the beginning of the competitive season, with no other significant changes in hip strength observed throughout the season. Individual and frequent hip strength monitoring throughout the season and a more individualized exercise prescription approach may be needed for rugby union players, in addition to a more generalized focus on improving adductor and abductor strength.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e569-e580"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142729808","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":"Individual Acceleration-Speed Profile Variables: Comparison and Reliability Between Linear and Curvilinear Sprints.","authors":"Sergio Miras-Moreno, Amador García-Ramos, Matic Sašek, Oskar Cvjetičanin, Nejc Šarabon, Iztok Kavčič, Darjan Smajla","doi":"10.1519/JSC.0000000000005027","DOIUrl":"10.1519/JSC.0000000000005027","url":null,"abstract":"<p><strong>Abstract: </strong>Miras-Moreno, S, García-Ramos, A, Sašek, M, Cvjetičanin, O, Šarabon, N, Kavčič, I, and Smajla, D. Individual acceleration-speed profile variables: comparison and reliability between linear and curvilinear sprints. J Strength Cond Res 39(4): e538-e545, 2025-The aim of this study was to compare linear sprint (LS) and curvilinear sprint (CS) to provide (a) the goodness-of-fit of individual acceleration-speed profile (ASP) and (b) the magnitude and within- and between-session reliability of the ASP variables (A 0 [theoretical maximal acceleration], S 0 [theoretical maximal velocity], and AS slope [slope of the linear ASP]). Twenty-one sports science students performed 2 identical experimental sessions composed of 3 LS trials and 6 CS trials (3 for each testing side). The individual ASP was modeled considering only the fastest or combining the 3 trials of each sprint type. The individual ASP presented a very high goodness-of-fit for the 3 sprint types, but slightly higher for best (range r2 = 0.98 [0.75-1.00]) compared with combined trials (range r2 = 0.95 [0.84-0.99]). Linear sprints revealed higher S 0 (effect size [ES] ≥ -1.88; p < 0.001) and AS slope (ES ≥ -2.80; p < 0.001) but lower A 0 (ES ≥ 1.15; p < 0.001) compared with CS. The ASP variables generally showed an acceptable within-session absolute reliability (range coefficient of variation [CV] = 4.5% [2.4-6.9%]) but an overall poor relative reliability for AS slope (range intraclass correlation coefficient = 0.44 [0.24-0.69]). The between-session reliability was greater for the combined trials (range CV = 4.7% [1.9-8.6%]) compared with the best trial (range CV = 6.1% [2.9-8.7%]). This study opens the possibility of using the ASP to monitor CS, preferably by combining multiple trials to increase its between-session reliability.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e538-e545"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142869489","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":"Countermovement Jumps and Acute to Chronic Workload Ratios in Low, Moderate, and High Jump Load Groups Throughout a Division I Volleyball Season.","authors":"Gabriel J Sanders, Stacie Skodinski, Damjana V Cabarkapa, Mason Howard, Dimitrije Cabarkapa, Roger O Kollock, Corey A Peacock","doi":"10.1519/JSC.0000000000005030","DOIUrl":"10.1519/JSC.0000000000005030","url":null,"abstract":"<p><strong>Abstract: </strong>Sanders, GJ, Skodinski, S, Cabarkapa, DV, Howard, M, Cabarkapa, D, Kollock, RO, and Peacock, CA. Countermovement jumps and acute to chronic workload ratios in low, moderate, and high jump load groups throughout a Division I volleyball season. J Strength Cond Res 39(4): 457-465, 2025-The purpose of the study was to evaluate the effects of low, moderate, and high jump loads on the acute to chronic workload ratio (ACWR) and neuromuscular fatigue throughout a Division I volleyball season. Twelve female volleyball athletes were monitored throughout a competitive season to track daily jump loads and measure neuromuscular fatigue based on twice-weekly countermovement jumps (CMJs) using a dual force plate. Jump loads were categorized into thirds (low, moderate, high-volume) to assess changes in neuromuscular fatigue, and a secondary evaluation examined differences in the ACWR. The results of this study were statistically significant with a p ≤ 0.05. The Wilks Lambda test in the multivariate analysis of variance found there were main effects for low, moderate, and high jump load groups ( F = 50.498, p < 0.001), weeks ( F = 3.136, p < 0.001), and significant group by week interactions ( F = 1.751, p < 0.001) for jump loads and CMJ test results. There was no main effect of week for ACWR ( F = 0.634, p = 0.849), and although statistically different, there were minimal changes in the ACWR between groups. There were significant variations in jump loads and CMJ performance between low, moderate, and high jump load groups across a 16-week season, most notably after week 5. In addition, the data highlight the limitations of the ACWR when detecting changes in athlete fatigue throughout the season.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"457-465"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142869472","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":"The Effects of Percentage-Based, Rating of Perceived Exertion, Repetitions in Reserve, and Velocity-Based Training on Performance and Fatigue Responses.","authors":"Nicholas Cowley, Vaughan Nicholson, Ryan Timmins, Gabriella Munteanu, Tandia Wood, Amador García-Ramos, Cameron Owen, Jonathon Weakley","doi":"10.1519/JSC.0000000000005026","DOIUrl":"10.1519/JSC.0000000000005026","url":null,"abstract":"<p><strong>Abstract: </strong>Cowley, N, Nicholson, V, Timmins, R, Munteanu, G, Wood, T, García-Ramos, A, Owen, C, and Weakley, J. The effects of percentage-based, rating of perceived exertion, repetitions in reserve, and velocity-based training on performance and fatigue responses. J Strength Cond Res 39(4): e516-e529, 2025-This study assessed the effects of percentage-based training (%1RM), rating of perceived exertion (RPE), repetitions in reserve (RIR), and velocity-based training (VBT) on (a) acute kinematic outputs, perceptions of effort, and changes in neuromuscular function during resistance training; and (b) neuromuscular fatigue and perceptions of soreness 24 hours after exercise. In a randomized crossover design, 15 subjects completed a %1RM, RPE, RIR, and VBT training condition involving a fatiguing protocol followed by 5 sets of the free-weight back squat and bench press at 70% of 1 repetition maximum. Subjects returned at 24 hours to assess neuromuscular fatigue and perceived soreness. Percentage-based training and RPE allowed the smallest volume loads, with %1RM prescription causing sets to be regularly taken to failure. Alternatively, RIR and VBT allowed greater maintenance of training volume. Velocity-based training had the most accurate training prescription, with all sets being within 5% of the intended starting velocity, while the RPE and %1RM prescriptive methods caused subjects to train with loads that were increasingly inaccurate. The RPE prescriptive method had the lowest reported values for differential RPE while the %1RM had the greatest change across the session. At no point were there between-group differences in measures of neuromuscular fatigue or perceived soreness. These findings demonstrate that autoregulatory prescriptive methods can be used to mitigate the risk of training to failure, ensure accurate training prescription that can maintain training volume, and enhance within-training kinematic outputs without altering neuromuscular fatigue or perceptions of soreness.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e516-e529"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950504","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":"An Efficient and Accurate Approach for Estimating the Free-Weight Back Squat 1-Repetition Maximum Based on the 2-Point Method and Optimal Minimal Velocity Threshold.","authors":"Zongwei Chen, Fengping Xiao, Yaxu Mao, Xiuli Zhang, Amador García-Ramos","doi":"10.1519/JSC.0000000000005040","DOIUrl":"10.1519/JSC.0000000000005040","url":null,"abstract":"<p><strong>Abstract: </strong>Chen, Z, Xiao, F, Mao, Y, Zhang, X, and García-Ramos, A. An efficient and accurate approach for estimating the free-weight back squat 1-repetition maximum based on the 2-point method and optimal minimal velocity threshold. J Strength Cond Res 39(4): e530-e537, 2025-This study aimed to compare the accuracy of nine 1-repetition maximum (1RM) estimation methods based on velocity recordings during the free-weight back squat. In a counterbalanced order, 39 resistance-trained male subjects performed 2 sessions against 6 loads (∼40, 50, 60, 70, 80, and 90% of 1RM) and 2 sessions against only 2 loads (∼40 and 90% of 1RM) followed by the actual 1RM attempts. The first session of each procedure was used for obtaining minimal velocity thresholds (MVTs) and the second session was used for 1RM estimation. Predicted 1RMs were calculated by entering 3 MVTs (i.e., actual MVT [i.e., the MVT associated with the actual 1RM], general MVT [i.e., 0.30 m·second -1 ], and optimal MVT [i.e., the MVT that minimizes the differences between the actual and predicted 1RMs]) into 3 load-velocity relationship (LVR) regression equations (multiple-point [i.e., using data of 6 loads from the multiple-point test], extracted 2-point [i.e., using data of the lightest and heaviest loads from the multiple-point test], and 2-point [i.e., using data of 2 loads from the 2-point test]). Alpha was set at 0.05. The main findings revealed that only the 1RMs predicted by the optimal MVT showed acceptable accuracy (raw errors ≤0.8 kg, absolute errors ≤4.0%) compared with the actual 1RM. The analysis of variance failed to reveal a significant main effect of the \"type of LVR model\" ( p = 0.079). Therefore, we recommend using the 2-point method combined with the optimal MVT to obtain an efficient and accurate 1RM estimation during the free-weight back squat.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e530-e537"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142869433","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":"Wellness and Session Rating of Perceived Exertion in Professional Basketball Players Within Different Weekly Contexts.","authors":"Roberto Molina, Daniel Lapresa, Javier Arana, Ildefonso Álvarez, Hugo Salazar","doi":"10.1519/JSC.0000000000005023","DOIUrl":"10.1519/JSC.0000000000005023","url":null,"abstract":"<p><strong>Abstract: </strong>Molina, R, Lapresa, D, Arana, J, Álvarez, I, and Salazar, H. Wellness and session rating of perceived exertion in professional basketball players within different weekly contexts. J Strength Cond Res 39(4): e546-e551, 2025-The objective of this article was to analyze the level of well-being-through the wellness questionnaire-and the training load-based on the session rating of perceived exertion (sRPE)-in professional basketball players within different weekly contexts during the season 2020/2021. The team analyzed played 2 competitions: Endesa League (Asociación de Clubes de Baloncesto)-the highest level of competition in Spain-and the Basketball Champions League at the European level. Non-parametric statistics have been used because of the size of the sample and the ordinal nature of the scores. The contrast of related groups has not been significant for the wellness variable, remaining stable scores throughout different weekly contexts (weeks without competition, regular weeks with 1 game, and congested weeks with 2 or more games). Regarding the training load results, a significant effect size has been found in the contrast of medians depending on the proximity to the game in regular weeks and congested weeks, while in weeks without competition, moments of load alternation have been detected. This work is an example of the practical application of the wellness-sRPE relationship as an effective indicator within the week periodization.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e546-e551"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142864716","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":"Estimation of Whole-Body Bone Mineral Density Through Air Displacement Plethysmography in a Large Sample of Elite Athletes.","authors":"Meghan K Magee, Jennifer B Fields, Andrew Jagim, Brittanie Lockard, Angela Miller, Debra Stroiney, Margaret T Jones","doi":"10.1519/JSC.0000000000005024","DOIUrl":"10.1519/JSC.0000000000005024","url":null,"abstract":"<p><strong>Abstract: </strong>Magee, MK, Fields, JB, Jagim, A, Lockard, B, Miller, A, Stroiney, D, and Jones, MT. Estimation of whole-body bone mineral density through air displacement plethysmography in a large sample of elite athletes. J Strength Cond Res 39(4): 427-432, 2025-Dual-energy x-ray absorptiometry (DXA) is used to determine bone mineral density (BMD) and body composition. Regulations and cost may limit DXA's utility in some athletic settings. Air displacement plethysmography (ADP), while able to measure body composition, does not measure BMD. The purpose was to evaluate the influence of body composition parameters obtained from ADP on BMD. Collegiate athletes (males, n = 153; females, n = 208) underwent ADP and DXA assessments. For ADP testing, the Brozek equation was used to estimate body fat percent (BF%) and fat-free mass (FFM) from body density. Dual-energy x-ray absorptiometry tests were completed to obtain BMD using the whole-body scan mode. Stepwise regression was conducted using age, body mass, height, sex, race, FFM (ADP), BF% (ADP), and sport type as independent variables. Total BMD (DXA) was the dependent variable. Accuracy and precision of the final equation were evaluated through Bland-Altman and linear regression. The final regression equation yielded an R2 of 0.691 with race, mass, BF%, age, and sport type as significant predictors ( p < 0.05) of BMD. Bland-Altman and linear regression showed systematic {95% confidence interval [CI] (-0.619 to -0.360)} and proportional bias (95% CI [0.173-0.374]). Although an ADP-derived regression equation may not provide a precise prediction of BMD, it may be useful to establish risk for low BMD if DXA is unavailable. Dual-energy x-ray absorptiometry may not be feasible for some athletic programs; therefore, an estimation equation for BMD derived from ADP values is advantageous for practitioners. This equation may assist in screening athletes for risk of low BMD.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"427-432"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142729693","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":"Differences in Anthropometric Parameters, Physical Fitness, and Kicking Speed in Young Football Players According to Performance Level, Playing Position, and Relative Age Effect: A Population-Based Study.","authors":"Hjalti R Oddsson, Katrín Ý Friðgeirsdóttir, Lára Hafliðadóttir, Ingi Þ Einarsson, Hafrún Kristjánsdóttir, Jose M Saavedra","doi":"10.1519/JSC.0000000000005041","DOIUrl":"10.1519/JSC.0000000000005041","url":null,"abstract":"<p><strong>Abstract: </strong>Oddsson, HR, Friðgeirsdóttir, KÝ, Hafliðadóttir, L, Einarsson, IÞ, Kristjánsdóttir, H, and Saavedra, JM. Differences in anthropometric parameters, physical fitness, and kicking speed in young football players according to performance level, playing position, and relative age effect: a population-based study. J Strength Cond Res 39(4): e561-e568, 2025-The objectives of this study were to determine (a) the differences, both in male and female players, in anthropometric parameters, physical fitness, and kicking speed based on the players' level and position on the field; (b) whether there is a relative age effect based on the players' level, and (c) whether there is a relationship between the relative age effect and the anthropometric parameters, physical fitness, and kicking speed parameters. Eight hundred twenty-six football players (15.76 ± 2.60 year old, 75.7% male) participated in the study. Players were grouped into elite and nonelite, as well as based on their field position and birth quartile. Nonparametric tests were used to study differences by level and by position or trimesters. Chi-square goodness of fit analysis was performed to know the association between elite and nonelite players regarding the relative age effect. Physical fitness parameters and kicking speed were higher in elite players than in nonelite players (5.834 ≥ χ2 ≤ 48.079; p < 0.001). There were differences in anthropometric and physical fitness parameters and kicking speed depending on the player's position: goalkeeper vs. outfield players (7.648 ≥ χ2 ≤ 26.078; p < 0.001) except in jump tests. There was a relative age effect in elite male players ( χ2 = 26.313; p < 0.001) but not in female players, and it was related to anthropometric and physical fitness parameters. This population-based study offers insights into the variables that differentiate elite from nonelite players at young ages, with differences in the relative age effect between male and female players, which can be used by coaches to identify key performance variables.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e561-e568"},"PeriodicalIF":2.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142877173","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":"https://doi.org/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 XX(X): 000-000, 2024-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, V̇o2peak = 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":""},"PeriodicalIF":2.5,"publicationDate":"2025-03-04","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}

{"title":"Biceps Femoris EMG Activity During Incline Treadmill Running and Nordic Hamstring Task.","authors":"Turan A Akyürek, Hayri Ertan, Abdulkerim Darendeli","doi":"10.1519/JSC.0000000000005049","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005049","url":null,"abstract":"<p><strong>Abstract: </strong>Akyürek, TA, Ertan, H, and Darendeli, A. biceps femoris EMG activity during incline treadmill running and nordic hamstring task. J Strength Cond Res XX(X): 000-000, 2024-Although the Nordic hamstring exercise (NHE) is an effective method for strengthening the knee flexors, untrained individuals or intermediate level athletes may have difficulty performing it. In this study, we propose incline treadmill running as an alternative knee flexor exercise. The aim of this study was to compare the biceps femoris (BF) muscle activity (electromyography, EMG) levels between NHE and 10% grade treadmill running at 3 speeds. Nineteen recreationally active men were recruited for the study. Maximum voluntary contraction (MVC) with the knee flexors were completed. Nordic hamstring exercise and 10% grade treadmill running tasks were performed in a randomized counterbalanced order. Biceps femoris EMG activity was recorded during the measurements. Statistical significance was set to p < 0.05. We found that the peak EMG amplitude for BF was higher during the NHE (∼63% MVC) than during treadmill running at a 10% grade across low-to-moderate speeds. Increasing the running speed from 3.61 m·s-1 to 4.16 m·s-1 (∼49% MVC) raised the peak EMG amplitude by approximately 10% MVC. In addition, the variability in EMG amplitude for BF was greater during 10% grade treadmill running than during NHE. Although the peak EMG activity was greater during the NH task, it reached comparable levels when performing 10% grade treadmill running at a moderate running speed. Our results suggest that incline treadmill running can be an alternative knee flexor exercise that can be individualized by adjusting treadmill grade and speed, particularly for untrained individuals.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605297","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}