Journal of Strength and Conditioning Research最新文献

{"title":"Validity and Test-Retest Reliability of Repetitions-In-Reserve Across Different Low-Loads in the Barbell Bench Press With Blood Flow Restriction.","authors":"William M Grant, Paul S R Goods, Bradley A Wall, Charlie J Davids, Benjamin J Narang, Tadej Debevec, Brendan R Scott","doi":"10.1519/JSC.0000000000005190","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005190","url":null,"abstract":"<p><strong>Abstract: </strong>Grant, WM, Goods, PSR, Wall, BA, Davids, CJ, Narang, BJ, Debevec, T, and Scott, BR. Validity and test-retest reliability of repetitions-in-reserve across different low-loads in the barbell bench press with blood flow restriction. J Strength Cond Res XX(X): 000-000, 2025-Repetitions-in-reserve (RIR) allows the standardization of effort between individuals during resistance training. This study investigated the validity and reliability of predicting RIR during low-load resistance training with blood flow restriction (BFR). Twenty subjects were assessed for bench press one-repetition maximum (1RM), before 4 experimental trials (20, 30, 30, 40% 1RM) comprising 4 sets (30, 15, 15, 15 repetitions; 30 seconds rest) with continuous BFR at 60% arterial occlusion pressure. After 15 repetitions in the final set, subjects estimated RIR before continuing the set to failure. Differences between estimated RIR and actual repetitions to failure were calculated (RIRerror). Test-retest reliability of RIRerror was determined from repeated 30% 1RM trials using intraclass correlation coefficients (ICC) and coefficients of variation (CV). Differences and associations were assessed by repeated measures ANOVA and correlational analyses. The fewest fourth set repetitions were performed at 40% 1RM (median [interquartile range] = 8 [5-16] repetitions), followed by 30% 1RM (30 [19-37]) and 20% 1RM (90 [53-114]). RIRerror was significantly higher with 20% 1RM (52 [23-76]) than 30% 1RM (9 [2-15]; p < 0.001) but was not analyzed at 40% 1RM (because 14/20 subjects completed ≤15 repetitions). Repetitions-in-reserve predictions were moderately reliable (ICC: 0.980, CV: 13.6%), but with wide limits of agreement (-7 to 7 repetitions). Number of fourth set repetitions was almost perfectly correlated with RIRerror (R2 = 0.90-0.94). Repetitions-in-reserve should not replace 1RM training prescriptions for low-load BFR. Results suggest that 30% 1RM is an appropriate load to begin with for trained individuals using a 75-repetition BFR scheme.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612184","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":"Prediction of the Maximal Metabolic Steady State From Heart Rate Variability Using a Submaximal Incremental Ramp Test.","authors":"Bruce Rogers, Juan M Murias, Pablo R Fleitas-Paniagua","doi":"10.1519/JSC.0000000000005196","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005196","url":null,"abstract":"<p><strong>Abstract: </strong>Rogers, B, Murias, JM, and Fleitas-Paniagua, PR. Prediction of the maximal metabolic steady state from heart rate variability using a submaximal incremental ramp test. J Strength Cond Res XX(X): 000-000, 2025-Recent studies have demonstrated that the metabolic rate at the heavy-severe exercise intensity boundary can be determined by identifying the respiratory compensation point (RCP) and the second heart rate variability threshold (HRVT2) from incremental ramp testing. This study examined whether the HRVT2 could be extrapolated from submaximal portions of the incremental test. Fifteen subjects (5 men, 10 women, age 23 ± 4 years, V̇o2max 42.6 ± 8.0 ml·kg-1·min-1) underwent incremental cycling ramp testing measuring gas exchange variables along with an open-source application recording detrended fluctuation analysis (DFA a1) and RR intervals. RR data from ramp start to the point at which DFA a1 reached 0.75 were used for HRVT2 extrapolation. Comparisons were made between the V̇o2 and HR at the RCP and HRVT2. Mean values for RCP vs. HRVT2 V̇o2 and HR were not statistically different, 39.0 ± 9.7 vs. 38.8 ± 11.1 ml·kg-1·min-1 and 168 ± 9 vs. 168 ± 12 bpm, respectively, with equivalence verified. Pearson's r correlation coefficients were 0.92 and 0.60 for RCP vs. HRVT2 V̇o2 and HR, respectively. Bland-Altman analysis showed negligible bias of 0.2 ml·kg-1·min-1 (LOA ±9.0) for V̇o2 and +1 bpm (LOA ±20 bpm) for HR. DFA a1 at the RR interval testing limit was 0.72 ± 0.04 with an HR of 163 ± 12. In this group of healthy recreationally active subjects, the HRVT2 V̇o2 and HR extrapolated from submaximal portions of the incremental test maintained similar agreement and equivalence to the V̇o2 and HR at the RCP as seen in prior studies using testing to exhaustion.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612212","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 Maximal and Supramaximal Accentuated Eccentric Loading on the Barbell Bench Press.","authors":"Margaret M Michalak, Timothy J Suchomel, Beau K Greer, Steven A Long, Christober B Taber","doi":"10.1519/JSC.0000000000005176","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005176","url":null,"abstract":"<p><strong>Abstract: </strong>Michalak, MM, Suchomel, TJ, Greer, BK, Long, SA, and Taber, CB. The effects of maximal and supramaximal accentuated eccentric loading on the barbell bench press. J Strength Cond Res XX(X): 000-000, 2025-The effects of accentuated eccentric loading (AEL) were examined on barbell bench press mean and peak performance metrics across various concentric and eccentric loads. Eighteen strength-trained men (age: 23.8 ± 4.0 years; height: 180.2 ± 5.7 cm; body mass: 95.8 ± 6.6 kg, training age: 2 ± 14 years, bench press 1 repetition maximum (1RM): 120.7 ± 17.0 kg, relative strength ratio: 1.27 ± 0.17 kg·kg-1) participated. Subjects completed repetitions using concentric loads ranging from 40 to 80% 1RM in 10% increments during each experimental session. The AEL protocols used 100% (AEL100) or 110% (AEL110) of concentric 1RM during the eccentric action, and the eccentric load remained the same as the concentric load during the traditional loading session. An analysis of variance with repeated measures was used to analyze the effects of loading condition and concentric load (3 × 5) on concentric power, force, velocity, and eccentric repetition duration. Greater concentric force outputs were observed at 60-80% loads compared with 40% (p < 0.05). In addition, 40% loading elicited greater concentric velocities compared with the 60-80% loads (p < 0.05). The magnitude of the concentric load showed a greater change in performance metrics than the loading condition, alluding to AEL protocols having too great an effect on movement mechanics to result in consistent performance enhancements. Thus, it seems the efficacy of AEL at various concentric loads depends on the magnitude of eccentric loading and the relative strength index of subjects.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612213","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":"Integration of a Knee Flexor Bias or Hip Hinge Bias Resistance Training Program With Combined High-Speed Running in Academy Soccer Players.","authors":"Steven Ross, Nicholas J Ripley, John J McMahon, Paul Comfort","doi":"10.1519/JSC.0000000000005210","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005210","url":null,"abstract":"<p><strong>Abstract: </strong>Ross, S, Ripley, NJ, McMahon, JJ, and Comfort, P. Integration of a knee flexor bias or hip hinge bias resistance training program with combined high-speed running in academy soccer players. J Strength Cond Res XX(X): 000-000, 2025-Strength training has been shown to mitigate risk of hamstring strain injury and enhance athletic performance. However, most training studies are focused on single exercise interventions and, therefore, lacking in ecological validity. In this study, we investigated the effects of combined resistance training and curvilinear high-speed running, with resistance training sessions having either a hip hinge bias (Romanian deadlift; RDL) or knee flexor bias (Nordic hamstring exercise; NHE), on knee flexor strength, jump, and sprint performance. In total, 37 male academy soccer players (17.1 ± 0.2 years; height, 178.3 ± 2.5 cm; body mass, 70.6 ± 0.7 kg) were randomized into 3 groups (RDL, NHE, and control) and completed 6 weeks of training. Knee flexor strength was improved in both intervention groups compared with the control (p ≤ 0.05; g = 0.85-1.62); however, adaptations in sprint (g = 1.14-1.44) and jump performance (g = 1.08-1.57) were superior in the NHE group than in the RDL and control groups. The results of the study indicate that both interventions were effective in improving knee flexor strength and athletic performance, but interventions that include the NHE seem to be more effective.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612209","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":"Development of Stretch-Shortening Cycle Function in Girls During Maturation and in Response to Training: A Narrative Review.","authors":"Lee D McGarrigal, Christopher I Morse, David T Sims, Georgina K Stebbings","doi":"10.1519/JSC.0000000000005191","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005191","url":null,"abstract":"<p><strong>Abstract: </strong>McGarrigal, LD, Morse, CI, Sims, DT, and Stebbings, GK. Development of stretch-shortening cycle function in girls during maturation and in response to training: A narrative review. J Strength Cond Res 39(8): e1061-e1069, 2025-The aim of this narrative review was to examine stretch-shortening cycle (SSC) function and to explore its effects on the athletic performance in girls during maturation and in response to plyometric training (PT), where there has been limited focus to date. The SSC is an integral component of explosive actions such as sprinting and jumping. Literature shows that the SSC develops during maturation because of several morphological, neurophysiological, and structural mechanisms, and that the SSC response can be amplified by training. Research suggests that boys experience \"accelerated adaptation\" in slow and fast SSC function as they mature, but to date, similar studies in girls are limited and often contradictory. Plyometric training capitalizes on the ability of the SSC to generate greater force production by including an eccentric muscle action quickly followed by a concentric action. However, the number of PT studies involving youth female athletes is lacking, with only 10% of all PT studies including female subjects aged <18 years. This is surprising given that PT can enhance athletic performance and reduce the risk of noncontact anterior cruciate ligament injuries in girls. After PT, boys experience \"synergistic adaptation,\" which is the symbiotic relationship between PT strategically programmed to coincide with the development of the SSC that is being concurrently enhanced by the processes of growth and maturation. Establishing if girls experience periods of accelerated and synergistic adaptation in slow and fast SSC function after PT would likely influence future training in this population, which has traditionally been underserved.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612144","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":"Unresisted Sprints Versus Heavy Resisted Sled Training: Relationships With Performance Indicators and Implications for Training Prescription in Elite Youth Rugby Players.","authors":"Santiago Zabaloy, Tomás T Freitas, Javier Gálvez-González, Eduardo Tondelli, Lucas A Pereira, Irineu Loturco","doi":"10.1519/JSC.0000000000005215","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005215","url":null,"abstract":"<p><strong>Abstract: </strong>Zabaloy, S, Freitas, TT, Gálvez-González, J, Tondelli, E, Pereira, LA, and Loturco, I. Unresisted sprints versus heavy resisted sled training: relationships with performance indicators and implications for training prescription in elite youth rugby players. J Strength Cond Res XX(X): 000-000, 2025-The aim of this study was to analyze the associations between sprint velocities achieved under unresisted and resisted (50% body mass [BM]) sprint conditions, squat 1-repetition maximum (squat 1RM) and its associated strength deficit (SDef; from 40 to 90% squat 1RM), and horizontal and vertical jump performance in elite youth rugby players. Twenty-five under-19 youth male rugby players (n = 25; age: 17.3 ± 0.9 years) participated in this study and completed the following tests during the preparation period leading up to the 2024 in-season period: unresisted and resisted 30-m sprints, squat 1RM, countermovement jumps, and standing long jumps. Results showed that unresisted and resisted sprint velocities were significantly associated with both jump tasks (r: 0.46-0.76; p < 0.019), while relative squat 1RM measures (i.e., 1RM relative to BM) demonstrated stronger correlations, compared with absolute 1RM values, with sprint velocities under both conditions, as well as with vertical and horizontal jump metrics (r: 0.40-0.74; p < 0.045). SDefs across the entire range of loads (i.e., 40-90% squat 1RM) were also significantly associated (r: 0.84-0.99; p < 0.001). In summary, the present findings highlight the importance of considering relative strength as an additional measure of strength performance, particularly when the primary objective is to enhance a wide range of sport-specific capabilities. Finally, the associations observed among all values of SDef indicate that reducing this strength-derived variable, especially under lighter loading conditions, is highly constrained or even impossible.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612183","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 Rest Interval Configuration Between Sets on Volume Load During Five Sets of Bench Press and Back Squat Exercise.","authors":"Yuta Yamazaki, Kota Shimamori, Kazuki Takizawa, Taichi Yamaguchi, Keisuke Shibata","doi":"10.1519/JSC.0000000000005202","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005202","url":null,"abstract":"<p><strong>Abstract: </strong>Yamazaki, Y, Shimamori, K, Takizawa, K, Yamaguchi, T, and Shibata, K. Effects of rest interval configuration between sets on volume load during five sets of bench press and back squat exercise. J Strength Cond Res XX(X): 000-000, 2025-The present study examined the effect of 3 different rest interval configurations between sets on volume load during 5 sets of bench press (BP) and back squat (SQ) exercises. Thirteen recreationally resistance-trained male subjects (22.3 ± 3.9 years, 173.8 ± 7.3 cm, 73.5 ± 6.1 kg, BP 1 repetition maximum [1RM]: 90.6 ± 12.6 kg, SQ 1RM: 124.4 ± 23.0 kg) performed 5 sets of BP and SQ at 85% of 1RM load until momentary failure for the following 3 trials in random order; BP followed by SQ using 4- (4-minute trial) and 8-minute rest intervals between sets (8-minute trial), and BP with SQ performed alternately with a 4-minute rest interval between the 2 exercises to provide a 8-minute rest interval between each exercise (Alternating trial). The volume load in BP for the 8-minute trial (2,164.0 ± 519.1 kg) was significantly (p < 0.01) greater than that of the 4-minute trial (1,668.3 ± 365.9 kg), and Alternating trial (1911.3 ± 453.9 kg) did not differ from the other 2 trials. The volume load in SQ for the 8-minute trial (2,899.2 ± 471.9 kg) and Alternating trial (2,777.7 ± 814.0 kg) were significantly (p < 0.01, p < 0.05, respectively) greater than that of the 4-minute trial (2,336.7 ± 618.5 kg). These results suggest that prolonging rest interval between sets contributes to increase volume load in BP and SQ, and alternately performed the 2 exercises are beneficial for both improving volume load and time efficiency.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612145","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":"Influence of Proximity to Failure, Relative Intensity, and Volume on Voluntary Performance and Fatigue Symptoms After Resistance Training: A Systematic Review.","authors":"Daniel Varela-Olalla, Juan Del Campo-Vecino, Carlos Balsalobre-Fernández","doi":"10.1519/JSC.0000000000005194","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005194","url":null,"abstract":"<p><strong>Abstract: </strong>Varela-Olalla, D, del Campo-Vecino, J, and Balsalobre-Fernández, C. Influence of proximity to failure, relative intensity, and volume on voluntary performance and fatigue symptoms after resistance training: a systematic review. J Strength Cond Res XX(X): 000-000, 2025-Fatigue management is of paramount importance and holistic approaches that include neuromuscular and perceptual factors have been developed in recent years because knowledge of the sites of the neuromuscular system that can be altered, and its perceptual impact, is mandatory for programing adequate stimulus-fatigue ratios. Most of the information in this regard comes from continuous whole-body exercise and isometric training, with less information regarding holistic fatigue analysis during traditional resistance training (RT). This review aims to analyze the influence of RT variables on voluntary performance, neuromuscular and perceived fatigue variables. Search was performed on PubMed and Web of Science following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, using terms related to resistance training and fatigue. Records were included if they provide comparisons between RT protocols in terms of acute fatigue in healthy humans. Results from fifty-one articles were included which indicate that contractile function, afferent feedback and perceptual responses are more affected during RT than muscle activation parameters being set duration, proximity to failure and total volume the main determinants of the impairments. Higher fatigue is induced as sets approach failure with high training volumes and densities, especially for protocols using light loads.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612208","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":"Minimal Role of Hamstring Hypertrophy in Strength Transfer Between Nordic Hamstring and Stiff-Leg Deadlift: A Blinded Randomized Controlled Trial.","authors":"Titouan Morin, Valentin Doguet, Antoine Nordez, Arnault Caillet, Lilian Lacourpaille","doi":"10.1519/JSC.0000000000005159","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005159","url":null,"abstract":"<p><strong>Abstract: </strong>Morin, T, Doguet, V, Nordez, A, Caillet, A, and Lacourpaille, L. Minimal role of hamstring hypertrophy in strength transfer between nordic hamstring and stiff-leg deadlift: a blinded randomized controlled trial. J Strength Cond Res XX(X): 000-000, 2025-Strength transfer refers to the gain in strength in a nontrained exercise resulting from training another exercise. This study aims to determine whether whole and selective hamstring hypertrophy influences the magnitude of strength transfer between the Nordic hamstring exercise (NHE) and the stiff-leg deadlift (SDL). Using a blinded randomized controlled design, 36 resistance-untrained individuals were assigned to a control group (CON), an NHE group, or an SDL group. The 2 resistance training programs were performed 3 times per week for 9 weeks. Semimembranosus (SM), semitendinosus (ST), and biceps femoris (BF) hypertrophy was estimated from changes in the muscle volume using 3D ultrasound. Strength transfer was measured by changes in the 1RM of the nontrained exercise. After the resistance training programs, similar and significant whole hamstring hypertrophy was observed in both training groups (NHE: 11.4 ± 6.5%, and SDL: 7.0 ± 8.1%). The NHE group and SDL group presented a selective hypertrophy of ST (24.3 ± 10.8%) and SM (11.2 ± 12.7%), respectively. Conversely, no difference in strength transfer was observed between the NHE group (10.7 ± 8.5%) and the SDL group (20.7 ± 15.0%) (p = 0.06; 95% CI 0.3-20.4%, d = 0.87). Finally, nonsignificant correlations were found between strength transfer and both whole and selective hamstring hypertrophy (r ≤ 0.45), except for the BF in SDL (r = 0.60). We conclude that hamstring hypertrophy has a minimal role in strength transfer in resistance-untrained individuals. These findings suggest that, even with hypertrophy, coaches and practitioners should include both Nordic hamstring and stiff-leg deadlift exercises in the same training program to enhance hamstring strength in knee flexion and hip extension tasks, benefiting both performance and injury prevention.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612211","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 Force-Time and Muscle Activation Characteristics Between the Isometric Squat and Isometric Mid-Thigh Pull.","authors":"Lachlan P James, Charlie J Davids, Tomas Rodriguez-Anderson, Haresh T Suppiah, Benjamin F Mentiplay","doi":"10.1519/JSC.0000000000005198","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005198","url":null,"abstract":"<p><strong>Abstract: </strong>James, LP, Davids, CJ, Rodriguez-Anderson, T, Suppiah, HT, and Mentiplay, BF. A comparison of force-time and muscle activation characteristics between the isometric squat and isometric mid-thigh pull. J Strength Cond Res XX(X): 000-000, 2025-This investigation sought to establish the commonality of force-time curve characteristics between the isometric mid-thigh pull (IMTP) and isometric squat. In addition, the magnitude and timing of muscle activation (electromyography [EMG]) were examined at corresponding points on the force-time curve. Fifteen individuals (male: n = 12; age, 25.6 ± 4.7 years; body mass: 84.3 ± 9.2 kg; female: n = 3; age; 23.5 ± 4.9 years, body mass; 63.8 ± 12.4 kg) performed trials of the IMTP and the isometric squat while simultaneous measures of muscle activation were collected from the vastus medialis [VM], vastus lateralis [VL], biceps femoris [BF], and latissimus dorsi [LD]. A shared variance (r2) of 74% was found for net peak force between tests. A shared variance of 27-48% was demonstrated for early stage measures of force up to 200 ms from onset. Large (VM, VL) to very large (BF, LD) significant relationships for mean EMG were revealed between conditions. Large to very large significant relationships for each EMG epoch were present between conditions for VM and LD. Larger and significantly greater mean muscle activation of the BF occurred in the IMTP. Peak force from the IMTP and isometric squat represent a common aspect of maximal strength. However, given the limited commonality between tests for early force-time characteristics, performance in 1 condition should not be considered representative of performance in the other condition across these measures. Practitioners interested in greater hamstring contribution to lower body maximal strength may prefer the IMTP.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144612142","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}