Journal of Strength and Conditioning Research最新文献

{"title":"Supramaximal Walkouts Protect Against Performance Decrements Experienced in Repeated Sets of Back Squats.","authors":"Timothy D Griest, Cameron M McCarthy, Liliana I Rentería, Kieran G P Paterson, Daniel F Eurich, Grant R Laskin, Michael J Ormsbee","doi":"10.1519/JSC.0000000000005085","DOIUrl":"10.1519/JSC.0000000000005085","url":null,"abstract":"<p><strong>Abstract: </strong>Griest, TD, McCarthy, CM, Rentería, LI, Paterson, KGP, Eurich, DF, Laskin, GR, and Ormsbee, MJ. Supramaximal walkouts protect against performance decrements experienced in repeated sets of back squats. J Strength Cond Res 39(6): 617-624, 2025-The purpose of this study was to determine whether performing supramaximal walkouts (SMW) enhances subsequent repeated back squat performance. Thirteen resistance-trained men (age: 23.2 ± 3.0 years, 1 repetition maximum [1RM] back squat: 2.1 ± 0.4 kg·bodymass -1 ) completed 2 trials in a randomized, counterbalanced, crossover design. Each trial began with 1 back squat at 92.5% 1RM (PRE). Five minutes post-PRE, subjects un-racked either 110% 1RM (SMW) or 30% 1RM (CON) for a 10-second hold. After 5 minutes rest, 3 sets of 1 back squat at 92.5% 1RM were completed with 5 minutes between each. Performance and muscle activation indicators were measured during each repetition. All data were analyzed through Friedman's 2-way ANOVA by ranks. Significance was set at p < 0.05. Average power and velocity decreased from PRE in all 3 sets ( p < 0.05) following CON. Following SMW, these variables decreased during POST2 and POST3 ( p < 0.05) but not POST1 ( p > 0.219). In addition, rating of perceived exertion was elevated at POST2 following CON ( p = 0.044), while there were no differences with SMW ( p = 0.716). Peak power, peak velocity, and electromyography amplitude of the vastus lateralis and gluteus maximus were unaltered ( p > 0.077). Performing an SMW at 110% 1RM before back squats may attenuate performance decrements resulting from repeated repetitions for 1 set and, therefore, could be used to maintain performance for 1 additional set during training.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"617-624"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143998322","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 Lower-Body Neuromuscular Performance Characteristics Between Three Professional Levels of Men's Basketball Competition.","authors":"Dimitrije Cabarkapa, Damjana V Cabarkapa, Quincy R Johnson, Nicolas M Philipp, Andrew C Fry","doi":"10.1519/JSC.0000000000005077","DOIUrl":"10.1519/JSC.0000000000005077","url":null,"abstract":"<p><strong>Abstract: </strong>Cabarkapa, D, Cabarkapa, DV, Johnson, QR, Philipp, NM, and Fry, AC. Differences in lower-body neuromuscular performance characteristics between three professional levels of men's basketball competition. J Strength Cond Res 39(6): e764-e768, 2025-While physical and physiological qualities that contribute to optimal on-court performance have been well-examined at the amateur level of basketball competition, they remain under-studied at the professional level of play. Thus, the purpose of this study was to examine differences in lower-body neuromuscular performance characteristics between 3 professional basketball leagues in Europe (i.e., ProA-Adriatic League; ProB-first national league; ProC-first regional league). Thirty-five athletes volunteered to participate in the present investigation. While standing on a uniaxial force plate system sampling at 1,000 Hz, each athlete performed 3 maximum-effort countermovement vertical jumps (CVJ) with no arm swing. One-way analysis of variance was used to examine between-level differences in force-time metrics within both the eccentric and concentric phases of the CVJ ( p < 0.05). The findings reveal the presence of multiple phase-specific differences between the 3 competitive levels. ProB athletes demonstrated higher eccentric peak velocity and eccentric peak and mean power than their ProC counterparts. ProA athletes revealed notably higher concentric mean and peak force and power production capabilities when compared with ProC athletes, including higher jump height and reactive strength index-modified. Overall, these results suggest superior stretch-shortening cycle performance in athletes competing at a higher level of professional basketball play, further supporting the importance of well-designed and implemented resistance training regimens targeted toward optimizing strength and power development.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e764-e768"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143974374","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":"Relationship Between Online Coaching Characteristics, Lifter Satisfaction, and Performance in Powerlifters.","authors":"Jason V Clarke, Alyssa-Joy Spence, Eric R Helms, Matt R Cross","doi":"10.1519/JSC.0000000000005099","DOIUrl":"10.1519/JSC.0000000000005099","url":null,"abstract":"<p><strong>Abstract: </strong>Clarke, JV, Spence, A-J, Helms, ER, and Cross, MR. The relationship between online coaching characteristics, lifter satisfaction, and performance in powerlifters. J Strength Cond Res 39(6): 666-671, 2025-This study aimed to understand the length, mode, and frequency of online powerlifting (PL) coaching delivery and their relationship with lifter satisfaction (LS) and PL performance. Powerlifters ( n = 113) completed a self-reported online survey on their online PL coaching experience. Participants reported a mean PL total of 621 ± 111 kg for men ( n = 59) and 382 ± 77 kg for women ( n = 54). Coaching relationships, on average, were 21.75 ± 14.5 months long, and mean increases in PL total were 14.6 ± 15.5% (14.01 ± 12.43% and 15.32 ± 18.52% for men and women, respectively). When asked how satisfied lifters were with their coaching experience on a scale of 1-5 (1 = extremely dissatisfied, 5 = extremely satisfied), most lifters reported either 4 ( n = 63) or 5 ( n = 42). Using regression analysis, no significant relationship between mode or frequency of communication and LS or change in PL total was observed. There was a positive relationship between longer coach-lifter relationships and greater increases in PL total ( p < 0.001). Higher coach education was associated with increases in PL total ( p = 0.024), although its relationship with satisfaction was inconsistent (positive for lower values and negative for higher, p < 0.005). Together, these results suggest a temporal component to the effectiveness of powerlifting coaching and a potentially positive association between a degree of formal education and key outcomes. Alongside these analyses, these data help create an understanding of current online PL coaching practices.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"666-671"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144006215","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":"Acute Glucose Tolerance in Response to Lower- and Higher-Load Resistance Exercise in Postmenopausal Women: Contribution of Aerobic Capacity and Body Composition.","authors":"Jasmine Paquin, Philippe St-Martin, Sarah-Ève Lord, Philippe Gendron, Martin Brochu, Isabelle J Dionne","doi":"10.1519/JSC.0000000000005096","DOIUrl":"10.1519/JSC.0000000000005096","url":null,"abstract":"<p><strong>Abstract: </strong>Paquin, J, St-Martin, P, Lord, S-E, Gendron, P, Brochu, M, and Dionne, IJ. Acute glucose tolerance in response to lower- and higher-load resistance exercise in postmenopausal women: Contribution of aerobic capacity and body composition. J Strength Cond Res 39(6): e749-e757, 2025-Glucose tolerance (GT), fat-free mass (FFM), and V̇o2peak are known to decline after menopause. Exercise recommendations advise ageing adults to perform heavy weights and low repetitions (HWLR) resistance exercise (RE). However, the most efficient RE parameters to improve acute GT in postmenopausal women (PMW) are unclear. Our aim was to determine how acute GT is influenced by 2 RE sessions of different loads (HWLR vs. low-weight and higher repetitions, LWHR), compared with a control condition, and examine potential contributors. After measuring baseline oral glucose tolerance (OGTT), FFM (DXA), and V̇o2peak (metabolic cart), 12 PMW underwent additional OGTTs (area under the curve-AUC; 2-h glucose) after 3 randomized experimental conditions (control, HWLR, and LWHR). Session volume was defined as the total weight lifted. The Cederholm's index was calculated to derive insulin sensitivity. There was a significant effect of RE on glucose AUC (1,109 ± 234 vs. 954 ± 149 and 974 ± 194 mmol/L × 120 minutes for control, HWLR, and LWHR; p < 0.005) and 2-h glucose (8.8 ± 2.5 vs. 7.0 ± 1.6 and 7.4 ± 2.0 mmol/L for control, HWLR, and LWHR; p < 0.04) with no difference between HWLR and LWHR. A greater volume was achieved with LWHR (4,292.1 ± 1,143.4 vs. 3,888.1 ± 1,042.1 kg, p < 0.05), although it was not significantly associated with post-RE GT. Fat-free mass was significantly associated with Cederholm's index at baseline only (r = 0.6, p < 0.05). Significant correlations were also found between V̇o2peak and glucose AUC for all conditions (all r ≤ -0.6 to 0.8; p < 0.05). We conclude that HWLR and LWHR both acutely improve GT in PMW, whereas V̇o2peak may be a stronger contributor than FFM.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":"39 6","pages":"e749-e757"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127991","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":"Associations Between Physical Performance and Golf Shot Data: A Pilot Study of Touring Professional Female Players.","authors":"Luke Robinson, Andrew Murray, Danny Glover, Dan Coughlan, Margo Mountjoy, Fiona Scott, Anthony Turner, Chris Bishop","doi":"10.1519/JSC.0000000000005090","DOIUrl":"10.1519/JSC.0000000000005090","url":null,"abstract":"<p><strong>Abstract: </strong>Robinson, L, Murray, A, Glover, D, Coughlan, D, Mountjoy, M, Scott, F, Turner, A, and Bishop, C. Associations between physical performance and golf shot data: a pilot study of touring professional female players. J Strength Cond Res 39(6): 687-694, 2025-This study examined the relationship between a comprehensive physical testing battery and golf shot data in touring professional female golfers. Nineteen players (age: 31.00 ± 5.64 years; height: 170.84 ± 7.24 cm; body mass: 67.74 ± 9.16 kg; wingspan: 127.37 ± 14.21 cm) volunteered to take part in the study. Each player completed a dynamic warm-up before engaging in a 90-minute testing session, which gathered information on both physical capacity and golf shot data, all of which was collected at a single Ladies European Tour event. Golf shot data included clubhead speed, ball speed, carry distance, and smash factor, using a Trackman 4 launch monitor. Physical testing included anthropometry data, seated thoracic rotation, isometric mid-thigh pull (IMTP), isometric bench press, countermovement jump (CMJ), and seated medicine ball throws for distance. Pearson's r correlations showed the CMJ to have the strongest and most consistent associations with golf shot performance ( r = 0.51-0.60). In addition, force at 100 ms during the IMTP also demonstrated large associations with carry distance ( r = 0.59), further highlighting the significance of rapid force production in the lower body. Collectively, the findings demonstrate the importance of lower body ballistic force production for female golfers, providing important information for practitioners regarding the relevant physical capacities for testing and training.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"687-694"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144006233","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":"Sex- and Position-Specific Countermovement Jump Outcome and Phase Characteristics in Australian Rules Football Players.","authors":"Peter K Edwards, Nicholas Blackah, Jay R Ebert, Dale Chapman","doi":"10.1519/JSC.0000000000005081","DOIUrl":"10.1519/JSC.0000000000005081","url":null,"abstract":"<p><strong>Abstract: </strong>Edwards, PK, Blackah, N, Ebert, JR, and Chapman, D. Sex- and position-specific countermovement jump outcome and phase characteristics in Australian rules football players. J Strength Cond Res 39(6): e774-e780, 2025-This study was designed to examine positional and sex differences in countermovement jump (CMJ) force-time characteristics among subelite male ( n = 111) and female ( n = 71) Australian football (AF) players and establish normative data for key performance output metrics. A total of 182 male and female players performed 3 maximal effort CMJs on dual force plates. Differences in variables including jump height, peak power, modified reactive strength index (RSI MOD ), and other force-time variables were compared using 1-way ANOVA and Cohen's d effect sizes. Statistical significance was set at p ≤ 0.05. Male players demonstrated significantly greater jump height (36.0 ± 5.2 cm vs. 25.9 ± 4.2 cm; p < 0.001) and RSI MOD (0.52 ± 0.11 vs. 0.39 ± 0.09; p < 0.001) compared with female players, with large effect sizes ( d = 1.18 and 2.08, respectively). Positional differences were observed in both sexes. Male midfielders exhibited a significantly shorter time to takeoff compared with backs (mean difference, -67.1 ms; p = 0.008). Female midfielders, compared with backs, also recorded significantly shorter time to takeoff (mean difference, -79.0 ms; p = 0.014) and higher RSI MOD values (mean difference, 0.05; p = 0.048). No significant differences were found in jump height or peak power between playing positions for either sex. These findings highlight different performance profiles between sexes and playing positions in AF, offering practitioners normative benchmarks to guide return-to-play decisions and optimize player physical development.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e774-e780"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144018725","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":"Electromyographic Analysis of the Support Scale in Gymnastics and Its Related Preconditioning Strengthening Exercises.","authors":"Giuseppe Rosaci, Federico Nigro, Matteo Cortesi, Simone Ciacci, Sandro Bartolomei, Silvia Fantozzi","doi":"10.1519/JSC.0000000000005074","DOIUrl":"10.1519/JSC.0000000000005074","url":null,"abstract":"<p><strong>Abstract: </strong>Rosaci, G, Nigro, F, Cortesi, M, Ciacci, S, Bartolomei, S, and Fantozzi, S. Electromyographic analysis of the planche in gymnastics and its related preconditioning strengthening exercises. J Strength Cond Res 39(6): 680-686, 2025-The support scale (SS) is a common upper body skill in gymnastics. Athletes typically introduce preconditioning strengthening exercises (PSEs) in their training routines to prepare this strength element. Despite the popularity of these exercises, their effectiveness in reproducing the muscle involvements of the SS is unknown. The aim of this study is to compare the muscular excitations, coactivation indices, and synergies between the SS and its related PSEs. Seven high-level ring specialist gymnasts (age: 23.9 ± 4.0 years, height: 165.9 ± 2.8 cm, body mass: 65.6 ± 3.1 kg, experience: 13.0 ± 3.0 years) performed the SS and 5 PSEs. Electromyographic activities of the pectoralis major (clavicular part), latissimus dorsi, triceps (long head), infraspinatus, trapezium (transverse), serratus anterior, biceps brachii, and anterior deltoid were recorded, and muscle synergies were studied. Large differences between the SS and its 5 PSEs were detected in the muscle activity of trapezius ( F = 8.937; p < 0.001; η 2 = 0.641), pectoral ( F = 5.235; p = 0.002; η 2 = 0.512), and biceps muscles ( F = 10.359; p < 0.001; η 2 = 0.674). The coactivation was different in the biceps/triceps ratio ( F = 5.980; p < 0.001; η 2 = 0.545) and the serratus/trapezium ratio ( F = 8.043; p < 0.001; η 2 = 0.617). The analysis of muscle synergies showed different simultaneous muscular activation in the PSEs compared with the SS. Thus, the results of this study provide evidence for a different use of PSEs in the training routine to improve SS performance.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"680-686"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12097699/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143523832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical Fitness Training and Performance at Air Force Basic Military Training in 2021.","authors":"Korey B Kasper, Meredith G Cockerell, G T Metten, Krystal A Davila","doi":"10.1519/JSC.0000000000005051","DOIUrl":"10.1519/JSC.0000000000005051","url":null,"abstract":"<p><strong>Abstract: </strong>Kasper, KB, Cockerell, MG, Metten, GT, and Davila, KA. Physical fitness training and performance at Air Force Basic military training in 2021. J Strength Cond Res 39(6): e824-e829, 2025-Basic Military Training (BMT) is the physically demanding initial entry training for all enlisted U.S. Air Force and Space Force recruits. This study evaluated the outcome and progression of trainee performance on BMT physical fitness assessments for calendar year 2021. Data from a routinely collected training database were analyzed for differences in pass and recycle rates between male and female trainees and across quarters. Costs associated with delays in training and separations were applied to estimate total costs of physical fitness failures to the Air Force. The pass rate of the fitness assessment upon arrival to BMT was 41%; 93% of trainees achieved a BMT-passing score in the fifth week of training. Ultimately, 2.0% of BMT trainees failed to graduate on schedule because of fitness failures, and 0.5% were separated because of repeated failures. In all, fitness failures resulted in $12.05 million in additional costs. There was a gender disparity, wherein female trainees had higher rates of graduation delays and separations and held a disproportionately high share of the costs associated with fitness failures. Results of the BMT physical training program should be compared with those of other entry level military training programs. Sports medicine and human performance professionals in military and tactical units should regularly collect operational data so that optimization efforts may be assessed.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e824-e829"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143988538","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":"Changes in Single Leg Countermovement Jump Force-Time Characteristics Pre, Post and 2 Days Postmatch in Elite Girls' Youth Soccer.","authors":"Jack T Fahey, Paul Comfort, Nicholas J Ripley","doi":"10.1519/JSC.0000000000005078","DOIUrl":"10.1519/JSC.0000000000005078","url":null,"abstract":"<p><strong>Abstract: </strong>Fahey, JT, Comfort, P, and Ripley, NJ. Changes in single leg countermovement jump force-time characteristics pre, post, and 2 days postmatch in elite girls' youth soccer. J Strength Cond Res 39(6): e788-e797, 2025-This study was designed to assess changes in force-time characteristics during the single leg countermovement jump pre- ( n = 122), immediately postmatch ( n = 121), and 2 days postmatch (MD +2, n = 105) in elite girls' soccer players ( n = 32, 13.9 ± 1.1 years, 163.4 ± 5.2 cm, 53.6 ± 8.2 kg), after 8 competitive matches, using force plates. Significant main effects were found for all variables ( p < 0.05). Trivial to small, yet significant increases in jump height (JH) and relative mean braking and propulsive forces were observed postmatch for both limbs. Trivial to small, yet significant increases in JH and jump momentum were observed MD +2 for both limbs. Trivial to small, yet significant increases were observed for body mass and time to take-off were observed MD +2 compared with postmatch for both limbs. Playing time was not associated with percentage change in force-time characteristics ( r ≤ 0.20). Competitive matches in elite girls' soccer seem to provide an insufficient stimulus to acute fatigue. Force-time characteristics were improved at postmatch and MD +2 when compared with prematch. This provides useful information for sports coaches and strength and conditioning coaches when prescribing training for progressive overload. Because girls' soccer players experience increased demands with age and competition levels, strength and conditioning coaches should consider the removal of second-day recovery sessions and include strength and high-intensity training on MD +2 to better prepare players to cope with the increasing demands and to reduce injury risk, which remains substantially higher than that for boys.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e788-e797"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144006239","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":"Unlocking the Body's Clock: The Role of Exercise Timing and Chronotype in Cardiometabolic Responses.","authors":"Jie Kang, Nicholas A Ratamess, Avery D Faigenbaum, Jill A Bush, Brian Fardman, Ariselle Vargas, Tyler Andriopoulos, Julia Melao, Eamonn O'Connell, Andrew Duff, Amy Cmielewski, Jena DeSalvo, Alexander Johnson, Matthew Watts","doi":"10.1519/JSC.0000000000005075","DOIUrl":"10.1519/JSC.0000000000005075","url":null,"abstract":"<p><strong>Abstract: </strong>Kang, J, Ratamess, NA, Faigenbaum, AD, Bush, JA, Fardman, B, Vargas, A, Andriopoulos, T, Melao, J, O'Connell, E, Duff, A, Cmielewski, A, DeSalvo, J, Johnson, A, and Watts, M. Unlocking the body's clock: the role of exercise timing and chronotype in cardiometabolic responses. J Strength Cond Res 39(6): 634-641, 2025-Exercise enhances skeletal muscle metabolism and promotes overall health. However, the time-of-day effect of exercise on physiological responses in humans remains less clear. This study investigated how exercise timing and individual chronotype influence cardiorespiratory and metabolic responses during aerobic exercise. Thirty healthy, young (20.9 ± 1.5 years) adults comprising 15 men and 15 women were recruited and classified using the Morningness-Eveningness Questionnaire into morning types (M-types, n = 5), neither types (N-types, n = 20), and evening types (E-types, n = 5). All subjects underwent a V̇ o2 max test and 2 randomized exercise trials at ∼75% V̇ o2 max for 30 minutes, 1 in the morning before 9 am and 1 in the afternoon after 3 pm . Oxygen uptake (V̇ o2 ), heart rate (HR), respiratory exchange ratio (RER), and rates of carbohydrate (COX) and fat oxidation (FOX) were determined during the last 15 minutes of each exercise bout. No significant differences in V̇ o2 and HR were found between am and pm . However, RER and COX were lower ( p < 0.05) in am (0.920 ± 0.012 and 27.83 ± 2.29 mg·kg -1 ·min -1 , respectively) than pm (0.941 ± 0.09 and 30.65 ± 1.66 mg·kg -1 ·min -1 , respectively), while FOX was marginally higher ( p = 0.077) in am (4.12 ± 0.63 mg·kg -1 ·min -1 ) than pm (3.07 ± 0.49 mg·kg -1 ·min -1 ). In addition, HR was higher ( p < 0.05) in E-types (188.2 ± 3.9) than in N-types (178.4 ± 2.0) and M-types (167.7 ± 4.0). These results suggest that morning aerobic exercise may be more effective in mobilizing fat as an energy source compared with afternoon exercise. The similar V̇ o2 and HR levels between morning and afternoon sessions imply that the time of day may not have a major impact on cardiorespiratory responses during submaximal aerobic exercise. However, exercising HR seems to vary across chronotypes, highlighting the need to consider individual circadian phenotypes when conducting training programs.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"634-641"},"PeriodicalIF":2.5,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144016467","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}