Journal of Sports Science and Medicine最新文献

{"title":"Mechanics of The Medial Gastrocnemius-Tendon Unit in Behaving more Efficiently in Habitual Non-Rearfoot Strikers than in Rearfoot Strikers during Running.","authors":"Liqin Deng,&nbsp;Xini Zhang,&nbsp;Boyi Dai,&nbsp;Songlin Xiao,&nbsp;Faning Zhang,&nbsp;Weijie Fu","doi":"10.52082/jssm.2023.582","DOIUrl":"https://doi.org/10.52082/jssm.2023.582","url":null,"abstract":"<p><p>This study aims to quantify how habitual foot strike patterns would affect ankle kinetics and the behavior and mechanics of the medial gastrocnemius-tendon unit (MTU) during running. A total of 14 runners with non-rearfoot strike patterns (NRFS) and 15 runners with rearfoot strike patterns (RFS) ran on an instrumented treadmill at a speed of 9 km/h. An ultrasound system and a motion capture system were synchronously triggered to collect the ultrasound images of the medial gastrocnemius (MG) and marker positions along with ground reaction forces (GRF) during running. Ankle kinetics (moment and power) and MG/MTU behavior and mechanical properties (MG shortening length, velocity, force, power, MTU shortening/lengthening length, velocity, and power) were calculated. Independent <i>t</i>-tests were performed to compare the two groups of runners. Pearson correlation was conducted to detect the relationship between foot strike angle and the MTU behavior and mechanics. Compared with RFS runners, NRFS runners had 1) lower foot strike angles and greater peak ankle moments; 2) lower shortening/change length and contraction velocity and greater MG peak force; 3) greater MTU lengthening, MTU shortening length and MTU lengthening velocity and power; 4) the foot strike angle was positively related to the change of fascicle length, fascicle contraction length, and MTU shortening length during the stance phase. The foot strike angle was negatively related to the MG force and MTU lengthening power. The MG in NRFS runners appears to contract with greater force in relatively isometric behavior and at a slower shortening velocity. Moreover, the lengthening length, the lengthening velocity of MTU, and the MG force were greater in habitual NRFS runners, leading to a stronger stretch reflex response potentially.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499162/pdf/jssm-22-582.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10308166","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":"Prediction of Half-Marathon Power Target using the 9/3-Minute Running Critical Power Test.","authors":"Javier Olaya-Cuartero, B. Pueo, Lamberto Villalon-Gasch, J. Jimenez-Olmedo","doi":"10.52082/jssm.2023.525","DOIUrl":"https://doi.org/10.52082/jssm.2023.525","url":null,"abstract":"Running power output allows for controlling variables that have been previously overlooked by relying solely on speed, such as surface, gradient and weight. The ability to measure this external load variable now enables the analysis of concepts that have predominantly been studied in cycling, such as the Critical Power (CP), in the context of running. This study aims to predict the CP target at which trained athletes run a half-marathon and determine whether races of this distance can serve as a valid alternative to update the CP record. A group of nine trained athletes performed the 9/3-minute Stryd CP test and participated in a half-marathon race in two separate testing sessions conducted in the field. The average power during a half-marathon race is a valid alternative method for determining the CP in trained athletes, as evidenced by the agreement (95% CI: -0.11 to 0.37 W/kg) and trivial systematic bias (0.13 W/kg) between methods. The linear regression model half-marathon power = 0.97 + 0.75·CP (W/kg) showed low standard error of estimate (0.29 W/kg) and significant large association between methods (r = 0.88; p = 0.002). Coaches and athletes should be aware that the CP target for a half-marathon race is 97.3% of the CP determined by the 9/3-minute Stryd CP test.","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70666358","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":"Translation, Cultural Adaptation and Validation of Perceived Physical Literacy Instrument-Spanish Version (PPLI-Sp) for Adults","authors":"Maria Mendoza-Muñoz, Jorge Carlos-Vivas, Antonio Castillo-Paredes, Raymond Kim Wai Sum, Jorge Rojo-Ramos, Raquel Pastor-Cisneros","doi":"10.52082/jssm.2023.454","DOIUrl":"https://doi.org/10.52082/jssm.2023.454","url":null,"abstract":"To translate and culturally adapt the Perceived Physical Literacy Instrument (PPLI) questionnaire, as well as to evaluate the factor structure. A single-measure cross-sectional study was conducted. For the first phase of the study, a translation and cultural adaptation of the PPLI questionnaire was carried out, as well as an interview, with the aim of assessing the understanding of the instrument. In the second part of the study, exploratory (EFA) and confirmatory (CFA) factorial analyses were conducted. A total of 213 Spanish adults with a mean age of 27.40 (10.58) participated. EFA was performed because of the good results offered by the sampling adequacy indices (Bartlett test = 1081.848; df = 153; p < 0.001; and KMO test = 0.825). The factor solution comprised three correlated factors:1) physical competence, 2) motivation and confidence, and 3) knowledge and understanding. After the EFA, items 7, 9, 10, 11, 12, 13, 14, 15 and 17 were excluded. Therefore, through CFA, a factor structure of 9 items grouped into three dimensions was extracted. The PPLI-Sp version for adults, obtained from the back-translation process as well as after individual interviews, proved to be valid and reliable after the EFA and CFA analyses, obtaining an instrument of nine items, divided into three dimensions. This instrument can be used to determine the perception of physical literacy among different Spanish adult populations.","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135831410","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 Effect of Bicycle Saddle Widths on Saddle Pressure in Female Cyclists.","authors":"Zi-Jun Lin,&nbsp;Hsin-Huan Wang,&nbsp;Chia-Hsiang Chen","doi":"10.52082/jssm.2023.425","DOIUrl":"https://doi.org/10.52082/jssm.2023.425","url":null,"abstract":"<p><p>Choosing an unsuitable bicycle saddle increases the saddle pressure and discomfort during cycling. Women contract sports injuries more easily than men during cycling owing to their anatomy. To investigate the effect of saddle widths on the saddle pressure in female cyclists. Ten healthy women with an average age of 20.7 ± 1.3 years, height of 162 ± and 5.9 cm, weight of 56.1 ± 7.5 kg, and a sciatic bone width of 15.5 ± 1.4 cm were recruited for this study. The distributions of saddle pressure for four different saddle widths (i.e., narrow, moderate, wide, and self-chosen) were recorded using a saddle pressure mat. Participants were instructed to pedal steadily with a frequency of 90 RPM and a load of 150 watts. Thirty seconds of riding data was randomly retrieved for analysis. The trials were conducted with a counter-balanced design to minimize random errors. One-way repeated measures ANOVA was used to compare the saddle pressure of different saddle widths, and the significance level was set at α = 0.05. When wide saddles were used, the maximum and average pressure on the right surface of the posterior ischium were lower than those with narrow (p = 0.001, p = 0.012) and moderate (p = 0.016, p = 0.019) saddles. The area of pressure on the pubic bone was smaller when using a wide saddle than when using narrow (p = 0.005) and moderate (p = 0.018) saddles, and the area of pressure on the right posterior sciatic bone was larger under the wide saddle than under the narrow (p = 0.017) and moderate (p = 0.036) saddles. The average force was greater with the moderate saddle than with the wide (p = 0.008) and self-chosen (p = 0.025) saddles. Using a saddle with a width that is longer than the width of the cyclist's ischium by 1 cm can effectively improve the distribution of saddle pressure during riding, while providing better comfort.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499128/pdf/jssm-22-425.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10308160","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":"Acute Effects of Back Squat Combined with Different Elastic Band Resistance on Vertical Jump Performance in Collegiate Basketball Players.","authors":"Lin Shi,&nbsp;Xin Ye,&nbsp;Dong Han,&nbsp;Chengbo Yang,&nbsp;Yanhao Tu","doi":"10.52082/jssm.2023.502","DOIUrl":"https://doi.org/10.52082/jssm.2023.502","url":null,"abstract":"<p><p>The purpose of this study was to compare the acute effects of back squat exercise with or without elastic band on countermovement jump performance. Thirteen collegiate male basketball players (age: 20.5 ± 0.9 years; height: 188.5 ± 8.5 cm; body mass: 82.8 ± 12.9 kg) completed 5 familiarization and 4 experimental sessions separated by at least 48 hours. In the experimental sessions, the order of the conditions was randomized so that the participants performed 1 set of 3 repetitions of barbell back squat at 85% of their one-repetition maximum (1-RM), 1 set of 3 repetitions of back squat at 85% 1-RM with 20% variable resistance training (VRT), 30%VRT, or 40%VRT of the total load coming from the elastic band. Countermovement jump performance was assessed before (baseline), 30 seconds, 3 minutes, 6 minutes, and 9 minutes following each condition. Jump height, rate of force development, peak power, and vastus lateralis, vastus medialis, and medial gastrocnemius electromyography data were collected. Compared with the baseline, 30%VRT significantly improved jump height at 3 minutes post-exercise by 1.3 cm (<i>P</i> < 0.001) and 6 minutes post-exercise by 1.2 cm (<i>P</i> = 0.005); 40%VRT significantly improved jump height from 30 seconds up to the 9th minute (1.2 to 1.9 cm, <i>P</i> ≤ 0.036). The superior jump height was also accompanied by improved kinetic and electromyography data. No significant changes were observed in the barbell back squat and 20%VRT conditions. In conclusion, back squat at 85% 1-RM with 40% elastic band resistance led to superior vertical jump performance with an optimal time window of 3 minutes.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499146/pdf/jssm-22-502.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10309552","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":"Acute Physiological and Perceptual Responses to Whole-Body High-Intensity Interval Training Compared with Equipment-Based Interval and Continuous Training.","authors":"Eric Tsz-Chun Poon,&nbsp;Ka Wing Chan,&nbsp;Waris Wongpipit,&nbsp;Fenghua Sun,&nbsp;Stephen Heung-Sang Wong","doi":"10.52082/jssm.2023.532","DOIUrl":"https://doi.org/10.52082/jssm.2023.532","url":null,"abstract":"<p><p>Low-volume, time-efficient high-intensity interval training (HIIT), which involves whole-body (WB) callisthenics exercises, has gained worldwide popularity in recent years. However, the physiological and perceptual impact of WB-HIIT in comparison to specialised, equipment-based training is relatively less studied. This study compared the acute physiological and perceptual responses to a single session of WB-HIIT, ergometer-based HIIT (ERG-HIIT) and conventional moderate-intensity continuous training (MICT). Fourteen physically inactive adults (age: 28.4 ± 6.5 years, VO_2peak: 31.0 ± 6.2 mL· kg^-1· min^-1) underwent three main trials (WB-HIIT: 12 x 30-s high-intensity callisthenics workout; ERG: HIIT: 12 x 30-s high-intensity cycling bouts; MICT: 30-min cycling at 50% peak power output) in a randomized cross-over order 3-7 days apart. The mean session heart rate (HR) and perceived exertion were comparable across all three protocols (<i>p</i> > 0.05). WB-HIIT attained a similar peak HR (87.4 ± 9.4 %HR_max) as that of ERG-HIIT (83.0 ± 8.6 %HR_max), and significantly greater than that of MICT (78.7 ± 5.5 %HR_max, <i>p</i> = 0.001). However, WB-HIIT induced significantly higher blood lactate levels (7.2 ± 1.8 mmol/L) compared to both ERG-HIIT (5.1 ± 1.3 mmol/L, <i>p</i> < 0.05) and MICT (3.1 ± 1.5 mmol/L, <i>p</i> < 0.001). The participants reported higher self-efficacy and greater enjoyment with WB-HIIT compared to MICT (<i>p</i> < 0.05). The mean HR and perceived exertion responses to WB-HIIT are comparable to those of equipment-based HIIT and MICT; however, WB-HIIT results in greater metabolic strain than both other modalities. Despite this, the overall perceptual responses to WB-HIIT are positive, suggesting that it could be a viable exercise alternative, especially for individuals with limited exercise time and restricted access to facilities and equipment.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499152/pdf/jssm-22-532.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10358809","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":"Predicting Injury and Illness with Machine Learning in Elite Youth Soccer: A Comprehensive Monitoring Approach over 3 Months.","authors":"Nils Haller, S. Kranzinger, C. Kranzinger, Julia C. Blumkaitis, Tilmann Strepp, P. Simon, Aleksandar Tomaskovic, J. O’Brien, Manfred Düring, T. Stöggl","doi":"10.52082/jssm.2023.475","DOIUrl":"https://doi.org/10.52082/jssm.2023.475","url":null,"abstract":"The search for monitoring tools that provide early indication of injury and illness could contribute to better player protection. The aim of the present study was to i) determine the feasibility of and adherence to our monitoring approach, and ii) identify variables associated with up-coming illness and injury. We incorporated a comprehensive set of monitoring tools consisting of external load and physical fitness data, questionnaires, blood, neuromuscular-, hamstring, hip abductor and hip adductor performance tests performed over a three-month period in elite under-18 academy soccer players. Twenty-five players (age: 16.6 ± 0.9 years, height: 178 ± 7 cm, weight: 74 ± 7 kg, VO2max: 59 ± 4 ml/min/kg) took part in the study. In addition to evaluating adherence to the monitoring approach, data were analyzed using a linear support vector machine (SVM) to predict illness and injuries. The approach was feasible, with no injuries or dropouts due to the monitoring process. Questionnaire adherence was high at the beginning and decreased steadily towards the end of the study. An SVM resulted in the best classification results for three classification tasks, i.e., illness prediction, illness determination and injury prediction. For injury prediction, one of four injuries present in the test data set was detected, with 96.3% of all data points (i.e., injuries and non-injuries) correctly detected. For both illness prediction and determination, there was only one illness in the test data set that was detected by the linear SVM. However, the model showed low precision for injury and illness prediction with a considerable number of false-positives. The results demonstrate the feasibility of a holistic monitoring approach with the possibility of predicting illness and injury. Additional data points are needed to improve the prediction models. In practical application, this may lead to overcautious recommendations on when players should be protected from injury and illness.","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70666609","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 Combined Exercise with Citrulline Supplementation on Body Composition and Lower Limb Function of Overweight Older Adults: A Systematic Review and Meta-Analysis.","authors":"Shihao Xie, Shuoqi Li, Shazlin Shaharudin","doi":"10.52082/jssm.2023.541","DOIUrl":"10.52082/jssm.2023.541","url":null,"abstract":"<p><p>The combined exercise with citrulline (CIT) supplementation is a potential adjuvant treatment approach to address the declining body composition and lower limb function of overweight older adults. However, research on this approach is limited. Thus, this study performed a meta-analysis review to explore the effects of combined exercise with CIT supplementation on body composition and lower limb function among overweight older adults. The search strategy and manuscript development of this study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Eligible studies were first searched through four databases (Web of Science, Scopus, PubMed, and EBSCO) from January 2003 until April 2023, followed by screening. The main inclusion criteria for the article selection are as follows: 1) Randomized Controlled Trial studies; 2) Participants aged over 55; 3) Studies involved exercise with CIT supplementation for the experimental group and exercise with Placebo (PLA) supplementation for the control group; 4) Body composition and lower limb function were measured at pre- and post-intervention. Subsequently, the Cochrane risk of bias assessment tool was utilized to evaluate the selected studies' quality. The Standardized Mean Difference (SMD) was chosen as the suitable effect scale index, and the mean differences of the data from the selected articles were analyzed using Revman 5.4 software with a 95% Confidence Interval (CI). A total of seven studies fulfilled the inclusion criteria and were selected for the meta-analysis. The included studies involved 105 males and 198 females, where 157 belonged to the PLA group and 146 from the CIT group. Significant improvements were observed among overweight older adults with CIT supplementation in 6-Minute Walking Test (6MWT) (P = 0.04, I² = 4%), SMD (95% CI) = -0.28 (-0.54, -0.01), and Lower Limb Strength (LLS) (P < 0.01, I² = 30%), SMD (95% CI) = -0.38 (-0.65, -0.12) compared to those with PLA supplementation. Combined exercise with CIT supplementation could be an effective non-pharmaceutical intervention to improve the physical function of overweight older adults by increasing their muscle strength.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499154/pdf/jssm-22-541.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10653946","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":"Translation, Cultural Adaptation and Validation of Perceived Physical Literacy Instrument-Spanish Version (PPLI-Sp) for Adults.","authors":"Maria Mendoza-Muñoz, Jorge Carlos-Vivas, Antonio Castillo-Paredes, Raymond Kim Wai Sum, Jorge Rojo-Ramos, Raquel Pastor-Cisneros","doi":"10.52082/jssm.2023.455","DOIUrl":"10.52082/jssm.2023.455","url":null,"abstract":"<p><p>To translate and culturally adapt the Perceived Physical Literacy Instrument (PPLI) questionnaire, as well as to evaluate the factor structure. A single-measure cross-sectional study was conducted. For the first phase of the study, a translation and cultural adaptation of the PPLI questionnaire was carried out, as well as an interview, with the aim of assessing the understanding of the instrument. In the second part of the study, exploratory (EFA) and confirmatory (CFA) factorial analyses were conducted. A total of 213 Spanish adults with a mean age of 27.40 (10.58) participated. EFA was performed because of the good results offered by the sampling adequacy indices (Bartlett test = 1081.848; df = 153; p < 0.001; and KMO test = 0.825). The factor solution comprised three correlated factors:1) physical competence, 2) motivation and confidence, and 3) knowledge and understanding. After the EFA, items 7, 9, 10, 11, 12, 13, 14, 15 and 17 were excluded. Therefore, through CFA, a factor structure of 9 items grouped into three dimensions was extracted. The PPLI-Sp version for adults, obtained from the back-translation process as well as after individual interviews, proved to be valid and reliable after the EFA and CFA analyses, obtaining an instrument of nine items, divided into three dimensions. This instrument can be used to determine the perception of physical literacy among different Spanish adult populations.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499136/pdf/jssm-22-455.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10309545","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":"Effects of Acute Loading Induced Fatigability, Acute Serum Hormone Responses and Training Volume to Individual Hypertrophy and Maximal Strength during 10 Weeks of Strength Training.","authors":"Aapo Räntilä,&nbsp;Juha P Ahtiainen,&nbsp;Keijo Häkkinen","doi":"10.52082/jssm.2023.559","DOIUrl":"https://doi.org/10.52082/jssm.2023.559","url":null,"abstract":"<p><p>This study investigated whether a strength training session-induced acute fatigue is related to individuals' strength training adaptations in maximal force and/or muscle hypertrophy, and whether acute responses in serum testosterone (T) and growth hormone (GH) concentrations during the training sessions would be associated with individual neuromuscular adaptations. 26 males completed the 10-week strength-training intervention, which included fatiguing dynamic leg press acute loading bouts (5 x 10 RM) at weeks two, four, six, and ten. Blood samples were collected before and after the loading and after 24h of recovery for serum T, GH, and cortisol (C) concentrations at weeks 2, 6, and 10. The cross-sectional area of the vastus lateralis was measured by ultrasonography. Isometric force measurements were performed before and immediately after loadings, and loading-induced acute decrease in maximal force was reported as the fatigue percentage. The subjects were split into three groups according to the degree of training-induced muscle hypertrophy after the training period. Increases in isometric force were significant for High Responders (HR, n = 10) (by 24.3 % ± 17.2, p = 0.035) and Medium Responders (MR, n = 7) (by 23.8 % ± 5.5, p = 0.002), whereas the increase of 26.2 % (±16.5) in Low Responders (LR, n = 7) was not significant. The amount of work (cm + s) increased significantly at every measurement point in all the groups. A significant correlation was observed between the fatigue percentage and relative changes in isometric force after the training period for the whole group (R = 0.475, p = 0.022) and separately only in HR (R = 0.643, p = 0.049). Only the HR group showed increased acute serum GH concentrations at every measurement point. There was also a significant acute increase in serum T for HR at weeks 6 and 10. HR showed the strongest correlation between acute loading-induced fatigue and isometric force gains. HR was also more sensitive to acute increases in serum concentrations of T and GH after the loading. Acute fatigue and serum GH concentrations may be indicators of responsiveness to muscle strength gain and, to some extent, muscle hypertrophy.</p>","PeriodicalId":54765,"journal":{"name":"Journal of Sports Science and Medicine","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10499158/pdf/jssm-22-559.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10358806","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}