{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T09:09:27Z","timestamp":1780304967656,"version":"3.54.0"},"reference-count":44,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T00:00:00Z","timestamp":1780272000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Muscle hypertrophy and strength increase are significantly influenced by the distribution of muscle fiber types in individuals. Individuals exposed to similar training intensity in fitness and bodybuilding exhibit different levels of adaptation suggesting that muscle fiber type may influence training outcomes. The aim of this study is to comparatively examine the strength development that occurs in fitness and bodybuilding athletes with different muscle fiber types (Type I, Type II, and Mixed) following a standardized resistance training program. Materials and Methods: The study was conducted using a quasi-experimental design based on a single-group pre-test\u2013post-test model, with no control group. A total of 48 male athletes aged 19\u201326 years (22.75 \u00b1 1.68) who had been regularly training in fitness and bodybuilding for at least two years voluntarily participated in the study. Muscle fiber types of the participants were indirectly estimated based on the number of repetitions performed at 80% of one-repetition maximum (1RM) in the bench press exercise, and individuals were divided into three groups: Type I, Type II, and mixed. All participants underwent a resistance training program for 6 weeks, 3 days a week, at 80% 1RM intensity and in the range of 8\u201312 repetitions. Data were analyzed using Shapiro\u2013Wilk normality test, Wilcoxon Signed-Rank Test, and Mann\u2013Whitney U. Results: The findings showed statistically significant increases between pre-test and post-test measurements in all groups. When percentage improvements were examined, the highest increase was observed in individuals with Type II muscle fiber type, and the lowest increase was observed in individuals with Type I muscle fiber type. Conclusions: In conclusion, the findings indicate that resistance training increases strength development in all muscle fiber types, but the level of development differs depending on the muscle fiber type. These findings highlight the importance of training programs based on individual muscle fiber type characteristics.<\/jats:p>","DOI":"10.3390\/medicina62061069","type":"journal-article","created":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T08:09:16Z","timestamp":1780301356000},"page":"1069","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Comparison of Strength Adaptation Responses Among Individuals with Different Muscle Fiber Type Profiles"],"prefix":"10.3390","volume":"62","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1386-6458","authenticated-orcid":false,"given":"Enes","family":"Beltekin","sequence":"first","affiliation":[{"name":"Department of Sports Management, Faculty of Sport Sciences, Bingol University, 12000 Bingol, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yunus","family":"Berk","sequence":"additional","affiliation":[{"name":"Department of Coaching Education, Faculty of Sport Sciences, Van Y\u00fcz\u00fcnc\u00fc Y\u0131l University, 65080 Van, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u0130hsan","family":"Kuyulu","sequence":"additional","affiliation":[{"name":"Department of Recreation, Faculty of Sport Sciences, Bingol University, 12000 Bingol, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6396-761X","authenticated-orcid":false,"given":"Dan Iulian","family":"Alexe","sequence":"additional","affiliation":[{"name":"Department of Physical and Occupational Therapy, \u201cVasile Alecsandri\u201d University of Bacau, 600115 Bac\u0103u, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Teodora","family":"Isac","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Medicine and Pharmacy \u201cCarol Davila\u201d, 050474 Bucharest, Romania"},{"name":"Fundeni Clinical Institute, 022328 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1994-4998","authenticated-orcid":false,"given":"Gabriel St\u0103nic\u0103","family":"Lupu","sequence":"additional","affiliation":[{"name":"Department of Physical and Occupational Therapy, \u201cVasile Alecsandri\u201d University of Bacau, 600115 Bac\u0103u, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R\u0103zvan Andrei","family":"Tomozei","sequence":"additional","affiliation":[{"name":"Department of Physical Education and Sport, \u201cAlexandru Ioan Cuza\u201d University of Ia\u0219i, 700506 Ia\u0219i, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alina Elena Plasiciuc","family":"Ciobanu","sequence":"additional","affiliation":[{"name":"Department of Health and Motricity, \u201cConstantin Br\u00e2ncu\u0219i\u201d University of T\u00e2rgu Jiu, 210185 T\u00e2rgu Jiu, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,1]]},"reference":[{"key":"ref_1","unstructured":"Berk, Y. (2024). Fitness ve V\u00fccut Geli\u015ftirme, Duvar Yay\u0131nlar\u0131."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"485","DOI":"10.1007\/s00421-017-3792-9","article-title":"The development of skeletal muscle hypertrophy through resistance training: The role of muscle damage and muscle protein synthesis","volume":"118","author":"Damas","year":"2018","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"4294","DOI":"10.1111\/febs.12253","article-title":"Mechanisms regulating skeletal muscle growth and atrophy","volume":"280","author":"Schiaffino","year":"2013","journal-title":"FEBS J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"a029769","DOI":"10.1101\/cshperspect.a029769","article-title":"Adaptations to endurance and strength training","volume":"8","author":"Hughes","year":"2018","journal-title":"Cold Spring Harb. Perspect. Med."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Khanal, P., Morse, C.I., He, L., Herbert, A.J., Onamb\u00e9l\u00e9-Pearson, G.L., Degens, H., Thomis, M., Williams, A.G., and Stebbings, G.K. (2022). Polygenic models partially predict muscle size and strength but not low muscle mass in older women. Genes, 13.","DOI":"10.3390\/genes13060982"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1091","DOI":"10.1096\/fasebj.9.11.7649409","article-title":"Genetic determinism of fiber type proportion in human skeletal muscle","volume":"9","author":"Simoneau","year":"1995","journal-title":"FASEB J."},{"key":"ref_7","unstructured":"Kraemer, W.J., Fleck, S.J., and Deschenes, M.R. (2011). Exercise Physiology: Integrating Theory and Application, Lippincott Williams & Wilkins."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1113\/jphysiol.1996.sp021617","article-title":"Force-velocity properties of human skeletal muscle fibres: Myosin heavy chain isoform and temperature dependence","volume":"495","author":"Bottinelli","year":"1996","journal-title":"J. Physiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1111\/j.1749-6632.1977.tb38182.x","article-title":"Fiber Types and Metabolic Potentials of Skeletal Muscles in Sedentary Man and Endurance Runners","volume":"301","author":"Saltin","year":"1977","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1080\/026404198366443","article-title":"Carnosine and taurine contents in individual fibres of human vastus lateralis muscle","volume":"16","author":"Harris","year":"1998","journal-title":"J. Sports Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1007\/s00726-006-0364-4","article-title":"Influence of \u03b2-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity","volume":"32","author":"Hill","year":"2007","journal-title":"Amino Acids"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"e70059","DOI":"10.1111\/sms.70059","article-title":"Fiber Type\u2013Specific Adaptations to Exercise Training in Human Skeletal Muscle: Lessons From Proteome Analyses and Future Directions","volume":"35","author":"Hostrup","year":"2025","journal-title":"Scand. J. Med. Sci. Sports"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1007\/s40279-023-01937-7","article-title":"Maximal Number of Repetitions at Percentages of the One Repetition Maximum: A Meta-Regression and Moderator Analysis of Sex, Age, Training Status, and Exercise","volume":"54","author":"Nuzzo","year":"2024","journal-title":"Sports Med."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1810","DOI":"10.1093\/ptj\/81.11.1810","article-title":"Human skeletal muscle fiber type classifications","volume":"81","author":"Scott","year":"2001","journal-title":"Phys. Ther."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"157","DOI":"10.5604\/20831862.1099047","article-title":"The Relationship Between the Number of Repetitions Performed at Given Intensities Is Different in Endurance and Strength Trained Athletes","volume":"31","author":"Richens","year":"2014","journal-title":"Biol. Sport"},{"key":"ref_16","first-page":"50","article-title":"An Introduction to Types of Quasi-Experimental Designs","volume":"124","author":"Capili","year":"2024","journal-title":"Am. J. Nurs."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"World Medical Association (2013). World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects. JAMA, 310, 2191\u20132194.","DOI":"10.1001\/jama.2013.281053"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2633","DOI":"10.1007\/s00421-011-1879-2","article-title":"A review of the acute effects of static and dynamic stretching on performance","volume":"111","author":"Behm","year":"2011","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"439","DOI":"10.2165\/00007256-200333060-00005","article-title":"Warm up I: Potential mechanisms and the effects of passive warm up on exercise performance","volume":"33","author":"Bishop","year":"2003","journal-title":"Sports Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"196","DOI":"10.1123\/ijspp.2018-0800","article-title":"Dynamic warm-up with a weighted vest: Improvement of repeated change-of-direction performance in young male soccer players","volume":"15","author":"Turki","year":"2020","journal-title":"Int. J. Sports Physiol. Perform."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Schoenfeld, B.J., Grgic, J., Van Every, D.W., and Plotkin, D.L. (2021). Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum. Sports, 9.","DOI":"10.3390\/sports9020032"},{"key":"ref_22","first-page":"222","article-title":"Effects of Variations of the Bench Press Exercise on the EMG Activity of Five Shoulder Muscles","volume":"9","author":"Barnett","year":"1995","journal-title":"J. Strength Cond. Res."},{"key":"ref_23","first-page":"587","article-title":"The influence of grip width and forearm pronation\/supination on upper-body myoelectric activity during the flat bench press","volume":"19","author":"Lehman","year":"2005","journal-title":"J. Strength Cond. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2857","DOI":"10.1519\/JSC.0b013e3181e840f3","article-title":"The mechanisms of muscle hypertrophy and their application to resistance training","volume":"24","author":"Schoenfeld","year":"2010","journal-title":"J. Strength Cond. Res."},{"key":"ref_25","first-page":"533","article-title":"A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements","volume":"38","author":"Saeterbakken","year":"2020","journal-title":"J. Sports Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1123\/pes.1.4.336","article-title":"Resistance Training and Youth","volume":"1","author":"Kraemer","year":"1989","journal-title":"Pediatr. Exerc. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1519\/00126548-200110000-00004","article-title":"Muscle Fiber Types and Training","volume":"23","author":"Karp","year":"2001","journal-title":"Strength Cond. J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"277","DOI":"10.5114\/biolsport.2021.99705","article-title":"Prediction of muscle fiber composition using multiple repetition testing","volume":"38","author":"Hall","year":"2021","journal-title":"Biol. Sport"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"e13804","DOI":"10.1002\/jcsm.13804","article-title":"Heavy Strength Training in Older Adults: Implications for Health, Disease and Physical Performance","volume":"16","author":"Berg","year":"2025","journal-title":"J. Cachexia Sarcopenia Muscle"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Aslam, S., Habyarimana, J.D.D., and Bin, S.Y. (2025). Neuromuscular adaptations to resistance training in elite versus recreational athletes. Front. Physiol., 16.","DOI":"10.3389\/fphys.2025.1598149"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"M\u0103nescu, D.C. (2025). Computational Analysis of Neuromuscular Adaptations to Strength and Plyometric Training: An Integrated Modeling Study. Sports, 13.","DOI":"10.20944\/preprints202507.2419.v1"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1123\/ijsnem.22.4.292","article-title":"Gene polymorphisms and fiber-type composition of human skeletal muscle","volume":"22","author":"Ahmetov","year":"2012","journal-title":"Int. J. Sport Nutr. Exerc. Metab."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Fuku, N., Kumagai, H., and Ahmetov, I.I. (2019). Genetics of muscle fiber composition. Sports, Exercise, and Nutritional Genomics, Elsevier.","DOI":"10.1016\/B978-0-12-816193-7.00014-2"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"22","DOI":"10.2165\/00007256-199417010-00003","article-title":"Acute and chronic response of skeletal muscle to resistance exercise","volume":"17","author":"Abernethy","year":"1994","journal-title":"Sports Med."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1177\/002215540004800506","article-title":"Fiber type composition of the vastus lateralis muscle of young men and women","volume":"48","author":"Staron","year":"2000","journal-title":"J. Histochem. Cytochem."},{"key":"ref_36","first-page":"11","article-title":"Relationship Between Repetitions and Selected Percentages of One Repetition Maximum","volume":"1","author":"Hoeger","year":"1987","journal-title":"J. Strength Cond. Res."},{"key":"ref_37","first-page":"699","article-title":"The relationship between maximal repetition performance and muscle fiber type as estimated by noninvasive technique in the quadriceps of untrained women","volume":"20","author":"Douris","year":"2006","journal-title":"J. Strength Cond. Res."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"845","DOI":"10.1519\/JSC.0b013e31816a5ee4","article-title":"Fiber type composition and capillary density in relation to submaximal number of repetitions in resistance exercise","volume":"22","author":"Terzis","year":"2008","journal-title":"J. Strength Cond. Res."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"648","DOI":"10.1152\/japplphysiol.00636.2019","article-title":"Muscle fiber typology substantially influences time to recover from high-intensity exercise","volume":"128","author":"Lievens","year":"2020","journal-title":"J. Appl. Physiol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2021","DOI":"10.1080\/17461391.2023.2207077","article-title":"Muscle typology influences the number of repetitions to failure during resistance training","volume":"23","author":"Hardeel","year":"2023","journal-title":"Eur. J. Sport Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1152\/physrev.00015.2007","article-title":"Skeletal muscle fatigue: Cellular mechanisms","volume":"88","author":"Allen","year":"2008","journal-title":"Physiol. Rev."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"393","DOI":"10.1111\/j.1469-7793.2001.0393i.x","article-title":"ATP utilization for calcium uptake and force production in different types of human skeletal muscle fibres","volume":"531","author":"Szentesi","year":"2001","journal-title":"J. Physiol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3093","DOI":"10.1016\/j.yexcr.2010.05.019","article-title":"Skeletal muscle: Energy metabolism, fiber types, fatigue and adaptability","volume":"316","author":"Westerblad","year":"2010","journal-title":"Exp. Cell Res."},{"key":"ref_44","first-page":"746","article-title":"Muscle fiber characteristics and performance correlates of male Olympic-style weightlifters","volume":"17","author":"Fry","year":"2003","journal-title":"J. Strength Cond. Res."}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/6\/1069\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T08:48:57Z","timestamp":1780303737000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/62\/6\/1069"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,1]]},"references-count":44,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["medicina62061069"],"URL":"https:\/\/doi.org\/10.3390\/medicina62061069","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,1]]}}}