{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T01:47:08Z","timestamp":1791942428645,"version":"4.3.4"},"reference-count":31,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T00:00:00Z","timestamp":1791849600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T00:00:00Z","timestamp":1791849600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/100014440","name":"Ministerio de Ciencia, Innovaci\u00f3n y Universidades","doi-asserted-by":"publisher","award":["10.13039\/501100011033"],"award-info":[{"award-number":["10.13039\/501100011033"]}],"id":[{"id":"10.13039\/100014440","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sports Med - Open"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Interlimb asymmetries (ILA) have been associated with an increased risk of injury and decreased athletic performance. However, despite the growing number of training interventions targeting ILA, their comparative effectiveness relative to general strength and conditioning approaches has not yet been systematically reviewed.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>This systematic review aimed to compare the effectiveness of asymmetry-focused training interventions versus general training programs in reducing ILA and improving physical performance in athletic populations. Specifically, it sought to compare individualized training programs that first identify the weaker limb during pre-testing and subsequently prescribe a greater training stimulus to that limb with general training protocols that apply the same training stimulus to both limbs, as well as unilateral approaches with bilateral training strategies.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Following PRISMA 2020 guidelines, a systematic search was conducted in Web of Science, PubMed, and SPORTDiscus up to April 2025. Eligible studies involved healthy athletes (aged 12\u201330\u00a0years) who completed \u22654-week lower-limb training interventions that either applied a greater stimulus to the weaker limb (e.g., starting sets with the weaker side or adding volume) or used unilateral training approaches that applied the same training stimulus to both limbs regardless of baseline ILA values. To be included, studies were required to assess both pre-to-post changes in ILA and at least one physical performance outcome. The risk of bias was assessed using a modified Cochrane tool.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Eleven studies comprising 297 athletes met the inclusion criteria. Reductions in ILA were more consistent in asymmetry-focused and unilateral training groups compared to general and bilateral training groups, respectively. Most interventions also led to improvements in physical performance, with asymmetry-focused and unilateral protocols typically producing greater gains in single-limb tasks, although bilateral training showed more favourable effects in bilateral tasks. However, variability in training protocols and outcome measures across studies limits the generalizability of these findings.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Asymmetry-focused strategies, such as starting unilateral exercises with the weaker limb or increasing its training volume, appear to be more effective for reducing ILA than non-individualized unilateral training. These approaches are practical, safe, and potentially beneficial in athletic settings. However, further high-quality research is needed to confirm their superiority over non asymmetry-focused unilateral or bilateral training and to establish clear guidelines for their implementation.<\/jats:p>\n                    <jats:p>\n                      <jats:italic>Registration<\/jats:italic>\n                      PROSPERO-CRD420251023232.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s40798-026-01119-5","type":"journal-article","created":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T01:17:22Z","timestamp":1791940642000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Are Asymmetry-Focused Training Interventions More Effective than General Programs in Reducing Interlimb Asymmetries and Improving Athletic Performance? A Systematic Review"],"prefix":"10.1186","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-5844-5116","authenticated-orcid":false,"given":"Antonio","family":"Martos-Arregui","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Iago","family":"Rojas-Cepero","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xing","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0608-8755","authenticated-orcid":false,"given":"Amador","family":"Garc\u00eda-Ramos","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francisco Javier","family":"Rojas-Ruiz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mar","family":"Cepero-Gonz\u00e1lez","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,10,13]]},"reference":[{"key":"1119_CR1","doi-asserted-by":"publisher","DOI":"10.1519\/JSC.0000000000004384","author":"C Bishop","year":"2023","unstructured":"Bishop C, De Keijzer KL, Turner AN, Beato M. Measuring interlimb asymmetry for strength and power: a brief review of assessment methods, data analysis, current evidence, and practical recommendations. J Strength Cond Res. 2023. https:\/\/doi.org\/10.1519\/JSC.0000000000004384.","journal-title":"J Strength Cond Res"},{"key":"1119_CR2","doi-asserted-by":"publisher","DOI":"10.1519\/SSC.0000000000000264","author":"C Bishop","year":"2016","unstructured":"Bishop C, Read P, Chavda S, Turner A. Asymmetries of the lower limb: the calculation conundrum in strength training and conditioning. Strength Cond J. 2016. https:\/\/doi.org\/10.1519\/SSC.0000000000000264.","journal-title":"Strength Cond J"},{"key":"1119_CR3","doi-asserted-by":"publisher","DOI":"10.52082\/jssm.2021.317","author":"A P\u00e9rez-Castilla","year":"2021","unstructured":"P\u00e9rez-Castilla A, Garc\u00eda-Ramos A, Janicijevic D, Miras-Moreno S, De la Cruz JC, Rojas FJ, et al. Unilateral or bilateral standing broad jumps: which jump type provides inter-limb asymmetries with a higher reliability? J Sports Sci Med. 2021. https:\/\/doi.org\/10.52082\/jssm.2021.317.","journal-title":"J Sports Sci Med"},{"key":"1119_CR4","doi-asserted-by":"publisher","unstructured":"Parkinson AO, Apps CL, Morris JG, Barnett CT, Lewis MGC 2021 The calculation, thresholds and reporting of inter-limb strength asymmetry: A systematic review. J. Sports Sci. Med. https:\/\/doi.org\/10.52082\/jssm.2021.594","DOI":"10.52082\/jssm.2021.594"},{"key":"1119_CR5","doi-asserted-by":"publisher","DOI":"10.1519\/JSC.0000000000002729","author":"C Bishop","year":"2021","unstructured":"Bishop C, Lake J, Loturco I, Papadopoulos K, Turner A, Read P. Interlimb asymmetries: the need for an individual approach to data analysis. J Strength Cond Res. 2021. https:\/\/doi.org\/10.1519\/JSC.0000000000002729.","journal-title":"J Strength Cond Res"},{"key":"1119_CR6","doi-asserted-by":"publisher","DOI":"10.1519\/SSC.0000000000000371","author":"C Bishop","year":"2018","unstructured":"Bishop C, Read P, Lake J, Chavda S, Turner A. Interlimb asymmetries: understanding how to calculate differences from bilateral and unilateral tests. Strength Cond J. 2018. https:\/\/doi.org\/10.1519\/SSC.0000000000000371.","journal-title":"Strength Cond J"},{"key":"1119_CR7","doi-asserted-by":"publisher","DOI":"10.1080\/02640414.2011.647047","author":"TA Exell","year":"2012","unstructured":"Exell TA, Irwin G, Gittoes MJR, Kerwin DG. Implications of intra-limb variability on asymmetry analyses. J Sports Sci. 2012. https:\/\/doi.org\/10.1080\/02640414.2011.647047.","journal-title":"J Sports Sci"},{"key":"1119_CR8","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2025.1551523","author":"W Sun","year":"2025","unstructured":"Sun W, Li H, Qu L, Zhou Y, Cao X, Wang K, et al. Unilateral plyometric training effectively reduces lower limb asymmetry in athletes: a meta-analysis. Front Physiol. 2025. https:\/\/doi.org\/10.3389\/fphys.2025.1551523.","journal-title":"Front Physiol"},{"key":"1119_CR9","doi-asserted-by":"publisher","DOI":"10.1519\/SSC.0000000000000701","author":"F Bettariga","year":"2022","unstructured":"Bettariga F, Turner A, Maloney S, Maestroni L, Jarvis P, Bishop C. The effects of training interventions on interlimb asymmetries: a systematic review with meta-analysis. Strength Cond J. 2022. https:\/\/doi.org\/10.1519\/SSC.0000000000000701.","journal-title":"Strength Cond J"},{"key":"1119_CR10","doi-asserted-by":"publisher","DOI":"10.1123\/ijspp.2018-0920","author":"O Gonzalo-Skok","year":"2019","unstructured":"Gonzalo-Skok O, Moreno-Azze A, Arjol-Serrano JL, Tous-Fajardo J, Bishop C. A comparison of 3 different unilateral strength training strategies to enhance jumping performance and decrease interlimb asymmetries in soccer players. Int J Sports Physiol Perform. 2019. https:\/\/doi.org\/10.1123\/ijspp.2018-0920.","journal-title":"Int J Sports Physiol Perform"},{"key":"1119_CR11","doi-asserted-by":"publisher","first-page":"754","DOI":"10.52082\/jssm.2024.754","volume":"23","author":"J Cao","year":"2024","unstructured":"Cao J, Xun S, Zhang R, Zhang Z, Journal of Sport Science and Medicine. Effects of unilateral, bilateral and combined plyometric jump training on asymmetry of muscular strength and power, and change-of-direction in youth male basketball players. J Sports Sci Med. 2024;23:754\u201366. https:\/\/doi.org\/10.52082\/jssm.2024.754.","journal-title":"J Sports Sci Med"},{"key":"1119_CR12","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2024.1361719","author":"W Zhang","year":"2024","unstructured":"Zhang W, Chen X, Xu K, Xie H, Chen J, Zhu Z, et al. The potential of a targeted unilateral compound training program to reduce lower limb strength asymmetry and increase performance: a proof-of-concept in basketball. Front Physiol. 2024. https:\/\/doi.org\/10.3389\/fphys.2024.1361719.","journal-title":"Front Physiol"},{"key":"1119_CR13","doi-asserted-by":"publisher","DOI":"10.1519\/JSC.0000000000004573","author":"F Ujakovi\u0107","year":"2023","unstructured":"Ujakovi\u0107 F, \u0160arabon N. The effects of workload difference between limbs in plyometric and strength exercises in reducing asymmetry in change of direction ability during basketball season. J Strength Cond Res. 2023. https:\/\/doi.org\/10.1519\/JSC.0000000000004573.","journal-title":"J Strength Cond Res"},{"key":"1119_CR14","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph18168270","author":"A Moreno-Azze","year":"2021","unstructured":"Moreno-Azze A, Arjol-Serrano JL, Falc\u00f3n-Miguel D, Bishop C, Gonzalo-Skok O. Comparison of three eccentric overload training strategies on power output and interlimb asymmetry in youth soccer players. Int J Environ Res Public Health. 2021. https:\/\/doi.org\/10.3390\/ijerph18168270.","journal-title":"Int J Environ Res Public Health"},{"key":"1119_CR15","doi-asserted-by":"publisher","DOI":"10.1123\/IJSPP.2019-0265","author":"E Pardos-Mainer","year":"2020","unstructured":"Pardos-Mainer E, Casaj\u00fas JA, Bishop C, Gonzalo-Skok O. Effects of combined strength and power training on physical performance and interlimb asymmetries in adolescent female soccer players. Int J Sports Physiol Perform. 2020. https:\/\/doi.org\/10.1123\/IJSPP.2019-0265.","journal-title":"Int J Sports Physiol Perform"},{"key":"1119_CR16","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2018.00265","author":"R Ramirez-Campillo","year":"2018","unstructured":"Ramirez-Campillo R, Sanchez-Sanchez J, Gonzalo-Skok O, Rodr\u00edguez-Fernandez A, Carretero M, Nakamura FY. Specific changes in young soccer player\u2019s fitness after traditional bilateral vs. unilateral combined strength and plyometric training. Front Physiol. 2018. https:\/\/doi.org\/10.3389\/fphys.2018.00265.","journal-title":"Front Physiol"},{"key":"1119_CR17","doi-asserted-by":"publisher","DOI":"10.1123\/ijspp.2015-0743","author":"O Gonzalo-Skok","year":"2017","unstructured":"Gonzalo-Skok O, Tous-Fajardo J, Suarez-Arrones L, Arjol-Serrano JL, Casaj\u00fas JA, Mendez-Villanueva A. Single-leg power output and between-limbs imbalances in team-sport players: unilateral versus bilateral combined resistance training. Int J Sports Physiol Perform. 2017. https:\/\/doi.org\/10.1123\/ijspp.2015-0743.","journal-title":"Int J Sports Physiol Perform"},{"key":"1119_CR18","doi-asserted-by":"publisher","DOI":"10.3390\/sports9120158","author":"A Moreno-Azze","year":"2021","unstructured":"Moreno-Azze A, Arjol-Serrano JL, Falc\u00f3n-Miguel D, Bishop C, Gonzalo-Skok O. Effects of three different combined training interventions on jump, change of direction, power performance, and inter-limb asymmetry in male youth soccer players. Sports. 2021. https:\/\/doi.org\/10.3390\/sports9120158.","journal-title":"Sports"},{"key":"1119_CR19","doi-asserted-by":"publisher","DOI":"10.1519\/jsc.0000000000002608","author":"SJ Maloney","year":"2019","unstructured":"Maloney SJ. The relationship between asymmetry and athletic performance: a critical review. J Strength Cond Res. 2019. https:\/\/doi.org\/10.1519\/jsc.0000000000002608.","journal-title":"J Strength Cond Res"},{"key":"1119_CR20","doi-asserted-by":"publisher","DOI":"10.1007\/s11332-025-01390-1","author":"Z Li","year":"2025","unstructured":"Li Z, Lei S, Zhang H, Wang X, Sun Y, Fan J, et al. Effects of unilateral and bilateral plyometrics training on basketball players\u2019 leg power and change of direction ability. Sport Sci Health. 2025. https:\/\/doi.org\/10.1007\/s11332-025-01390-1.","journal-title":"Sport Sci Health"},{"key":"1119_CR21","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.n71","author":"MJ Page","year":"2021","unstructured":"Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. The BMJ. 2021. https:\/\/doi.org\/10.1136\/bmj.n71.","journal-title":"The BMJ"},{"key":"1119_CR22","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph19020671","author":"J Kabacinski","year":"2022","unstructured":"Kabacinski J, Szozda PM, Mackala K, Murawa M, Rzepnicka A, Szewczyk P, et al. Relationship between isokinetic knee strength and speed, agility, and explosive power in elite soccer players. Int J Environ Res Public Health. 2022. https:\/\/doi.org\/10.3390\/ijerph19020671.","journal-title":"Int J Environ Res Public Health"},{"key":"1119_CR23","doi-asserted-by":"publisher","DOI":"10.1519\/13843.1","author":"MA Newman","year":"2004","unstructured":"Newman MA, Tarpenning KM, Marino FE. Relationships between isokinetic knee strength, single-sprint performance, and repeated-sprint ability in football players. J Strength Cond Res. 2004. https:\/\/doi.org\/10.1519\/13843.1.","journal-title":"J Strength Cond Res"},{"key":"1119_CR24","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.d5928","author":"JPT Higgins","year":"2011","unstructured":"Higgins JPT, Altman DG, G\u00f8tzsche PC, J\u00fcni P, Moher D, Oxman AD, et al. The Cochrane Collaboration\u2019s tool for assessing risk of bias in randomised trials. BMJ. 2011. https:\/\/doi.org\/10.1136\/bmj.d5928.","journal-title":"BMJ"},{"key":"1119_CR25","unstructured":"The Cochrane Collaboration. Review Manager Web (RevMan Web). 2020."},{"key":"1119_CR26","doi-asserted-by":"publisher","unstructured":"So\u00f1\u00e9n DF, Miguel DF, Azze AM, De La Fuente FP 2021 Unilateral and bilateral Influence of pliometric training in lower limb power and asymmetry in karatekas. Retos. https:\/\/doi.org\/10.47197\/retos.v0i39.78818","DOI":"10.47197\/retos.v0i39.78818"},{"key":"1119_CR27","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph19031029","author":"O Gonzalo-Skok","year":"2022","unstructured":"Gonzalo-Skok O, S\u00e1nchez-Sabat\u00e9 J, Tous-Fajardo J, Mendez-Villanueva A, Bishop C, Piedrafita E. Effects of direction-specific training interventions on physical performance and inter-limb asymmetries. Int J Environ Res Public Health. 2022. https:\/\/doi.org\/10.3390\/ijerph19031029.","journal-title":"Int J Environ Res Public Health"},{"key":"1119_CR28","doi-asserted-by":"publisher","DOI":"10.1016\/j.jesf.2025.06.003","author":"M Tao","year":"2025","unstructured":"Tao M, Nassis GP, Song Y, Yin M, Zhu C, Lyu M, et al. Impact of training volume settings between unilateral training and bilateral training on athletic performance: a systematic review and meta-analysis. J Exerc Sci Fit. 2025. https:\/\/doi.org\/10.1016\/j.jesf.2025.06.003.","journal-title":"J Exerc Sci Fit"},{"key":"1119_CR29","doi-asserted-by":"publisher","DOI":"10.1519\/JSC.0000000000002923","author":"BB Appleby","year":"2019","unstructured":"Appleby BB, Cormack SJ, Newton RU. Specificity and transfer of lower-body strength: influence of bilateral or unilateral lower-body resistance training. J Strength Cond Res. 2019. https:\/\/doi.org\/10.1519\/JSC.0000000000002923.","journal-title":"J Strength Cond Res"},{"key":"1119_CR30","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0327237","author":"B Deng","year":"2025","unstructured":"Deng B, Yan R, Sui X, Lin G, Ding S, Li D, et al. Effects of unilateral and bilateral complex-contrast training on lower limb strength and jump performance in collegiate female volleyball players. PLoS ONE. 2025. https:\/\/doi.org\/10.1371\/journal.pone.0327237.","journal-title":"PLoS ONE"},{"key":"1119_CR31","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2023.1128250","author":"W Zhang","year":"2023","unstructured":"Zhang W, Chen X, Xu K, Xie H, Li D, Ding S, et al. Effect of unilateral training and bilateral training on physical performance: a meta-analysis. Front Physiol. 2023. https:\/\/doi.org\/10.3389\/fphys.2023.1128250.","journal-title":"Front Physiol"}],"container-title":["Sports Medicine - Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s40798-026-01119-5.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1186\/s40798-026-01119-5","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s40798-026-01119-5.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T01:17:23Z","timestamp":1791940643000},"score":1,"resource":{"primary":{"URL":"https:\/\/link.springer.com\/10.1186\/s40798-026-01119-5"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,13]]},"references-count":31,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,12]]}},"alternative-id":["1119"],"URL":"https:\/\/doi.org\/10.1186\/s40798-026-01119-5","relation":{},"ISSN":["2198-9761"],"issn-type":[{"value":"2198-9761","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,13]]},"assertion":[{"value":"22 September 2025","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"24 September 2026","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"13 October 2026","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"Not applicable.","order":1,"name":"Ethics","label":"Ethics Approval and Consent to Participate","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"Not applicable.","order":2,"name":"Ethics","label":"Consent for Publication","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare that they have no competing interests.","order":3,"name":"Ethics","label":"Competing Interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"156"}}