{
  "abstract": "Background\n\nLanding alterations during single leg hop to distance (SLHD) testing persist after anterior cruciate ligament (ACL) reconstruction and may contribute to a high risk of re-injury. Increased thigh muscle co-activation is recognised as a common neuromuscular adaptation after ACL injury, but conflicting results have been reported for jump landings. Therefore, this study aimed to assess changes in co-activation at one year post-reconstruction during the landing of a SLHD and to evaluate whether a 2D knee flexion scoring system could identify landings with heightened co-activation.Method\n\nThis cross-sectional study assessed 18 sportingly active individuals one year after ACL-reconstruction alongside 18 matched control participants. Co-activation of the quadriceps and hamstring musculature during landing was recorded via electromyography. Additionally, peak knee flexion was assessed and scored as < 60°, between 60° and 80 ° and > 80° with a clinically practical 2D analysis. Co-activation was compared between the ACL-reconstructed leg, the contralateral leg and the matched control leg as well as between 2D-scored trials with statistical parameter mapping (SPM).Results\n\nSPM analysis revealed greater thigh muscle co-activation in ACL-reconstructed leg compared to the matched control leg from 229 ms to 250 ms after initial contact (p = 0.007). No significant differences were observed between the ACL-reconstructed and contralateral leg. 2D knee flexion scoring did not reveal differences in co-activation during landing.Conclusion\n\nNeuromuscular control is not fully restored at one year post-ACL-reconstruction, and consideration of thigh muscle co-activation during single leg hop testing could be important. However, a 2D knee flexion scoring system is not suitable for revealing co-activation differences among recreational sportingly active people, and alternative methods are needed to assess these neuromuscular adaptations in the clinic.Trial registration\n\nThe study was pre-registered at the German Clinical Trials Register (DRKS-ID: 00023002).",
  "abstract_shown": true,
  "affiliations": [
    "Department of Health Professions, Physiotherapy, Bern University of Applied Sciences, Murtenstrasse 10, Bern, CH-3008, Switzerland. jano.probst@orange.fr.",
    "Department of Health Professions, Physiotherapy, Bern University of Applied Sciences, Murtenstrasse 10, Bern, CH-3008, Switzerland."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Jano Probst"
    },
    {
      "affs": [
        1
      ],
      "name": "Patric Eichelberger"
    },
    {
      "affs": [
        1
      ],
      "name": "Aglaja Busch"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/crdestwe35a1r.bib",
  "cited_by": 0,
  "doi": "10.1186/s12891-026-10236-x",
  "fulltext_url": "https://europepmc.org/articles/PMC13721325",
  "id": "crdestwe35a1r",
  "issns": [
    "1471-2474"
  ],
  "landing_url": "https://europepmc.org/article/MED/42963538",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Research"
    ],
    [
      "openalex",
      "2746|Knee injuries and reconstruction techniques"
    ]
  ],
  "openalex": "W7171809513",
  "pdf_url": "https://europepmc.org/articles/PMC13721325?pdf=render",
  "pmcid": "PMC13721325",
  "pmid": "42963538",
  "published": "2026-07-30",
  "publisher": "BMC",
  "ris": "https://research.draconitic.com/paper/crdestwe35a1r.ris",
  "sources": [
    {
      "first_seen": "2026-11-02T03:21:43Z",
      "native_id": "MED:42963538",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42963538"
    },
    {
      "first_seen": "2026-11-03T12:22:02Z",
      "native_id": "PMC13721325",
      "source": "pmc",
      "url": "https://doi.org/10.1186/s12891-026-10236-x"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2746|Knee injuries and reconstruction techniques",
      "subfield": "surgery"
    }
  ],
  "title": "Thigh muscle co-activation during a single leg hop for distance one year after ACL-reconstruction and its relationship with a 2D knee flexion score: a cross-sectional study.",
  "title_text": "Thigh muscle co-activation during a single leg hop for distance one year after ACL-reconstruction and its relationship with a 2D knee flexion score: a cross-sectional study.",
  "type": "peer-reviewed",
  "updated_at": "2026-11-03T12:22:02Z",
  "url": "https://research.draconitic.com/paper/crdestwe35a1r",
  "venue": "BMC musculoskeletal disorders",
  "versions": []
}