{
  "abstract": "Strength-based screening has documented limitations. Adaptive Force (AF) offers an alternative--it captures the adaptive holding capacity under rising external load, not addressed by strength testing. This study examined the association between AF-based muscle stability and musculoskeletal complaints in 23 football (soccer) players, comparing AF-derived and conventional strength parameters, with preliminary follow-up. AF and maximal voluntary isometric contraction (MVIC) were measured across five bilateral muscle groups (knee extensors/flexors; hip flexors/adductors/abductors). AF parameters (maximal isometric AF, maximal AF, AF-Ratio), MVIC and hamstrings-to-quadriceps (H:Q) ratio were compared by complaint status assessed via questionnaire at baseline and six-month follow-up (n=13).\n\nStability deficits were strongly associated with complaints (OR=54.0, 82% side concordance). AF-Ratio discriminated between players with and without complaints (d=-1.47, AUC=0.93), strongest for hip abductors (d=-1.64). Players with follow-up complaints showed lower baseline AF-Ratio (d=-1.45, AUC=0.86) and more stability deficits (d=1.67). MVIC and H:Q ratio discriminated in neither analysis (p>0.500, AUC[≤]0.44); AF-Ratio outperformed both at baseline (p[≤]0.002) and follow-up (p[≤]0.028).\n\nAF-based stability assessment may capture neuromuscular deficits related to complaints that conventional strength testing misses, with preliminary follow-up data suggestive of predictive value. The concept of functional instability syndrome provides a mechanistic framework for non-contact injuries and complaints. AF-based stability assessment may hold potential for screening and return-to-sport decisions--pending prospective validation.",
  "abstract_shown": true,
  "affiliations": [
    "Center of Orthopedics, Traumatology and Plastic Surgery, University Hospital Brandenburg, Brandenburg Medical School Theodor Fontane, Brandenburg an der Havel,"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "L. V. Schaefer"
    },
    {
      "name": "F. N. Bittmann"
    },
    {
      "name": "J. Ulrich"
    },
    {
      "name": "R. Prill"
    },
    {
      "name": "R. Becker"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5xdtekmv56b4d.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.07.07.26357205",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.07.07.26357205v3.full",
  "id": "5xdtekmv56b4d",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.07.07.26357205v3",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "sports medicine"
    ],
    [
      "openalex",
      "2732|Sports injuries and prevention"
    ]
  ],
  "openalex": "W7167942359",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.07.07.26357205v3.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-07-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5xdtekmv56b4d.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:12Z",
      "native_id": "10.64898/2026.07.07.26357205",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.07.07.26357205v3"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2732|Sports injuries and prevention",
      "subfield": "surgery"
    }
  ],
  "title": "Muscle stability deficits and musculoskeletal complaints in football players: Adaptive Force Ratio outperforms conventional strength parameters--a cross-sectional study with preliminary follow-up",
  "title_text": "Muscle stability deficits and musculoskeletal complaints in football players: Adaptive Force Ratio outperforms conventional strength parameters--a cross-sectional study with preliminary follow-up",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:12Z",
  "url": "https://research.draconitic.com/paper/5xdtekmv56b4d",
  "venue": "medRxiv",
  "versions": []
}