Victorian Institute of Sports Assessment – Achilles questionnaire, German version

Abstract

The Victorian Institute of Sports Assessment – Achilles questionnaire, German version (VISA-A-G) is an internationally recognized, disease-specific patient-reported outcome measure (PROM) designed to quantify the clinical severity, functional impairment, and athletic limitations associated with Achilles tendinopathy. Adapted from the original Australian English index formulated by Robinson and colleagues at the Victorian Institute of Sport Assessment, the VISA-A-G fills an imperative clinimetric void within German-speaking orthopedic, sports medicine, and physical rehabilitation contexts. The scale assesses three core dimensional domains: localized symptom manifestation (specifically early morning stiffness and movement-evoked pain), functional capacity during standard weight-bearing tasks, and physical activity or sports participation thresholds under progressive mechanical tendon loading. Comprising eight discrete items, the questionnaire utilizes mixed metric response formats, including 10-point numerical rating scales and multi-tiered categorical physical capacity questions. Items 1 through 7 contribute up to 10 points each, while Item 8 utilizes a conditional multi-tiered branching format scored out of 30 points, yielding an aggregate continuous scale ranging from 0 to 100. Lower aggregate scores represent profound functional disability, persistent pain, and total activity cessation, whereas a score of 100 denotes an asymptomatic, unrestricted, and fully functional individual.

Psychometric evaluation of the VISA-A-G confirms outstanding reliability and robust construct validity across varied clinical and athletic cohorts. In validation cohorts encompassing preoperative surgical candidates, conservatively treated tendinopathy patients, asymptomatic competitive runners, and sedentary controls, the instrument exhibited exceptional concurrent validity when benchmarked against classic clinical grading criteria, including the Percy and Conochie tendon classification ($r = 0.95$) and the Curwin and Stanish athletic pain classification ($r = -0.95$). Test-retest reliability over a one-week interval demonstrated moderate to excellent temporal stability, with intraclass correlation coefficients (ICC) ranging between 0.60 and 0.97 across sub-cohorts, while inter-rater reliability achieved near-perfect agreement ($ICC = 0.99$). Discriminant validity confirmed pronounced score divergence between symptomatic pathology and healthy baselines without confounding ceiling effects in athletic control samples. Consequently, the VISA-A-G provides an essential, standardized evaluative instrument for clinical trials, longitudinal rehabilitation monitoring, and cross-cultural epidemiological research in sports medicine.

Keywords

VISA-A, VISA-A-G, Achilles tendinopathy, patient-reported outcome measure, sports medicine, cross-cultural adaptation, psychometrics, tendon rehabilitation, clinimetrics, athletic overuse injury, physical function assessment

Authors

The cross-cultural adaptation and psychometric validation of the German version of the Victorian Institute of Sports Assessment – Achilles questionnaire was conducted by leading orthopedic and sports medicine researchers at the Institute of Sports Medicine Frankfurt am Main:

• Prof. Dr. med. Heinz Lohrer — Institute of Sports Medicine Frankfurt am Main, Otto-Fleck-Schneise 10, 60528 Frankfurt am Main, Germany. Corresponding contact: [email protected].
• Dr. Tanja Nauck — Institute of Sports Medicine Frankfurt am Main, Otto-Fleck-Schneise 10, 60528 Frankfurt am Main, Germany. Academic contact: [email protected].

Purpose

Achilles tendinopathy is an extraordinarily widespread, debilitating overuse pathology characterized by localized mechanical pain, microstructural collagen disorganization, tendon thickening, and diminished load-bearing capacity. It occurs with remarkable frequency not only among elite track-and-field athletes, distance runners, and court-sport competitors, but also within recreationally active individuals and sedentary populations. Historically, the clinical monitoring of Achilles tendon disorders was severely constrained by the use of broad, clinician-derived classification systems (such as the Percy and Conochie system or the Curwin and Stanish scale). Although clinically intuitive, these legacy rubrics lacked granular responsiveness to incremental therapeutic progress, exhibited substantial inter-examiner variability, and failed to systematically capture the subjective, lived functional limitations experienced by patients across diverse loading profiles.

The primary clinical and psychometric objective of developing the VISA-A-G was to translate, cross-culturally adapt, and validate the English-language VISA-A questionnaire into standard German in accordance with international methodological guidelines established for self-report health status instruments. Prior to the publication of the VISA-A-G, German-speaking orthopedists, sports physical therapists, and musculoskeletal scientists lacked a validated, disease-specific PROM. Clinicians frequently relied either on translated generic lower-limb scores (e.g., the Foot and Ankle Outcome Score [FAOS] or the American Orthopaedic Foot & Ankle Society [AOFAS] rating systems) or on unvalidated, ad-hoc institutional translations. Generic instruments inevitably suffer from substantial ceiling effects when administered to athletic cohorts and lack the biomechanical specificity required to evaluate tendon-specific stretch-shortening cycles.

In clinical practice, the VISA-A-G serves as an indispensable tool for longitudinal monitoring, baseline staging, and clinical decision-making. By transforming subjective complaints into an objective continuous score between 0 and 100, the instrument enables clinicians to quantitatively evaluate tissue recovery trajectories, establish readiness for progressive return-to-play protocols, and determine the therapeutic efficacy of interventions such as heavy slow resistance (HSR) training, eccentric loading regimens, extracorporeal shockwave therapy (ESWT), or surgical debridement. In research contexts, the availability of a validated German version facilitates multinational, multi-center clinical trials, enabling standardized meta-analytic data pooling and international cross-comparison across European clinical populations without linguistic or cultural bias.

Psychological Construct

The underlying construct evaluated by the VISA-A-G is the clinical severity and functional impairment of Achilles tendinopathy. Within contemporary biopsychosocial frameworks and clinimetrics, this construct is conceptualized as a multi-tiered, latent continuum reflecting the interplay between physical tendon load tolerance, functional capacity during daily locomotion, and pain-related behavioral adaptation. The questionnaire integrates three interrelated sub-dimensions into a composite index:

1. Pain and Symptom Perception

This sub-dimension assesses localized mechanical pain, tendon stiffness, and delayed symptom exacerbation following weight-bearing activity. Tendon pain is characteristically load-dependent; microvascular and neurogenic ingrowth within pathological tendon tissue causes nociceptive sensitization that peaks following periods of immobility and during dynamic loading. The VISA-A-G targets these hallmark phenomena directly:

• Early morning stiffness duration: Captures the temporal duration of stiffness upon first weight-bearing in the morning, reflecting inflammatory exudate, altered ground substance viscosity, and resting tissue hypomobility.
• Warmed-up ambulation pain: Evaluates the presence of pain during level-ground walking after general daily warm-up, establishing whether minimal physiological loads trigger nociceptive responses.
• Post-activity latency pain: Measures symptom latency within two hours following a standardized 30-minute walk, detecting delayed mechanical irritability characteristic of tendon matrix decompensation.

2. Functional Movement and Mechanical Loading Tolerance

The functional dimension quantifies the patient’s capacity to perform isolated lower-extremity kinetic tasks that impose increasing tensile, compressive, and elastic strain across the triceps surae-Achilles tendon complex:

• Stair descent: Descending stairs requires controlled eccentric elongation of the gastrocnemius-soleus complex, generating high tensile stress across the midportion and insertional fibers of the Achilles tendon.
• Single-leg heel raises: Performing ten consecutive single-leg calf raises from a flat surface isolates the contractile and force-transmission integrity of the posterior calf musculature, unmasking localized mechanical failure and pain inhibition.
• Single-leg hopping capacity: Hopping introduces high-velocity stretch-shortening cycles (SSCs) that demand rapid tendon energy storage and release. Quantifying pain-free hopping repetitions assesses the threshold between physiological elastic recoil and nociceptive failure.

3. Athletic Participation and Load-Duration Thresholds

The physical activity dimension assesses the patient’s real-world capacity to engage in sports, occupational labor, or intensive recreational pursuits. Because elite athletes and highly active individuals often exhibit high pain tolerance, simple categorical assessments of whether an individual is “active” fail to capture clinical severity. The VISA-A-G solves this problem by evaluating:

• Current level of sports participation: Categorizes whether the individual is completely sidelined, performing modified training, training at full volume with diminished performance, or competing unhindered at their pre-injury baseline.
• Conditional sport duration and pain thresholds: Employs a branching metric that rewards asymptomatic, long-duration athletic training while systematically penalizing early-onset exercise pain, training cessation, or severe functional incapacitation that prevents basic physical loading.

Theoretical Framework

The conceptual foundation of the VISA-A-G integrates principles from modern tendon biomechanics, orthopedic clinimetrics, and behavioral medicine. Foremost among these is the Tendon Continuum Model formulated by Cook and Purdam (2009). This paradigm posits that tendinopathy progresses through three distinct, non-linear phases: reactive tendinopathy, tendon dysrepair (failed healing response), and degenerative tendinopathy. Pathophysiologically, the condition is not a classical acute inflammatory state (such as “tendinitis”), but rather a dynamic cellular and matrix remodeling process characterized by tenocyte proliferation, hypervascularization, ground substance accumulation, and disorganized collagen bundles.

From a clinimetric perspective, the VISA-A-G translates the mechanical and biological tenets of the continuum model into a patient-reported framework. In healthy tendon physiology, the tendon functions as a spring, effectively transferring muscular forces and storing elastic strain energy during movements such as running and jumping. When pathological changes occur, mechanical load-bearing capacity decreases dramatically. The theoretical architecture of the VISA-A-G reflects this graded hierarchy of mechanical loading: starting with low-strain static recovery (morning stiffness), advancing through low-load continuous movement (level walking and stair descent), progressing to moderate concentric-eccentric muscle-tendon contractions (repetitive heel raises), and culminating in high-rate elastic energy storage and release tasks (hopping and sports competition).

Simultaneously, the scale is anchored in the International Classification of Functioning, Disability and Health (ICF) established by the World Health Organization. Within the ICF model, musculoskeletal health conditions must be evaluated across three operational tiers: Body Functions and Structures (evaluated via morning stiffness and localized palpation pain), Activity Limitations (captured by walking, descending stairs, and calf-raise deficits), and Participation Restrictions (evaluated by athletic engagement, training volume reduction, and competition withdrawal). By spanning all three ICF dimensions, the VISA-A-G provides a holistic index that bridges physiological tissue pathology and social/athletic role fulfillment.

Validity

The psychometric validation of the German version was executed via rigorous empirical methodology published by Lohrer and Nauck (2009), adhering to international clinimetric guidelines. The validation protocol evaluated construct validity, concurrent validity, and known-groups (discriminant) validity across a well-characterized multi-group cohort.

Concurrent and Criterion-Related Validity

To establish concurrent validity, the VISA-A-G was compared against established historical clinical assessment instruments. Specifically, participants were evaluated using the Percy and Conochie tendon classification and the Curwin and Stanish classification for the effect of pain on athletic performance:

• Percy and Conochie Correlation: Spearman rank-order correlation analysis revealed an exceptionally strong positive correlation of $r = 0.95$ between the VISA-A-G and the Percy and Conochie classification. This demonstrated that as clinician-rated anatomical and functional grades improved, patients’ self-reported scores aligned with remarkable fidelity.
• Curwin and Stanish Correlation: Evaluating the VISA-A-G against the Curwin and Stanish scale yielded an inverse correlation of $r = -0.95$. Because the Curwin and Stanish scale assigns higher numerical grades to worse clinical impairment (e.g., continuous pain disrupting all sports and daily living), this robust negative correlation confirms that higher VISA-A-G scores correspond directly to minimal functional disruption.

Known-Groups Discriminant Validity

A central psychometric requirement of any specialized PROM is its capacity to discriminate reliably between distinct clinical subpopulations exhibiting varying degrees of pathology. Lohrer and Nauck evaluated four distinct groups ($N = 109$ total):

• Preoperative surgical patients with chronic, recalcitrant unilateral Achilles tendinopathy ($n = 15$)
• Conservatively treated patients with unilateral symptoms undergoing active rehabilitation ($n = 15$)
• Asymptomatic, highly active competitive runners recruited from regional athletics clubs ($n = 31$)
• Asymptomatic university pharmacology students representing general non-athletic controls ($n = 48$)

The VISA-A-G exhibited profound discriminatory power across these groups ($p < 0.001$). Symptomatic patients scored significantly lower than both healthy control cohorts. Preoperative surgical candidates displayed the lowest mean scores (mean: 28 to 35 points), reflecting profound functional disability. Conservatively managed patients demonstrated intermediate scores (mean: 45 to 60 points). In stark contrast, asymptomatic university students achieved near-perfect scores (mean: $96.8 \pm 5.1$), and asymptomatic competitive runners similarly registered high scores (mean: $97.6 \pm 4.2$). These results confirm that the German translation is free from aberrant skewness in healthy individuals while remaining sensitive to severe pathological impairment.

Reliability

Reliability testing for the VISA-A-G focused primarily on temporal stability (test-retest reliability) and inter-examiner consistency (inter-rater reliability), which are fundamental for tracking clinical trajectories and therapeutic responses over time.

Test-Retest Reliability

To evaluate temporal stability, the questionnaire was administered on two separate occasions spaced seven days apart to a stable subset of both symptomatic patients and healthy controls. Because Achilles tendinopathy is a chronic condition that does not resolve within seven days in the absence of surgical intervention, this interval was chosen to prevent biological clinical change while minimizing memory recall bias. The resulting Intraclass Correlation Coefficients (ICC) for the aggregate score ranged from $ICC = 0.60$ to $ICC = 0.97$ across different sub-cohorts. The total score demonstrated excellent reproducibility, confirming that the tool is sufficiently stable for longitudinal assessment.

Inter-Rater Reliability

Inter-rater reliability was assessed by having two independent clinicians administer or oversee the questionnaire administration. The analysis revealed near-perfect agreement, with an aggregate Intraclass Correlation Coefficient of $ICC = 0.99$ and a Pearson product-moment correlation coefficient of $r = 0.97$. This confirms that questionnaire completion is impervious to administrator bias, whether supervised by a sports physician or completed independently as a self-report instrument.

Item-Level Reliability Considerations

Analysis of individual item metrics revealed that while items 1 through 5, 7, and 8 maintained very high stability ($ICC > 0.80$), Item 6 (measuring the number of pain-free single-leg hops) displayed a lower retest stability coefficient ($ICC = 0.44$). Lohrer and Nauck noted that single-leg hopping imposes immediate, high-magnitude peak tensile loads on the Achilles tendon; consequently, a patient’s physical execution or subjective apprehension during dynamic hopping can vary day-to-day based on acute neuromuscular fatigue, footwear, or surface conditions. Nevertheless, this localized item variability did not compromise the composite score’s high reliability.

Factor Analysis

In the initial cross-cultural validation study by Lohrer and Nauck (2009), classical clinimetric methodology was prioritized over extensive exploratory or confirmatory factor modeling. The authors aimed to ensure linguistic, cultural, and conceptual equivalence with the established Australian index rather than alter its established eight-item structural integrity. By maintaining the eight items unaltered, the researchers ensured direct comparability with global trials utilizing the original scale.

Subsequent psychometric investigations of the VISA-A across international cohorts (including Swedish, Italian, Spanish, and broader European adaptations) have evaluated the latent factor structure through Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). These evaluations consistently suggest that while the VISA-A is clinically interpreted as a unidimensional composite score representing “clinical severity,” it statistically operates as a multidimensional construct driven by two to three primary latent factors:

• Factor 1: Dynamic High-Load Athletic Function: Dominated by high factor loadings from Items 7 and 8 (sporting participation and loading thresholds), which account for the greatest proportion of variance in athletic populations.
• Factor 2: Weight-Bearing Daily Living and Local Symptoms: Characterized by robust loadings from Items 1, 2, 3, and 4 (morning stiffness, walking pain, post-walking latency, and stair descent).
• Factor 3: Isolated Musculotendinous Performance: Represented primarily by Items 5 and 6 (single-leg calf raises and pain-free hopping repetitions).

Goodness-of-fit evaluations in structural equation models across the international literature demonstrate that a hierarchical model—wherein a higher-order overarching construct of “Achilles Tendinopathy Severity” subsumes these correlated sub-factors—yields satisfactory fit indices (Comparative Fit Index [$CFI$] $ge 0.94$; Root Mean Square Error of Approximation [$RMSEA$] $le 0.08$). These structural metrics confirm that while subscales can be conceptualized for analytical research, the aggregation into a single 100-point index remains methodologically justified.

Instrument / Measurement Tool

The Victorian Institute of Sports Assessment – Achilles questionnaire, German version (VISA-A-G), is structured as follows:

• Test Type: Disease-specific Patient-Reported Outcome Measure (PROM); self-administered or clinician-administered questionnaire.
• Target Population: Adult athletic and non-athletic patients presenting with midportion or insertional Achilles tendinopathy, as well as healthy controls undergoing lower-extremity screening.
• Age Group: 18 years of age and older.
• Administration Time: Approximately 5 to 10 minutes.
• Item Count: 8 questions.
• Response Scale: 8 items, mixed response formats including Likert-type scales and categorical time-based options. Items 1 through 6 utilize 0–10 continuous visual or numerical rating scales; Item 7 uses a 4-tier ordinal categorical scale (scores 0, 4, 7, 10); Item 8 is a conditional multi-tiered branching question scored from 0 to 30.
• Scoring Architecture:
  • Items 1 through 7 are scored out of 10 points each (maximum 70 points).
  • Item 8 is scored out of 30 points.
  • Total possible score is calculated by direct summation: $\text{Total Score} = \sum_{i=1}^{8} \text{Item}_i$.
  • Theoretical range is 0 to 100 points.
• Interpretation:
  • 100 points: Perfect tendon health, complete absence of pain, and full unrestricted physical activity.
  • > 90 points: Clinically asymptomatic or optimal recovery status.
  • 60 to 89 points: Mild to moderate tendinopathy with partial activity preservation.
  • 30 to 59 points: Moderate to severe tendinopathy with substantial athletic limitation and daily functional deficits.
  • < 30 points: Profound, disabling pathology commonly seen in surgical candidates or severe insertional tears.

Permissions & Fee and Test Year

The German adaptation of the VISA-A was formally published in 2009 by Heinz Lohrer and Tanja Nauck in the peer-reviewed journal BMC Musculoskeletal Disorders. The research was conducted under open-access dissemination paradigms. The VISA-A-G is in the public academic domain and may be freely utilized for non-commercial clinical, academic, and research purposes without royalty fees. Clinicians and clinical investigators are requested to cite the original validation publication (Lohrer & Nauck, 2009) and the foundational Australian index paper (Robinson et al., 2001) in all reports, clinical trial registries, and academic publications.

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13. Items of the Scale (Questionnaire)