Exercise parameters to consider for Achilles tendinopathy: a modified Delphi study with international experts

Key points

1. 01Contraction intensity was ranked the top priority for midportion Achilles tendinopathy rehabilitation, ahead of volume and contraction type.
2. 02For insertional Achilles tendinopathy, limiting ankle dorsiflexion range during exercises reached consensus as the most critical parameter, with full dorsiflexion avoided to reduce compressive load on the tendon insertion.
3. 03Four parameters reached consensus of major influence for midportion AT: intensity of contraction, total time under tension, number of repetitions and sets, and type of contraction.
4. 04Three parameters reached consensus for insertional AT: range of ankle dorsiflexion, intensity of contraction, and number of repetitions and sets.
5. 05Pain was ranked highly by experts overall but did not reach the predefined consensus threshold, as it is generally used as a regulatory guide for other parameters rather than a direct modulator of tendon properties.

How it was conducted

Design

Three-round modified Delphi consensus study

Participants

17 international experts in Achilles tendinopathy exercise rehabilitation (94.4% retention from 18 invited); predominantly clinician-researchers from Australia, Europe, and North America

Parameter pool

16 exercise parameters based on the heel raise exercise, including 12 from a literature review and 4 added through steering committee discussion or round 1 suggestions

Consensus criteria

Median score 4 or above, at least 75% of experts rating 4 or 5, and IQR of 1 or less on a 5-point Likert scale (1=no influence, 5=very high influence)

Round 3

Experts ranked parameters by importance; both the consensus-meeting parameters and all parameters were ranked separately

What they found

• 4 parameters reached consensus of major influence for midportion AT: intensity of contraction, total time under tension, number of repetitions and sets, and type of contraction.
• 3 parameters reached consensus of major influence for insertional AT: range of ankle dorsiflexion, intensity of contraction, and number of repetitions and sets.
• For insertional AT, range of ankle dorsiflexion during exercise achieved median 5.0 and IQR 0.00 in round 2, with 100% of experts rating it 4 or 5.
• Intensity of contraction achieved median 5.0 and IQR 1.00 with 82.35% rating 4 or 5 in round 2 for both midportion and insertional AT.
• 32.1% of ratings changed between round 1 and round 2, indicating meaningful revision after feedback.
• 12 of the 14 initial parameters plus 2 added in round 2 were assessed; all parameters beyond the 4 (midportion) and 3 (insertional) consensus items failed to meet either the major or minor influence consensus thresholds.

Limitations

• The expert panel was composed exclusively of researchers and clinician-researchers; non-researcher clinicians and patients were not included, which may limit applicability to everyday practice settings.
• Geographical representation was restricted to seven countries, with Africa and Asia not represented, limiting generalisability of the recommendations.
• The number of Delphi rounds was capped at three to reduce attrition, which may have prevented consensus on parameters whose scores were close to the threshold.
• The questionnaire was structured around the heel raise exercise; results may not fully apply to more specific exercises such as plyometrics, and the study did not differentiate between patient subgroups such as active versus inactive individuals.

Why it matters

For patients

Patients with Achilles tendinopathy can expect their physiotherapist to pay particular attention to how hard they contract during heel raises and, if the tendon is affected at the heel bone insertion, to avoid dropping the heel below the step until later in rehabilitation.

For clinicians

Clinicians should prioritise prescribing contraction intensity across all cases of AT, and for insertional AT should also carefully control the range of dorsiflexion to minimise compressive load, while recognising that parameters such as pain monitoring and session frequency remain important even without formal consensus.

For readers

This Delphi study provides the first structured expert consensus on which heel raise exercise variables to prioritise in AT rehabilitation, offering a practical framework for standardising exercise prescription and guiding future clinical trial design.