Rate of improvement of pain and function in mid-portion Achilles tendinopathy with loading protocols: a systematic review and longitudinal meta-analysis

Key points

1. 01The VISA-A is a validated 0 to 100 questionnaire combining Achilles pain, function, and activity; higher scores mean better status.
2. 02This is a longitudinal meta-analysis tracking within-group change over time, not a comparison against a control group.
3. 03Pain and function improved as early as 2 weeks and reached the minimal clinically important difference by about 4 weeks.
4. 04Improvement peaked at 12 weeks with a mean change of 21.11 points (SD 6.61) on the VISA-A.
5. 05Because tendon structure does not change within 2 weeks and muscle hypertrophy takes at least 4 weeks, early gains may be driven by neural or pain-processing mechanisms.

How it was conducted

Design

Systematic review with longitudinal meta-analysis (within-group change from baseline), PROSPERO registered

Search

PubMed, CINAHL (Ovid), CINAHL (EBSCO) plus grey literature to July 2017; 24 studies and 31 cohorts included

Participants

Adults over 18 with mid-portion Achilles tendinopathy for more than 3 months; mean ages 26 to 51 years

Intervention

Loading protocols (heavy eccentric calf training, heavy slow resistance, eccentric overload, Stanish protocol), with placebo only when paired with the loading arm

Outcomes

VISA-A questionnaire pooled mean change from baseline at each time point from 2 weeks to 6 months

Analysis

Multivariate mixed-model meta-analysis that did not converge, so pooled means and SDs were calculated per time point without between-study variance

What they found

• VISA-A improvement appeared by 2 weeks and reached the minimal clinically important difference by about 4 weeks.
• Peak improvement at 12 weeks: mean VISA-A change 21.11 points (SD 6.61).
• Studies with 6-month follow-up showed a plateau or slight decline after 12 weeks (only 3 cohorts at 6 months).
• 10 of 20 randomised trials (50%) were at high risk of bias; all 4 cohort studies were at critical risk of bias.
• 23 of 24 studies had samples under 50, indicating high small-study bias; overall GRADE quality rated very low.

Limitations

• The mixed-model meta-analysis failed to converge, so within- and between-study variability could not be accounted for and no true effect size was produced.
• There was no control or comparison group, so improvement cannot be separated from natural history or placebo.
• Most studies were small (under 50 participants) and at high or critical risk of bias, and a funnel plot suggested publication bias at 12 weeks.
• Only 3 cohorts reported 6-month outcomes, making the later time points imprecise.

Why it matters

For patients

If you start a calf loading program for Achilles pain, you can often expect noticeable improvement within the first few weeks, building toward larger gains by about 3 months.

For clinicians

Use the roughly 2-week onset and 12-week peak to set patient expectations, while remembering this maps a treatment trajectory rather than proving the program causes the change.

For readers

Achilles loading programs improve symptoms early and peak around 12 weeks, but this descriptive trajectory rests on very low quality evidence.