Education and exercise supplemented by a pain-guided hopping intervention for male recreational runners with midportion Achilles tendinopathy: a single cohort feasibility study

Key points

1. 01Recruitment (100%), retention (87%), and follow-up (93%) rates all met or exceeded feasibility targets
2. 02Overall exercise adherence was 70% but fidelity to prescribed sets, reps, and progression was only 50% overall, dropping to 22-23% for double-leg jumps and single-leg hops
3. 03VISA-A (pain and function) improved by a mean of approximately 20.7 points from baseline to 12 weeks
4. 04Three moderate adverse events occurred, all linked to participants ignoring advice and performing explosive activities outside the program
5. 05Leg stiffness during submaximal and fatigue hopping increased significantly, suggesting the intervention addresses stretch-shortening cycle deficits

How it was conducted

Design

Single-cohort feasibility study

Participants

15 male recreational runners with midportion Achilles tendinopathy (ultrasound-confirmed), aged 18-55, running at least once per week

Setting

One private physiotherapy clinic in Melbourne, Australia

Intervention

12-week pain-guided progressive program: education plus 4-level exercise (isometrics, isotonics, double-leg jumps, single-leg hops and running), with pain threshold of 3/10 NRS guiding progression

Primary outcomes

Recruitment, retention, follow-up rates, adverse events, exercise adherence and fidelity, acceptability

Secondary outcomes

VISA-A, kinesiophobia (TSK), Achilles Tendon Beliefs Questionnaire, pain anxiety (PASS-20), physical tests, hopping leg stiffness and endurance

What they found

• Recruitment rate: 100% (15 of 15 eligible enrolled); retention: 87% (2 withdrew); 12-week outcome completion: 93%
• Exercise adherence across all exercises: 70% (SD 2.7); fidelity: 50% (SD 3.9); single-leg hop adherence was highest at 100%, seated heel raise lowest at 46%
• VISA-A improved from mean 62.23 (SD 17.36) at baseline to 74.00 at 4 weeks (partial eta-squared 0.452) and 86.23 at 12 weeks (partial eta-squared 0.740); overall effect size 0.740
• ATBQ (maladaptive beliefs) decreased significantly at 12 weeks: effect size 0.508
• Pain during single-leg hops decreased significantly at 4 weeks (partial eta-squared 0.761) and between 4 and 12 weeks (0.461); overall effect size 0.788
• Pain during hopping to fatigue decreased significantly at 4 weeks (partial eta-squared 0.660) and 4-12 weeks (0.533); overall effect size 0.772
• Leg stiffness during submaximal hopping increased from 44.99 kN/m (SD 12.32) at baseline to 53.28 kN/m at 4 weeks (partial eta-squared 0.298) and 60.46 kN/m at 12 weeks; overall effect size 0.540
• Hopping-to-fatigue duration increased from 39.23 s (SD 14.85) to 47.15 s at 4 weeks (partial eta-squared 0.367) and 55.38 s at 12 weeks; overall effect size 0.441
• At 12 weeks, 5 participants were satisfied and 8 very satisfied with treatment
• Three moderate adverse events (2 medial gastrocnemius tears, 1 grade 1 lateral knee ligament tear) occurred when participants performed explosive activities against advice

Limitations

• No control group, so natural history and placebo effects cannot be separated from treatment effects
• Small, all-male sample (n=15) limits generalisability to women and other populations
• Exercise fidelity was low for plyometric components (22-23%), meaning many participants did not receive the intended intervention dose
• Safety profile remains unclear because adverse events were caused by non-adherence to advice, not by the intervention itself, making risk estimation difficult

Why it matters

For patients

Recreational runners with midportion Achilles tendinopathy may be able to safely perform progressive hopping exercises as part of rehabilitation, provided they follow pain-guided progression rules and avoid sudden explosive activities.

For clinicians

This feasibility data supports designing a full RCT of pain-guided hopping added to standard care; clinicians should note that fidelity monitoring and strategies to reduce gym-dependent exercises are needed before scaling this protocol.

For readers

This is a small pilot study without a control group, so the improvements seen are promising but cannot yet be attributed to the hopping component specifically; a powered RCT is the required next step.