The efficacy of radial shockwave therapy compared with sham shockwave therapy in insertional Achilles tendinopathy. A randomised controlled trial

Radial shockwave therapy (rSWT): rSWT will be administered by an adequately trained physiotherapist. The participant will receive a 3000-shock dose of rSWT (Chattanooga device) applied to the most painful area on the affected side Achilles tendon. Gel will be used to conduct pressure waves to the tendon. Intensity of application will start on two bars of pressure, with frequency set to continuous and eight per second. The target self-reported pain will be >4/10 until the highest tolerable pain (numerical pain rating scale, 0=no pain, 10=worst pain imaginable). If self-reported pain drops below 5/10 the rSWT probe will be moved to a different region within the region of interest (area 2cm squared surrounding the starting location). If the pain remains below 5/10 at all parts within the region of interest the rSWT pressure setting will be progressed from two bar of pressure (this will always be the starting point) up to and including five bar of pressure (the maximum in the machine being used) so as to achieve the desired self-reported pain output. This process will be repeated as necessary until the shock dose of 3000 is completed (at 10 Hz, so the treatment lasts for 5 minutes). Participants will receive an identical rSWT treatment on three occasions (baseline, and approx. week 1 and 2), each separated by a approximaly 7 days (minimum 5 days and maximum 10 days).

Post rSWT treatment:
Immediately after the rSWT, participants will be asked whether they believe they were in the intervention or placebo group.

After that, an appropriately trained researcher, who is blind to treatment allocation will deliver advice and a 12-week exercise program to all participants. This includes an evidence-based and progressively loaded exercise protocol for Achilles tendinopathy, education about physical activity modification and resumption, and advice about progressing and regressing exercise load, based on a pain monitoring model. The researcher will also provide education about Achilles tendinopathy (pathology, pain, risk factors, prognosis, treatments, recovery times). Participants will be reviewed by the researcher at Imaging at Olympic Park (IOP) at weeks 1 and 2 weeks (when repeat shockwave is applied) to modify the exercise as required (e.g. progress load, modify technique). The researcher will have a teleconference (Zoom) meeting with participants at week 6 to ask whether they have any questions or issues with the exercise or education intervention. Additionally, participants will be provided with basic online exercise videos and education and the researchers contact details that they can use at any time. Participants will be advised to refrain from using other physical therapy interventions and non-steroidal anti-inflammatory medications but will be advised to take paracetamol (up to 4g/day) for pain relief as required.

Details of the exercise program:
a) who is administering the program: physiotherapist (@ baseline with further progressions and guidance @ 1, 2 weeks, and zoom support at 6 weeks). ie participants will be followed up @ 5 weeks via Zoom. Participants will also be sent a weekly email encouraging them to complete the exercises and report any issues they may be having (if they express they are having issues a researcher will call them to discuss)
b) the mode of administration: independently at home.
c) the level of intensity: will be adjusted by the participants themselves based on pain and repetitions in reserve. They will be advised to do 15 repetitions x 4 sets, once a day for three times a week. If they experience less than 5/10 pain and have 2 reps in reserve, then they will be advised to add weights in 5kgs increments. If pain is >5/10 they will be advised to revert to an isometric version of the exercise
d) the frequency/duration of program, 15 repetitions x 4 sets, once a day for three times a week for 12 weeks.
e) the exercises include standing knee straight and knee bent isotonic (eccentric and conentric) calf raises
f) exercise progression: Participants will progress and regress exercise themselves based on criteria outlined above. They will also be reviewed by the researcher at Imaging at Olympic Park (IOP) at 1 and 2 weeks to administer subsequent rSWT sessions and to modify the exercise as required (e.g. progress load, modify technique). There will also be a brief Zoom session at 6 weeks to check progress, check exercises and provide advice.

Details of the education program:
a) who administers the education: physiotherapist (@ baseline with further reinforcement and guidance @ 1, 2 weeks, and a Zoom meeting at 6 weeks, as well as weekly email support [opportunity to ask questions and voice concerns])
b) the mode of administration: Face to face supported by videos and education leaflets.
c) the frequency/duration of program: 12 weeks. single session at the beginning of the program and then with further reinforcement and guidance @ week 6 via a Zoom meeting and weekly email support).
d) the education program will be delieverd in 15-20 minutes in the first session.

Strategies to monitor adherence: adherence will be assessed via self report questionnaire at 6 and 12 weeks (via email or text link to a Qualtrics survey).