If Mr Redfern has recommended that you undertake some gastrocnemius stretches then read this guidance as to how to perform these specific stretches.
Peroneal Tendonitis Exercises, PDF, Foot
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What are the best stretches for the Achilles tendon?
A guide to basic stretches - Mayo Clinic
Lower Leg Calf Stretches (Gastrocnemius & Soleus)
The Fallacy of Calf Stretching
Calf Muscle (Gastrocnemius, Soleus & Achilles Tendon) Stretches Archives
A guide to basic stretches - Mayo Clinic
Best Exercises for Patellar Tendonitis - Physical Therapy Simplified
How to stretch your gastrocnemius
Calf Stretches
Best Stretches for a Sprained Ankle - Vive Health
Calf Strain Exercises : Treatment Considerations - [P]rehab
Easy Pulled Quad Stretches and Exercises - Vive Health
Best Exercises for Patellar Tendonitis - Physical Therapy Simplified