I heard an initially depressing but worthwhile comment during a seminar for physio’s who prescribe 3 sets of 10 exercises as “you may be doing something to help your patients, at least initially…”
The theme of this was very much that to get changes in power (and to a certain extent hypertrophy), you need to be loading heavy e.g., three sets of five at 85% of 1RM. This is pretty hard to achieve with body weight (for a gastroc/soleus complex) and ideally prescription through a physio (or other suitably qualified professional) would ensure you’re not going to injure something in the process.
For years, Rehab protocols for ruptured Achilles were incredibly conservative given the huge fear of re-rupture, however these days are far more progressive. We know that offloading tendons for long periods of time has very little going for it beyond the initial stages of healing.
From a tendon healing state, a couple of years down the track things should be sound but they will still respond to loading, just make loading progressive and I’d suggest working toward heavy to get the changes. If you or your PT get imaginative enough, gym work doesn’t need to be a bore. Sessions also don’t need to be hours long and as Coach Chad points out, you can do it in a way as to not get massive (which you will then have to carry uphill with you)