Chad doctor states the obvious

The elbow isn't a weight-bearing joint and she's talking rubbish.

Literally one quick google search, first result, peer reviewed:

results showed that patients with a BMI over 40 were at higher risk of being affected by lateral epicondylitis [tennis elbow] than those with normal BMI.

All the 5 level II studies report the association between obesity measured in terms of BMI and tendon conditions, with OR ranging between 1.9 (95% CI: 1.1–2.2) and 5.6 (1.9–16.6). Conclusions: The best evidence available to date indicates that obesity is a risk factor for tendinopathy.