Keep in mind, no medical advice and just some notes based on knowledge and scientific studies!

Physical analysis

Balint is physically very fit and flexible and accordingly showed no limitations except for a slight shortening of the hip flexors (ilipsosas left; rectus femoris right).

He has developed knee pain around the kneecap in his left leg as a result of overloading from jogging and squash. Pathologies such as jumpers knee (Patella tendon inflammation) and runners knee (IT band inflammation) seem unlikely. The pain occurs irregularly and when it does, then especially in the slight bending of about 30 - 40 degrees.

His hip did not have a tilted posture (was confirmed by therapists), which indicated that there was no structural dysbalance. My guess is a weakness/dysbalance between the individual muscles of the quatriceps (vasturs medialis or laterais), causing the knee disc to rub against the bone during flexion (also possible neuromuscular dyscontrol).

Physcial advice:

Strengthen the muscles of the quatriceps carefully and stretch the muscle of the calves. Next session look further into exercice to reprogramm neuromuscular function.

Nutrition:

He primarily wants to lose about 5 kg of weight to improve his boulder performance but lose as little muscle as possible. However, he only eats about 50 g of protein a day, 70% of which is vegan, 20% vegetarian and 10% meat and fish.

The traditional view of eating plenty of carbohydrates and little protein is now outdated, and as long as there is no pre-existing kidney disease, it is always beneficial to eat more protein, especially during the diet.

In addition, when cooking/frying, he should take care to avoid oils such as sunflower or safflower (too much pro-inflammatory omega 6) and switch to e.g. refined olive oil. Virgin oils have a lower smoke point and form toxic substances during frying.

Nutrition Advice

Especially if the protein source is plant-based, it should be consumed more due to the biological value of only 50% in some plant proteins. 2 g/kg body weight is a good goal, but anything over 50 g daily would be a significant improvement.

Supplements:

He already takes MSM for skin care und anti-inflammatory purposes in joints and bones.