In regards to the problems as listed below:

- Hyper extension of hemiplegic knee?

You are currently utilizing strengthening of Quads + Hams?

You mentioned TA tightness, but this is not present?

How about the Calves? Is there activation in the gastroc? If the gastroc is not activating, and the TA is compensating in some manner or another you may be getting lengthening during stance.

Have you tried strengthening the Gastroc concomitantly? As well what exercises have you completed to strengthen the hamstrings? Isolated curls will not necessarily strengthen the hamstrings sufficiently.

An exercise I would recommend is the following, which is an adaptation of the RDL which has been found to activate the Biceps femoris (via EMG activity) the most:

Position patient with support, slight bend in knee.

Provide 1 Kettle bell to lift:

Perform lift as follows:

Raise weight from the ground while extending the torso in a deadlift fashion while maintaining the slight knee flexion.

* this will train the muscle in an already shortened position, while maximally stimulating the hamstrings over its entire range:
Ref: Medicine and Science in Sports and Exercise 32(5): S55, 2000

The key for this is safety, obviously the non-hemiplegic side must be supported.

Request feedback re: above