Theraband CLX Pattern Assisted Active Straight Leg Raise for "Tight" Hamstrings
If their PSLR is 10 degrees better or more, or has less perceptions of tightness or discomfort, most likely it is a motor control issue and not adaptive shortening, which is very rare if the patient is actually moving with any regularity.
If you have ever used a Pilates Reformer for a type of pattern assistance, or RedCord, you would know that the light passive pull into straight leg raise often modulates the perception of hamstring "tightness."
I like the Theraband CLX (continuous loops) because you can easily loop it around your foot/shoe and grab the loops for hand holds. With the leg that is stabilizing, try to keep the foot facing the ceiling and for extra pelvic disassociation, I try to lightly drive my heel into the floor.
Pattern Assisted ASLR with Theraband CLX
This works great if you have less than an easy 80-90 ASLR as a dynamic warm up prior to activity/sport. If it does not improve dramatically after 2-3 sets or so, you may need to modulate the perception of tightness further with an EDGE Mobility Band wrapped around the "tight" part.
Keeping it Eclectic....