The jumping leg syndrome is a problem of apana vayu.
Yes, in many cases the problem can be due to ama that is blocking the channels. Therefor the problem can be caused by any of the 3 dosas:
vataja - irregular symptoms, stabbing pain or no pain
pittaja - burning pain or inflammation in lower back
kaphaja - edema, bloating, swelling or heaviness in pelvic area
Ama can mix with any of the 3 dosas and cause apana to move in a wrong or erratic manner. This usually disrupts vyana vayu after some time and then it becomes more difficult to treat.
It can also be a nirama condition and only due to high dosa. In this case there would not be signs of ama on tongue or pulse.
It can also be a secondary effect from another pathology. It is best to find out if this is the case by normal examinations with a neurologist. If they cannot find anything then it is a problem only of apana moving downward in a wrong way.
It is best to avoid marma treatments at first unless you are very, very good at diagnosis and treatment through them.
TREATMENT: use oil massage daily if possible to control vata dosa and apana. In order to get results in difficult cases you need to also use local heat (svedhana) on the lower back with oil (snehana) either during the massage or after the massage. This will control apana faster and stop the problem.
The local snehana and svedhana treatments can also be taught to the patient who can do them at home before be for 20 mins. Use sesame oil or a medicated oil to reduce vata, or Ayurvedic oils with ashwagandha in them.
An anti-vata lifestyle is very important to help this treatment work.