Thanks for your enquiry. Well if you want to enquire about the role of traction in cervical disc lesion. The answer is that cervical traction will definitely help in relieving the signs and symptoms of the root compression. For more information see my reply on cerical disc lesion elswhere in this forum.

For detail studies see the best availabe texts on the subject. These are

Therapeutic Exercise Foundations and techniques third edition by Carolyn Kisner & Lynn Allen Colby

Textbook of orthopaedic medicine by Cyriax/Coldham Vol II Treatment by manipulation massage and injection 11th Edition.

Mobilization of the Spine A Primary handbook of clinical methods By Gregory P. Grieve Fifth Edition.

If there is weakness in the upper limb. Perform a manual muscle testing and do the grading the musces. Use the graded active ROM exercises to maintain and increase the strenght in the upper limb muscles. In the mean time treat the main problem there in cervical spine. Use modalities like SWD, Ultrasound therapy and microwave diathermy, etc to relive the pain and inflammation and oedema aroung the affected nerve roots in cervical spine. Avoid Acitive exercises of spine in acute stage. Use Isometric exercises in the beginning.

I think that it will be of help to you.