Perturbation techniques

  •  Double-Leg Foam Balance Activity: Subject stands on a soft foam surface with both feet on the ground. Therapist attempts to perturb patient balance in random fashion.

Exercise dosage/progression: The duration of the activity is approximately 30 seconds.The difficulty is progressed as the subject improves by progressing to ball catching with therapist perturbing subject’s balance while standing on foam and progressing to single-leg support if tolerated without knee pain, swelling, or buckling.


  • Tiltboard Balance Training: The subject stands on a tiltboard with both feet on the board. The therapist perturbs the tiltboard in forward and backward and side-toside directions for approximately 30 seconds each.

Exercise dosage/progression: The difficulty of the activity is progressed by adding ball catching during the perturbations and progressing to single-limb support perturbations if the subject tolerates single-limb weight bearing without knee pain, swelling, or buckling.


  • Rollerboard and Platform Perturbations: The subject stands with one limb on a stationary platform and the other limb on a rollerboard. Therapist perturbs rollerboard in multiple directions, at random, and the subject attempts to resist the perturbations. The activity lasts approximately 30 seconds. The activity is repeated by changing the limbs on the platform and the rollerboard.

Exercise dosage/progression: The activity may begin with subject in the semi-seated position, with hips resting on plinth if the subject has difficulty doing the activity in full standing. The activity is progressed to the full standing position when the subject is able to tolerate this position without pain.