Table 1 FAST intervention program content

Squats to approximately 30 degrees of hip and knee flexion “as fast as possible” to promote a sudden braking action.

Typical instruction: “Unlock your knees and stop the downward movement as quickly as possible.”

The core element of the FAST intervention, step training is to be included in every treatment session. Participants will lean, pivoting at their ankles until they need to take protective step(s) to stop themselves from falling. A typical instruction is provided (below); however, treatment physiotherapists will tailor instructions and feedback to the participant, based on their performance and abilities.

Typical instruction: “Lean [forward/backward/to the side] and let yourself fall like a tree until you feel like you are losing your balance. The goal is to take steps that are long enough and fast enough that you are able to regain your balance.”

Progressions of step activities are listed below in increasing level of difficulty:

 a. Simple blocked practice

Stepping leading with each leg in each direction is practiced in blocks of 10 reps.

 b. Semi-random practice:

 c. Random practice:

Stepping leading with the P leg in all 3 directions - forward, backwards, and laterally to P side, then leading with the NP leg in all 3 directions.

 d. Random nomination of lead leg with reduced movement planning time:

Therapist randomly nominates the lead leg after leaning in the forward or backward direction has been initiated by the participant.

 e. Concurrent task planning:

Participants asked to perform a simple concurrent cognitive task (e.g. counting backwards from 10) as they lean and step. Start with the simple blocked practice (2a) and progress to random practice (2c).

 a. Step over -4-square exercise: Masking tape will be affixed to the floor in a ‘+’ design creating 4 squares. The participant will begin with both feet in a square facing forward, and move in a counterclockwise direction through each square in sequence until they reach the ‘start’ square; they will than move in a clockwise direction to again return to the ‘start’ square [32]. The following instructions are given to the patient ‘try to complete the sequence as fast as possible without touching the tape lines. Both feet must make contact with the floor in each square. If possible, face forward during the entire sequence.’ Timing and accuracy can be used as feedback.

Progress – ask Participant to ‘bound’, rather than step over the pattern.

 b. Additional stepping and bounding activities

For these exercises ‘shock absorption’ by the landing leg is to be emphasized (return to mini-squats to emphasize if necessary). Therapists will monitor to insure any pre-existing musculoskeletal symptoms are not aggravated. Activities will be practiced first in a forward direction, then progressing to lateral and then backwards directions; start with blocked practice (as in 2a), then progress to random practice schedule (as in 2c).