Table 1 Neuromuscular exercise intervention program. For a higher quality of movement, participants were constantly instructed to position their knee over the foot and to avoid a medial (valgus) or lateral (varus) position of the knee in relation to the foot (neutral knee positioning)
Exercise | Description | Sets, Frequency, Break between sets |
|---|---|---|
1. Forward and backward sliding or stepping | Standing on the affected leg and sliding the opposite leg forward and backward (level 1) or stepping with the opposite leg forward and backward (level 3) while bending and straightening the affected side. Affected leg is nearly straight when feet are together and bent when feet are apart. Progression of level 1 (level 2) or level 3 (level 4) is achieved by adding an elastic resistance band around the affected leg to apply a varus-directed force during the movement. The participant is required to counteract in order to maintain the knee in the neutrally aligned position | 3 sets of 10 reps, break of 30–60 s between sets |
2. Sideways exercises | Standing on the affected leg and sliding or stepping the opposite leg forward and backward (level 1). Progression is achieved by adding an elastic resistance band around the affected leg to apply a varus-directed force during the movement. The participant is required to counteract in order to maintain the knee in the neutrally aligned position (level 2). Further progression is to additionally stand on foam (level 3) and closing the eyes during the movement (level 4) | 3 sets of 10 reps, break of 30–60 s between sets |
3. Functional hip muscle strengthening | Standing sideways to a wall with the non-affected leg closest to the wall so that the hip, thigh and knee are all slightly bent and touching the wall. Slightly bend affected knee (15–20°) and push leg into the wall and hold (isometric abduction, level 1). For progression, slowly bend and straighten affected knee while maintaining the push (level 2). For further progression, stepping sideways in both directions with a low resistance elastic band (level 3) or a higher resistance elastic band (level 4) around ankles, maintaining the slight knee bend | Level 1 + 2: 20 s hold, short break between efforts, two sets of 5 reps, break of 30–60 s between sets Level 3 + 4: total of 30 steps in each direction |
4. Functional knee muscle strengthening | Standing with back to the wall, feet hip-width apart and one foot length away from the wall. Slowly sliding down the wall to about 30° knee bend, then sliding up again (level 1). For progression, shifting weight to be more over the affected leg (level 2). For further progression, rising from sitting down position on a chair (feet parallel, level 3) and with increased weight on the affected leg (feet in step position, level 4) | 3 sets of 10 reps, break of 30–60 s between sets |
5. Step-ups and touch-downs | Placing affected leg onto a step. Slowly stepping up onto the step. Touching opposite foot to the step then stepping back down slowly to the starting position (level 1). Stepping up on a higher step (level 2). For further progression, standing on the step and touching non-affected side to the floor in front and then behind the step (level 3). Touch-downs from a higher step (level 4) | 3 sets of 10 reps, break of 30–60 s between sets |
6. Balance | Lifting opposite side in front off the floor and balance on the affected leg (level 1) or stepping forward and lifting opposite side behind (level 2), with progressions adding arm movements (level 3) or stepping forward onto foam (level 4) | 2Â min practice |