Mechanics, Analysis and Training of Standing Up

Question 1

Important components: standing up

Answer 1

Pre-extension phase:
- Feet placed back so ankles are behind knees
- Incline of trunk forwards by flexion at the hips with extended trunk
Extension phase:
- Dorsiflexion of ankle to bring knees forwards
- Sequence of lower limb extensions at knees, hips and ankles

Question 2

Adaptive strategies: standing up

Answer 2

Pre-extension phase:
- Weight borne through intact side primarily
- Wide BoS
Extension phase:
- Falls backwards
- Pushes through arms
- Weight borne through intact side primarily
- Final alignment flexed

Question 3

How do we assess impairments in standing up?

Answer 3

• Item 4 of MAS
• Maximum weight through affected foot
• Timed 5 repetitions (sit to stand from chair)

Question 4

What kinematics are involved in standing up?

Answer 4

• Typical movement duration is 1.5s
• CM moves forwards then upwards
• Feet placed back (105 degree knee flexion)
• Shoulder moves forwards, upwards and back slightly
• Thighs off at 30% movement duration
• Knee moves forwards slightly and back to the start position

Question 5

What kinetics are involved in standing up?

Answer 5

At thighs off, force through feet is 150% of BW to propel the body upwards to standing

Question 6

What is the effect of foot placement on standing up?

Answer 6

When the dominant foot was forward/elevated peak vertical force increased, rate of development of peak vertical force increased, and EMG in tib ant and quads in the non-dominant (affected) leg increased. Asymmetry of vertical forces was greatest in the middle of tasks, and the affected foot back promoted loading of the affected side. Therefore interventions should have feet back, with unaffected foot forwards and elevated to increase difficulty

Question 7

What is the effect of initial alignment and timing on standing up?

Answer 7

The maximum force needed to be sustained over a longer period of time when there was no initial active hip flexion, and the peak acceleration of hip flexion coincides with the onset of knee extension. Therefore, we can conclude that in interventions, we should start from an upright trunk position, encourage rapid movement of shoulders forwards and up, and do not allow a pause at thighs-off

Question 8

What is the effect of seat height on standing up?

Answer 8

Joint movements around the knee and hip decrease as seat height increases, the amount of muscle activity decreases as seat height increases, and the muscle activity in lower limbs decreases when arm rests were used.
Therefore, we can conclude that in interventions we should discourage the use of arms, increase seat height to decrease difficulty, or decrease seat height to increase difficulty