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In Part 1, we explored how length–tension relationships influence supported seating. The same principles apply in standing—but the clinical challenge is different.
Length–Tension in Standing
Unlike seating approaches, supported standing occurs for shorter durations and often introduces stretch, which can be beneficial for maintaining range of motion.
However, if not managed appropriately, stretching in standing can increase discomfort, reduce the child’s tolerance to standing, and drive compensatory postures, particularly when viewing the body as an inter-linked chain.
The goal with supported standing and maintaining range of motion is to ensure it is appropriate and tolerable. We need to understand the true range of motion the individual has, through hands on assessment, and establish what range of motion is comfortable to them in standing.
Is it possible to gradually build tolerance and duration in standing and even improve range?
Or do we need to accommodate and maintain current muscle lengths?
Do we consider releasing stretch on a muscle to improve positioning some elsewhere in the body chain?
The impact of length-tension relationships in standing
Gastrocnemius tightness
Typical standing encourages knee extension and ankles positioned in neutral. The gastrocnemius muscle is lengthened in this position because it crosses both joints and works on knee flexion and ankle plantarflexion.
For some children with higher tone or already reduced range of motion, moving into a true extended standing position can increase tension too much and cause too much discomfort. Stretching at one joint may cause compensatory movement at the other, for example heel rise when extending the knees or knee flexion when dorsiflexing the ankle.
Clinical consideration:
- Adjustable footplates that allow some appropriate plantarflexion can reduce distal gastrocnemius tension and aid extensibility proximally at the knee. It can possibly enable knee extensors to work on end range activation during more active standing in the frame.
- Depth adjustable knee supports that can accommodate knee flexion contractures and tightness, but can also be gradually moved into extension as appropriate.
- Further food for thought: the Soleus muscle is a single joint ankle plantarflexor that is thought to be a major anti-gravity muscle in standing and walking [1]. It is commonly reduced in volume and weak across GMFCS levels in Cerebral Palsy [1,2]. Could use of fixed AFO’s positioned at plantigrade, and footplates positioned in a similar manner, in standing affect the activity of a weak and shortened soleus in these populations? Could there then be consideration towards allowing some plantarflexion in these orthoses or footplate position to encourage soleus activity?
Hip flexor tightness
When knees flex, hips flex and when knees extend, hips extend. This can easily be overlooked when positioning in standing frames, as hip and knee flexor tightness are common issues in individuals requiring standing frame support. Whilst improving knee extension can be a key factor in maximising weightbearing and encouraging a stretch to muscles like the hamstrings and gastrocnemius, it can place tension through tight hip flexors and influence posture elsewhere in the chain.
For example, placing tension on key hip flexors, such as the iliopsoas muscle complex which originates from the iliac fossa of the pelvis, sacrum and transverse processes of lumbar vertebrae, can affect pelvic position. As the hip moves into extension, a shortened resting length in this complex may pull the pelvis into anterior tilt and create an exaggerated lordosis in standing.
Clinical considerations:
- If lordosis is a concern try reducing tension at the knee with adjustable knee supports, within an appropriate range.
- Try bringing the pelvis into a more neutral position with de – rotational pelvic belts or adjustable pelvic pads.
Hip adductor tightness
Hip adductor tightness presents an additional challenge in supported standing, particularly if applying alternative standing strategies.
As discussed in our previous blog on abducted standing, introducing hip abduction in standing is often used to reduce hip adductor tone and maintain hip stability through optimal re-positioning of the femoral head within the hip joint. Typically, the aim is for 15-30 degrees of hip abduction at each hip, in neutral hip extension.However, where adductors are tight, pushing further into hip abduction may result in discomfort and reduced standing tolerance.
True hip abduction may also not occur as the tension is increased, and there may be compensatory movements, such as internal lower limb rotation. Tension along the medial femoral and tibial attachments of some of the adductor muscles can contribute to rotation of the lower limb inwards. Again, extending the hip into neutral with existing tightness in the iliopsoas complex can cause anterior pelvic tilt. This reduces the intended therapeutic benefit and loading of the joint, and may increase unwanted stress through the limb.
Clinical considerations:
- If a stander has a hip abduction feature, introduce abduction gradually and within available range.
- More contemporary thinking has suggested smaller amounts of abducted standing is more tolarable, especially in those with spasticity, between 10 to 20 degrees per leg.
- Observe for compensatory postures at the lower limb and pelvis.
Key Message
Thinking in Chains, Not Joints
Supported standing should be individualised and it should be about creating a position that is:
- achievable
- comfortable
- sustainable
Respecting length–tension relationships allows us to reduce compensation, improve tolerance, and support more effective outcomes.
References:
[1] Sahrmann AS, Stott NS, Besier TF, Fernandez JW, Handsfield GG. Soleus muscle weakness in cerebral palsy: Muscle architecture revealed with Diffusion Tensor Imaging. PLoS One. 2019 Feb 25;14(2):e0205944.
[2]Handsfield GG, Meyer CH, Abel MF, Blemker SS. Heterogeneity of muscle sizes in the lower limbs of children with cerebral palsy. Muscle Nerve. 2015.
