There is extensive evidence to show that prolonged over-exertion during manual wheelchair propulsion can result in chronic damage to the shoulder joint and other structures. The risk of damage is thought to be higher for children because of their lower upper body strength. Recent medical research has highlighted the fact that propelling a wheelchair using the push rim produces high directional shoulder forces, and this correlates with coracoacromial arch pathology as shown by an MRI scan, and also physical discomfort. That research recommended that researchers and clinicians find ways to reduce the forces and moments experienced by the shoulder during wheelchair propulsion. Modified wheelchair design including a new method of self propulsion is a way to achieve this, without the loss of freedom for the chair user.
NuDrive EVO - A Solution Using a Lever Drive System on your Wheelchair
NuDrive EVO system uses a lever action with mechanical advantage to reduce the force needed to propel the wheelchair, while at the same time changing the action needed to one which is gentler on the upper body muscle groups.
A new study funded by the National Institute of Disability in the USA shows that lever propulsion systems shift the shoulder joint load by decreasing the superior glenohumeral force while increasing the range of motion. They also found lower posterior shoulder force and decreased adductor moment. Together these reduced demands on the shoulder have the potential to reduce commonly experienced shoulder pain and injury, preventing long-term shoulder degradation.