Katie Hohman, MPT

Body weight supported systems are used for gait training with a patient that cannot bear full weight on their lower extremities due to various diagnoses.  The system allows for patients that are typically non-ambulatory to begin a gait training program under the instruction of a physical therapist.   This concept for rehabilitation utilizes an external device to support a percentage of the patient’s body weight, creating an upright and safe environment during their treatment. 

Many physiological benefits are associated with this type of rehabilitation.  This device allows for symmetrical loading of the lower extremities.  A patient can work on equal weight distribution over their base of support.  Equal weight distribution is important in providing the proper biomechanics to correct step length deficits and time distribution between limbs.  “Parasympathetic tones typically associated with neurological pathologies can be reduced through partial-weight therapy.  Minimizing parasympathetic stimuli helps to reduce muscular tension, in turn allowing for increased range of motion and focus on motor control exercises1.”  By unloading a percentage of a patient’s body weight, it allows for them to exercise with less stress on their cardiopulmonary system.  “VO2 levels are maintained better at 40% unweighing than at 0%; the patient can then exercise for a longer period of time1.”  With post-surgical patients, the unweighing system can be used to provide a safe environment and allow for accommodating any weight bearing restrictions.  Patients suffering from low back pain can also take advantage of this device during therapy.  The harness can act to provide vertical traction while the patient is performing any standing exercises; this will allow for more decreased pain during their treatment. 

This system not only provides a safe environment for the patients, but also for the treating therapist.  It can be utilized with an obese patient or a patient at risk for falls without putting the therapist or patient at risk of injuring themselves.  The harness provides “proprioceptive feedback in regards to location of the trunk over the base of support and will allow your patient to work with more confidence during rehabilitation”. 

There are many types of patients that would be appropriate to use this type of rehabilitation.  Any patient that cannot fully weight bear would be the best candidate for using this type of equipment.  Post-surgical patients that have weight bearing restrictions during ambulation would benefit from early gait training.  Any neurological patient that does not have the strength in their lower extremities to participate in a traditional gait training program would be ideal for using this system.  Neurological patients with balance deficits would also benefit.  Due to the unweighing aspect of this system, it would be great for patients suffering from low back pain.  The therapist can implement an exercise program that allows the patient to perform standing exercises, while reducing the amount of pressure on their spine.  This will allow the patient to work longer and more efficiently during their exercise session with less pain.  Other diagnoses that would benefit from this type of therapy include: lower extremity or spinal fractures, ACL tear or reconstruction, total knee or hip replacement patients, osteoarthritis or rheumatoid arthritis, DDD, spinal surgery, and amputees.2

In a study by Visintin et al., stroke patients were examined to compare the benefits of body weight supported treadmill training to gait training with full weight bearing through their lower extremities. 

The results of this randomized clinical trial indicate that subjects with stroke who received 6 weeks of gait training with BWS recovered better balance and walking abilities than those who received similar gait training while bearing full weight on their lower extremities. A 3-month post-training follow-up revealed that subjects trained with BWS continued to have significantly higher scores for over ground walking speed and lower limb motor recovery.3(p1122)

The article by Barbeau,et al., compared studies of animals with a complete spinal cord transection and factor that enhanced their locomotor function.  “SCI subjects have a wide spectrum of walking speed abilities, ranging from incapable of walking to walking as fast as normal subjects.”4 

During locomotor training, the animal was supported by the tail and, thus, only allowed to bear a portion of its weight, so that it could walk with proper paw placement on the treadmill, while its forelimbs stood on a platform.  The proportion of weight supported was adjusted according to the animal’s locomotor abilities, and this training regimen was conducted on a daily basis.  After a period of 3-4 weeks of training, the animal was capable of walking with its hindlimbs at different treadmill speeds while completely supporting the weight of its hindquarters with proper paw placesment.  Moreover, the cat’s gait pattern was comparable in many respects to that recorded before spinalization as well as that reported elsewhere for the intact adult cat. 4(p16)

It was concluded in this study that the combination of locomotor training and pharmacological approaches following a spinal cord injury are very important aspects of the recovery process.

The Biodex Unweighing System is used to remove a percentage of a patient’s body weight when performing standing activities or gait training.  It can hold up to 180 pounds of weight and contains a scale that will calculate what percentage of body weight it is assisting.  The system is suspended from a single point at the top of the frame.  A single point system allows for normalized pelvic and trunk rotation during ambulation.1  Each patient evaluated to use this system must also be assessed for the proper shoes and lower extremity bracing to safely and correctly being gait training and standing.  The number of staff members needed to work with a patient using this system is entirely dependent upon their functional level and what activities you plan on performing.  A hemiplegic patient may only require the assistance of one therapist to retrain proper lower extremity biomechanics in the effected side.  A quadriplegic patient, however, will need at least two therapists to best utilize this type of treatment.
Body weight assisted therapy has many benefits to patients with various diagnoses and conditions.  Research studies3,4 prove that there are certainly better outcomes with body weight assisted training as compared to full weight bearing treatment programs.  Patients will be able to recover quicker and more complete than ever before.

1. Biodex Unweighing System. Available at: http://www.biodex.com/rehab/unweighing/unweighing_apps.htm. Accessed on 10/23/09.
2. Lund D. The use of unweighing – clinical applications. Available at: http://www.pneumex.com/sitebuildercontent/sitebuilderfiles/3-use.pdf. Accessed on 10/25/09.
3. Visintin M, Barbeau H, Korner-Bitensky N, Mayo NE. A new approach to retrain gait in stroke patients through body-weight support and treadmill stimulation. Stroke. 1998;29: 1122-1128.
4. Barbeau H, Pepin A, Norman KE, Ladouceur M, Leroux A. Walking after spinal cord injury: control and recovery. Neuro Scientist. 1998;4: 14-24.