Body-Weight Support Treadmill Training
BWSTT is a treatment approach that has been developed from earlier research in cats which showed recovery of stepping movements following transection of the spinal cord.
This showed that with support of the body weight and stimulation of muscle activity, along with assistance to move the feet potential recovery of stepping movements was possible.
Barbeau and Rossignol then suggested suspending individuals from an overhead lift and assisting the legs to step following stroke or spinal cord injury, leading to the development of specialized treadmills, support systems, and rehabilitation approaches.
Stroke and spinal cord injury are the two most researched areas with this type of therapy.
BWSTT requires a specially designed apparatus to take up some of the weight of an individual as they walk and/or run on a treadmill. A harness both supports and lifts the trunk to take up some of the individual’s body weight allowing for variable loading and unloading.
BWSTT can create demands to generate patterned muscle activity in the legs for reciprocal, symmetrical loading and unloading required for efficient walking and running.
At the same time the displacement achieved through this stepping movement helps produce postural activity in other body parts, especially the trunk for better alignment, loading and balance. This rhythmical patterned activity is underpinned by spinal neural networks called central pattern generators (CPG’s). (Duysens and Van de Crommert 1998).
These networks do not function alone and are modulated by higher areas of the central nervous system and also by sensory feedback. This sensory feedback is an integral part of the overall motor control system and is critical in modifying CPG-generated activity in order to facilitate constant adaptations to the environment (MacKay-Lyons 2002). Sensory feedback adapts the CPG to the influences from the current environment (Frigon and Rossignol 2006).
To encourage experience-dependent plasticity in the central nervous system BWSTT needs to be performed at adequate speeds, lower limb loading, and with patterns of activity that allows the central nervous system to interpret as normal walking inputs (Sullivan et al. 2002).
Specific elements are emphasised as sensory signals to improve transition from stance to stepping in alternate legs. Gaining sufficient stride length so that as a leg moves behind adequate stretch is placed on hip flexor muscles to promote a step and adequate loading and unloading to promote drive from the feet to raise the body to move up and forward are particularly emphasised. (Van de Crommert et al. 1998; Pearson 2008;).
Possible effects of BWSTT
Measurable changes in fitness, function, and cardiovascular health after stroke (Ivey et al. 2008) as well as psychological well-being and health-related quality of life (Hicks and Ginis 2008).
BWSTT can increase walking speed post-stroke making community walking more likely. (Sullivan 2002).
BWSTT specific to spinal cord injury refer to reviews by Mehrholz et al. (2008) and Wessels et al. (2010).
MNC therapists have used this equipment with a variety of patients but always with careful consideration of their medical fitness in respect of cardiovascular status, any seizure history etc and always with sufficient postural activity so that the stepping movements increase their efficiency against gravity and do not lead to compensatory fixation behaviour.
Many different measurable goals may be set:
- Increasing speed and exercise tolerance
- Improving postural control and reducing the need to depend on arm support so normalising tone in upper limbs
- Lower limb strengthening/increased lower limb range of movement
- Ability to cope with slopes of walking surface and increased confidence
- Developing ability to run in some patients where the harness gives the initial safety and confidence to move to this new level
Therapists hands on may well be required to help facilitate a more symmetrical walking pattern but then may be withdrawn as automatic stepping responses occur. The treadmill is used also without the BWS in many patients if it is not required
Some supporting references
Ada, L. et al. 2010. “Mechanically assisted walking with body weight support results in more independent walking than assisted overground walking in non-ambulatory patients early after stroke: a systematic review.” J Physiother 56(3): 153-61.
Barbeau, H; Rossignol, S. 1994 “Enhancement of locomotor recovery following spinal cord injury” Current Opinion in Neurology: Trauma and rehabilitation:
Dietz, V. 2003. “Spinal cord pattern generators for locomotion.” Clin Neurophysiol 114 (8): 1379-89.
Dietz, V., and J. Duysens. 2000. “Significance of load receptor input during locomotion: a review.” Gait Posture 11 (2): 102-10.
Duncan, P. W. et al. 2011. “Body-weight-supported treadmill rehabilitation after stroke.” N Engl J Med 364 (21): 2026-36.
Duysens, J., and H. W. Van de Crommert. 1998. “Neural control of locomotion; The central pattern generator from cats to humans.” Gait Posture 7 (2): 131-141.
Frigon, A., and S. Rossignol. 2006. “Functional plasticity following spinal cord lesions.” Prog Brain Res 157 : 231-260.
Grillner, S. et al. 2008. “Neural bases of goal-directed locomotion in vertebrates – An overview.” Brain Research Reviews 57 (1): 2-12.
Hicks, A. L., and K. A. Ginis. 2008. “Treadmill training after spinal cord injury: it’s not just about the walking.” J Rehabil Res Dev 45 (2): 241-8.
Lynskey, J. V. et al. 2008. “Activity-dependent plasticity in spinal cord injury.” J Rehabil Res Dev 45 (2): 229-40.
MacKay-Lyons, M. 2002. “Central Pattern Generation for Locomotion: A review of the evidence.” Physical Therapy 82 (1)
Mehrholz, J., J. Kugler, and M. Pohl. 2008. “Locomotor training for walking after spinal cord injury”. Cochrane database of systematic reviews (Online). 2008(2):CD006676.
Moseley, A. M. et al. 2005. “Treadmill training and body weight support for walking after stroke.” Cochrane Database Syst Rev (4): CD002840.
Pearson, K. G. 2008. “Role of sensory feedback in the control of stance duration in walking cats.” Brain Research Reviews 57 (1): 222-227.
Sullivan, K. J. et al. 2002. “Step training with body weight support: effect of treadmill speed and practice paradigms on poststroke locomotor recovery.” Arch Phys Med Rehabil 83 (5): 683-91.
Van de Crommert, H. W. et al. 1998. “Neural control of locomotion: sensory control of the central pattern generator and its relation to treadmill training.” Gait Posture 7 (3):251-263.
Wessels, M., C. Lucas, I. Eriks, and S. de Groot. 2010. “Body weight -supported gait training for restoration of walking in people with an incomplete spinal cord injury: a systematic review.” J Rehabil Med.Jun;42(6):513-9