Abstract
Delayed motor development may occur in children with Down syndrome, cerebral palsy or children born preterm, which in turn may limit the child's opportunities to explore the environment. Neurophysiologic and early intervention literature suggests that task-specific training facilitates motor development. Treadmill intervention is a good example of locomotor task-specific training.
To assess the effectiveness of treadmill intervention on locomotor motor development in pre-ambulatory infants and children under six years of age who are at risk for neuromotor delay.
In March 2011 we searched CENTRAL (The Cochrane Library 2011, Issue 1), MEDLINE (1948 to March Week 2, 2011), EMBASE (1980 to Week 11, 2011), PsycINFO (1887 to current), CINAHL (1937 to current), Science Citation Index (1970 to 19 March 2011), PEDro (until 7 March 2011), CPCI-S (1990 to 19 March 2011) and LILACS (until March 2011). We also searched ICTRP, ClinicalTrials.gov, mRCT and CenterWatch.
We included randomised controlled trials, quasi-randomised controlled trials and controlled clinical trials that evaluated the effect of treadmill intervention in children up to six years of age with delays in gait development or the attainment of independent walking or who were at risk of neuromotor delay.
Four authors independently extracted the data using standardised forms. Outcome parameters were structured according to the "Body functions" and "Activity and Participation" components of the International Classification of Functioning, Disability and Health, Children & Youth version (ICFCY), which was developed by the World Health Organization.
We included five studies, which reported on treadmill intervention in 139 children. Of the 139 children, 73 were allocated to treadmill intervention groups, with the other children serving as controls. The studies varied in the type of population studied (children with Down syndrome, cerebral palsy or who were at risk for neuromotor delay); the type of comparison (for example, treadmill versus no intervention, high intensity treadmill versus low intensity); the time of evaluation (during the intervention or at various intervals after intervention), and the parameters assessed. Due to the diversity of the studies, we were only able to use data from three studies in meta-analyses and these were limited to two outcomes: age of onset of independent walking and gross motor function.Evidence suggested that treadmill intervention could lead to earlier onset of independent walking when compared to no treadmill intervention (two studies; effect estimate -1.47; 95% confidence interval (CI): -2.97, 0.03), though these trials studied two different populations and children with Down syndrome seemed to benefit while it was not clear if this was the case for children at high risk of neuromotor disabilities. Another two studies, both in children with Down syndrome, compared different types of treadmill intervention: one compared treadmill intervention with and without orthotics, while the other compared high versus low intensity treadmill intervention. Both were inconclusive regarding the impact of these different protocols on the age at which children started to walk.There is insufficient evidence to determine whether treadmill intervention improves gross motor function (two studies; effect estimate 0.88; 95% CI: -4.54, 6.30). In the one study evaluating treadmill with and without orthotics, results suggested that adding orthotics might hinder gross motor progress (effect estimate -8.40; 95% CI: -14.55, -2.25).One study of children with Down syndrome measured the age of onset of assisted walking and reported those receiving the treadmill intervention were able to walk with assistance earlier than those who did not receive the intervention (effect estimate -74.00; 95% CI: -135.40, -12.60). Another study comparing high and low intensity treadmill was unable to conclude whether one was more effective than the other in helping children achieve supported walking at an earlier age (effect estimate -1.86; 95% CI: -4.09, 0.37).One study of children at high risk of neuromotor disabilities evaluated step quality and found a statistically significant benefit from treadmill intervention compared to no treadmill intervention (effect estimate at 16 months of age: -15.61; 95% CI: -23.96, -7.27), but was not able to conclude whether there was a beneficial effect from treadmill training on step frequency at the same age (effect estimate at 16 months of age: 4.36; 95% CI: -2.63, 11.35). Step frequency was also evaluated in children with Down syndrome in another study and those who received high intensity rather than low intensity treadmill training showed an increased number of alternating steps (effect estimate 11.00; 95% CI: 6.03, 15.97).Our other primary outcome, falls and injuries due to falls, was not measured in any of the included studies.
The current review provided only limited evidence of the efficacy of treadmill intervention in children up to six years of age. Few studies have assessed treadmill interventions in young children using an appropriate control group (which would be usual treatment or no treatment). The available evidence indicates that treadmill intervention may accelerate the development of independent walking in children with Down syndrome. Further research is needed to confirm this and should also address whether intensive treadmill intervention can accelerate walking onset in young children with cerebral palsy and high risk infants, and whether treadmill intervention has a general effect on gross motor development in the various subgroups of young children at risk for developmental delay.