Reduced cardiorespiratory fitness (cardiorespiratory deconditioning) is a common consequence of traumatic brain injury (TBI). Fitness training may be implemented to address this impairment.
The primary objective of this updated review was to evaluate whether fitness training improves cardiorespiratory fitness in people who have sustained a TBI. The secondary objectives were to evaluate whether fitness training improves body function and structure (physical and cognitive impairments, psychological responses resulting from the injury), activity limitations and participation restrictions in people who have sustained a TBI as well as to evaluate its safety, acceptance, feasibility and suitability.
We searched 10 electronic databases (the Cochrane Injuries Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Embase; PubMed (MEDLINE); CINAHL; AMED; SPORTDiscus; PsycINFO; PEDro and PsycBITE) and the International Clinical Trials Registry Platform for relevant trials. In addition we screened reference lists from systematic reviews related to the topic that we identified from our search, and from the included studies, and contacted trialists to identify further studies. The search was run in August 2017.
Randomised controlled studies with TBI participants were eligible if they compared an exercise programme incorporating cardiorespiratory fitness training to usual care, a non-exercise intervention, or no intervention.
Data collection and analysis
Two authors independently screened the search results, extracted data and assessed bias. We contacted all trialists for additional information. We calculated mean difference (MD) or standardised mean difference (SMD) and 95% confidence intervals (CI) for continuous data, and odds ratio with 95% CI for dichotomous data. We pooled data when there were sufficient studies with homogeneity.
Two new studies incorporating 96 participants were identified in this update and were added to the six previously included studies. A total of eight studies incorporating 399 participants are included in the updated review. The participants were primarily men aged in their mid-thirties who had sustained a severe TBI. No studies included children. The studies were clinically diverse with regard to the interventions, time postinjury and the outcome measures used. At the end of intervention, the mean difference in peak power output was 35.47 watts (W) in favour of fitness training (MD 35.47 W, 95% CI 2.53 to 68.41 W; 3 studies, 67 participants; low-quality evidence). The CIs include both a possible clinically important effect and a possible negligible effect, and there was moderate heterogeneity among the studies.
Five of the secondary outcomes had sufficient data at the end of intervention to enable meta-analysis: body composition (SMD 0.29 standard deviations (favouring control), 95% CI -0.22 to 0.79; 2 studies, 61 participants; low-quality evidence), strength (SMD -0.02 (favouring control), 95% CI -0.86 to 0.83; 2 studies, 23 participants; very low-quality evidence), fatigue (SMD -0.32 (favouring fitness training), 95% CI -0.90 to 0.26; 3 studies, 130 participants; very low-quality evidence), depression (SMD -0.43 (favouring fitness training), 95% CI -0.92 to 0.06; 4 studies, 220 participants; very low-quality evidence), and neuromotor function (MD 0.01 m (favouring fitness training), 95% CI -0.25 to 0.27; 2 studies, 109 participants; moderate-quality evidence). It was uncertain whether fitness training was more or less effective at improving these secondary outcomes compared to the control interventions. Quality of life was assessed in three trials, but we did not pool the data because of substantial heterogeneity. Five of the eight included studies had no dropouts from their intervention group and no adverse events were reported in any study.
There is low-quality evidence that fitness training is effective at improving cardiorespiratory deconditioning after TBI; there is insufficient evidence to draw any definitive conclusions about the other outcomes. Whilst the intervention appears to be accepted by people with TBI, and there is no evidence of harm, more adequately powered and well-designed studies are required to determine a more precise estimate of the effect on cardiorespiratory fitness, as well as the effects across a range of important outcome measures and in people with different characteristics (e.g. children). In the absence of high quality evidence, clinicians may be guided by pre-exercise screening checklists to ensure the person with traumatic brain injury is safe to exercise, and set training parameters using guidelines established by the American College of Sports Medicine for people who have suffered a brain injury.