Sport concussion is commonly assessed using a battery of tests that evaluate neurocognitive functioning, postural control and self-report symptoms. The degree to which concussion affects each of these measures is unclear. Thus, the purpose of this meta-analysis is to systematically review and quantify the effect of sport concussion on each assessment measure when administered immediately post-injury and in the 2 weeks following injury. PubMed and PsychINFO databases were searched from January 1970 to June 2006, from which 39 were included for review. Studies were selected for review if they included concussed athletes who were evaluated using one of the three assessment measures. One post-morbid assessment must have been completed within 14 days of injury and compared with a baseline measure or control group. Study design, type of neurocognitive assessment, timing of assessment following injury and number of post-concussion assessments were extracted as potential moderators. Sport-related concussion had a large negative effect (mean Delta; 95% confidence interval) on neurocognitive functioning (-0.81; -1.01, -0.60), self-report symptoms (-3.31; -6.35, -0.27) and postural control (-2.56; -6.44, 1.32) in the initial assessment following injury. A reduced, but large effect, was also seen in the 14 days following the initial assessment for neurocognitive functioning (-0.26; -0.46, -0.06), self-report symptoms (-1.09; -2.07, -0.11) and postural control (-1.16; -2.59, 0.27). Our findings demonstrated large effects for each aspect of the assessment battery. These findings support the use of the multifaceted concussion evaluation.

Exercise reduces depressive symptoms among patients with a chronic illness. Patients with depressive symptoms indicative of mild-to-moderate depression and for whom exercise training improves function-related outcomes achieve the largest antidepressant effects.

The authors investigated the effect of chronic exercise on feelings of energy and fatigue using meta-analytic techniques. Chronic exercise increased feelings of energy and lessened feelings of fatigue compared with control conditions by a mean effect delta of 0.37. The effect varied according to the presence or absence of a placebo control or whether chronic exercise was completed alone or in combination with an additional therapy. Investigations that used a placebo control and examined chronic exercise alone found no effect of chronic exercise on feelings of energy and fatigue. Certain placebo controls may increase feelings of energy and lessen feelings of fatigue when used with older adults or people with psychological distress. The results highlight the need for research identifying the most useful control conditions for accurately interpreting mental health outcome data obtained in chronic exercise investigations.

Approximately 20% of adults worldwide report persistent fatigue. Physical activity is a healthful behaviour that has promise for combating feelings of fatigue and low energy. This article summarises the epidemiological literature that examined the association between physical activity and feelings of energy and fatigue. Twelve population-based studies conducted between January 1945 and February 2005 that concurrently measured physical activity and feelings of energy and fatigue were located. All of the studies suggested that there was an association between physical activity and a reduced risk of experiencing feelings of low energy and fatigue when active adults were compared with sedentary peers (odds ratio = 0.61; 95% CI 0.52, 0.72). The effect was heterogeneous and varied according to study design and the energy/fatigue measure used in the study. Because epidemiological comparisons cannot establish direction of causality, standard criteria for evaluating strength of evidence in epidemiological studies (i.e. strength of association, temporal sequence, consistency, dose response and biological plausibility) were used to judge whether the observed association between physical activity and feelings of energy and fatigue suggest causality in the absence of adequate experimental evidence. There was agreement among the studies suggesting a strong, consistent, temporally appropriate dose-response relationship between physical activity and feelings of energy and fatigue. No compelling evidence has confirmed any plausible biological mechanisms that explain the apparent protective effect of physical activity against feelings of low energy and fatigue. Nonetheless, the epidemiological evidence is sufficiently strong to justify better controlled prospective cohort studies and randomised controlled trials.

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