045 for difference in effects in the meta-regression).

There was a large effect (SMD = 0.68, 95% CI 0.49 to 0.87) on strength in the trials that targeted strength, and only a small effect (SMD = 0.32, 95% CI 0.09 to 0.55) in those that did not. Therefore, for greater effects on strength, it is suggested that programs target strength by specifically providing weights or other forms of resistance and aiming for an intensity and dose of strength training Panobinostat chemical structure as for instance suggested by the ACSM guidelines for healthy adults, ie, 8–10 strength-training exercises, with 8–12 repetitions of each exercise twice a week at an intensity where only 8–12 repetitions can be done without resting ( Haskell et al 2007). This review found a moderate effect of physical activity on balance but only six studies had tested this outcome. Trials in older people suggest that physical activity which includes a high challenge to balance leads to a greater reduction in falls than physical activity that does not provide such a challenge to balance (Sherrington et al 2008). This review does not provide clear evidence on the best way to improve balance in middle-aged

people. Yet as previous work has pointed to the importance of ‘specificity’ in training, ie, people get better at learn more what they practise, it seems likely that the best way to improve balance would be with exercises which involve challenges to balance such as tennis, dancing, tai below chi, exercise to music, and running. The current ACSM guideline for adults

aged under 65 does not mention balance training, whereas the guideline for those over 65 does recommend balance training for those at risk of falls (Haskell et al 2007). The present review provides evidence that balance can be improved in people under 65 and previous work has shown the importance of balance as a risk factor for falls and that balance deteriorates with age. We therefore, suggest that a recommendation that all people undertake physical activities that challenge balance be considered for inclusion in future guidelines. The meta-analysis found a moderate effect of physical activity on endurance (usually measured by walking distance). Endurance has not been clearly identified as a risk factor for falls but it is linked to frailty (Fried and Guralnik 1997) in older adults and is important in maintaining reserve capacity of the cardiovascular system which also deteriorates with increasing age in order to maintain the ability to perform activities of daily living. Again the ACSM guidelines about endurance training are supported by this analysis (Haskell et al 2007).