On 2014 Jun 12, Gordon Warren commented:

This is not a meta-analysis and does not claim to be.

On 2013 Nov 18, James C Coyne commented:

Yikes, this is a really badly conducted and interpreted meta analysis. Thanks, Hilda Bastian, for calling this to our attention and offering alternative references.

On 2013 Nov 18, Hilda Bastian commented:

The conduct and reporting of this systematic review falls so far short of the standards and criteria covered by PRISMA for reporting (Moher D, 2009) and quality appraisal tools such as AMSTAR, that this review does not meet current expectations of a systematic review.

While conclusions about effectiveness are made, result data from the primary studies are not provided, nor are methods of data extraction and analysis discussed. Despite the large number of included trials, no meta-analyses of suitable data were performed and no reason for this was given.

What constituted exercise was not specified and the reason for excluding studies prior to 2000 is not given. The reasons for inclusion and exclusion of studies are not entirely clear: for example, studies were excluded because of concomitant drug therapy, which, while a reasonable criterion, was not included in their list. A full list or explanation of exclusions is not provided.

The search strategy as reported appears to be simplistic and does not include adequate search terms or key databases such as PEDRO. The number of studies for the stages in PRISMA’s flow diagram are not provided (duplicates removed, records screened). The quality of included studies is not assessed.

If you are interested in reading a systematic review on this question, consider Umpierre D, 2011 - see the DARE critical appraisal.

On 2013 Nov 18, Hilda Bastian commented:

The conduct and reporting of this systematic review falls so far short of the standards and criteria covered by PRISMA for reporting (Moher D, 2009) and quality appraisal tools such as AMSTAR, that this review does not meet current expectations of a systematic review.

While conclusions about effectiveness are made, result data from the primary studies are not provided, nor are methods of data extraction and analysis discussed. Despite the large number of included trials, no meta-analyses of suitable data were performed and no reason for this was given.

What constituted exercise was not specified and the reason for excluding studies prior to 2000 is not given. The reasons for inclusion and exclusion of studies are not entirely clear: for example, studies were excluded because of concomitant drug therapy, which, while a reasonable criterion, was not included in their list. A full list or explanation of exclusions is not provided.

The search strategy as reported appears to be simplistic and does not include adequate search terms or key databases such as PEDRO. The number of studies for the stages in PRISMA’s flow diagram are not provided (duplicates removed, records screened). The quality of included studies is not assessed.

If you are interested in reading a systematic review on this question, consider Umpierre D, 2011 - see the DARE critical appraisal.