::Jahnke et al. do not specifically conclude "This suggests that qigong may be effective primarily as gentle physical exercise." (a conclusion provided by ), though it appears to be reasonable.  It would be more accurate to offer a qualifier like "however" and "studies generally have not been designed to distinguish the cause of beneficial effects".  Here is more possible rewording (also see above): 

 :::Research did not evaluate the importance of exercise versus other facets of qigong practice such as meditation, breathing, balance, quality of instruction, depth of practice, and difference in forms. 

 :::Research has not been conducted to evaluate different facets of qigong practice such as exercise, meditation, breathing, balance, quality of instruction, depth of practice, and difference in forms. 

 ::I leave it to you to correct the grammar and be sure the meaning is clear and verifiable.