“…Almost all studies reported a follow-up period of less than 1 year; 11,14,[17][18][19]21,23,24,27,28,31,33 several tested participants straight after the intervention; 15,16,29,30 and some did not include or state any follow-up period. 20,22,25,32 Therefore, it cannot be determined whether any of the reported improvements persisted. Less than half of the 22 studies included recruited more than 100 participants, 11,15,17,21,23,24,26,29,30,32 and several studies suffered from a high dropout rate, 18,19,28,32,33 with only 18% of participants in 6 months.…”