Table 4.

Summary of findings and certainty of evidence.

No. of Studies	Quality Assessment			Outcome	No. of Participants		Effect (95 %CI)	Certainty (GRADE)
	Risk of Bias	Inconsistency	Imprecision		Training	No Training
Effect of training on 12-month LBP incidence
2	Not serious	Not serious	Serious	Nordic Questionnaire	432	317	OR = 0.83 (0.59,1.16)	Moderate
Effect of training on LBP intensity – Pre-existing LBP
2	Serious	Serious	Not Serious	VAS	130	132	MD = −2.92 (−5.44 -0.41)	Low
Effect of training on LBP intensity – No pre-existing LBP
2	Serious	Not Serious	Serious	VAS	113	112	MD = −0.06 (−0.63, 0.52)	Low

Abbreviations: GRADE – Grading of Recommendations, Assessment, Development and Evaluations, LBP – lower back pain, VAS – visual analogue scale, MD – mean difference (units out of 10), OR – odds ratio.