Table 2.

Summary of the quality assessment of the instruments

	Reliability	Agreement	Validity	Responsiveness	Interpretability
Muscle endurance of short neck flexors (9 articles)	+	?	?	0	0
Manual muscle examination (1 article)	?	0	0	0	0
Craniocervical flexion test (4 articles)	-	?	0	0	0
Dynamometer (3 articles)	?	0	0	0	0
Timed weighted overhead test (1 article)	?	0	0	0	0
Cervical PILE test (2 articles)	+	?	0	0	0

+ Positive

? Doubtful

- Inadequate

0 No information