Effect of external and internal cues on core muscle activation during the Sahrmann five-level core stability test

Table 1 Participants’ demographics

		Group 1 (External cue)		Group 2 (Internal cue)
		n	%	n	%
Gender	Male	13	37.14	11	33.33
	Female	22	62.68	22	66.67
Athlete	Yes	13	37.15	10	30.3
	No	22	62.85	23	69.70
Exercise	0 days/week	8	22.86	6	18.18
	1-2 days/week	11	31.42	13	39.4
	3-4 days/week	12	34.29	12	36.36
	5-7 days/week	4	11.43	2	6.06

Table 2 Explanation of each exercise of the Sahrmann five-level core stability test

Levels	Description
Level 1	The participant will slowly raise one leg to a position of approximately 90º hip flexion and 90º knee flexion. The participant will then attempt to bring the opposite leg to the same position in the same manner (i.e. “final position”)
Level 2	From the final position of level 1, the participant will slowly lower one leg, so the heel contacts the ground/plinth. Then the leg will slide out until the knee is fully extended
Level 3	From the final position of level 1, the participant will slowly lower one leg, so the heel is approximately 12 cm above the plinth. Then the leg will slide out until the knee is fully extended
Level 4	From the final position of level 1, the participant will slowly lower both legs together as the heels are contacting the plinth. Then the legs will slide out until the knee is fully extended
Level 5	From the final position of level 1, the participant will slowly lower both legs simultaneously until they are approximately 12 cm above the plinth. Then the legs will slide out until the knees are fully extended

Table 3 Summary of linear mixed effects model; main effects and interactions

Effect	P value	df	F
Cueing (with and without cue)	0.014a	1, 1922.96	5.99
Cue type (external and internal cue)	0.1306	1, 2.3438	65.80
Muscle groups (TA/IO, EO and RA)	0.000b	2, 1922.97	19.80
Exercise levels (level 1, II, III, IV, V)	0.0001b	4, 1922.96	67.19
Cueing and muscle interaction	0.177	2, 1922.95	1.73
Cueing and exercise level interaction	0.009a	4, 1922.93	3.35
Muscle and exercise level interaction	0.018a	4, 1922.93	2.30
Cueing and muscle and exercise level interactions	0.091	4, 1922.93	1.71

^aP < 0.05;

^bP < 0.01.

Note 1: Model terms was tested with Satterwhite method. Note 2 The following variable is used as a random-effects grouping factor “id”. Note 3 Type III Sum of Squares.