Table 2.

Results of forward regressions to predict knee motion^*

	OA group					Control group
Dependent variable	R	R2	F	df	P	R	R2	F	df	P
Dependent variable: knee flexion during WA
Independent variable
MQ (WA), MH (WA), LG (WA)	0.432	0.187	1.682	3, 22	0.200	0.441	0.195	1.531	3, 19	0.239
MQH (P), LQG (P), MQH (WA), LQG (WA)	0.609	0.371	3.097	4, 21	0.038†	0.685	0.469	3.979	4, 18	0.017†
Dependent variable: knee extension during MS
Independent variable
MQ (MS), LQ (MS), LH (MS)	0.669	0.447	5.926	3, 22	0.004†	0.146	0.021	0.145	3, 20	0.932
MQH (MS), LQH (MS), MQG (MS), LQG (MS)	0.713	0.509	4.397	4, 17	0.013†	0.173	0.030	0.132	4, 17	0.969

^*Separate forward regressions were performed for the OA and control groups to predict knee motion from individual muscle magnitudes and muscle co-contractions that were found to be different between the groups. OA = osteoarthritis; WA = muscle activity during weight acceptance phase; MQ = muscle activity of the medial quadriceps; MH = muscle activity of the medial hamstrings; LG = muscle activity of the lateral gastrocnemius; MQH = co-contraction between MQ and MH; P = muscle activity during preparation phase; LQG = co-contraction between lateral quadriceps and LG; MS = muscle activity during midstance phase; LQ = muscle activity of the lateral quadriceps; LH = muscle activity of the lateral hamstrings; LQH = co-contraction between LQ and LH; MQG = co-contraction between MQ and medial gastrocnemius.

^†Independent variable significantly changed the R² value at P ≤ 0.050.