Table 4.

Comparison of ultrasonographic trunk muscle parameters between the high- and low-risk fall groups classified according to Berg Balance Scale

	High-risk fall group (n=19)	Low-risk fall group (n=36)	p-value
Rectus abdominis
NPS thickness (mm)	6.94±2.20	7.95±2.23	0.117
PS thickness (mm)	6.86±2.45	7.81±2.36	0.103
NPS contractility	1.23±0.13	1.16±1.10	0.061
PS contractility	1.10±0.09	1.10±0.10	0.852
Contractility ratio	1.11±0.09	1.06±0.06	0.001**
External oblique
NPS thickness (mm)	3.09±1.27	3.86±1.12	0.011*
PS thickness (mm)	3.12±1.08	3.79±0.95	0.008*
NPS contractility	1.32±0.19	1.26±0.19	0.193
PS contractility	1.15±0.13	1.17±0.15	0.710
Contractility ratio	1.15±0.16	1.07±0.08	0.048*
Internal oblique
NPS thickness (mm)	6.06±1.79	7.05±2.36	0.159
PS thickness (mm)	5.73±1.83	6.88±2.14	0.037*
NPS contractility	1.37±0.14	1.27±0.14	0.044*
PS contractility	1.17±0.13	1.20±0.13	0.381
Contractility ratio	1.16±0.14	1.05±0.07	<0.001**
Transversus abdominis
NPS thickness (mm)	2.91±1.36	3.30±1.34	0.125
PS thickness (mm)	2.76±1.34	3.13±1.26	0.172
NPS contractility	1.57±3.55	1.65±0.51	0.979
PS contractility	1.28±0.27	1.51±0.47	0.026*
Contractility ratio	1.25±0.33	1.09±0.14	<0.001**
Erector spinae
NPS thickness (mm)	33.7±4.27	39.5±6.15	0.001**
PS thickness (mm)	33.9±4.02	38.1±6.55	0.019*
NPS contractility	1.20±0.13	1.18±0.09	0.818
PS contractility	1.10±0.07	1.14±0.09	0.028*
Contractility ratio	1.10±0.07	1.04±0.04	0.002**

Values are presented as mean±standard deviation.

Value of NPS thickness and PS thickness was measured on resting state.

NPS, non-paretic side; PS, paretic side.

^*p<0.05,

^**p<0.01 by Mann-Whitney U-test.