Table 4.

Mean ± SD kinematics of limb collapse as a function of age group, slip outcome, the presence or absence of a protective stepping response, and as related to the odds of falling.

Variable		Young		Older			Odds Ratio
		Recover (n = 31)	Fall:Step (n = 11)	Recover (n = 8)	Fall:Step (n = 18)	Fall:No-Step (n = 10)	For Falling a
At Slip Onset:
ZHIP	(%bh)	43.9 ± 1.5	43.6 ± 1.7	42.8 ± 0.8 e	41.8 ± 1.7 e	42.4 ± 1.6	2.17 j
dZHIP/dt	(%bh/s)	37.1 ± 8.2	38.0 ± 8.3	28.4 ± 6.0 e	23.1 ± 5.3 e	23.2 ± 4.8	2.27 j
At Start of Hip Descent:
From Onset	(ms)	284 ± 110	245 ± 38	347 ± 95 d	321 ± 74 d	268 ± 35	1.16
ZHIP	(%bh/s)	52.1 ± 1.4	51.1 ± 1.8	51.3 ± 1.0	47.9 ± 2.2 c	47.9 ± 2.2 i	7.14 k
From Step Initiation to Touchdown:b
ΔZHIP	(%bh)	−1.2 ± 1.6	−5.8 ± 2.6 h	−0.3 ± 1.7 e	−3.1 ± 1.9 e,h	–	7.69 j
ΔdZHIP/dt	(%bh/s)	−17.5 ± 17.6	−31.7 ± 22.8 f	−19.5 ± 16.3	−38.4 ± 28.2 f	–	2.56 j
At 1st Step Touchdown:
ZHIP	(%bh)	50.7 ± 1.6	45.0 ± 2.3 h	50.4 ± 1.1	44.1 ± 2.6 h	–	101.95 k

Z_HIP = height of hip midpoint; dZ_HIP/dt = vertical velocity of hip midpoint; bh = body height; Δ = change

^aFactor by which the odds of falling change for a decrease of 1 SD in the variable across all subjects.

^bStep initiation could not be identified in 1 Young Recover, 1 Young Fall:Step, and 3 Older Fall:Step subjects.

^cp < .001 vs. Young Fall:Step and Older Recover (interaction of age group and slip outcome).

^dp < .01 vs. Young

^ep ≤ .001 vs. Young (main effect of age group).

^fp < .01 vs. Recover

^hp < .001 vs. Recover (main effect of slip outcome).

ⁱp < .01 vs. Older Recover.

^jp < .01

^kp < .001 for Odds Ratio ≠ 1.