Table 3.

Adjusted Associations of Total Sitting Hours per Day, Total Sedentary Hours per Day, and Walking Speed Outside the Home With Change in Calf Muscle Characteristics Among Participants With Peripheral Arterial Disease

Average Annual Changes in Calf Muscle Characteristics	No Walking Outside the Home (n =12)	Casual Strolling (0–2 miles/h) (n =148)	Average or Normal (2–3 miles/h) (n =114)	Briskly or Striding (>3 miles/h) (n =23)	p Trend
Walking speed outside the home
Calf muscle area, mm2/yr	−381	− 291	−286	−334	0.965
Calf muscle percent fat, %/yr	+1.25	+1.39	+1.33	+1.33	0.932
Calf muscle density, g/cm3/yr	−1.43*	−1.03†	−0.46	−0.32	0.0007
Hours spent sitting per day
Average annual declines	<4 h (n = 49)	4–7 h (n = 128)	8–11 h (n = 82)	≥12 h (n = 40)
Calf muscle area, mm2/yr	−285	− 309	−277	−314	0.983
Calf muscle percent fat, %/yr	+0.74	+1.44	+1.57	+1.47	0.220
Calf muscle density, g/cm3/yr	−0.92	−0.57	−0.74	−1.06	0.554
Total sedentary hours (sitting and lying down) per day
Average annual declines	<10 h (n = 31)	10 to < 14 h (n = 112)	14 to <18 h (n = 81)	≥18 h (n = 75)
Calf muscle area, mm2/yr	−284	− 323	−296	−262	0.437
Calf muscle percent fat, %/yr	+0.99	+1.30	+1.73	+1.22	0.641
Calf muscle density, g/cm3/yr	−0.69	−0.61	−0.73	−0.95	0.196

Analyses adjusted for age, sex, race, tibia length (muscle area only), prior year muscle measurement, body mass index, smoking, ankle brachial index, study cohort, leg symptoms, and comorbidities. N = 437.

^*p = 0.060 for the pairwise comparison between no walking outside the home and a walking speed of brisk or striding.

^†p = 0.025 for the pairwise comparison between casual strolling and a walking speed of brisk or striding.