Table 2.

Physiological results from sub-maximal workloads (N = 19).

Work period	Inclination (°)	V (km·h−1)	Heel elevator (cm)	HR (b·min−1)	CF (s·min−1)	VO2 (mL·kg−1·min−1)	RPE	Cvert (mL·kg−1·${\text{m}}_{\text{vert}}^{-1}$)§
1	13	3.8	0.0	167 ± 15	82 ± 7	44.7 ± 3.3	15 ± 3	3.14 ± 0.23*
2			6.1	170 ± 14	85 ± 8	46.6 ± 2.8	15 ± 3	3.28 ± 0.20*#
3	15	3.2	0.0	168 ± 15	72 ± 8	43.2 ± 2.9	14 ± 2	3.03 ± 0.21
4			6.1	169 ± 15	77 ± 7	42.8 ± 2.8	14 ± 3	3.00 ± 0.20
5	17	2.9	0.0	167 ± 16	68 ± 6	42.4 ± 2.6	14 ± 2	2.98 ± 0.18
6			6.1	168 ± 16	71 ± 6	42.1 ± 2.3	14 ± 2	2.96 ± 0.16
7	19	2.6	0.0	167 ± 16	65 ± 6	42.6 ± 2.3	14 ± 2	2.99 ± 0.16
8			6.1	167 ± 16	66 ± 9	41.6 ± 2.0	14 ± 2	2.92 ± 0.14
9	21	2.4	0.0	167 ± 17	63 ± 6	42.5 ± 1.9	15 ± 2	2.98 ± 0.14
10			6.1	167 ± 16	65 ± 5	41.4 ± 2.1	14 ± 2	2.91 ± 0.15
11	23	2.2	0.0	165 ± 18	61 ± 5	43.0 ± 2.1	15 ± 2	3.02 ± 0.15
12			6.1	165 ± 18	63 ± 7	41.5 ± 2.3	14 ± 2	2.91 ± 0.16

Vertical velocity (Vvert measured as mvert· h⁻¹), was held constant at 854 mvert· h⁻¹ in all work periods. Values are mean ± standard deviation (SD). °, degrees; V, speed; km·h⁻¹, kilometer per hour; HF, heart frequency; b·min⁻¹, beats per minute; CF, cycle frequency; s·min⁻¹, steps per minute; VO₂, oxygen uptake; mL·kg⁻¹·min⁻¹, milliliters per kilogram bodyweight per minute; RPE, rate of perceived exertion measured by Borg scale; C_vert, oxygen cost of vertical displacement; mL·kg⁻¹ ·mvert⁻¹, milliliter oxygen per kg bodyweight per vertical meter.

^*p < 0.01: higher than in all other inclinations.

^#p < 0.01: worse effect of heel elevator than in all other inclinations.

^§p < 0.01: lower C_vert with increased inclination.