TABLE 4.

Best fit regression models for all tested variables in relation to relative walking speeds.

	Best fit model	Adj R 2	SEE	F (2, 235)	Parameter estimates
Variables					Constant	b1	b2
r $\dot{\mathit{V}}$ O2 (mL⋅kg−1⋅min−1)	Quadratic	0.525	2.108	131.962***	12.035	2.165	0.566
EE (kcal⋅min−1)	Quadratic	0.311	1.043	53.089***	3.678	0.677	0.189
MCT (mL⋅kg−1⋅km−1)	Exponential	0.592	1.140	344.444***	180.894	0.168
ME (%)	Quadratic	0.109	4.064	15.515***	16.968	1.234	−0.917
HR (beats⋅min−1)	Quadratic	0.215	14.544	33.430***	107.487	7.527	1.922
$\dot{\mathit{V}}$ E (L⋅min−1)	Quadratic	0.360	4.852	67.714***	20.747	3.516	1.176
%Fat (%)	Quadratic	0.076	20.994	10.803***	59.482	−5.984	−2.367
Fat (g⋅kg−1⋅h−1)	ns	ns	ns	ns	ns	ns
CHO (g⋅kg−1⋅h−1)	Quadratic	0.293	0.236	50.086***	0.404	0.145	0.057
RPE	Exponential	0.322	0.231	113.330***	8.419	0.159
SF (stride⋅s−1)	Quadratic	0.607	0.073	183.814***	0.876	0.090	−0.010
SL (m⋅stride−1)	Quadratic	0.694	0.121	270.322***	1.305	0.182	−0.011
SD (s)	Exponential	0.601	0.085	358.304***	1.162	−0.104
SPD (s)	Exponential	0.654	0.099	448.427***	0.739	−0.136
CoV SF	Quadratic	0.059	0.006	8.454***	0.022	−0.002	0.001
CoV SL	Quadratic	0.060	0.006	8.560***	0.022	−0.002	0.001
CoV SD	Quadratic	0.060	0.006	8.560***	0.022	−0.002	0.001
CoV SPD	Quadratic	0.031	0.008	4.843**	0.031	−0.000	0.002

Adj, adjusted; SEE, standard error of estimate; r $\dot{V}{O}_2$ , relative oxygen consumption; EE, energy expenditure; MCT, metabolic cost of transport; ME, mechanical efficiency; HR, heart rate; $\dot{V}$ E, minute ventilation; %Fat, percent fat oxidation; Fat/CHO, rate of fat/carbohydrate oxidation relative to body weight; RPE, rating of perceived exertion; SF, stride frequency; SL, stride length; SD, stride duration; SPD, support phase duration; CoV, coefficient of variation. Significant model fit, **p < 0.01, ***p < 0.001.