. 2023 Aug 22;66:102859. doi: 10.1016/j.redox.2023.102859

Table 4.

Predictive models for the maximal functional reserve (MFR).

Predictive model for the maximal functional reserve (MFR) expressed as kJ per kg of lower extremities lean mass (LLM)
Predictor	Estimate	SE	95% Confidence Interval		t	p	Stand. Estimate	95% Confidence Interval		Model	Model fit measures
Predictor	Estimate	SE	Lower	Upper	t	p	Stand. Estimate	Lower	Upper	Model	R	R2	P
Intercept	−0.18099	0.14754	−0.47993	0.11795	−1.23	0.228
Accumulated VO₂ (mL· kg LLM⁻¹)	0.00503	0.000206	0.00461	0.00545	24.47	< .001	0.8226	0.7545	0.8908	1	0.97	0.941	< .001
O₂ deficit (mL·kg LLM⁻¹)	0.00295	0.000547	0.00185	0.00406	5.4	< .001	0.1871	0.1169	0.2572	2	0.985	0.97	< .001
Mean power in MFR test (w·kg LLM⁻¹)	0.04553	0.00703	0.03129	0.05977	6.48	< .001	0.1425	0.0979	0.1871	3	0.992	0.983	< .001
MHC I + IIa (%)	−0.00451	0.00165	−0.00786	−0.00116	−2.73	0.01	−0.056	−0.0977	−0.0144	4	0.993	0.986	< .001

Predictive model for the accumulated O₂uptake during the MFR test expressed as mL per kg of lower extremities lean mass (LLM)
Intercept	555.8	111.992	327.09	784.52	4.96	< .001
O₂ deficit (mL·kg LLM⁻¹)	1.77	0.211	1.33	2.2	8.36	< .001	0.685	0.5174	0.85211	1	0.771	0.594	< .001
Frontal lobe TOI (a.u.)	−5.3	1.566	−8.5	−2.1	−3.38	0.002	−0.289	−0.4635	−0.11455	2	0.81	0.655	< .001
SERCA1 protein expression (a.u.)	−57.53	25.052	−108.69	−6.37	−2.3	0.029	−0.183	−0.345	−0.02022	3	0.85	0.723	< .001
Keap1 protein expression (a.u.)	−54.93	25.98	−107.99	−1.87	−2.11	0.043	−0.174	−0.3418	−0.00592	4	0.877	0.769	< .001
SERCA2 protein expression (a.u.)	13.88	5.284	3.09	24.67	2.63	0.013	0.208	0.0464	0.37019	5	0.895	0.801	< .001
Myoglobin protein expression (a.u.)	−39.07	17.571	−74.96	−3.19	−2.22	0.034	−0.197	−0.3776	−0.01606	6	0.91	0.829	< .001

Predictive model for the O₂deficit during the MFR test expressed as mL per kg of lower extremities lean mass (LLM)
Intercept	−14.359	20.685	−56.271	27.553	−0.694	0.492
pSer⁴⁰Nrf2 protein expression (a.u.)	73.477	20.476	31.99	114.965	3.589	< .001	0.452	0.197	0.7077	1	0.484	0.234	0.001
MAOD (mL·kg LLM⁻¹)	0.406	0.125	0.152	0.66	3.237	0.003	0.399	0.149	0.6494	2	0.612	0.374	< .001
Log SOD1 protein expression (a.u.)	−53.736	24.788	−103.961	−3.51	−2.168	0.037	−0.274	−0.53	−0.0179	3	0.667	0.445	< .001

Predictive model for the mean power in MFR test expressed as W per kg of lower extremities lean mass (LLM)
Intercept	13.3272	2.66098	7.9355	18.7188	5.01	< .001
O₂ cost, O₂/Work (mL·kJ⁻¹)	−0.054	0.00838	−0.071	−0.037	−6.44	< .001	−0.652	−0.857	−0.4468	1	0.572	0.327	< .001
VO₂max (mL·kg LLM⁻¹)	0.0611	0.01293	0.0349	0.0873	4.72	< .001	0.457	0.2613	0.6536	2	0.727	0.528	< .001
Keap1 protein expression (a.u.)	−1.5425	0.56474	−2.6868	−0.3982	−2.73	0.01	−0.277	−0.4821	−0.0715	3	0.771	0.594	< .001
SERCA2 protein expression (a.u.)	0.3192	0.12625	0.0634	0.575	2.53	0.016	0.245	0.0486	0.4407	4	0.809	0.654	< .001

MAOD, maximal accumulated oxygen deficit; MCH, myosin heavy chain; Nrf2, nuclear factor (erythroid-derived 2)-like 2; SERCA, sarco-endoplasmic reticulum Ca²⁺ ATPase; Keap1, kelch-like ECH-associated protein 1; SOD, superoxide dismutase; Log, logarithm.