Table 12.

Recommended methodological guidelines for a future study on human physical performance of CoQ₁₀.

Physical activity:	Four types: No physically active or light activity (<3 d/week), Moderately active (3–5 d/week), Very active (5–7 d/week), High level athletes.
Age (years):	Four types: ≤33, 34–48, 49–64, ≥65
Diet:	Homogenise the sample according to the type of diet
Dosage	4.0–4.5 mg/kg/d of Ubiquinol or Ubiquinone with Phytosome or Ubiquinone with vehicle to increase bioavailability, or explaining perfectly the diet related to the administration.
Placebo	Yes, double blinded.
Type of study	Parallel, never crossover to avoid training and supplementation effect
Tissue concentration (plasma)	Mandatory. Always after 24 h after last doses of placebo or study substance. Recommended before and after exercise stress test. Determined always as “μmol/mol Chol” and added as “μg/mL”.
Tissue concentration (muscle)	Very recommended. Indispensable to know mitochondrial density. Determined as “nmol/g protein”
Treatment period	>1 week.
Effort test before and after supplementation	Characterization of the maximal oxygen consumption of every subject by a graded maximal exercise test. Evaluation of the metabolic efficiency under, at and upper the anaerobic threshold. Long duration exercise at a submaximal level to evaluate oxidative and inflammatory pattern. Evaluation of subjective fatigue perception