Fitmate pro

The EEG signals were continuously recorded with a conventional gel-based cap (Waveguard original, ANT Neuro) with 64 AgCl electrodes in a layout based on the extended international 10–20 system for electrode placement (Jurcak et al., 2007 (link)). CPz and AFz were used as reference and ground, respectively. Nasion, inion, and preauricular points were used as anatomical landmarks to position the EEG cap. Conductive gel for electrophysiological measurements was used (OneStep Cleargel, H+H Medizinprodukte), and impedance was kept below 10 kΩ (6.11 ± 2.18 kΩ) to comply with current standards in cognitive neurosciences. The EEG cap was connected to an EEG mobile amplifier (eego sports, ANT Neuro b. v., Hengelo, Netherlands), and the sampling rate was 1,024 samples/s, using the corresponding eego software (ANT Neuro b. v., Hengelo, Netherlands). A Monark Cycle-Ergometer (939 E, Monark Exercise AB, Vansbro, Sweden), power-controlled by an external device (Fitmate-PRO, Cosmed, Rome, Italy), was used for the endurance cycling task. Two qualified researchers collected the data. The data collection occurred in a quiet and safe environment to guarantee the participants’ comfort.

RMR was assessed using a Parvo Medics’ TrueOne^® 2400 (ParvoMedics, Sandy, UT) integrated metabolic measurement system. The metabolic measurement system was calibrated prior to every assessment. RMR was assessed for 20 min as participants lay supine under a hood. The first 5 min were discarded and the remaining time of the test was averaged [18 (link)] for the calculation of RMR. Due to a mechanical issue with the primary metabolic measurement system, seven (five from the continuous group and two from the refeed group) subjects’ RMR was assessed at baseline and post-intervention using a Cosmed FitMate Pro™ (Cosmed, Italy). Similar to the primary metabolic measurement system, the first 5 min of RMR data collection was discarded.

Resting energy expenditure (REE), and maximum oxygen consumption (VO2 max) ml/min was measured by indirect calorimetry using the Fitmate Pro (Cosmed, Rome, Italy), which has good validity and reliability for assessment of REE in adults [56 (link)]. Energy expended during human performance can be measured by the volume of oxygen witch can consume while exercising at maximum capacity. VO2 max is the maximum rate of oxygen consumption.

The protocol of the graded exercise test to assess aerobic capacity has been recently described in details (Nikolaidis et al., 2018a (link)). Briefly, it consisted of running on a calibrated treadmill with initial speed of 8 km.h⁻¹ which was increasing every minute by 1 km.h⁻¹ till exhaustion. HR was recorded continuously during the test by Team2 Pro (Polar Electro Oy, Kempele, Finland). Minute ventilation and VO₂ were recorded by a gas analyzer (Fitmate Pro, Cosmed, Rome, Italy). Plateau of VO₂ (primary criterion), blood lactate, age-predicted HR_max [calculated using Tanaka’s formula, i.e., 208-0.7 × age (Tanaka et al., 2001 (link))] and rate of perceived exertion (RPE) Borg category-ratio scale (Borg, 1998 ) (secondary criteria) were used as criteria of VO₂max. Due to the difficulty identifying a plateau of VO₂, VO₂ was considered maximal once the secondary criteria were fulfilled. Blood samples were taken 5 min after termination of test [i.e., within the recommended range of 1–8 min (Howley et al., 1995 (link))], and lactate concentration was analyzed (Accutrend, Roche, Germany).

After a standardized warm-up protocol consisting of low-intensity running (7 km/h on a treadmill), players performed an incremental test with an initial speed of 8.0 km/h, increasing 0.5 km/h every 30 s until exhaustion (Technogym, Exite Run 600, Italy). Exhaustion was declared voluntarily by the participant or by the incapacity to perform the effort at the predetermined speed. The treadmill slope was fixed at 2%. Values of VO_2max were determined using a gas analyzer (Fitmate Pro, Cosmed, Italy) which allowed data to be collected on a breath-by-breath basis. The highest VO₂ value obtained during each stage was recorded as VO_2max after achieving VO₂ plateau considering the <2 SD (Taylor et al., 1955 (link)).
Heart rate (HR) was also assessed during the protocol using a heart rate monitor (H10, Polar, Finland) allowing the researchers to determine the maximal HR (HR_max) during the effort. The test occurred at the same hour and day of the week for both assessments (pre- and post-10 weeks). The treadmill test was carried out in a room with a stable temperature (21°C) and relative humidity (55%).

VO₂max and maximal heart rate measurements during exercise were examined through treadmill maximal exercise test (COSMED Pulmonary-Function Equipment 37 Via dei Piani di monte Savello I-00040 Rome ITALY) using an analyzer (Fitmate PRO version 1.2 cosmed). This dynamic and maximum test, until fatigue, consists in increasing the speed of 1 km/h every 2 min, after warm up of 5 min with a 6 km/h speed until the participant could no longer continue. Heart rate was continually monitored throughout the exercise test using (Polar Electro Oy, Kempele, Finland). Verbal encouragement was provided throughout the test to ensure that a maximal effort was achieved.

Indirect calorimetry was applied to assess the resting metabolic rate, using a Cosmed Fitmate Pro apparatus. A minimum 30-min measurement of absorbed oxygen and exhaled carbon dioxide was performed, and the amount of energy expended was calculated on the basis of the energy equivalent for oxygen.
All the studied women abstained from any strenuous physical activity for at least 24 h prior to the test. The measurement was made in the early morning, in a sitting position, in silence, without artificial light sources, and at room temperature.
Furthermore, using the Harris–Benedict formula, basal metabolism was calculated, then total metabolism, taking the subjects’ level of physical activity into account [17 ].