Physiologic Adaptations to Interval and Continuous Running at Low Volume and Vigorous Intensity Over 14-Weeks.

The relative maximal oxygen uptake was taken by individual connected to a metabolic gas analyzer (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota) through which the gas samples were collected and measured each 10 seconds during the test. The participants were submitted to a ramp protocol with an initial velocity of 8.0 km/h (0% of inclination), progressive increments, a final velocity of 18 km/h (2% de inclination). The duration was equal to 10 minutes or until voluntary exhaustion.

The absolute maximal oxygen uptake was taken by individual connected to a metabolic gas analyzer (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota) through which the gas samples were collected and measured each 10 seconds during the test. The participants were submitted to a ramp protocol with an initial velocity of 8.0 km/h (0% of inclination), progressive increments, a final velocity of 18 km/h (2% de inclination). The duration was equal to 10 minutes or until voluntary exhaustion.

The criterion for determining the total time reaching in maximal VO2 test was associated with the time immediately preceding heart rate shown a reduction of five or more beats.

The HR was collected pre and post training on maximal VO2 test. Initially, with the individual on the treadmill (Inbrasport Master Super, Porto Alegre, Brazil), electrodes (Micromed) were placed at the manubrium, right and left iliac crest for measured heart rate (HR) (derivation CM5) and were connected to an electromyography equipment (Micromed®). HR values were visualized through Elite software (Micromed Biotechnology, Brasilia, Brazil).

Capillary blood samples (25 µl) were obtained from the finger of each subject during all tests and the [La] were measured using an (Accutrend®Plus Roche Diagnostics Gesellschaft mit beschränkter Haftung , Mannheim, Germany). The measuring range was 0.8-22 millimole (mM). The sample is collecting (Accu-Chek® Softclix) and first applied to a coded yellow test strip (Accutrend Blood measure-Roche) with a reagent chemical substance. Blood was added to the strip by letting it drip from a finger; in accordance with the instrument's instructions. The finger never touched the strip's pad in order to exclude any possible interference due to the sweat. All [La] were collected by a single, experienced investigator.

To measure body mass Filizola scales with a stadiometer was used.

The RPE was collected at maximal test (see description of test on outcome measure "Maximal Oxygen Uptake"). Relative to overall feelings were collected by Category Ratio Scale (CR10) during the last 15 s of each stage using the Borg category (0 - 10) scale. Instructions for RPE were that "0" corresponds to rest, and "9 - 10" corresponds to maximal exertion. This verbal procedure was explained before initiating exercise.

The subjects underwent a set of anthropometric assessments, which followed the norms of the International Society for Advancement of Kinanthropometry. The fat mass was calculated by percentage using the equation proposed by Jackson and Pollock (1978) from seven skinfold measurement. To measure the skinfolds, a Sanny Professional Skinfold Caliper was used.

Submaximal tests were done at the same treadmill (Treadmill® TR9100HR, Life Fitness, USA) as training.Before the test, all subjects should be able to do it at moderate-high intensity. The test began with three minutes of progressive warm-up. During the first minute, the subject maintains a light level; during the second and third minutes of the warm-up, the intensity was moderate. Starting from the fourth minute, the subject should be able to maintain a velocity for the next seven to ten minutes. This load can be adjusted as required, through verbal communication between the subject and the evaluator. The test finishes at the end of 10 minutes.The test velocity should be clearly constant at the end of the test. Heart rate were monitored and recorded at the end of each minute, e.g. 10 seconds before ending each measured minute, and the last measurement were at the end of the 10 minutes. The objective of this procedure was to identify the HR values for training intensities.

Capillary blood samples (25 µl) were obtained from the finger of each subject during all tests and the [La] were measured using an (Accutrend®Plus Roche Diagnostics Gesellschaft mit beschränkter Haftung , Mannheim, Germany). The measuring range was 0.8-22 mM. The sample is collecting (Accu-Chek® Softclix) and first applied to a coded yellow test strip (Accutrend Blood Measure-Roche) with a reagent chemical substance. Blood was added to the strip by letting it drip from a finger; in accordance with the instrument's instructions we never let the finger touch the strip's pad in order to exclude any possible interference due to the sweat.

Submaximal tests were done at the same treadmill (Treadmill® TR9100HR, Life Fitness, USA) as training.Before the test, all subjects should be able to do it at moderate-high intensity. The test began with three minutes of progressive warm-up. During the first minute, the subject maintains a light level; during the second and third minutes of the warm-up, the intensity was moderate. Starting from the fourth minute, the subject should be able to maintain a velocity for the next seven to ten minutes. This load can be adjusted as required, through verbal communication between the subject and the evaluator. The test finishes at the end of 10 minutes. The test velocity should be clearly constant at the end of the test. Values of velocity were monitored and recorded at the end of each minute, e.g. 10 seconds before ending each measured minute, and the last measurement were at the end of the 10 minutes. The objective of this procedure was to identify the value of that speed has stabilized.

The RPE was collected at submaximal test (see description of test on outcome measure "HR at submaximal test"). Relative to overall feelings were collected by Category Ratio Scale (CR10) during the last 15 s of each stage using the Borg category (0 - 10) scale. Instructions for RPE were that "0" corresponds to rest, and "9 - 10" corresponds to maximal exertion. This verbal procedure was explained before initiating exercise.