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

Not Applicable

Completed

Conditions: Exhaustion - Physiological

Interventions: Other: running training

Registration Number: NCT01816451

Lead Sponsor: University of Trás-os-Montes and Alto Douro

Brief Summary: The purpose of this study was to verify physiological responses to constant-load (continuous) vs. variable-intensity (interval) during 14 weeks of aerobic exercise on active men. The hypothesis was that would be differences in physiological variables on distinct modes of execution performed on the treadmill over a period of 14 weeks of training.

Detailed Description: Initially there were thirty five subjects, but due factors outside the present study, three individuals were excluded from the program. Two individuals during maximal exercise test (VO2) showed clinical impairment test being interrupted by the doctor and the third individual presented a plantar fasciitis in the early familiarization. Thirty two healthy and active males volunteered to participate in the study. All subjects exercised habitually, with at least 1 year experience aerobic training. The Human Ethics Committee of Rio de Janeiro Federal University approved this study (no 58659/02471312.8.0000.5257).The subjects performed a total of nine visits to the laboratory of the Brazilian Navy at City of Rio de Janeiro for physical tests on different days, except between visits I-II and VII-III. The interval between visits was one week between visits II-III-IV and VIII-IX, six weeks between the first day of training and visits V, four weeks between V-VI-VIII. All subjects from interval and continuous groups performed a total of 46 sessions of supervised running program.

Recruitment & Eligibility

Status: COMPLETED

Sex: Male

Target Recruitment: 35

Inclusion Criteria

self reporting no contraindication to high-intensity exercise.
physically active on cardiorespiratory activities in a regular basis for at least six months.
presence of negative responses on all items of the Questionnaire of Physical Activity Readiness (PAR-Q Test).

Exclusion Criteria

make use of medication that may interfere with the results, especially inhibitors appetites and dietary supplements.
presence of joint problems that prevents the achievement of training.
presence of disorders such as diabetes, dyslipidemia and anemia
have performed intense exercise with lowers members before the training sessions.

Study & Design

Study Type: INTERVENTIONAL

Study Design: FACTORIAL

Arm && Interventions

Group	Intervention	Description
interval	running training	The running training for interval group were performed on a treadmill for a period of 14 weeks, with a frequency of three times a week, lasting 20-minutes per session thus completing 46 sessions of training. The intensity and volume of training both were adapted according to the recommendations of the American College of Sports Medicine. The interval training group intensities ranged between 84-87% of maximal heart rate (HRmax) (vigorous intensity), 88-93%HRmax (near maximum intensity) and 94-99% HRmax (maximum intensity).
continuous	running training	The running training for continuous group were performed on a treadmill for a period of 14 weeks, with a frequency of three times a week, lasting 20-minutes per session thus completing 46 sessions of training. The intensity and volume of training both were adapted according to the recommendations of the American College of Sports Medicine.The continuous group ran at an intensity of \~87% of maximal heart rate (HRmax)

Primary Outcome Measures

Name	Time	Method
Total Time Reaching on Maximal Test (tVO2max)	Pre and post 14 weeks/46 sessions of training	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.
Heart Rate on Maximal Test	Pre and post 14 weeks at rest (5 min sitting; before start the test), during the test (to determine max), and 60s and 120s immediately after the end of the test (on sitting position)	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).
Blood Lactate Concentrations on Maximal Test	Pre and post 14 weeks/46sessions on rest (5 min sitting position; before start the test); 1-3-5 min immediately after the end of the test (on sitting position).	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.
Body Mass (BM)	Body Mass was collected pre and post training	To measure body mass Filizola scales with a stadiometer was used.
Rate of Perceived Exertion (RPE) on Maximal Test	Pre and post 14 weeks/46 sessions of training	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.
Fat Mass (%)	Pre and post 14 weeks/46 sessions of training	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.
Relative Maximal Oxygen Uptake	Pre and post 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.
Absolute Maximal Oxygen Uptake	Pre and post 14 weeks	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.

Secondary Outcome Measures

Name	Time	Method
Heart Rate on Submaximal Test	Pre; during (retest I 0-6weeks; retest II 0-10 weeks) and post 14 weeks/46sessions training: rest (5-min sitting; before start the test); maximal during the test (maxHRsub); 60s-120s immediately after the end of the test (on sitting position).	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.
Blood Lactate on Submaximal Test	Pre; during (retest I 0-6weeks; retest II 0-10 weeks) and post 14 weeks/46 sessions training: rest (5-min sitting; before start the test); 1-3-5 minutes immediately after the end of the test (on sitting position).	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 Velocity [Vsub]	Pre; during (retest I 0-6weeks; retest II 0-10 weeks) and post 14 weeks/46sessions of training	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.
Rate of Perceived Exertion (RPE) on Submaximal Test	Pre; during (retest I 0-6weeks; retest II 0-10 weeks) and post 14 weeks/46sessions training	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.