Different Training (Aerobic, Resistance or Mixed) Physical Programs Affect to Physiological Responses (TRAINING2014)
Condition: Health Behavior
Study type: Interventional

Summary: 
      Background. The cardiovascular and cardiorespiratory coupling (CVCRC), focusing to recognize
      the synergies of standard or modified physiology that promote healthy. The investigators aim
      to study the effects of different training modalities and detraining on CVCRC.

      Methods. 32 young males were distributed in four randomized training groups: aerobic (AT),
      resistance (RT), aerobic plus resistance (AT+RT) and control (C). They were tested before,
      after the training (6 weeks) and after the detraining (3 weeks) through a graded maximal
      test. A principal component (PC) analysis of the time series of selected cardiovascular and
      cardiorespiratory variables was performed to evaluate the CVCRC. The PC1 coefficient of
      congruence in the 3 experimental conditions (before, after training and after detraining) was
      calculated for each group.
    

Detailed description: 
      The study of the cardiovascular and cardiorespiratory coupling (CVRC) is a hot topic in the
      medical literature focused to recognize the synergies that are present in healthy physiology
      [7, 8]. Several effects as aging [9], diseases [8] or mental state interventions [10] on
      cardiorespiratory coupling have been investigated, however, although its potential interest,
      there are no studies on the effects of training programs and detraining.

      Two main types of training programs (aerobic- AT and resistance- RT) have been widely
      investigated by their important and different physiological effects [11]. Its combination
      (AT+RT), has been recently recommended with health purposes for extensive types of population
      [12-14].

      The physiological effects of aerobic training programs has been traditionally evaluated
      through the cardiorespiratory reserve and the detection of maximal or threshold subsystem
      variables [1]. As a complex adaptive system (CAS), the human organism acts as an indivisible
      and integrated whole that cannot be reduced to the sum of its subsystems functions [2]. In
      this CAS the cardiovascular and cardiorespiratory subsystems are interdependent and interact
      in a dynamic and nonlinear way, i.e. non-proportional, which needs to be approached through
      nonlinear models [3], the study of time series and complex systems (CS) methodologies [4]. As
      the CAS enter every new situation with an existing set of capabilities [5] and exchange
      continuously information with their environment her/his behavior is unique and unexpected at
      short term (weeks, months) [6], the usual duration of common training programs.

      In order to study the couplings and coordination between multiple variables in CAS, CS
      approaches propose the detection of the so-called order parameters, collective or
      coordinative variables, because they capture the order or coordination of the system [3, 15].
      The principal component (PC) analysis is a common statistical technique that has been used to
      recognize such coordinative variables in a vast domain of biological research fields like:
      motor control [16], brain dynamics [17], DNA replication [18] or protein folding [19]. The PC
      analysis reduces the data dimension of highly coupled systems extracting the smallest number
      of components that account for most of the variation in the original multivariate data and
      summarize it with little loss of information. PCs are extracted in decreasing order of
      importance so that the first PC accounts for as much of the variation as possible and each
      successive component accounts for a little less [20]. The number of PCs reflects the
      dimensionality of the system, being a decrease of the number of PCs indicative of a major
      coupling (less dimensions) and vice-versa. The number of PCs changes when the system suffers
      a nonlinear change, i.e. a qualitative or coordinative reconfiguration. The PCs technique
      applied to kinematic variables has been successfully used to study the effects of motor
      learning processes [16], but has not been applied yet to study training effects on
      physiological variables.

      The aim of this research was to investigate the dimensional changes of the CVCRC before and
      after a period of 6 weeks of different training modalities (AT, RT and AT+RT) and 3 weeks
      after detraining in healthy young men.

      Material and Methods Participants. To determine the sample size a power analysis was
      performed. Using an effect size of d = .80, alfa < .05, power (1 - beta) = .95, with three
      repeated windows, we estimated a sample size = 32 [21]. Thirty-two healthy physically active
      males, physical education students (age 21.2 ± 2.4 y., height of 177.1 ± 0.66 cm, mean body
      mass 71.0 ± 5.1 kg and mean body -mass index 22.6 ± 1.7 kg·m-2) with no sport specialization
      but engaged in a wide range of aerobic activities at least three times a week volunteered to
      participate in this study. After the baseline tests they were distributed in four randomized
      groups for the 6 weeks of training: aerobic (AT), resistance (RT), aerobic+resistance (AT+RT)
      and control (C).

      Procedure. Participants completed a standard medical questionnaire to confirm their healthy
      status and signed an informed consent form. All experimental procedures were approved by the
      local bio-ethics committee and were carried out in accordance with the ethical guidelines
      laid down in the Helsinki Declaration. After the baseline cardiorespiratory testing and
      maximal strength and power tests (see below) they followed 3 times a week their assigned
      specific training program:

        1. AT group (n = 8): they pedalled 60 min at 60% of their individual maximum workload (60%
           Wmax). This workload was increased by 5% weekly unless the participant was unable to
           keep the pace throughout the session. Heart rate was monitored during all the sessions.

        2. RT group (n = 8): they performed twice a 30 min strength circuit[14]. Forty per cent of
           1RM for the upper body (i.e., squat, chest press, shoulder press, triceps extension,
           biceps curl, pull-down [upper back]), and 60% for the lower body (quadriceps extension,
           leg press, leg curls [hamstrings], and calf raise) were used as starting weights. They
           allowed the participants a maximum of 12 repetitions which included a slow controlled
           movement (2s up and 4s down). The resting period between exercises was 2 min. Workloads
           were adjusted weekly, with resistance being increased as needed (typically 5 up to 10%)
           if the participant was able to lift the weight comfortably (i.e., more than 12
           repetitions).

        3. AT+RT group (n = 8): they pedalled at 60% Wmax during 30 min and performed once the
           strength circuit (as R group).

        4. C group (n = 8): continued with their usual activities, without any special training.

      Cardiorespiratory testing. The incremental cycling test (Excalibur, Lode, Groningen,
      Netherlands) started at 0W and the workload increased 20W/min until exhaustion participants
      could not keep the prescribed cycling frequency of 70rpm during more than 5 consecutive
      seconds. All tests were performed in a well-ventilated lab; the room temperature was 23ºC and
      the relative humidity 48%, with variations of no more than 1ºC in temperature and 10% in
      relative humidity. During the test the subjects breathed through a valve (Hans Rudolph 2700,
      Kansas City, MO, USA) and respiratory gas exchange was determined using an automated
      open-circuit system (Metasys, Brainware, La Valette, France). Oxygen and CO2 content and air
      flow rate were recorded breath by breath. Before each trial, the system was calibrated with a
      mixture of O2 and CO2 of known composition (O2 15%, CO2 5%, N2 balanced) (Carburos Metálicos,
      Barcelona, Spain) and with ambient air. Hemodynamic information of participants was
      determined with non-invasive finger cuff technology (Nexfin, BMEYE Amsterdam, Netherlands).
      The Nexfin device provides continuous blood pressure (BP) monitoring from the resulting pulse
      pressure waveform, and calculates: systolic and diastolic blood pressure (SBP and DBP).
      Participants were connected by wrapping an inflatable cuff around the middle phalanx of the
      finger. The finger artery pulsing is 'fixed' to a constant volume by application of an
      equivalent change in pressure against the blood pressure resulting in a waveform of the
      pressure (clamp volume method). Electrocardiogram (ECG) was continuously monitored (DMS
      Systems, DMS-BTT wireless Bluetooth ECG transmitter and receiver, software DMS Version 4.0,
      Beijing, China). The tests were carried out at least 3 hours after a light meal and
      participants were instructed not to perform any vigorous physical activity for 72 hours
      before testing. Participants repeated this test after 6 weeks of training and after 3 weeks
      of detraining.

      Maximal strength and power testing. Maximal strength and maximal power of upper and lower
      limbs, respectively, were measured (Musclelab Power System, Porsgruun, Norway) in each
      participant. Estimated 1 RM-chest press and 1RM-squat based on submaximal loads was
      calculated. In the chest press exercise the load started with 25 kg, and continued with 35
      kg, 45 kg, 55 kg, 65 kg, etc. and in the squat exercise they started with 45 kg and continued
      with 65 kg, 85 kg, 105 kg, etc. until they could not perform 1 repetition. Based on these
      results the maximal 1RM was registered and the force/velocity relationship graph was plotted
      to determine the maximal power.

      All exercise tests were carried out at least 3 hours after a light meal and participants were
      instructed not to perform any vigorous physical activity for 72 hours before testing.
      Participants repeated these tests after 6 weeks of training and after 3 weeks of detraining.

      Data analysis The following maximal values of performance and cardiorespiratory variables
      were registered during the tests: maximal cycling workload (Wmax), maximal oxygen uptake (VO2
      max), maximal expiratory ventilation per minute (VE max), maximal heart rate (HR max),
      maximal 1RM-squat and maximal 1RM-chest. The group means in the different conditions were
      compared using the non-parametric Friedman.

      A PC analysis of the time series of the following selected cardiorespiratory variables:
      expired fraction of O2 (FeO2), expired fraction of CO2 (FeCO2), ventilation (VE), systolic
      blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) was performed to
      obtain information about the CVCRC in each participant. The median of PC1 coefficient of
      congruence was obtained in each group and condition (before, after training and detraining).
      The null hypothesis of a constant PC congruence median over the control group and the
      training groups was tested through non-parametric Kruskal-Wallis. Mann Whitney U matched
      pairs test analysis was also performed to assess statistically significant differences
      between each couple of different conditions. Effect sizes (Cohen's d) were computed to
      demonstrate the magnitude of standardized medians' differences where effects reached p < .05
      level.
    

Intervention name(s): Training resistance; Training aerobic; Training resistance+aerobic
Intervention type(s): Other; Other; Other
Intervention description(s): After the baseline tests they were distributed in four randomized groups for the 6 weeks of training: aerobic (AT), resistance (RT), aerobic+resistance (AT+RT) and control (C).; After the baseline tests they were distributed in four randomized groups for the 6 weeks of training: aerobic (AT), resistance (RT), aerobic+resistance (AT+RT) and control (C).; After the baseline tests they were distributed in four randomized groups for the 6 weeks of training: aerobic (AT), resistance (RT), aerobic+resistance (AT+RT) and control (C).
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Basic Science
Keywords: physical training; aerobic training; resistance training