Effectiveness of Reverse vs. Traditional Linear Training Periodization in Triathlon

present research aimed to analyze the modi cation in performance, body composition, and autonomic modulation of reverse and traditional linear training periodization in amateur triathletes. We analyzed running and swimming performance, strength manifestation, body composition, and autonomic modulation before and after a traditional linear training periodization (four weeks of volume-based training plus four weeks of intensity-based training plus two-week tapering), a reverse linear training periodization(four weeks of intensity-based training plus four weeks of volume-based training plus two-week tapering), and a free training control physical active group (10-week free training) in 32 amateur athletes. Independently of the periodization model, the combination of two four-week mesocycles followed by a two-week taper is an e ciency strategy to avoid overreaching, obtaining an increase in parasympathetic modulation. Moreover, both types of training periodization proposed in this study do not modi ed body composition of amateur triathletes. Also, compared with traditional periodization, reverse periodization e ciently improves horizontal jump performance. Finally, reverse and traditional periodization were an e ective strategy to improve running biomechanical, performance, and physiological variables, as well as e cient periodization strategies to improve swimming technical ability, aerobic, and anaerobic swimming performance. Keywords:swimming; running; strength; heart rate variability; body composition 1. Introduction To reach competitive performance, a variety of di erent training periodization strategies have been applied, varying the distribution of training volumes and intensities during the di erent training structures of macrocycles, mesocycles, and macrocycles [1–11]. Within these periodization models, the traditional linear periodization based on developing high-volume and low-intensity

performance. Keywords:swimming; running; strength; heart rate variability; body composition 1. Introduction To reach competitive performance, a variety of di erent training periodization strategies have been applied, varying the distribution of training volumes and intensities during the di erent training structures of macrocycles, mesocycles, and macrocycles [1–11]. Within these periodization models, the traditional linear periodization based on developing high-volume and low-intensity training during the rst periods of the macrocycle, with progressive increases in training intensity and simultaneous decreases in training volumes of the consecutive periods, have been one of the most used [12,13]. Recently, a new periodization model is emerging in opposition to the traditional linear periodization model: The reverse periodization [2,7,14–16]. According to the reverse training periodization model, athletes can start their training preparation with high-intensity and low-volume training, while gradually decreasing intensity and increasing volume or, depending on the sport, maintaining intensity and increasing volume during the following training periods [1]. Reverse training periodization has been studied in physical tness, strength training, swimming, and rowing, obtaining increases in muscular endurance, maximum strength, and endurance performance [9,10,16,17]. Int. J. Environ. Res. Public Health2019,16, 2807; doi:10.3390 /ijerph16152807 /journal/ijerph

Int. J. Environ. Res. Public Health2019,16, 2807 2 of 13 The high-intensity interval training, basic for reverse training periodization, showed similar or higher adaptations than high volume of traditional linear training, in muscle bu ering capacity and glycogen content, GLUT4, and maximal glucose transport activity in skeletal muscle [18–20]. In this line, high intensity interval training (HIIT) produced an increased sympathetic modulation, not negatively e ecting cortical arousal and maintaining strength manifestations, but decreasing technical swimming skills if no drills were performed alongside the HIIT training [5,21,22]. A key factor regarding training is e ciency; reverse training periodization has been found to be an e ective and time-e cient strategy (since with less training time get the same or larger adaptations) to improve performance mainly for swimming events where the anaerobic threshold is an important performance indicator [15], as well as a model that produces a higher adaptive autonomic response compared with traditional linear periodization [16]. This new model has been studied in di erent endurance sports such as rowing, running, and swimming [1,2,10,14,23–25], but not in triathlon. Based on the literature, we proposed the present research to analyze the modi cation in running and swimming performance, strength adaptations, body composition, and autonomic modulation of reverse and traditional linear training periodization in triathletes. Changes in running, swimming and horizontal jump performance, autonomic modulation, and body composition were analyzed before and after two 10-week reverse and traditional linear triathlon training programs. We hypothesized that reverse training periodization would achieve higher performance than traditional periodization 2. Materials and Methods 2.1. Experimental Approach to the Problem Changes in running, swimming and horizontal jump performance, autonomic modulation, and body composition were analyzed before and after two 10-week reverse and traditional linear triathlon training programs. 2.2. Subjects 24 amateur physical active triathletes (11 males: 27.7 5.7 years; 175.2 5.0 cm; 70.6 6.3 kg; and 13 females: 26.8 6.8 years; 164.7 4.6 cm; 58.5 4.1 kg; 5.6 0.4 training sessions/week: 55.2 25.9 min/session; 7.0 1.5 h of training/week;>1 year of experience on triathlon training; competing at national level in sprint and Olympic triathlon distances) participated in

2.2. Subjects 24 amateur physical active triathletes (11 males: 27.7 5.7 years; 175.2 5.0 cm; 70.6 6.3 kg; and 13 females: 26.8 6.8 years; 164.7 4.6 cm; 58.5 4.1 kg; 5.6 0.4 training sessions/week: 55.2 25.9 min/session; 7.0 1.5 h of training/week;>1 year of experience on triathlon training; competing at national level in sprint and Olympic triathlon distances) participated in the present research. Participants were randomly divided into two di erent experimental groups: Reverse periodization (RP) group: They performed 4-week intensity training, 4-week volume training, and 2 weeks of tapering (n=11). Descriptive characteristics of the participants are shown in Table. Table 1.Descriptive characteristics of the participants at baseline in the three groups, mean SD. Group n (Male/Female) Age (years) Height (cm) Weight (Kg) Number of Session/Week Minutes Per Session Hours of Training Per Week RP 11() 25.6 6.8 170.5 6.2 65.4 8.5 5.5 0.2 45.9 24.8 6.9 2.2 TP 13 () 28.2 9.6 170.5 7.6 66.6 8.7 5.6 0.3 46.3 25.3 7.0 2.1 CG 8 (4 /4) 25.9 3.4 166.1 3.9 62.4 5.3 5.8 0.2 48.2 28.2 7.1 2.0 RP: Reverse periodization; TP: Traditional periodization; CG: Control group. Traditional periodization (TP) group: They performed 4-week volume training, 4-week intensity training, and 2 weeks of tapering (n=13). In addition, a physical active control group (CG) was included to control ambient in uences and to conduct an experimental design, as previous studies in periodization have used [3]. In this research, they conducted free training without any control by the researchers.

Int. J. Environ. Res. Public Health2019,16, 2807 3 of 13 The study design and the procedures employed were in accordance with ethical standards and the Declaration of Helsinki. Each participant was fully informed of the risks associated with the study and they gave a written informed consent before starting the study. If subjects were under 18 years old, written informed consent was obtained from their parents or legal tutor. 2.3. Evaluation Test We evaluated before starting the training programs, after 8 weeks, and after 10 weeks; in the three experimental groups, the following variables we evaluated in this 2-day sequence: Day 1: Body composition, autonomic modulation by heart rate variability (HRV), and swimming performance; Day 2: Maximal horizontal jump and running performance. 2.4. Body Composition Test Body composition was assessed with a segmental multifrequency bioimpedance analyzer Tanita BC-600, which uses an eight-point tactile electrode method to take readings from the body. We used the protocol of Clemente-Suarez et al. [26], where participants are informed the day before to come to the test with 1 h of no drink, 2 h of no food intake, with no consumption of drug, medicaments, or ca eine the previous 24 h, and to have urinated and defecated. We conducted the test at the same time, in the same participant order, and in the same place, with a constant temperature and humidity. To carry out the tests, the participants stood upright on foot electrodes on the instrument platform, with legs and thighs apart and arms not touching the torso. They were barefoot and without excess clothing. Four foot electrodes were used, two of which were oval-shaped and two heel-shaped, and prior to testing, both the skin and the electrodes were cleaned and dried, then participants were asked to grip the palm and thumb electrodes (two of each electrode per athlete) according to previous report [27]. Body height was measured using a commercial scale. We analyzed parameters of (I) body mass, (II) body mass index, (III) skeletal muscle mass, (IV) water, and (V) fat percentage. 2.5. Heart Rate Variability Test Before the swimming warm-up, triathletes performed

were asked to grip the palm and thumb electrodes (two of each electrode per athlete) according to previous report [27]. Body height was measured using a commercial scale. We analyzed parameters of (I) body mass, (II) body mass index, (III) skeletal muscle mass, (IV) water, and (V) fat percentage. 2.5. Heart Rate Variability Test Before the swimming warm-up, triathletes performed an HRV test using a Polar RS800CX HR monitor (Polar Electro, Kempele, Finland), which lasted for 10 min in a supine, lying in a stretcher in a room with controlled temperature following the procedures of previous research (7). Each participant conducted the HRV test at the same time of the day. The R-R series were analyzed using Kubios HRV software (version 2.0, Biosignal Analysis and Medical Imaging Group, University of Kuopio, Finland). The following HRV variables were assessed: (I) Low-frequency (LF) band/high-frequency (HF) band ratio; (II) percentage of di erences between adjacent normal R-R intervals more than 50 ms (PNN50); (III) square root of the mean of the sum of the squared di erences between adjacent normal R-R intervals (RMSSD); (IV) mean heart rate; and (V) total power. 2.6. Swimming Tests To analyze swimming performance, we conducted the tests proposed by Gynn [28] to analyze critical speed. Participants performed a 1500 m aerobic swimming standardized warm-up, then a 50 m maximal swimming test, followed by 15 min of rest and a 400 m maximal swimming test. In the 50 m test, we analyzed: (I) Rate of perceived exertion (RPE) with the 6–20 level Borg scale and (II) nal heart rate (HR) and (III) speed. In the 400 m test, we analyzed: (IV) Stroke index (V) RPE, (VI) nal HR, and (VII) critical speed. Biomechanical parameters were recorded by a slow-motion video camera and analyzed later in a display as previous studies [15].

Int. J. Environ. Res. Public Health2019,16, 2807 4 of 13 2.7. Maximal Horizontal Jump Test Subjects performed a standardized warm-up that consisted of 10 min of running (light aerobic). Then, participants performed two maximal horizontal jumps as previously reported [29]. Both jumps were performed with the hands on the waist, to avoid the arm movement inertia, and the best attempt was used for the statistical analysis. Subjects performed a standardized warm-up that consisted of 10 min of running (light aerobic). Then, participants performed two maximal horizontal jumps as previously reported [29]. Both jumps were performed with the hands on the waist, to avoid the arm movement inertia, and the best attempt was used for the statistical analysis. 2.8. Running Test Running performance was measured by the mean speed of a maximal e ort around 2000 m, which is associated with the maximal aerobic speed measured in incremental test conducted in laboratory [30]. After a 10 min aerobic standardized warm up and the maximal horizontal jump test, participants were instructed to run 2000 m at maximal speed in a track surface (temperature 16.1 2.4 C; 60.2 2.4% humidity). Capillary blood samples (5 L) for blood lactate concentration ([La-]) analysis were collected from the earlobe immediately after the end of the running test and analyzed using a Lactate Pro analyzer (Lactate Pro, Kyoto, Japan). Variables of (I) stride index (SI=speed x stride length), (II) speed, (III) RPE, (IV) nal HR, and (V) [La-] were evaluated. Biomechanical parameters were recorded by a slow-motion video camera and analyzed later in a display as in previous studies [15]. 2.9. Training Protocol The randomized design included three di erent macrocycles, and was conducted after a 4-week training period similar in both training groups: Reverse training periodization (RP): Composed of a 4-week mesocycle based on high-intensity and low-volume training (Z2 and Z3), 4-week mesocycle based on high-volume and low-intensity training (Z1), and 2-week mesocycle of tapering (combining Z1, Z2, and Z3 with low volume). Traditional linear training periodization (TP): Composed of a 4-week mesocycle based on high-volume and low-intensity training (Z1), 4-week mesocycle based on high-intensity and

(RP): Composed of a 4-week mesocycle based on high-intensity and low-volume training (Z2 and Z3), 4-week mesocycle based on high-volume and low-intensity training (Z1), and 2-week mesocycle of tapering (combining Z1, Z2, and Z3 with low volume). Traditional linear training periodization (TP): Composed of a 4-week mesocycle based on high-volume and low-intensity training (Z1), 4-week mesocycle based on high-intensity and low-volume training (Z2 and Z3), and 2-week mesocycle of tapering (combining Z1, Z2, and Z3 with low volume). Control group training (CG): Free training group during 10-week period (free distribution in Z1, Z2, and Z3); researchers did not any intervene in their training patterns. Training zones were classi ed according to previous literature in three training zones: Zone 1 (Z1), low-intensity training 65%–80% HRmax; zone 2 (Z2), anaerobic threshold training 80%–95% HRmax; and zone 3 (Z3), high-intensity training>95% HRmax (21). HRmax of participants was obtained in previous training sessions, in order to obtain an individual value of this parameter, not using formulas. Both RP and TP training macrocycles were designed in a low-volume and high-intensity training paradigm as proposed by previous researchers [8,16,31–33], just di erentiating between them in the distribution of the two rst mesocycles. Participants performed a training session of each discipline (swimming, cycling, and running) twice per week. The training load of swimming, cycling, and running sessions conducted by the triathletes was quanti ed each week using the HR and volume of training to nally assess the training impulse (TRIMP) [34] method (Figure).

Int. J. Environ. Res. Public Health2019,16, 2807 5 of 13 Figure 1. Training impulse (TRIMP) of reverse training periodization group (RP), traditional linear periodization group (TP), and control group (CG) during the three mesocycles of the 10-week macrocycle of training according to the three disciplines. 2.10. Statistical Analysis Data collection, treatment, and analysis were performed using SPSS for Windows statistical package (v.24.0). Descriptive statistics (mean and standard deviation) were calculated. Before using parametric tests, the assumption of normality and homoscedasticity were veri ed using the Kolmogorov–Smirnov test. A two-way (group moment) analysis of variance with repeated measures and Bonferroni post hoc was used to investigate di erences in variables. The 95% con dence intervals as well as the e ect size (ES) are presented in the annexes. ES was tested by Cohen's D [ES=(Posttest mean—Pretest mean)/Pretest SD]. For all procedures, a level ofp 0.05 was selected to indicate statistical signi cance. 3. Results Table the three groups. There were no signi cant di erences in any group between pre- and post-training values. In addition, no signi cant di erences were observed among groups before and after the training program. The results of the e ects on heart rate variability variables (Table) before and after the training program showed no signi cant di erences in CG. Also, no signi cant di erences were observed among groups in any moment. However, there were signi cant di erences in RP group in LF/HF, PNN50 between the evaluation performed at 8 weeks and the nal evaluation (10 weeks). Moreover, signi cant di erences were found in TP group in total power among the three moments, in LF between basal at 10 weeks and between 8 weeks and 10 weeks' evaluation and in between 8 weeks and 10 weeks moments. These di erences were a main time e ect. Table 400 m test performance, increasing the stroke index. In addition, a signi cant increase in RP from basal values to the end of second mesocycle and the end of taper among groups and in TP at the end of the 8 and 10 weeks in

weeks and 10 weeks moments. These di erences were a main time e ect. Table 400 m test performance, increasing the stroke index. In addition, a signi cant increase in RP from basal values to the end of second mesocycle and the end of taper among groups and in TP at the end of the 8 and 10 weeks in horizontal jump were found (Table). Lactate concentration presented an increased value at the end of the 8 weeks of training in RP (Table). These di erences were a main time e ect.

Int. J. Environ. Res. Public Health2019,16, 2807 6 of 13 Table 2.Data of body composition test before, after 8 weeks of training, and after two weeks of tapering in the three groups, mean SD. RP (n=11) TD ( n=13) CG ( n=8) Intergroup Comparations Basal 8 Weeks 10 Weeks Basal 8 Weeks 10 Weeks Basal 8 Weeks 10 Weeks F P Weight (Kg) 63.9 7.1 63.8 6.4 63.5 6.5 67.7 9.5 67.8 10.3 67.7 10.0 65.5 8.1 64.6 6.7 64.6 6.7 0.757 0.558 Fat mass (%) 15.8 5.0 15.1 4.8 15.1 5.3 15.6 5.4 15.7 5.5 15.9 5.0 17.0 5.5 16.5 6.8 16.5 6.8 0.289 0.884 Muscle mass (Kg) 51.0 6.3 51.6 6.1 51.4 6.6 54.5 9.6 54.4 9.9 54.2 9.6 50.7 8.0 51.4 8.4 51.4 8.4 0.677 0.611 Bone mass (Kg) 2.7 0.3 2.8 0.3 2.7 0.3 2.9 0.5 2.9 0.5 2.9 0.5 2.7 0.4 2.7 0.4 2.7 0.4 0.573 0.683 Water (%) 61.1 3.2 62.4 3.1 62.4 3.5 61.3 4.0 61.7 3.4 61.5 3.0 60.3 2.7 60.8 3.9 60.8 3.9 0.438 0.781 RP: Reverse periodization; TP: Traditional periodization; CG: Control group. Table 3.Heart rate variability values before, after 8 weeks of training, and after two weeks of tapering in the three groups, mean SD. RP (n=11) TP ( n=13) CG ( n=8) Intergroup Comparations Basal 8 Weeks 10 Weeks Intrag Comp Basal 8 Weeks 10 Weeks Intrag Comp Basal 8 Weeks 10 Weeks Intrag Comp F P LF (ms 2 ) 1294.9 897.2 1837.0 2869.7 2453.3 3128.8 1372.0 1109.5 557.6 293.4 10,696.0 15,625.1 B>810>8 1185.6 1517.8 1865.1 2583.6 1532.1 2665.4 2.740 0.055 HF (ms 2 ) 553.7 624.1 284.3 108.2 2725.5 4147.9 427.6 531.4 223.8 149.2 7566.8 13442.1 316.4 242.0 1182.8 2705.5 1211.8 2693.4 1.394 0.271 LF/HF 5.4 6.6 6.1 8.5 1.6 1.5 8>10 7.2 10.6 4.0 3.4 2.1 7.7 4.3 4.9 5.0 5.3 2.2 1.3 0.563 0.623 PNN50 % 13.0 15.27.7 3.6 23.4 18.910>8 11.2 14.16.3 3.7 18.1 17.9 6.9 3.6 5.8 3.0 7.2 2.3 1.268 0.398 RMSSD (ms) 32.1 16.3 41.0 38.6 72.1 66.3 44.5 42.923.7 8.2 110.9 109.3 41.2 42.4 44.8 45.8 42.9 46.1 2.780

6.6 6.1 8.5 1.6 1.5 8>10 7.2 10.6 4.0 3.4 2.1 7.7 4.3 4.9 5.0 5.3 2.2 1.3 0.563 0.623 PNN50 % 13.0 15.27.7 3.6 23.4 18.910>8 11.2 14.16.3 3.7 18.1 17.9 6.9 3.6 5.8 3.0 7.2 2.3 1.268 0.398 RMSSD (ms) 32.1 16.3 41.0 38.6 72.1 66.3 44.5 42.923.7 8.2 110.9 109.3 41.2 42.4 44.8 45.8 42.9 46.1 2.780 0.058 Mean HR (bpm) 69.7 21.865.6 9.1 62.3 7.2 69.0 23.260.2 7.9 60.2 8.7 65.6 9.1 67.0 7.1 65.5 6.8 1.682 0.1236 TPo (ms 2 ) 9935.4 12531.9 21,883.0 23050.9 9024.9 8948.2 4889.6 2889.7 7044.3 9558.1 10,5435.0 14,8253.0 10>8>B 5890.0 5390.9 20,438.6 38,887.5 6234.9 5950.6 1.668 0.237 RP: Reverse periodization; TP: Traditional periodization; CG: Control group; Intrag. Comp.: Intragroup comparation. TPo: Total power; LF: Low-frequency; HF: High-frequency, Norm: Normalized; PNN50: Percentage of di erences between adjacent normal R-R intervals more than 50 ms; RMSSD: Square root of the mean of the sum of the squared di erences between adjacent normal R-R intervals; HR: Heart rate. B=Basal; 8: Eight-week evaluation; 10: 10 weeks evaluation.

This study compares reverse and traditional training periodization effects on triathletes' performance.