Changes in Anthropometric and Performance Parameters in High-Level Endurance Athletes during a Sports Season

anthropometric and performance parameters related to aerobic metabolism are associated with performance in endurance runners and are modi ed according to the training performed. The objective of this study was to investigate the ergospirometric and body composition changes in endurance runners during a sports season in relation to their training. Twenty highly trained men endurance runners performed an incremental test until exhaustion (initial, and at 3, 6, and 9 months) on a treadmill to determine maximal oxygen consumption (VO 2max), second ventilatory threshold (VT 2), and their associated running speeds. Skinfolds, perimeters, and weights were measured. No changes were obtained in VO 2max or VT 2during the study, although their associated running speeds increased (p< 0.05) after 3 months of the study. Decreases in fat mass (p< 0.05) and muscle mass (p< 0.05) were observed at the end of the season (9 months). Changes occurred in the different skinfolds according to the characteristics of the training performed during

were obtained in VO 2max or VT 2during the study, although their associated running speeds increased (p< 0.05) after 3 months of the study. Decreases in fat mass (p< 0.05) and muscle mass (p< 0.05) were observed at the end of the season (9 months). Changes occurred in the different skinfolds according to the characteristics of the training performed during the season. In conclusion, vVO 2max and vVT 2increase with a greater volume of kilometres trained and can be adversely affected by loss of muscle mass. Keywords:skinfolds; fat mass; muscle mass; maximal oxygen consumption; endurance 1. Introduction Different physiological and anthropometric parameters have been investigated for being associated with performance in endurance runners [1,2]. Parameters related to aero- bic function such as maximal oxygen consumption (VO2max) and the second ventilatory threshold (VT2) or anaerobic threshold (AT) have been identi ed as determining factors in endurance runners [3]. Performing an incremental stress test to voluntary exhaustion with gas exchange measurement is the most commonly used method to determine these parameters in endurance runners [4]. Highly trained elite endurance runners present high values of VO2max [5], although it is not a determining parameter for performance prediction in homogeneous groups [6]. Previous studies reported no difference in VO2max values between middle- and long- distance (3000–10000 m) well-trained runners [7,8]. Running speed at maximal oxygen consumption (vVO2max) has been established as a better performance predictor, since highly trained endurance runners can maintain this speed from four to seven minutes, although there is variability among subjects [9]. Another performance factor is VT2, which shows the ability to sustain the highest percentage of VO2max for a long time [10]. Research in high level endurance runners has reported higher values of VT2and its associated velocity (vVT2) than in recreational runners; therefore, high-level runners can maintain faster running speeds for longer [11,12]. Likewise, endurance runners must have adequate anthropometric and body compo- sition parameters, since an excess of weight without an increase in strength will cause a decrease in running speed [8]. Several anthropometric and body composition values are Int. J. Environ. Res. Public Health2021,18, 2782.

in recreational runners; therefore, high-level runners can maintain faster running speeds for longer [11,12]. Likewise, endurance runners must have adequate anthropometric and body compo- sition parameters, since an excess of weight without an increase in strength will cause a decrease in running speed [8]. Several anthropometric and body composition values are Int. J. Environ. Res. Public Health2021,18, 2782.

Int. J. Environ. Res. Public Health2021,18, 2782 2 of 11 associated with running performance, such as body weight, fat mass, muscle mass, calf skinfold, and sum of 6 (å6) skinfolds [1,7,13,14]. An appropriate energy intake in runners is crucial to preserve optimal body function and maintain a lean body composition to enhance performance [15]. The use of question- naires that collect data on the foods and beverages consumed by the subjects over several days to determine the nutritional intake is common in athletes [16]. Periodisation of the different training loads that runners perform, changes in volume and intensity during the sports season, in uence the adaptations and performance in the runners [17]. There are few longitudinal studies in homogeneous groups of runners that in- clude different evaluation moments and have investigated the changes in anthropometrics and performance parameters throughout a sports season as a consequence of the training sessions performed [18]. Therefore, the main objective of this study was to measure the changes in body composition, anthropometric, and performance parameters related to aerobic function by measuring skinfold thickness and performing an incremental test until exhaustion in highly trained endurance men runners at four evaluation points (each 3 months) throughout a sports season in relation to the volume and intensity of km trained per week. 2. Materials and Methods 2.1. Participants Twenty highly trained men endurance runners (23 3 years old; height: 1.77 0.05 m) participated in the research and were studied at four time points during the athletic season, in the rst week of October, January, April, and July. All subjects participated voluntarily, were informed about the purpose of the study, and gave their written consent. The study was approved by the Ethics Committee of the University of Extremadura (Register number 52/2012), and all procedures were in accordance with the Helsinki Declaration ethical guidelines updated at the World Medical Assembly in Fortaleza (Brazil) in 2013 for investigations with human subjects. Athletes were recruited from different training groups from the same region. They competed in cross country, road races, and 1500 to 5000 m race modalities, and they had a personal

number 52/2012), and all procedures were in accordance with the Helsinki Declaration ethical guidelines updated at the World Medical Assembly in Fortaleza (Brazil) in 2013 for investigations with human subjects. Athletes were recruited from different training groups from the same region. They competed in cross country, road races, and 1500 to 5000 m race modalities, and they had a personal best of 3:37.79–4:08.24 for 1500 m and 13:11.01 and 15:10.35 in 5000 m. The inclusion criteria were to have been training regularly for at least 5 years, performing at least 6 sessions and 70 km per week (km/w) during the season, and to have competed in regional, national, and international events. Exclusion criteria were not having trained for extended periods due to injury or any other reason, or having changed nutritional habits and diet. Before the study, the runners were informed about the energy and macronutrient intake guidelines for athletes established by the American College of Sports Medicine [19] that they had to follow according to the training carried out and their personal characteristics. 2.2. Training Characteristics All the runners performed a traditional periodisation with two competitive periods (Figure). The rst competitive period for the runners began in January through February, when runners competed in cross-country competitions, and the second one was in June and July, when runners competed in track and eld events of between 1500 and 5000 m. The rst preparatory period began in October through December, and the second one was from March to May. In the preparatory periods, runners trained high volumes of km/w at low and moderate intensities. In competitive periods, the runners reduced the volume of km/w but trained at high intensities. Before the initial measurement, the athletes had completed four weeks of adaptive training after the rest period of the previous season. The characteristics of the weekly and accumulated training during the season are detailed in Table. A pulsometer equipped with GPS was used to track the training loads during the season. Runners used their usual equipment (Vantage M, Polar, Finland; 5, Suunto,

training after the rest period of the previous season. The characteristics of the weekly and accumulated training during the season are detailed in Table. A pulsometer equipped with GPS was used to track the training loads during the season. Runners used their usual equipment (Vantage M, Polar, Finland; 5, Suunto,

Int. J. Environ. Res. Public Health2021,18, 2782 3 of 11 Finland; Forerunner 235, Garmin, USA). Runners used the clocks daily in their workouts, and weekly intensity and volume data were collected in the tests. Figure 1.Periodisation during the season. Table 1.Training loads in the runners during the season. Training Load Initial 3 Months 6 Months 9 Months Total (km/week) 85.12 13.1 106.52 15.78 93.53 14.56 74.55 13.8 >VT 2 (km/week) 4.10 0.5 12.68 2.03 18.66 2.8 16.45 3.1 VT 2 (km/week) 81.02 12.6 93.84 13.75 74.87 11.4 58.10 10.7 VT2intensity below second ventilatory threshold; >VT2intensity above second ventilatory threshold. Depending on the period of the season, they also performed two weekly sessions of resistance training with a high volume (3–5 sets of 8–25 repetitions of whole-body exercises) and moderate intensity (30–70% of 1 Repetition maximum and plyometric training. 2.3. Nutritional Assessment The macronutrient composition of the participants' diets was determined using a database [20]. The athletes completed a 3-day nutritional questionnaire on two working days and one weekend day, where they indicated the amount (in grams) of all food ingested on those days. 2.4. Anthropometric Measures The participants' characteristics were measured in the morning and always at the same time (9:00–10:00). Participants were informed that they should go to the laboratory well hydrated after an overnight fast and refrain from intense training or competition for at least 72 h prior to testing. Body weight was measured to the nearest of 0.01 kg using a calibrated electronic digital scale (Seca 769, Hamburg, Germany). Height was measured with an accuracy of 0.1 cm using a wall mounted stadiometer (Seca 220, Hamburg, Germany). Arm and leg perimeters were obtained (in a relaxed 90ºposition) with an accuracy of 1 mm using a tape (Seca 212. Hamburg, Germany). Skinfold thicknesses (abdominal, suprailiac, tricipital, subscapular, thigh, and leg) were measured with a Harpenden calliper (Holtain skinfold calliper, Crosswell, UK). Measurements were taken three times by an expert in kinanthropometry techniques (accredited level 1) who had previously shown a test–retest reliability of r > 0.9, in accordance with the recommendations of the International Society for the Advancement

212. Hamburg, Germany). Skinfold thicknesses (abdominal, suprailiac, tricipital, subscapular, thigh, and leg) were measured with a Harpenden calliper (Holtain skinfold calliper, Crosswell, UK). Measurements were taken three times by an expert in kinanthropometry techniques (accredited level 1) who had previously shown a test–retest reliability of r > 0.9, in accordance with the recommendations of the International Society for the Advancement of Kinanthropometry [21]. Body composition was calculated according to the indications of the Spanish Kinanthropometry group [22].

Int. J. Environ. Res. Public Health2021,18, 2782 4 of 11 2.5. Physical Performance Evaluation After taking anthropometric measurements, to measure the runners' ergospirometric parameters and performance, they carried out an incremental test until exhaustion on a treadmill (Powerjog, Birmingham, UK) with an ergospirometer system equipped with a gas analyser (Metamax, Cortex Biophysik, Germany). A pulsometer (Vantage M, Polar, Finland) was used to evaluate the maximal heart rate. After a 10 min warm-up, the runners initiated the test at a speed of 10 km/h, which increased by 1 km/h every 400 m until voluntary exhaustion. VO2max was determined according to the following criteria: there had to be a plateau in oxygen uptake (VO2), an increment in carbon dioxide (CO2) elimination, and an increment in the ventilatory volume (VE) induced by the increases in the test velocity and the respiratory exchange ratio (RER) had to exceed 1 [23]. The aerobic threshold (VT1) and VT2were determined according to the three-phase model to monitor training [24]. 2.6. Statistical Analysis Statistical analysis was carried out with IBM SPSS Statistical software version 21.0 (IBM Co., Armonk, NY, USA). The results are expressed as x sd, where x is the mean value and sd is the standard deviation. Before the analyses, all variables were checked for normality of distribution with Kolmogorov–Smirnov tests. The data were analysed by repeated measurements analysis of variance (ANOVA) and with the Bonferroni post hoc test for moment/period as the categorical variable. Partial eta squared ( p 2 ) was used as an effect size measure of ANOVA. Threshold values for assessing magnitudes of standardised effects were p 2 0.01, p 2 0.06, and p 2 0.14 for small, medium, and large, respectively [25]. The equality of variances between the differences was assessed with Mauchly's test of sphericity. When sphericity was violated, Greenhouse–Geisser corrected p-values were used. A simple linear regression model was used to determine associations between ergospirometric and body composition parameters. Pearson's correlation coef cient (r), the coef cients, and determination coef cients (R 2 ) were calculated. Ap 0.05 was considered statistically signi cant. 3. Results Nutritional intake of energy

with Mauchly's test of sphericity. When sphericity was violated, Greenhouse–Geisser corrected p-values were used. A simple linear regression model was used to determine associations between ergospirometric and body composition parameters. Pearson's correlation coef cient (r), the coef cients, and determination coef cients (R 2 ) were calculated. Ap 0.05 was considered statistically signi cant. 3. Results Nutritional intake of energy and macronutrients in the runners during the season is shown in Table. There were no signi cant differences in energy and macronutrient intake during the season. Table 2.Energy and macronutrient intake in the runners during the season. Parameters Initial 3 Months 6 Months 9 Months p 2 Energy (kcal/d) 2855 511.3 2795.4 427.2 2902.4 522.5 3108.7 770.2 0.07 CH (g/kg/d) 5.26 1.21 5.28 1.14 6.25 1.38 6.13 1.50 0.03 Protein (g/kg/d)1.73 0.79 1.69 0.35 1.85 0.53 1.89 0.63 0.05 Lipids (g/kg/d) 1.78 0.40 1.63 0.28 1.58 0.52 1.72 0.74 0.05 CH: carbohydrates. Table ated with VO2max and VT2, as well as the performance results obtained in the different incremental tests of the runners during the sports season.

Int. J. Environ. Res. Public Health2021,18, 2782 5 of 11 Table 3.Ergospirometric and performance parameters of the runners. Parameters Initial (M SD) 3 Months (M SD) 6 Months (M SD) 9 Months (M SD) p F p 2 (CI 95%) SEM (CI 95%) SEM (CI 95%) SEM (CI 95%) SEM VO 2max (mL/kg/min) 68.02 4.73 (65.80–70.23) 1.05 67.72 9.76 (65.14–71.83) 1.59 68.65 7.14 (65.66–72.06) 1.53 68.80 7.50 (65.29–72.31) 1.67 0.306 1.269 0.07 VT 2(% VO 2 max) 91.02 2.43 (89.86–92.19) 0.55 91.49 3.59 (91.02–94.48) 0.82 91.34 3.08 (89.85–92.46) 0.62 90.96 2.07 (89.27–92.05) 0.42 0.675 0.511 0.04 vVO 2max (Km/h) 20.20 0.98 (19.68–20.61) 0.22 20.90 1.13 ** (20.24–21.33) 0.26 20.71 1.22 ** (20.15–21.27) 0.26 20.67 1.75 (19.82–21.47) 0.39 0.095 2.071 0.12 vVT 2 (Km/h) 19.27 0.80 (18.45–20.06) 0.19 20.00 0.89 ** (19.19–20.36) 0.16 19.65 1.27 (18.81–19.89) 0.21 19.41 1.65 (18.14–20.33) 0.28 0.182 1.889 0.08 RER 1.05 0.03 (1.03–1.07) 0.00 1.05 0.05 (1.03–1.07) 0.00 1.05 0.04 (1.02–1.07) 0.01 1.04 0.04 (1.03–1.06) 0.01 0.877 0.088 0.02 Maximum heart rate 190.6 9.45 (185.4–193.7) 1.97 192.9 8.01 (190.9–198.3) 1.77 193.3 8.95 (189.1–196.8) 1.85 193.8 7.52 (189.1–197.3) 1.95 0.786 0.485 0.04 Distance (m) 4543.3 42.1 (4346–4740) 94.16 4608.6 49.8 (4338–4800) 109.9 4677.0 56.2 (4450–4970) 124.77 4720.7 65.9 (4416–5025) 145.54 0.423 0.790 0.06 Time (min) 20.30 1.85 (19.45–21.18) 0.41 21.00 2.17 (19.98–22.13) 0.51 21.10 2.04 (20.17–21.99) 0.43 20.70 2.67 (19.47–21.97) 0.59 0.709 0.141 0.03 RER: respiratory exchange ratio; VO2max: maximal oxygen consumption; VT2: second ventilatory threshold; vVO2max: running speed at maximal oxygen consumption; vVT2: running speed at second ventilatory threshold; **p< 0.01 difference between 0 vs. 3–6; SEM: standard error of the mean; CI: con dence interval;p: value intergroup. Table four time points during the sports season. Table 4.Body composition parameters of the runners during the season. Parameters Initial (M SD) 3 Months (M SD) 6 Months (M SD) 9 Months (M SD) p F p 2 (CI 95%) SEM (CI 95%) SEM (CI 95%) SEM (CI 95%) SEM Body mass (kg) 65.35 7.46 (61.85–68.83) 1.66 65.31 7.53 (61.26–68.42) 1.70 64.58 7.21 # (61.69–68.37) 1.60 64.59 7.47 # (61.09–68.08) 1.67 0.030 2.557 0.21 Bone mass (kg) 11.96

Parameters Initial (M SD) 3 Months (M SD) 6 Months (M SD) 9 Months (M SD) p F p 2 (CI 95%) SEM (CI 95%) SEM (CI 95%) SEM (CI 95%) SEM Body mass (kg) 65.35 7.46 (61.85–68.83) 1.66 65.31 7.53 (61.26–68.42) 1.70 64.58 7.21 # (61.69–68.37) 1.60 64.59 7.47 # (61.09–68.08) 1.67 0.030 2.557 0.21 Bone mass (kg) 11.96 1.02 (11.49–12.44) 0.22 11.84 1.09 (11.27–12.34) 0.25 11.96 1.13 (11.47–12.48) 0.24 11.98 1.09 (11.4612.48) 0.24 0.950 0.096 0.02 Fat mass (kg) 5.59 1.27 (4.99–6.17) 0.28 5.41 1.10 (4.83–6.10) 0.25 5.25 0.86 * (4.89–5.68) 0.18 5.22 0.99 * (4.87–5.77) 0.22 0.012 2.737 0.29 Muscle mass (kg) 32.12 4.09 (30.20–34.03) 0.91 32.26 4.09 (30.04–33.90) 0.91 31.71 4.00 (30.12–33.85) 0.89 31.72 4.16 * (29.77–33.26) 0.93 0.072 2.433 0.15 Abdominal S. (mm) 9.70 2.65 (8.46–10.93) 0.59 9.87 2.82 (8.45–11.24) 0.66 8.22 1.86 ** (7.45–9.16) 0.40 8.84 2.34 # (7.73–9.93) 0.52 0.021 2.776 0.26 Suprailiac S. (mm) 5.68 1.27 (5.08–6.27) 0.28 6.14 0.88 (5.67–6.52) 0.20 5.51 0.98 (5.05–6.08) 0.21 5.99 1.17 (5.44–6.53) 0.26 0.276 1.749 0.08 Subscapular S. (mm) 8.23 1.53 (7.51–8.94) 0.34 8.40 1.94 (7.45–9.37) 0.45 7.87 1.39 (7.26–8.50) 0.29 8.20 1.66 (7.41–8.97) 0.37 0.785 0.355 0.04 Tricipital S. (mm) 6.24 1.58 (5.50–6.97) 0.35 6.06 1.34 (5.36–6.68) 0.31 5.98 1.35 (5.40–6.61) 0.28 6.52 1.72 (5.70–7.32) 0.38 0.689 0.292 0.03 Front Thigh S. (mm) 8.48 3.12 (7.01–9.93) 0.69 8.76 2.88 (7.30–10.14) 0.67 8.67 2.64 (7.52–9.87) 0.56 8.18 2.30 (7.10–9.25) 0.51 0.717 0.169 0.03 Calf S. (mm) 8.26 3.15 (6.77–9.54) 0.65 6.70 2.09 ** (5.59–7.62) 0.48 8.65 2.44 ## (7.54–9.53) 0.47 7.74 2.15 * ## (6.73–8.74) 0.48 0.023 2.617 0.26 å6 skinfolds (mm) 46.59 11.11 (41.35–51.61) 2.44 45.92 8.80 (41.30–50.14) 2.10 44.89 7.60 (41.62–48.41) 1.62 45.46 8.54 (41.46–49.44) 1.90 0.764 0.293 0.04 Arm P. (cm) 27.61 2.37 (26.49–28.71) 0.53 27.54 2.49 (26.30–28.76) 0.58 27.11 2.39 (26.07–28.19) 0.50 27.09 2.67 (25.83–28.33) 0.59 0.513 0.433 0.05 Leg P. (cm) 36.20 2.01 (35.25–37.14) 0.44 36.25 1.88 (35.22–36.96) 0.41 36.14 1.76 (35.44–37.11) 0.40 36.03 1.99 (35.09–36.95) 0.44 0.575 0.431 0.04 S: skinfold; P: perimeter;å6 skinfolds: sum six skinfolds. *p< 0.05 difference between 0 vs. 3–6–9; **p< 0.01 difference between 0

The study examines the impact of training on endurance runners' body composition and performance metrics.