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JEPonline

Differences between Gender and Biological Agein Heart Rate Deflection Point during ProgressiveMaximal Intermittent Testin Young Athletes

Gislaine Cristina de Souza1,2,Ana Carla Santos Mariano2,Carla Caroline de Souza Rodrigues2, Pablo Ramon Domingos2,3, Raul Osiecki1, Fernando Roberto de Oliveira2

1Center for the Study of Physical Performance, Federal University of Paraná, Paraná, Brazil, 2Nucleus of Human Movement Studies, Department of Physical Education, Federal University of Lavras, Minas Gerais, Brazil, 3Motor Evaluation Laboratory, Federal University of Juiz de For a, Minas Gerais, Brazil

ABSTRACT

Souza GC, Mariano ACS, Rodrigues CCS, Domingos PR, Osiecki R, De Oliveira FR. Differences between Gender and Biological Age in Heart Rate Deflection Point during Progressive Maximal Intermittent Test in Young Athletes.JEPonline2016;19(1):107-113.The purpose of this study was to compare the variables found in heart rate deflection point (HRDP) through the Carminattis’s Test (TCar)between young female and male in relation to maturation periods. Thirty five athletic teenagers (19 males, age = 16.6 ±2.4 yrs and 16 females, age = 15.3 ± 2.5 yrs) underwent a progressive maximal intermittent field test after determination of sexual maturation. In order to identify the physiological transition points, the differences of the heart rate (HR) values derived from linear and polynomial fits using all HR points were calculatedusing the Dmax method. TheVelocity Peak (VP)and the velocity measured on HRDP were lower in girls than in boys (P<0.05) in the pubertal and after-pubertal periods. The occurrence intensity on HRDP was also lower in the pre-pubertal boys compared to the after-pubertal boys (P<0.05). The percentage of HRpeak on pubertal girls was lower thanafter-pubertal period girls (P<0.05). No significant differences were found in HR peak or in HR and %VPobtained at HRDP(P<0.05). The results suggest that the maturation period associated with gender plays an important role in physiologicalvariables identified in TCar.

Key Words: Heart rate, Carminatti’s test, Maturation, Anaerobic threshold

INTRODUCTION

The evaluation of the anaerobic threshold (AT) has been widely used to determine aerobic fitness in intermittent and endurance sports. Some authors have demonstrated that the heart rate deflection point (HRDP) is found in similar intensities to the lactate threshold during a progressive test. Thus, the HRDP is reported as a noninvasive, inexpensive and easily applicable tool to determine the anaerobic threshold(7,10).

Alternatively,maximal intermittent field tests, likeCarminattis’s Test (TCar), have been proposed for the identification of HRDP. These tests are cheaper and more specific (5). Carminatti (4) reported that the HRDP, identified by the Dmáx-Kara method, during the TCar test is similar to maximum lactate steady state. Besides,in runners, the Velocity Peak (VP), the Peak Heart Rate (HRpeak) and the final lactate are similar between the TCar and the continuous track progressive test(VAMEVAL)(6).

Lucía and colleagues (11) reported that the HRDP depends onthe contraction of left ventricle. This action happens in response to the function of circulating catecholamines and potassium, and that it has a relation with the efficiency of cardiac function during the effort test. Ferreira et al.(9)identified that in young runners, the intensity of occurrence of the HRDP in relation to VPmay be lower in boys than in girls. This finding may be justified bythe different anaerobic capacity related to gender.

However, the identification of a physiologic consideration in regards to HRDP as it relates to different biological periods and genders is unclear in the literature.Ré (12) affirms that usually after the puberty, girls do not improve their performance in sport in the same linearity as boys do. After the menarche, the human physical characteristics and morphofunctional fitness are modified (13). Thus, it is plausible the hypothesis of different levels of aerobic fitness accordingly to the maturation age in both genders after the identification of AT. Thepurpose of this research was to compare the variables found in HRDP through the TCar test(5)between young female and male subjects in relation to maturation periods.

METHODS

Subjects

Thirty-five young track and field athletes agreed to participate inthisstudy (19 males, age = 16.6 ±2.4 yrs, weight = 61.7 ± 12 kg, height = 172.4 ± 8.6 cm and 16 females, age = 15.3 ± 2.5 yrs, weight = 52.5 ± 8.5 kg, height = 164.9 ± 8.1 cm).The subjects had a minimum of 1 yr of training to prepare for competition at the state and national levels. The subjects and their parents were informed about the methodological aspects, risks, and benefits of this study.

Procedures

Following the subjects’ signing of the consent form to participate in the study, and the approval of the Ethics Committee, the evaluation of the anthropometry and the sexual maturity wascarried out. The analysis of sexual maturation was been done following the Tanner criteria (16)through self-evaluation of pictures of Stages of Sexual Maturation. The first menstruation period was recorded and, then, the subjectsperformed the TCar test (5)in a multi-sports court.

Anthropometric Assessment

Body mass was determined using the digital scale (Britânia®). Stature was obtained through a professional estadiometer (Sanny®).

TCarProtocol

The athletes were instructed to avoid intense physical exercise for 24 hrs prior to the test. They were also told not to eat 2hrs before the test. The test was preceded by a warm-up that consisted of 10 minof jogging followed by 5 min of stretching. In males and females under 15 yrs of age, the initial distance and velocity were 15 m and 9 km·h-1(12 sec), respectively. In males and females older than 15 yrs of age, the initial distance and velocity were 20 m and 12 km·h-1(12 sec), respectively. After, at each stage was incremented 1m to the initial distance (0.6 km·h-1). Between each run there was a space of 2.5 m and 6 sec for recovery. Each stage lasts 90 sec of shuttle run. The velocity was controlled by an audible beep of the Sphera Portable Server software. Exhaustion was determined when a subject failed twice consecutively to performthe shuttle run at the beep time. The VP was determined for the last distance completed. The Heart Rate (HR) was registered using a HR portable monitor (Polar Electro Oy, FI – 90440, Kempele, Finland) at the end of each stage.

Heart Rate Deflection Point (HRDP)

The HRDP was identified using the method proposed by Kara et al.(10).A HR of 140 beats·min-1or higher was plotted in each stage versus the corresponding velocity. The transition point was identified as the maximal distance between a third order polynomial fitpassing through all HR points and a linear fit connecting the two extreme values.

Statistical Analysis

The data normality was tested using the Shapiro-Wilk test. The ANOVAtwo-way test with Bonferroni'spost hoc was used for the determination of differences among the variables obtained in HRDP between the males and females during the maturation period pre-pubertal, pubertal, and after-pubertal. Only the percentage of HR peak measured on HRDP was noted non-parametric of which the Kruskal Wallis Test and Mann-Whitney's U Test were used. Significance was set at P≤0.05.

RESULTS

The HRpeak and the VP are described on Table 1. The velocity and heart rate in absolute and relatives terms for the subjects’ HRDP pursuant with the maturation period in the females and males are presented in Table 2.

Table 1. Heart Frequency of Peak and Velocity Peak were found on TCarPursuant with the Maturation Period in Girls and Boys (Mean ± SD).

Girls / Boys
PP
(n=5) / P
(n=7) / AP
(n=4) / PP
(n=3) / P
(n=8) / AP
(n=8)
HR peak (beats·min-1) / 202± 19 / 201± 6 / 197± 5 / 206± 13 / 203± 8 / 197± 5
Velocity peak (km·min-1) / 14.0 ± 1.1 / 13.6± 1.2a / 14.6± 0.9b / 15.9± 0.8 / 15.9± 1.6 / 17.3± 1

BP = Pre-pubertal; P = Pubertal; AP = After-pubertal; HR = Heart rate; VP= Velocity peak; Significant differences (P≤0.05):abetween P Girls x P Boys, P=0.015; bbetween AP Girls x AP Boys, P=0.014

Table 2. The Velocity and Heart Rate in Absolutes and Relatives Terms found on HRDP Pursuant with the Maturation Period in Girls and Boys (Mean ± SD).

HRDP Girls / HRDP Boys
PP
(n=5) / P
(n=7) / AP
(n=4) / PP
(n=3) / P
(n=8) / AP
(n=8)
HR (beats·min-1) / 190± 10 / 187± 10 / 190± 10 / 190± 14 / 187± 11 / 183± 6
%HRpeak / 96.3± 4.7 / 93.2± 2.7† / 96.5± 2.5 / 92.3± 3 / 92.3± 5.1 / 92.9 ± 3.4
Velocity (km·min-1) / 11.5± 0.5 / 11.0± 1.1a / 12.5± 0.6b / 12.4 ± 0.3* / 13.1± 1.3 / 14.3± 0.6
%VP / 84.6± 6.9 / 80.9± 4.1 / 86.2± 7.9 / 78± 5.8 / 82.5± 5.9 / 83.1± 3.3

BP = Pre-pubertal; P = Pubertal; AP = After-pubertal; HR = Heart rate; VP= Velocity peak;HRDP =Heart rate deflection point. Significant differences (P≤0.05):abetween P Girls x P Boys, P=0.002; bbetween AP Girls x AP Boys, P=0.041; *between PP Boys x AP Boys P = 0.05; †between P Girls x AP Girls, P=0.05

DISCUSSION

The purpose of this study was to compare the variables identified in HRDP duringa maximal intermittent progressive test (TCar) in young female and male athletes in relation to maturation periods. The main findings were the differences: (a) in VP between the males andthe females' maturation periods; (b) in velocity measured on HRDP between the males and the females' maturation periods; (c) in pre-pubertal (PP)versus after-pubertal (AP) periods in the males; and (c) in percentage HRpeakin the females' pubertal (P) versus after-pubertal (AP) periods.

The findings indicate that although HRpeak was similar in the males and females, the VP was significantly lowerin the females versus the males on the P periods (13.6 ± 1.2vs. 15.9 ± 1.6 km·h-1, respectively) as was the APperiods (14.6 ± 0.9 vs.17.3 ± 1 km·h-1, respectively). These findings are in agreement with the Ferreira's et al.(9)in which the maturation period was not considered, but the authors identified that the VP was lower in the females than in the males (13.4 ± 0.8 vs. 15.4 ± 1.7 km·h-1, respectively). The primaryexplanation is likely to be the subjects’ hormonal changes, such as the increase of testosterone in the males and the increase of progesterone and estrogen in the females. These hormonal changes favor an increase in the females’ body fat (specially the breast and hip regions) that may have lowered the performance in the female subjects. Also, the male subjects’ higher muscle massafter puberty may provide an advantage in sports (12). Interestingly, while Bõhme (2)showed that there was not a direct influence of the sexual maturation in track and field practitioners, the female athletes’ performance may be influenced by body fat and chronological age during endurance test of 9 min.

The velocity in HRDP was lower in females versus the males in P periods (11 ± 1.1 vs.13.1 ± 1.3 km·h-1, respectively) and AP (12.5 ± 0.6vs.14.3 ± 0.6 km·h-1, respectively)and, thereby, was lower in the males’ in PP than AP. These results indicate that malesexperienced anaerobic threshold at a higher velocity that was close to the VP.In other words, they have a better aerobic performance (7). However, the girls remained in similar levels, with lesser influence of the sexual maturation on performance improvement (12). In opposition,Armstrong (1)didn’t find changes in absolute VO2 relative to sexual maturation in relation to the gender. Hence, thesechanges may be associated with the subjects’ genetic predisposition to this variable.

While the females’percentageof HR peak relativeto HRDP was lower in the P period than in the AP period, the absolute values were similar. This would appear to be a change in left ventricular function among trained and untrained teenager of female gender(15). Otherwise, the increased production of estrogen that is responsible for female sexual characteristics also acts on the cardiovascular system (13). Nonetheless, therewas not a significant difference between the males and females in absolutes and relatives values of the HR identified on anaerobic threshold. This findingis in agreement with Rowland's et al. (14) study that didnot find differences between males and females in ventricular function during the exercise.

Regarding HRDP in young athletes, the results in the present studysupports the current literature. In particular, Ferreira-Júnioret al.(8)found a HR in TCar of 185 ± 9 beats·min-1 (92 ± 2%) for the male subjects and, in addition,Ferreira et al.(9)reported during a continuous progressive field test a HR of 186 ± 11 beats·min-1 (90,8 ± 5%) for males and 187 ± 9 beats·min-1 (94.2 ± 3.1%) for females. Also, Buchheitet al. (3)identified a HR during a treadmill test of 187 ± 9 beats·min-1 (92.1 ± 0.4%). Therefore, while the HRDP identified in an intermittent field test can be considered an assessment of aerobic fitness of athletes, there are no comparisons of the HRDP with the athletes' biological age (BA). Biological age must be considered because it can cause differences in some predictors of HRDP, especially between the genders and the young maturation periods.

Limitation of the Study

The lack of measurement of blood lactate for the identification of lactate threshold was a limitation in the present study. More studies that measure lactate threshold in young athletes are needed.

CONCLUSIONS

The variables in the intermittent progressive test show different responses according to the maturation period in relation to gender on VP and on the velocity of occurrence of HRDP between the males and females’ maturation periods on velocity measured on HRDP inpre-pubertal males versus after-pubertal periods and on percentage of HRpeak on females’ pubertal versus after-pubertal periods. The TCartest can be used to for identify the anaerobic threshold in young track and field athletes.

Address for correspondence: Gislaine Cristina de Souza, Departament of Physical Education of Federal University of Parana, Parana, Brazil. Street Sagrado Coração de Jesus. Phone (55) 41 9145-4389. Email:

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