uccess in the athletic performance is related to the several factors, one of which is training [1]. Although training is done with different physical, technical and tactical goals, but in endurance disciplines, especially in athletics, the role of physical and physiological factors is very prominent. On this basis, some endurance instructors believe that people with higher maximal oxygen consumption are able to perform better [1]. The role of these factors is more prominent in trained athletes who have achieved maximum oxygen consumption [2]. The importance of endurance and strength and the relationship between them in sports activities is evident, and when strength and endurance are discussed, physiological and functional issues also arise. The effects of training on the structure and function of the heart depend on the type, intensity and duration of exercise, initial physical fitness, heredity and gender [5]. 
The effect of resistance training on the endurance has also been studied in the recent years. However, resistance training is not commonly used for endurance runners and it seems that no more than 50% of the maximum oxygen consumption is included in the strength training [9], and improving maximal oxygen consumption through this type of training is unlikely; however, some evidence suggests that adding resistance training to an aerobic exercise program has a positive effect on the performance of endurance athletes [10].
Due to the lack of research on cardiac adaptation with endurance and resistance training in elite runners and also on the effect of these trainings on physiological and functional factors and the record of elite runners, more study is needed. Therefore, the present study seeks to address the main question of whether the resistance and endurance training programs affect the physiological, functional and record factors of elite runners? And is there a difference between these two training programs? This research can take an effective and small step to identify and solve the problems of runners, and by presenting the results to the community, can help prevent and reduce problems.

This is a quasi-experimental study with Pre-test and Post-test design. The study population consisted of all elite male runners in North Khorasan province of Iran who were members of the Bojnourd city athletics team. Among them, 22 volunteers were selected by convenience and purposive sampling methods. First the study objectives and process were explained to them. The samples were then randomly divided into two groups of resistance training (n=11) and endurance training (n=11). Height of subjects was measured by a stadiometer (Saca, Saca Inc., Germany) with an accuracy of 5 mm, hip and waist circumference by a tape measure (Mabis, Japan) with a sensitivity of 5 mm, and body fat percentage and weight by using Bioelectric impedance device (Inbody, Inbody Inc., South Korea) with a sensitivity of 100 g. Subjects were allowed to enter the study after cardiovascular examination, blood pressure measurement and electrocardiography by a physician. 
The Bruce protocol on a treadmill was used to estimate the maximum oxygen consumption. The maximum strength of the subjects was measured using RM1 test according to McGuigan et al. method [18]. To measure the subjects' muscular endurance, McGill’s torso muscular endurance test was used in four modes: trunk flexion, trunk extension, right-side bridge, and left-side bridge. Total endurance in the all four directions was considered as final score. To measure the balance, the stork balance test was used according to its standard procedure. This test was performed separately on the dominant and non-dominant legs [19]. At the end, the subjects’ record was set using the 3000 meters running test. For this purpose, the subject runs 7.5 laps around the 400-meter track.
The training protocol included aerobic (endurance) and resistance trainings for 8 weeks, 3 sessions per week, each for 60 minutes. The aerobic training consisted of running on a treadmill for 21 minutes with intensity equal to 60-70% of the heart rate reserve. Training intensity was controlled by a heart rate monitor (POLAR, Finland). Pyramid model was used in resistance training. In each session, after 15 minutes of warming up, they performed each movement in 7 sets: 6 repetitions ×80%, 3 repetitions ×90%, 3 repetitions ×90%, 3×90% repetitions, 3 repetitions ×90%, 3 repetitions ×90%, and 6 repetitions ×80%, respectively with a 5 minute interval between each movement. The workouts included leg flexion, leg extension, leg press, squat, lat stretch, chest press, cross-body dumbbell, biceps, triceps, and sit-ups [20]. 
The collected data were analyzed by SPSS V. 21 software. After ensuring the normality of data distribution by Shapiro-Wilk test and the equality of variances by Levene’s test, repeated measures ANOVA was used for within-group and between-group comparisons. Significance level was considered P<0.05.

The results in Table 1 showed that within-group and between-group differences in heart rate, blood pressure, muscle strength, muscle endurance, balance and 3000-meter record were significant (P<0.05).


 

Runners’ heart rate and blood pressure increase after resistance and endurance training, which is due to the duration, nature and intensity of trainings with short rest intervals between sessions. It is suggested that these factors of trainings be moderated to reduce the muscle fatigue of runners.

Prior to study, a written informed consent was signed by the participants after explaining the study objectives and methods. They were assured of the confidentiality of their information, and were free to leave the study at any time.

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Implementation: Ali Asghar Saberi, Mehrdad Fathi; Final review of the manuscript: All authors; Conceptualization: Mehrdad Fathi; Data analysis: Keyvan Hejazi; Performing the study and compiling the manuscript: Keyvan Hejazi.

The authors declare no conflict of interest.

 

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