Relationship of simple reaction time and aerobic and anaerobic capacities with performance of recreational adult orienteers

This study aimed to examine the effects of Simple Reaction Time (SRT), Maximal Oxygen Uptake ( O2max) and Maximal Anaerobic Power (Pmax) on the performance of category A recreational adult orienteers of both sexes. Sixteen subjects (8 men and 8 women; age: 30 ± 4 and 27 ± 5 years; body mass 78.8 ± 5.9 and 69.2 ± 10.4 kg; SRT: 1.391 ± 0.19 and 1.317 ± 0.25 ms; O2max: 67.4 ± 3.22 and 48.5 ± 8.28 ml.kg-1.min-1; Pmax: 675.0 ± 149.6 and 458.4 ± 88.62 W), were submitted to three evaluation sessions: sample characterization (1st session); SRT Reaction Time Task v.2.0, O2max, and Pmax Running Anaerobic Sprint Test (2nd session); official Orienteering test (3rd session). Results of comparison (Student’s T-test) and relation (Pearson Product-Moment Correlation and Multiple Linear Regression) tests showed significant relationships between independent variables and performance. Pmax presented strong predictive power in the male group (41%), followed by SRT (32%) and O2max (27%). In the female group, SRT was the most predictive variable (54%), followed by O2max (32%) and Pmax (12%). These findings indicated that SRT, O2max, and Pmax are variables predictive of performance in recreational category A orienteers. Specifically in recreational orienteers with high cardiorespiratory capacities, Pmax seems to be the main predictor variable. Conversely, SRT becomes the variable with the greatest predictive power.


INTRODUCTION
Motor learning is characterized by changes in the ability to perform a given task based on experience and practice, usually systematized, influencing performance improvement. These changes occur in number, complexity and quality of execution, being of mechanical-organic or intentionality origin 1 . According to Guzman et al. 2 , learning success depends on many factors, mainly the development of motor skills considered as stable and / or lasting individual traits from inherited or acquired abilities.
Among the various motor capacities already identified, the Simple Response Time (SRT) -defined as the time interval from the visual, auditory or tactile stimulus to the beginning of a response is highlighted. According to Shanks et al. 3 , SRT represents the level of neuromuscular coordination in which stimuli are decoded by the body through different physicochemical and mechanical processes, propagating through afferent pathways until they reach the brain as sensory stimuli. Sequentially, the motor response is transmitted by efferent neurons that penetrate the medulla through the dorsal or sensory root by performing synapses and leading information to the desired motor unit 3 . In sports, especially in modalities whose performance is strongly influenced by cognitive aspects, for example, in Orienteering, SRT has been widely investigated 4 .
Orientation Sport, known as orienteering, consists of an endurance modality that involves physical and mental components aiming to travel a certain distance guided by a compass in the shortest possible time in varied and unknown terrain, passing through control points (CPs) indicated on a map made according to the rules of the International Orienteering Federation (IOF). Described as a cross-country type event, Orienteering differs from other sports modalities due to the influence of physiological 5 and cognitive 2 parameters on performance.
Chalopin 6 evaluated adult male orienteering athletes and verified average Maximum Oxygen Uptake ( O 2 max) values corresponding to 71.7 ± 5.7 ml.kg -1 .min -1 , similar to values found by Moser et al. 7 and Gjerset et al. 8 .
O 2 max values between 46.1 and 62.8 ml.kg -1 .min -1 were also pointed out in a review study published by Creagh and Reilly 5 as being determinant for good performance in Orienteering.
A possible justification for the importance of maximum cardiorespiratory capacity in performance in endurance tests, such as Orienteering, may be related to the Anaerobic Threshold (AT). Tartaruga et al. 9 investigated the relationships between O 2 TA and O 2 max of long distance runners according to body mass (traditional method), by the allometric exponent characteristic of the investigated group (b = 0.69) and by lean mass, and found strong correlations in all forms of expression (r = 0.64, 0.54 and 0.60, respectively). Creagh and Reilly 5 analyzed adult Orienteering athletes and found that AT is between 70 -78% of O 2 max, attributing the improvement in maximum cardiorespiratory capacity to the increase of AT. In fact, changes in AT and O 2 max can influence the performance of recreational exercises 9 .
The effect of exercise intensity on mental function during Orienteering has also been investigated and is represented by an inverted U-shaped curve corresponding to the relationship between physiological intensity and number of correct responses. Hintermann and Hintermann 10 have suggested that at high exercise intensities, mental tasks can be compromised as a result of the onset of mental fatigue. High blood ammonia concentrations released by the muscle during exercise can be one of the mechanisms responsible for mental fatigue, compromising performance, for example, in Orienteering 11 .
Despite the importance of maximum cardiorespiratory capacity, anaerobic parameters have also been decisive on specific occasions during Orienteering events. Dresel 12 investigated the high lactate concentrations during an Orienteering event and demonstrated the importance of anaerobic capacity in performance. Values between 4.4 and 6.7 mmol/L, with peak values close to 7.3 mmol/L, were observed in the first moments of Orienteering events. In addition, high maximum anaerobic power (Pmax) values were also observed, as already verified in other sport modalities 5 . Pmax corresponds to the highest amount of energy released per unit of time by a system. Anaerobic capacity is the total amount of energy available from this system.
Although there are studies highlighting the importance of SRT 2 and cardiorespiratory capacities 5 in Orienteering, interactions of these parameters with performance in category A adult practitioners of recreational exercises have been little investigated. In addition, it is known that other factors, such as sports experience can also influence performance in the modality 2 . Understanding and inducing performance-influencing variables through specific periodizations means respecting physiological and cognitive limits in order to obtain better results. Therefore, the aim of the present study was to investigate the relationships of SRT, O 2 max and Pmax in the performance of category A adult recreational orienteers of both sexes.

METHOD
Sixteen recreational adult orienteers, 8 men and 8 women, with sports experience of at least 2 years and 6 events / year in category A -registered in the Orienteering Federation of Paraná (FPO) and in the Brazilian Confederation of Orienteering (FBO) -free from injuries and medical and / or pharmacological treatments, voluntarily participated in the present study. The minimum sample number required for the study (n = 14, 7 males and 7 females) was determined considering the publications of Moser et al. 7 and Gjerset et al. 8 , using the Computer Programs for Epidemiologic Analyses -PEPI software, with 0.05 significance level and 80% power. All subjects were instructed not to consume caffeine or any type of stimulant 3-h prior to evaluation sessions, as well as to avoid intense physical activity for the last 24 h.

Experimental Procedures
Subjects were submitted to three evaluation sessions corresponding to the sample characterization (1 st session), specific tests to determine the magnitudes of independent variables (2 nd session) and an official Orienteering event (3 rd session), as demonstrated in the experimental design (see figure 1). The first two sessions, with the exception of the Pmax test, were performed in a laboratory specialized in biomechanical and energy analyses of human movement, with controlled temperature (25°C) and relative humidity (52%) according to international standards (ISO -8573-1). The third session corresponded to an Orienteering event recognized by FPO held in the Midwestern region of Paraná / BR. The present study was approved by the Ethics Research Committee of the State University of Mid-Western Paraná -UNICENTRO (3.185.736). After a brief neuromuscular warm-up (4 to 6 vertical jumps), subjects performed three bare maximum jumps in each experimental situation (SJ and CMJ), with a 2-min interval with maximum values in each situation analyzed.

nd session -Tests
SRT has been a tool adopted by psychologists and health professionals to investigate underlying behavioral processes, including the biological and cognitive principles of learning and memory. Consequently, several computer programs have been developed, among them, the Reaction Time Task v.2.0 -developed by Okazaki 13 and adopted in the present study. It is used to analyze paradigms related to cognition, allowing manipulating the execution time of the test and the type of stimuli with the aim of quantifying the number of responses and SRT. In the present study, subjects were submitted to a 5-min test in a quiet, isolated and noise-free place, according to procedures adopted by Shanks and Cameron 3 . Seated in front of a computer and using a mouse, visual stimuli (numbers and colors) were used to quantify the number of correct answers and SRT (mean value).
For the prediction of O 2 max, the protocol validated by Ebbeling et al. 14 was used, with determination power corresponding to 92% (estimated O 2 max = 0.15 + 1.03 * observed O 2 max), recommended for healthy non-athlete adults aged 20-59 years. The protocol consists in initially estimating maximum heart rate (HRmax) of each subject by adopting the equation: 208 -0.7 * age. After 5-min at rest, heart rate is measured (HRrest) and a 4-min warm-up is started on a treadmill. In the present study, MOVEMENT treadmill (model RT350, São Paulo, Brazil) was adopted. After warm-up, the speed was set for HR between 50% and 70% determined according to the following equations. After 4 minutes (1 st stage), treadmill inclination was raised to 5%, and the subject must remain at the same speed (2 nd stage). The two mean HR of the last 30 seconds corresponding to the third and fourth minutes are recorded. If there is variation greater than 5 bpm, a further 1 minute of test is added with a new record. HR to be considered in the O 2 max estimation (equation c) corresponds to the average of the last two records. The mentioned protocol was carried out in a multi-sport university gymnasium, and the running time in each of the six situations was measured through a system composed of two CEFISE (Speed Test 6.0, Nova Odessa, Brazil) photocells located at the ends of the course.

rd Session -Orienteering test
The third and last session, aimed at measuring performance, consisted of an Orienteering event recognized by FPO. All subjects, classified as adult A, according to rules of the Brazilian Orienteering Confederation (CBO), covered a minimum distance of 3.8 km for women and 4.6 km for men, with final performances corresponding to averages of test times of each subject of both groups. In this case, the shorter the test time, the higher the performance. The control and verification system adopted was ENTRAINEMENT SPORTident (16020, Locunolé, France). The test took place between 9 am and 11am, on a sunny day, with average temperature of 28ºC.

Statistical Procedures
Shapiro-Wilk tests were performed to verify data normality, Student's T for independent samples and Pearson's Linear Product-Moment Correlation. Finally, Multiple Linear Regression analysis -Enter method was performed. The significance level adopted in all the tests was 0.05 using the statistical package Statistical for Social Sciences Software -SPSS, version 20.0.

RESULTS
Despite similarities in age and body fat percentage, men and women presented statistically significant differences in variables body mass, height, hmax and Pmax LL , the latter being also different intra-group (see table 1). Male performance was higher, as was the average participation in official events (11 vs. 8 events / year) demonstrating a probable higher sporting experience of these subjects. ) values also showed statistically significant differences between men and women, indicating greater cardiorespiratory capacity of male subjects. However, SRT, number of cognitive hits and FI -commonly determined in intermittent high-intensity tests but associated with aerobic metabolism -did not present statistically significant inter-group differences. Mean values and standard deviations of independent variables corresponding to the 2 nd evaluation session are shown in table 2. Note: statistically significant inter-group differences (*) resulting from the application of the t-Students test for independent variables.
Strong and significant correlations (men: r = 0.89 and women: r = 0.97) between SRT and number of cognitive hits were also verified in both groups, demonstrating that the higher the SRT, the greater the number of cognitive hits and, consequently, better choices on the routes to be covered.
Finally, considering SRT, O 2 max and Pmax ABS in the prediction model, strong associations (men: 63.6% and women: 89.5%) with performance were observed. In the male group, Pmax ABS presented greater prediction capacity (b) of performance, followed by SRT and O 2 max. In the female group, SRT had higher propensity, followed by O 2 max and Pmax ABS (see table 3).

DISCUSSION
The aim of the present study was to investigate the associations of SRT, O 2 max and Pmax in the performance of category A recreational adult orienteers of both genders. As main result, it was verified that the larger the magnitudes of independent variables adopted in the present study, the shorter the test time -consequently, the higher the performance. Pmax and SRT were the parameters that presented greater capacity to predict performances in the male and female groups, respectively.
According to Cureton et al. 16 , sex is one of the main determinants of performance in several sports due to morphological and physiological differences between sexes. Aerobic capacity is an example, where female O 2 max values, corresponding to 70-75% of males, have been verified 17 . According to the Brazilian Society of Sports Medicine, although muscle fiber compositions are similar between men and women, Pmax tends to be higher in men due to higher cellular volumes, regardless of muscle fiber type. Although the adaptability to training is similar for men and women, larger cellular volumes give men greater cardiorespiratory and neuromuscular capacities, making sports performance of these subjects higher (6 to 15%) to that of women 17 .
In the present study, mean O 2 max and Pmax ABS values of the female group corresponded to 72% and 68%, respectively, of the male group -corroborating findings previously described. In addition, the average number of participations in events / year was also higher in the male group. Consequently, sex and the probable greater sport experience can justify the better average performance verified in the men, being 23% higher compared to women.
Variables hmax and Pmax LL , measured in SJ and CMJ tests, also presented higher values in the male group. Many studies have investigated the different neuromuscular responses resulting from vertical jumps of men and women 18 . Although several studies have demonstrated higher hmax and Pmax LL values due to the high rates of concentric and eccentric force production in men compared to women, some recent results have been contradictory 19 . Although differences in neuromuscular parameters are greatly attenuated when comparisons between sexes are conducted according to body mass values, plasma concentrations of the major anabolic hormones (testosterone, GH and IGF-1) at rest or after intense exercise, quite different between men and women, can justify these differences 20 . In addition, changes in the proportion of muscle fiber types may also interfere with the power production capacity, consequently, in the behavior of neuromuscular parameters, since women tend to present less difference in the proportion between type I and type II fibers when compared with men 21 .
Regarding performance in SJ and CMJ, strength parameters determinants of the power of lower limbs, have been investigated. Pulo et al. 22 point out that in CMJ, there is an eccentric movement of agonist muscles, followed by a concentric movement in which the jump result is attributed in large part to the use of elastic energy produced in the stretch-shortening cycle (CAE) and tendinous stiffness in velocity generation. Specifically in SJ, there is only the concentric phase, and performance is primarily attributed to the neural recruitment capacity. As a result of such characteristics, in which strength and velocity are requested differently in SJ and CMJ, there are differences in hmax and Pmax LL in the order of ± 15 and ± 23%, respectively 22 , justifying the findings of the present study.
FI has an inverse relationship with performance at high intensities and is directly related to cardiovascular problems 23 . According to Marque et al. 24 , changes in FI are related to possible aerobic adaptations, such as changes in oxidative capacity due to changes in circulating blood volume and changes in enzymatic and mitochondrial levels, influencing performance in high-intensity intermittent activities. However, although it is a variable predictive of fatigue in anaerobic tests, determined in high-intensity intermittent protocols, FI seems to be more associated with aerobic parameters 25 . In the present study, the male group presented significantly higher O 2 max and Pmax values compared to the female group. However, FI of both groups was similar, suggesting that aerobic parameters such as AT (Δ% of O 2 max) and movement economy were similar between groups. Likewise, SRT and number of cognitive hits were also similar between men and women, demonstrating that the level of neuromuscular coordination is similar among recreational adult orienteers, very different when compared with professionals or competitors of other sports 2 .
Although some predictive performance parameters in Orienteering do not present statistically significant intra-group differences, the present study demonstrates the existence of strong associations of SRT, O 2 max and Pmax with sports performance in both groups investigated. According to results, Pmax was the variable most predictive of performance (41%) in the male group, composed of more aerobically conditioned and homogeneous subjects. The female group presented SRT (54%) as the parameter with the highest performance prediction. According to Hébert-Losier 26 , subjects with high cardiorespiratory capacity, mainly Pmax, tend to perform better in Orienteering events due to the better use of the stretch-shortening cycle and the rapid production of maximum strength, especially of lower limbs. Moradi and Esmaeilzadeh 27 point out that factors such as age, caffeine and / or drug intake, diseases, lifestyle and practice of physical activity can influence SRT. In addition to these factors, recent studies have shown that body mass, especially obesity in young people, adults and the elderly can affect some cognitive parameters such as SRT 28 , which may be neuromechanically understood 28 . According to Skurvydas et al. 29 , the higher the body mass, especially of sedentary people whose cardiorespiratory capacity is not so determinant of sports performance, the greater the rigidity in kinematic chains, thus, the greater the SRT.
Moser et al. 7 investigated some physiological determinants of performance in Orienteering and verified the importance of AT. According to the authors, the AT is quickly reached, with effort remaining at high levels, suggesting an excessive energy expenditure with great anaerobic participation -something verified in the various changes in average speed from one point to the other (between 50 and 285 m.min -1 ) in the course of Orienteering events. That is, Orienteering is a sport modality that requires great aerobic resistance, with significant influence of Pmax -variables that determine sports performance, especially when experienced practitioners are analyzed.
On the other hand, Kolb et al. 30 investigated the influence of several Orienteering performance predictors and found that cognitive parameters can explain by approximately 46% the variability of results found among orienteers, which effect is strongly related to the ability to interpret the map -something in constant development with practice. Although SRT did not present statistically significant differences between men and women, in the present study, there was a strong prediction of performance by this variable, especially in the female group, corroborating the results found by Kolb et al. 30 . In groups composed of subjects with low cardiorespiratory capacity, SRT seems to become the variable with great capacity to predict the performance of recreational category A orienteers.

CONCLUSION
The present study allows concluding that SRT, O 2 max and Pmax are variables predictive of performance of category A adult recreational orientees of both sexes. Specifically in subjects with greater cardiorespiratory capacity, Pmax seems to be the main predictor variable in this modality. In contrast, SRT becomes the variable with the greatest predictive capacity. As practical application, the present study contributed with relevant information in the scope of training for better prediction and sports performance.