Creatine Kinase and Blood Lactate on High Intensity Short Period Exercise

High intensity of physical exercise in long period causes muscle damage. Muscle damage in physical exercise can occur due to muscle stretching followed by sarcomere disruption. Muscle damage can be detected by measuring several indicators or markers. Muscle protein efflux during severe physical activities signed by the increase of LDH (lactate dehydrogenase) and CK (Creatine Kinase). Many studies explained the effect of high intensity physical exercise in long period on muscle damage, but only few studies investigated the effect of high intensity exercise in short period. The purpose of research is to analyze the high intensity short period exercise on blood lactate and creatine kinase serum between elite and non-elite athlete. The post test only group design study was conducted to reach the aims of research. Seventy-five participants involved in this research and they were elite athletes (n=37) and non-elite athletes (n=38). The elite athletes were 24.71 ± 4.753 years old, while the non-elite athletes were 20.19 ± 1.619 years old. All participants perform Running -based Anaerobic Sprint Test (RAST) as a high-intensity short period exercise. The velocity of athletes was calculated for each running track. The blood for lactate level and creatine kinase (CK) measurement was taken as soon as they finished the RAST. The blood lactate level was 6.96 mmol/L (non-elite) and 5.5 mmol/L (elite). The serum level of CK was 241 (non-elite) and 198.8 (elite). Both of elite and non-elite CK level were higher than normal value. There was no difference in blood lactate (p=0.063) and serum level of CK (p=0.241) between elite and non-elite athlete. The conclusion was the blood lactate and CK serum level after high intensity short period increased higher than the normal value. There was not difference between elite and non-elite athletes, suggesting that the elite and non-elite athletes put in the same effort in performing and running the test. The recommendation of this research is that the high intensity short period exercise should be alternatively implemented to avoid muscle damage to athlete.


Introduction
Prolonged intense physical exercise raised the muscle damage [1]. Previous study suggested muscle breakdown is one of the sources of muscle fatigue during a triathlon [2], marathon [3] and resistance exercise [4]. Muscle damage in physical exercise occurs due to muscle stretching followed by sarcomere disruption. The damage of cell membranes resulted in impaired function. The muscle damage not only occurs in skeletal muscles, but also in heart muscle. Study in rat consequences that aerobic and anaerobic physical activities performed for 10 days without any rest-day may cause cardiac muscle damage. Physical activity may result in hypoxia and systemic adaptation [5].
There are two mechanism of muscle damage during exercise: mechanical and metabolic stress. The mechanical stress occurs on muscle during exercise induced by stretching of sarcomeres. When the contractile apparatus, muscle cytoskeleton and sarcolemma-associated proteins stretch over the maximal capacity, the sarcomere was disruptions [6]. Muscle extent during eccentric exercise raised muscle damage risk than either isometric or concentric exercise [7]. Loss of sarcolemma integrity followed by increasing of CK activity and loss of muscle function. Abnormality histological muscle structure was found following the elevation of serum CK [8].
Muscle damage can be detected by measuring several indicators or markers [9] [10]. Muscle protein efflux during severe physical activities signed by the increase of LDH (lactate dehydrogenase) and CK (Creatine Kinase). Blood lactate level is a common method for predicting the aerobic capacity [11]. Muscle damage can also cause an inflammatory reaction which is characterized by infiltration of inflammatory cells such as neutrophils and macrophages. The infiltration of these inflammatory cells has been implicated in producing secondary cytoskeletal disruptions to eccentrically exercised muscle [12].
Several studies on the effect of high-intensity exercise over a long period, i.e., all our running, long distances swimming, marathon, have been performed to observed the metabolic change. The metabolic changes in exercise markers such as oxygen consumption, blood lactate, and creatine kinase were analyzed in swimmers [13], runners [14] and endurance athletes [15].
Athlete is an individual who do physical activity in the long period. Regular training and competition have already been done in high intensity. High physical activity caused muscle fatigue, muscle damage and muscle soreness. Many studies suggested the effect of long period high intensity physical activity on the muscle damage, but only a little study suggested the effect of high intensity in a short period. The aim of this study was to compare the power, blood lactate and CK after short period high intensity physical activity.

Participants
The participants of this study joined voluntarily by the fill the approval questionary. Seventy-five male athletes participated in this study, consist of 37 elite athletes and 38 non-elite athletes. The inclusion criteria of elite athletes were the athlete who had been gold, silver and bronze medal in national or international competition. The non-elite athletes were students of Sport Faculty Universitas Negeri Semarang. They were 16-31 years old of elite athlete and 17-22 years of non-elite athletes.
All participants were examined by physician before tested, included blood pressure, rest heart rate, cardiac and lung function. The doctor decided whether the participant can take the exercise or not. The medical team was in standby during the test.

Exercise Protocol
Running Anaerobic-based Sprint Test (RAST) is a high intensity exercise which is done in short period. RAST was conducted to determine anaerobic capacity of athlete. The exam begin with 10-15 minutes warm-up session before main exercise. Participants take a starting position behind the start line. Participant runs at maximum pace completed six 35 meter running tracks, with 10 seconds rest allowed between each sprint track for turn around. The time spend was measured for each running track. Total time was summary of time spend to finished first-sixth tracks. Velocity was calculated for each track, which was the distance (35 meter) divided by the track's travel time.

Creatine Kinase and Blood Lactate Analysis
The CK levels were measured from the peripheral blood. The blood was collected from brachial vein in one hour after they finished the run. The blood was placed in plain tube without EDTA, transported to laboratory in the cool box. The serum level of CK was measured by Elisa.
Blood lactate level is indirect marker fatigue or damage of exercising muscle. Blood lactate was measured as soon as athlete finished the running test. The blood was taken from peripheral capillary. The determination of lactate used @Accutrend Plus for lactate strips.

Statistical Analysis
The data were collected, including the velocity, CK and blood lactate level. The value was presented as mean ± SD. All data were exam by the normality and homogeneity test. By the normal and homogenous data, the difference of average between elite and non-elite athlete was tested by one-way Anova.

Ethical Clearance
The investigation was approved by the Universitas Negeri Semarang Ethics Committee. The aim, purpose and exam procedure were explained to help participant understanding. All participants signed their written informed consent to participate in the study. The study was in agreements with the declaration of Helsinki of the World Medical Association.

Result
The medical doctor recommended that all participants be involved in study if they are in good health. The blood pressure range between 100/60 mmHg -140/90 mmHg. No one was not found to have heart and lung disorder. Age, body height, body weight, body mass index and rest heart rate of participants are presented in Table 1.
The velocity was different between elite athlete and non-elite athlete (Figure 1). Elite athlete are faster than non-elite athlete for all tracks. The peak of velocity was during third track, both elite and non-elite athlete. The decline of velocity was after the third track. The last track was the lowest velocity.
Blood lactate and CK serum were evaluated after anaerobic sprint test were presented in Table 2. The average of blood lactate and CK between elite and non-elite athlete were compared by one-way Anova to analyze the difference value. The value of creatine kinase, blood lactate and the difference were presented in Table 2.

Discussion
A kind of sport had a characteristic motor skill, i.e., sprint for soccer, vertical jump for volleyball and basketball player, power of arm for badminton player, etc. The motor skills can be trained by various training models, for example, 4 weeks sprint training enhanced vertical jump height of volleyball players [16]. Sprint training was conducted in high intensity but only in several seconds. The purposes of this investigation were to examine the effect of high intensity in short period of exercise on muscle damage marker between elite and non-elite athlete. RAST was chosen to examine the athletes because of the high intensity in short period. RAST is a practicable field test to estimate anaerobic capacity of athlete [17], [18]. RAST is widely used to measure anaerobic capacity in addition to the Wingate test. During the RAST we can know the maximum and minimum power, velocity and fatigue index.
The elite athletes get their achievement not only by the exercise factor, but also their talent. The genetic factor role in the determinant of elite athlete like ACTN3 [19], [20], [21]. The elite athlete and non-elite athlete differ in terms of level of competition. The difference in the level of competition is the implication of the difference in the frequency of training per week [22]. Gene, training and strong competitive mentality factors simultaneously form an elite athlete.
Lactate is the end products of glycolysis anaerobic. Blood lactate commonly increased after intensive exercise [14]. During intense or strenuous physical exercise blood lactate level can rise to very high. The accumulation lactate increased hydrogen ions concentration and corresponding acidosis. It is well known as a primary factor in muscle fatigue. RAST is a test which finished in several minute. Short activity may not cause accumulation of lactate. The lactate level of elite athlete and non-elite athlete was no difference. The elite and non-elite athlete were trained athletes. The trained athlete had well adaptation mechanism to eliminate lactate.
In comparison with the normal value, the level of CK was higher, both elite and non-elite athlete. Normal CK levels range from 55-170 U/L [23]. High CK levels during exercise are intended to ensure the availability of energy for muscle contraction. The high CK serum levels, without the other markers, do not necessarily indicate muscle damage. In strenuous exercise, serum CK may increase two or three times higher than normal in the resting condition [15].
The rest time between the effort may related with CK level. RAST was carried out by taking 6 tracks each 35 meters away, so that only required a short time to finish the test. The interval between tracks was very short, which is 10 seconds. The length of the rest interval affects the increase in CK levels in the blood, shorter rest intervals related to higher CK [4].
The velocity of elite athlete is higher than non-elite athlete for all tracks. The peak of velocity reaches on third track, and then begins to decline. The last track was the slowest. The velocity was affected on rises the serum creatine kinase. Previous study suggested that fast velocity of eccentric contractions produced higher serum CK activity than slower actions for the same time under tension [24]. The increase of CK activity during fast velocity might be activated by protein degradation signaling pathways (FOXO1 and FOXO3) and elevate myostatin content in rat skeletal muscle [25]. For concentric muscle actions, in which force and velocity was inversely related, it is likely that a slower movement speed would produce higher elevations in serum CK. [4]. In relation to the velocity during RAST, it is understandable that the average of CK of elite non-elite athletes was higher than elite athletes.
Many factors influenced the release of CK included gender, age, exercise type, genetic, exercise modality. The degree of CK elevation depends on the type and duration of exercise, i.e. aerobic or anaerobic [5], eccentric or concentric [26], [27], chronic or acute [28]. The nutrition influenced the CK serum level related exercise by their antioxidant role and suppressed the inflammatory response [29].
The greater elevation of CK was found in those untrained person [30], [31], [32]. It was understandable that there is no difference in CK and blood lactate level between elite and non-elite athlete. In this study, the non-elite athletes were recruited from student of sport faculty, so they did physical exercise regularly. The trained athlete had the capability adaptation to mechanical and metabolic stress-induced exercise. The muscle fiber proportion may be different between elite athlete and non-elite athletes, but the increase of CK following exercise-induced muscle damage may not be related to muscle fiber proportions of athletes [33].
However, this research still had some limitation. There was no data about the diet of athlete and the intensity of physical activity before test. In addition, CK serum level only check in once measurement and no follow-up after that. The previous study suggested that the CK serum level was already exist after several days.

Conclusions
Blood lactate and CK serum level are indirect marker of muscle damage. Established study appear that blood lactate and CK level increased after prolonged high intensity of physical activities. The high intensity short period physical exercise increased blood lactate and CK serum level higher than the normal value. There was not difference between elite and non-elite athletes, suggesting that the elite and non-elite athletes put in the same effort in performing and running protocol. From the results of this study, we recommend implementing high-intensity exercise in a short time to improve motor skills without fear of muscle damage.

Conflicts of Interest
There were no conflicts of interest to declare.