Background Information
Recovery duration in repeated high-intensity intermittent exercise (HIIE) is usually short, and it can last from 5-10 seconds to 2-4 minutes (Harbili, 2015). According to Baker and Buchan (2016), the duration of recovery during such HIIE as sprints can influence fatigue and the power of athletes. Thus, a person’s muscle fatigue and performance in repeated HIIE depend not only on the number of repetitions but also on the period of recovery (Baker & Buchan, 2016; Harbili, 2015). As a result, the rapid resynthesis of adenosine triphosphate (ATP) is observed during HIIE and reported by researchers (Harbili, 2015; Tschakert & Hofmann, 2013).
However, the ATP generation requires the use of different sources of energy, and these metabolic processes can require different time periods to guarantee maximum power output after a break in activities. To complete ATP resynthesis, the intracellular stored oxygen is required, as well as anaerobic sources of energy (Tschakert & Hofmann, 2013). If recovery phases are very long or short, the use of energy for ATP metabolism can be influenced significantly, and this aspect can result in muscle fatigue (Harbili, 2015; Tschakert & Hofmann, 2013). Still, according to McCallum (2017), fatigue is not directly correlated with ATP metabolism processes, and the researcher states that ATP levels do not represent any decrease that can be associated with different types of exercises. Therefore, it is necessary to study how recovery duration can influence the resynthesis of ATP and possible fatigue levels.
HIIE ATP Metabolism and Recovery Duration
During the first seconds of HIIE, this activity causes the rapid resynthesis of ATP with the help of the degradation of phosphocreatine (PCr) and with reference to glycolytic and aerobic pathways. After HIIE, the increased oxygen uptake and increased levels of lactic acid are observed to restore and improve metabolic processes (Baker & Buchan, 2016; Harbili, 2015). The associated process to influence muscle function is the removal of lactate from the blood. ATP and PCr stores become decreased in association with affected glycogen stores (Harbili, 2015; Tschakert & Hofmann, 2013). In order to complete these processes, recovery is required, and its duration affects further performance during HIIE. Thus, 2-4 minutes are needed to resynthesize ATP to about 80% or even 100% of its resting levels (Harbili, 2015). Recovery duration during sprints is usually shorter, and it is necessary to examine how it can influence ATP metabolism and associated fatigue levels.
Aims of the Report and the Research Question
This research aims to establish whether recovery duration has an effect on ATP production, lactic acid, and uric acid before and after repeated high-intensity exercise. In order to address the purpose of this report, the following research question is formulated to guide the development of the study:
Does recovery duration change fatigue and ATP metabolism in repeated high-intensity exercise?
Hypothesis
The primary hypothesis for this research states that repeated high-intensity intermittent exercise with short recovery duration will result in higher lactic acid and uric acid levels compared to long recovery duration. This hypothesis is supported by evidence from recent studies, according to which recovery duration influences ATP metabolism with the focus on differences in lactic acid and uric acid levels (Baker & Buchan, 2016; Harbili, 2015). These changes are also connected with the experienced muscle fatigue that depends on the completion of ATP metabolism processes with reference to recovery duration (Harbili, 2015; Tschakert & Hofmann, 2013).
References
Baker, J. S., & Buchan, D. (2016). High intensity exercise metabolism and muscle function: Implications for performance. Obesity Open Access, 2(2), 1-2.
Harbili, S. (2015). The effect of different recovery duration on repeated anaerobic performance in elite cyclists. Journal of Human Kinetics, 49(1), 171-178.
McCallum, S. (2017). Muscle fatigue, muscle recovery and how this knowledge applies to rock climbers. Duluth Journal of Undergraduate Biology, 4, 12-18.
Tschakert, G., & Hofmann, P. (2013). High-intensity intermittent exercise: Methodological and physiological aspects. International Journal of Sports Physiology and Performance, 8(6), 600-610.