1 decelerations, shuffles, and jumps) interspersed with low- to moderate-intensity periods. Furthermore, mean heart rate (HR) responses between 82% and 95% of maximum HR (HR max ) have been observed during basketball play (Stojanović, Aksović, et al., 2018). Despite the growing body of evidence detailing the activity demands and physi- ological responses encountered during a basketball match, the precise data concerning temporal changes in activity demands and internal response relative to playing level, are not well established and therefore the optimal training, preparatory, and recovery approaches for players are likely still to be developed. To date, several studies have quantified temporal changes in activity demands and physiological response during match-play in male basketball players. However, with inconsistent findings. In particular, a relatively con- sistent workload across playing periods has been reported in semi-professional female basketball players (Matthew & Delextrat, 2009; Scanlan et al., 2015). On the other hand, Ben Abdelkrim et al. (2007) and Janeira and Maia (1998) reported significant decreases in high-intensity activity and HR responses with game progression in elite junior and professional adult male basketball players. * Corresponding author: Karel Hůlka, e-mail karel.hulka@upol.cz, ORCID® record https://orcid.org/0000-0002-4543-0106 Article history: Received June 16 2021, Accepted April 5 2022, Published April 25 2022 Copyright: © 2022 The Author(s). Published by Palacký University Olomouc. This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This license does not cover any third-party material that may appear with permission in the article. ORIGINAL RESEARCH The influence of fatigue on internal and external load using game-based drills in junior and adult male basketball players Karel Hůlka * , Matěj Strniště, and Michal Hrubý Department of Sport, Faculty of Physical Culture, Palacký University Olomouc, Olomouc, Czech Republic Abstract Background: Fatigue demonstrated by decreasing performance seems to occur towards the ends of periods of matches and can lead to a win or loss of the match. Objective: This study aimed to assess the influence of fatigue on internal and external load using game-based drills in junior and adult male basketball players. Methods: A total of 50 elite basketball players participated in this study. Every participant was monitored by the Team Pro Polar system to find out heart rate and activity demands during a game-based drill. Mixed analysis of variance 2 × 4 was used. Results: Significant interactions between age category and playing quarter were found for distance covered (p = .001, η p 2 = .25). Significant interactions between age category and playing quarter were found for relative time in zone 3 (running, p = .013, η p 2 = .25) and zone 4 (high-intensity running, p = .004, η p 2 = .34). When comparing the last three min- utes of quarters, a significant main effect was found for playing quarter, when the distance covered (p = .001, η p 2 = .47) significantly decreased. A significant main effect was found for playing quarter, whereby relative time spent in zone 3 (p = .012, η p 2 = .09; quarter 1 vs. 4: p = .044) significantly increased, and in zone 4 decreased (p = .001, η p 2 = .29, moderate effect; quarter 1 vs. 4: p = .010). When comparing heart rate and activity demands during the last three minutes of playing quarters, the significant main effect for the age category was found in distance covered (p = .004, η p 2 = .27). It was greater in adult male players compared to junior players. Conclusions: The fatigue affects the distance covered, and intensity of activity demands during the last three minutes of quarters, but not the heart rate response of players. Keywords: heart rate, activity demands, specific conditioning ACTA GYMNICA, 2022, Volume 52, Article e2022.002 https://doi.org/10.5507/ag.2022.002 Introduction Modern basketball training brings a greater integration of technology for player monitoring during training or match-play. Combined monitoring of external demands and internal responses supplies a comprehensive insight into determining players’ readiness and identifying fatigue during match-play (Akubat et al., 2014). These outcomes can be used to design game-specific conditioning drills and training plans. The implementation of effective training strategies is essential to promote favourable physiological adaptations that improve performance and minimize the risk of developing non-functional overreaching, illness, and/or injury. A number of researchers have sought to quantify the activity demands and physiological responses encountered during basketball match-play (Ben Abdelkrim et al., 2007; Narazaki et al., 2009; Scanlan et al., 2012). The existing data demonstrate that basketball gameplay is highly intermit- tent and relies upon significant energy contributions from both the anaerobic and aerobic metabolic pathways (Hůlka et al., 2013). Previous review (Stojanović, Stojiljković, et al., 2018) suggests that basketball gameplay is comprised of short bouts of explosive tasks (e.g., accelerations, OPEN ACCESS