## 2 Materials and Methods
### Study Design and Procedures  
The study was performed in a randomized crossover design, and all participants performed three sessions across a 2-week period that included one load-velocity profile test for each individual load and two repeated sprint test sessions using the 1080 Sprint (1080 Motions, Stockholm, Sweden) for each individual load and variables (sprint time, peak force, power, velocity, step length, and stride frequency at 5 m split distance (0-20, 0-5, 5-10, 10-15, and 15-20 m). This is a resistance training device with intelligent drag technology and was developed for resisted and assisted sprint training that uses a servo motor (2000 RPM OMRON G5 Series Motor; OMRON Corporation, Kyoto, Japan). It can collect precise and frequent data on the velocity and pulling force exerted by the cable coiled around a spool. Recent studies suggest that the 1080 Sprint is valid and reliable for sprint performance and spatiotemporal variables [57; 58; 59; 60], and has been used in resisted sprint training for field and research [28; 61; 62; 63; 64]. Data (time, force, and velocity) were recorded at 333 Hz. The load-velocity profile was based on that in previous studies. To determine the load-velocity (L-v) relationship, all participants performed 1, 5, 8, 12, and 15 kg of resisted sprint at 35, 30, 25, 20, and 15 m, respectively [28; 40]. The \"normal mass resistance mode\" was used, simulating the inertial properties of a normal mass (a cable-driven weight stack) in gravity \"[http://1080 motion.com/](http://1080 motion.com/) (accessed on 6 June 2024)\". Previous research suggests that loads of 30% Vdec to loads of 50% Vdec are effective for initial acceleration [28; 40; 47]. The range of the loads considered very heavy resistance (>30% velocity decrement) in the classification of resisted sprint loads [65]. We chose to use 30% Vdec loads in this study,given that the athletes may have relatively low levels of muscular strength and would need to perform sprints repeatedly after a short 40 s rest period [13; 18; 39]. The loads of 30% Vdec for the participants was an average value of 10.9 \(\pm\) 0.79 kg. We employed rounding-up calculations to determine the load in the device. One week later, two sessions of resistance sprints were performed. Each session was separated by 48-72 h, and the other conditions were kept constant except for the rest interval. The temperature within the facility was controlled by an air conditioning system, and no wind was applied to the indoor wooden basketball court to prevent air resistance. The temperature and humidity during the experiment were 18-20 \({}^{\circ}\)C and 30-45%, respectively. All players were randomly assigned to either RST2M (Resisted Sprint Training with a 2 min rest interval) or RST40S (Resisted Sprint Training with a 40 s rest interval). To investigate the differences between RST2M and RST40S, they performed 6 repetitions of 20 m resisted sprints with 2 min and 40 s rest intervals, respectively, with Vdec (30%) load using 1080 Sprint (1080 Motion, Stockholm, Sweden). Prior to the test session, all participants performed a warm-up protocol, including 10 min of jogging, \(\sim\)10 min of dynamic warm-up, \(\sim\)10 min of sprint drill exercises, 2-4 submaximal to maximal sprints, and 2-3 resisted sprints under the 30% Vdec load as the test trials from a standing split-stance position (2-point stance). The resistance load was regulated using the Quantum computer application (1080 Motion), which also recorded all sprinting data for subsequent analysis. The 1080 Sprint was placed approximately 3 m behind the starting line, with the motor cord secured to the belt around the pelvis of the athlete. And the front foot placed on the start line. The athletes started from the 2-point stance and were instructed to start with the cues 3 s before (\"3...2...1...GOI\"). Quantum software can identify the athlete's position and initiate data collection at the start of their movement over a predetermined distance (20 m).