Polar team pro gps

The locomotor demands were monitored using a GPS with a sampling frequency of 10 Hz (Polar Team Pro GPS, Polar Electro, Kempele, Finland). The GPS was previously confirmed for accuracy and reliability to collect measures of total distance covered and distances covered at different speed thresholds [35 (link)]. The following measures were extracted for each training session: (i) dist/min (average distance covered per minute); (ii) maximum speed (MS) (peak speed registered in the session); (iii) Average speed (AS); (iv) Sprint (number of sprints >25 km/h).

The HR responses were collected using a heart rate sensor (Polar Team Pro GPS, Polar Electro, Kempele, Finland). Records of HR beats were taken in each second. The maximal HR (HR_max) was also considered by adding the peak HR detected during the YYIRT. This was used to determine the heart rate zones and the time spent in each of them: (i) Zone 1 (Z1; 51–60%HR_max); (ii) Zone 2 (Z2; 61–70%HR_max); (iii) Zone 3 (Z3; 71–80%HR_max); (iv) Zone 4 (Z4; 81–90%HR_max); and (v) Zone 5 (Z5; 91–100%HR_max). The main outcomes extracted for each training session were: (i) %HR_average; (ii) %HR_max; and (iii) time in HRZ5.

The participants were preliminarily analyzed for their final locomotor profile. In the week before starting the observation, they were tested for the maximal sprint speed in a 30-m sprint test and for their ability to perform repeated efforts in the 30–15 Intermittent Fitness test. The data collection was preceded by a 24-h rest and occurred in the afternoon (5 pm). The players performed a standardized warm-up protocol (FIFA 11+). After that, they rested for 3 min and started the 30-m sprint speed assessment. They started with a split position (using the preferred leg in front), and the peak speed was assessed using a Polar Team Pro GPS (10 hz, Polar, Kempele, Finland) which was confirmed for the validity and reliability to estimate their peak speed in the previous study. After performing two trials of the 30-m sprint (interspaced by 5 min rest), they recovered for 3 min and followed the 30–15 Intermittent Fitness tests. The original protocol was implemented, and the final velocity completed was registered as the main outcome. For the case of maximal sprint speed, the best speed in the two trials was considered the main outcome.