Predicting Lactate Threshold With Rate of Perceived Exertion in Young Competitive Male Swimmers.

The purpose of this study was to verify the effectiveness of the rate of perceived exertion threshold (RPET) for predicting young competitive swimmers' lactate threshold (LT) during incremental testing. We enrolled 13 male athletes (M age = 16, SD = 0.6 years) in an incremental test protocol consisting of eight repetitions of a 100-meter crawl with 2-minute intervals between each repetition. We collected data for blood lactate concentration ([La]) and Borg scale rate of perceived exertion (RPE) at the end of each repetition. The results obtained were: M RPET = 4.98, SD = 1.12 arbitrary units (A.U.) and M lactate threshold = 4.24, SD = 1.12 mmol.L-1, with [La] and RPE identified by the maximal deviation (Dmax) method without a significant difference (p > 0.05) and large correlations between DmaxLa and DmaxRPE at variables for time (r = 0.64), velocity (r = 0.67) and percentage of personal best time (PB) (r = 0.60). These results suggest that RPET is a good predictor of LT in young competitive swimmers.

Comparisons of recovery, external and internal load by playing position and match outcome in professional soccer

AIMS: To compare the internal and external load and the recovery by playing position and the match outcome (wins, losses or draws) in professional soccer. METHODS: 23 male professional soccer athletes from a team of the first division of the Brazilian Championship took part into the study (age 26.1 ± 3.8 years old, weight 77.5 ± 5.0 kg, height 177.6 ± 5.1 cm). During the games, athletes were monitored by GPS and the variables of external loads were taken. Additionally, the session rating of perceived exertion (session RPE) and the perceived recovery scale (PRS) were collected 30 minutes and 40h after the end of the matches, respectively. RESULTS: The external load was greater on full-backs and defense midfielders (p<0.05). The full-backs cover higher total distances compared to attackers, and, compared to all the others positions, they have more stimuli > 20 km/h, covering higher distances >20 km/h; these stimuli makes them to perceive less recovered than defenders, defense and attack midfielders (p<0.05). Moreover, the defenders are those who cover lower distances by the minute and the defense midfielders are those who present the lower Peak Velocity (p<0.05). There were no significant differences between GPS variables, internal load and recovery. In addition, it was found a correlation between the external and the internal load (r=0.66; p=0.001). CONCLUSIONS: The GPS variables and the perceived recovery are influenced by the playing position, but not by the match outcome.(AU)