Influence of Sprint Duration during Minimal Volume Exercise on Aerobic Capacity and Affect

The aims of this study were to investigate the influence of reduced-exertion, high-intensity interval training (REHIT), comparing a novel shortened-sprint protocol (SSREHIT) against a traditional protocol (TREHIT), on perceptual responses and to determine if changes in peak oxygen uptake (V˙O2peak) are attenuated with shorter sprints. Twenty-four healthy men undertook 15 sessions of SSREHIT or TREHIT. V˙O2peak was determined at baseline and after completion of each exercise condition. Affective (pleasure-displeasure) responses and perceived exertion were assessed during exercise to capture peak responses. Enjoyment was recorded 5-min after cessation of exercise. Compared to baseline, V˙O2peak increased in both groups (6% for SSREHIT [d=− 0.36] and 9% for TREHIT [d=− 0.53], p=0.01). Affective responses were more favourable for SSREHIT (p=0.001, d=1.62), but both protocols avoided large negative peaks of displeasure. Peak ratings of perceived exertion were lower for SSREHIT (p=0.001, d=− 1.71), although there were no differences in enjoyment (d=0.25). The results demonstrate both exercise conditions can increase V˙O2peak without overly compromising perceptual responses. Decreased sprint duration might further circumvent negative perceptual responses but might also attenuate physiological adaptations.

Caffeine and Sprint Cycling Performance: Effects of Torque Factor and Sprint Duration

Purpose:To investigate the influence of torque factor and sprint duration on the effects of caffeine on sprint cycling performance.Methods:Using a counterbalanced, randomized, double-blind, placebo-controlled design, 13 men completed 9 trials. In trial 1, participants completed a series of 6-s sprints at increasing torque factors to determine the torque factor, for each individual, that elicited the highest (Toptimal) peak power output (PPO). The remaining trials involved all combinations of torque factor (0.8 N·m−1·kg−1vsToptimal), sprint duration (10 s vs 30 s), and supplementation (caffeine [5 mg·kg−1] vs placebo).Results:There was a significant effect of torque factor on PPO, with higher values atToptimal(mean difference 168 W; 95% likely range 142–195 W). There was also a significant effect of sprint duration on PPO, with higher values in 10-s sprints (mean difference 52 W; 95% likely range 18–86 W). However, there was no effect of supplementation on PPO (P = .056). Nevertheless, there was a significant torque factor × sprint duration × supplement interaction (P = .036), with post hoc tests revealing that caffeine produced a higher PPO (mean difference 76 W; 95% likely range 19–133 W) when the sprint duration was 10 s and the torque factor wasToptimal.Conclusion:The results of this study show that when torque factor and sprint duration are optimized, to allow participants to express their highest PPO, there is a clear effect of caffeine on sprinting performance.

Decreasing sprint duration from 20 to 10 s during reduced-exertion high-intensity interval training (REHIT) attenuates the increase in maximal aerobic capacity but has no effect on affective and perceptual responses

Recent studies have demonstrated that modifying the “classic” 6 × 30-s “all-out” sprint interval training protocol by incorporating either shorter sprints (6 × 10-s or 15-s sprints) or fewer sprints (e.g., 2 × 20-s sprints; reduced-exertion high-intensity interval training (REHIT)) does not attenuate the training-induced improvements in maximal aerobic capacity. The aim of the present study was to determine if reducing the sprint duration in the REHIT protocol from 20 s to 10 s per sprint influences acute affective responses and the change in maximal aerobic capacity following training. Thirty-six sedentary or recreationally active participants (17 women; mean ± SD; age: 22 ± 3 years; body mass index: 24.5 ± 4.6 kg·m−2; maximal aerobic capacity: 37 ± 8 mL·kg−1·min−1) were randomised to a group performing a “standard” REHIT protocol involving 2 × 20-s sprints or a group who performed 2 × 10-s sprints. Maximal aerobic capacity was determined before and after 6 weeks of 3 weekly training sessions. Acute affective responses and perceived exertion were assessed during training. Greater increases in maximal aerobic capacity were observed for the group performing 20-s sprints (2.77 ± 0.75 to 3.04 ± 0.75 L·min−1; +10%) compared with the group performing 10-s sprints (2.58 ± 0.57 vs. 2.67 ± 3.04 L·min−1; +4%; group × time interaction effect: p < 0.05; d = 1.06). Positive affect and the mood state vigour increased postexercise, while tension, depression, and total mood disturbance decreased, and negative affect remained unchanged. Affective responses and perceived exertion were not altered by training and were not different between groups. In conclusion, reducing sprint duration in the REHIT protocol from 20 s to 10 s attenuates improvements in maximal aerobic capacity, and does not result in more positive affective responses or lower perceived exertion.

Characterization of the Sprint and Repeated-Sprint Sequences Performed by Professional Futsal Players, According to Playing Position, During Official Matches

The purposes of this study were to investigate sprints and to characterize repeated-sprint sequences (RS) performed by athletes during professional futsal matches. We analyzed 97 players during 5 official matches using the DVideo automatic tracking system. The sprints were analyzed during the first and second halves according to playing position, and RS were categorized according to the number of sprints and the time between them. The results showed an increase (F[1, 2520] = 3.96; P = .046) in the sprint duration from the first (mean = 3.1 ± 1.3) to the second half (mean = 3.2 ± 1.2). However, no differences were found for other variables (distance covered, peak velocity, initial velocity, recovery time between sprints, and sprints performed per minute) or among playing positions. In addition, when considering RS, the results showed that RS comprising two sprints interspersed with a maximum of 15 seconds of recovery were significantly more frequent than other RS. The findings of this study characterizing the sprinting features of futsal players can help coaches to plan physical training and assessments according to the requirements of the sport.

AN INVESTIGATION OF THE DECISION-MAKING PROCESS IN AGILE TEAMS

This paper first explores the decision-making process in agile teams using scrum practices and second identifies factors that influence the decision-making process during the Sprint Planning and Daily Scrum Meetings. We conducted 34 semi-structured interviews and 18 observations across four agile teams. Our findings show that a rational decision-making process is sometimes followed in the Sprint Planning and Daily Scrum Meetings and that three factors can influence the rational decision-making process: sprint duration, experience and resource availability. Additionally, decisions are not always made in a collaborative manner by team members. This research contributes to the decision-making literature and project management literature by highlighting difficulties pertinent to decision making in agile teams.

Performance Analysis of a World-Class Sprinter During Cycling Grand Tours

This investigation describes the sprint performances of the highest internationally ranked professional male road sprint cyclist during the 2008–2011 Grand Tours. Sprint stages were classified as won, lost, or dropped from the front bunch before the sprint. Thirty-one stages were video-analyzed for average speed of the last km, sprint duration, position in the bunch, and number of teammates at 60, 30, and 15 s remaining. Race distance, total elevation gain (TEG), and average speed of 45 stages were determined. Head-to-head performances against the 2nd–5th most successful professional sprint cyclists were also reviewed. In the 52 Grand Tour sprint stages the subject started, he won 30 (58%), lost 15 (29%), was dropped in 6 (12%), and had 1 crash. Position in the bunch was closer to the front and the number of team members was significantly higher in won than in lost at 60, 30, and 15 s remaining (P < .05). The sprint duration was not different between won and lost (11.3 ± 1.7 and 10.4 ± 3.2 s). TEG was significantly higher in dropped (1089 ± 465 m) than in won and lost (574 ± 394 and 601 ± 423 m, P < .05). The ability to finish the race with the front bunch was lower (77%) than that of other successful sprinters (89%). However, the subject was highly successful, winning over 60% of contested stages, while his competitors won less than 15%. This investigation explores methodology that can be used to describe important aspects of road sprint cycling and supports the concept that tactical aspects of sprinting can relate to performance outcomes.