Browsing Sport and Exercise Sciences by Authors
Movement characteristics, physiological and perceptual responses of elite standard youth football players to different high intensity running drillsGibson, Neil; Henning, Greig; Twist, Craig; Heriot-Watt University; University of Chester (Taylor & Francis, 2018-04-06)Purpose: To examine responses to high intensity running drills in youth football players. Methods: Seventeen players completed the YoYo Intermittent Recovery test level one (YYIR1) and a 15 m maximal sprint to quantify target running speeds. Players performed three conditions on separate occasions comprising: 12 x 15 s high intensity runs at 100% of the final YYIRT1 speed, 12 x ~4 s repeated sprints with ~26 s recovery, and combination running using both modalities. Heart rate was monitored continuously with PlayerLoadTM and movement characteristics using microtechnology. Ratings of perceived exertion and blood lactate responses were measured 2 min after the final repetition. The ratio of Flight:contraction time was calculated from a countermovement jump before and at 2 min and 14 hours after each condition. Data analysis used magnitude based inferences and effect sizes statistics. Results: Peak speed (1.1%; ES 0.23 ± 0.44) and mean speed over the initial 4s (6.3%; ES 0.45 ± 0.46) were possibly faster during combination compared to high intensity running with unclear differences when compared to repeated sprinting. This was despite most likely (21.6%; ES 7.65 ± 1.02) differences in prescribed speeds between conditions. There were likely reductions in F:C at 14 hours ratio after high intensity (-5.6%; ES –0.44 ± 0.32) and combination running (-6.8%; ES -0.53 ± 0.47). Changes in the repeated sprinting condition were unclear. Conclusions: Actual movement characteristics of high intensity running drills may not reflect those used to prescribe them whilst reductions in F:C ratio are still evident 14 hours after their completion.
Physiological, perceptual and performance responses associated with self-selected versus standardized recovery periods during a repeated sprint protocol in elite youth football players: A preliminary studyGibson, Neil; Brownstein, Callum; Ball, Derek; Twist, Craig; Heriot-Watt University; Northumbria University; University of Chester (Human Kinetics, 2017-05-31)Purpose: To examine the physiological and perceptual responses of youth footballers to a repeated sprint protocol employing standardized and self-selected recovery. Methods: Eleven male participants (13.7 ± 1.1 years) performed a repeated sprint assessment comprising 10 x 30 m efforts. Employing a randomized crossover design, repeated sprints were performed using 30 s and self-selected recovery periods. Heart rate was monitored continuously with ratings of perceived exertion (RPE) and lower body muscle power measured 2 min after the final sprint. The concentration of blood lactate was measured at 2, 5 and 7 minutes post sprinting. Magnitude of effects were reported using effect size (ES) statistics ± 90% confidence interval and percentage differences. Differences between trials were examined using paired student t-tests (p < 0.05). Results: Self-selected recovery resulted in most likely shorter recovery times (57.7%; ES 1.55 ± 0.5; p < 0.01), a most likely increase in percentage decrement (65%; ES 0.36 ±1 0.21; p = 0.12), very likely lower heart rate recovery (-58.9%; ES -1.10 ± 0.72; p = 0.05), and likely higher blood lactate concentration (p = 0.08-0.02). Differences in lower body power and RPE were unclear (p > 0.05). Conclusion: Self-selected recovery periods compromise repeated sprint performance.
Playing exposure does not affect movement characteristics or physiological responses of elite youth footballers during an intensified period of competition.Gibson, Neil; McCunn, Robert; MacNay, Sophie; Mullen, Thomas; Twist, Craig; Heriot-Watt University; University of Chester (Taylor & Francis, 2018-05-08)This study investigated the effect of playing time on physiological and perceptual responses to six, 60 min matches played over five days. Thirty youth football players (age = 14.1 ± 0.4 years; body mass = 57.4 ± 12.9 kg; stature 169.3 ± 7.7 cm) were grouped into low (<250 min; LPG, n = 18) and high (≥250 min; HPG, n = 12) match exposure groups and monitored daily for lower body power and perceived wellness. GPS technology was used to assess match running demands in total distance (m•min-1), low (<13 km•h-1) and high (≥13 km•h-1) speed running categories. Hypothesis based testing and effect sizes (ES) were used to analyse data. The HPG performed moderately more total distance (103.7 ± 10.4 cf. 90.2 ± 19.7 m•min-1, P = 0.03; ES=0.74 ± 0.63) and high speed running (26.7 ± 6.6 cf. 20.3 ± 6.5 m•min-1, P = 0.01; ES=0.87 ± 0.6) than the LPG across all six matches. Differences of a small magnitude were observed between groups for lower body power (P = 0.08; ES =0.59 ± 0.8) and perceived wellness (P = 0.09; ES=0.42 ± 0.4) which were both higher in the HPG. Youth football players appear well equipped to deal with intensified period of competition, such as those experienced in tournaments, irrespective of match exposure.