Relationship between velocity reached at VO2max and time-trial performances in elite australian rules footballers

Purpose: Running velocity reached at maximal oxygen uptake (vVO2max) can be a useful measure to prescribe training intensity for aerobic conditioning. Obtaining it in the laboratory is often not practical, and average velocities from time trials are an attractive alternative. To date, the efficacies of such practices for team sport players are unknown. This study aimed to assess the relationship between vVO2max obtained in the laboratory against two time-trial estimates (1500 m and 3200 m). Methods: During the early preseason, elite Australian Rules football players (n = 23, 22.7 ± 3.4 y, 187.7 ± 8.2 cm, 75.5 ± 9.2 kg) participated in a laboratory test on a motorized treadmill and two outdoor time trials. Results: Based on average velocity the 1500-m time-trial performance (5.01 ± 0.23 m·s−1) overestimated (0.36 m·s−1, d = 1.75), whereas the 3200-m time trial (4.47 ± 0.23 m·s−1) underestimated (0.17 m·s−1, d = 0.83) the laboratory vVO2max (4.64 ± 0.18 m·s−1). Despite these differences, both 1500-m and 3200-m time-trial performances correlated with the laboratory measure (r = -0.791; r = -0.793 respectively). Both subsequent linear regressions were of good ft and predicted the laboratory measure within ± 0.12 m·s−1. Conclusion: Estimates of vVO2max should not be used interchangeably, nor should they replace the laboratory measure. When laboratory testing is not accessible for team sports players, prescription of training intensity may be more accurately estimated from linear regression based on either 1500-m or 3200-m time-trial performance than from the corresponding average velocity

Reliability of the Ekblom Soccer-Specific Endurance Test

The aim of this study was to explore and quantify measurement reliability of the Ekblom endurance test. Experienced university soccer players (n = 19; age = 20.5 ± 2.5 years; mass = 80.4 ± 9.8 kg; and stature = 179.0 ± 6.0 cm) completed the Ekblom endurance test on 3 separate occasions. Time to complete trial 1 (549 ± 26 seconds) and trial 2 (547 ± 26 seconds) was analyzed, and despite no significant difference (F1,18 = 4.119, p = 0.057, [eta]P2 = 0.186) between trials, some evidence of systematic bias was observed in the data. Therefore, trial 2 data were compared with those of trial 3 (548 ± 27 seconds), with trial 1 data removed. The subsequent analysis (F1,18 = 0.740, p = 0.401, [eta]P2 = 0.039) showed a reduction in the risk of making a type II error when compared with the previous analysis. From the reliability analyses (3,1 intraclass correlation = 0.983, SEM = ±3 seconds, smallest worthwhile change = 5 seconds, standard error of prediction [95% confidence intervals] = ± 9 seconds), a high level of measurement reliability was observed and the sensitivity of the test to monitor changes was “good.” In summary, it was shown that a test that involves a variety of soccer-specific forms of locomotion can be highly reliable and sensitive to detect change. In light of the systematic bias found, we do, however, recommend a familiarization session to be scheduled before the introduction of this test

Effects of submaximal and supramaximal interval training on determinants of endurance performance in endurance athletes

We compared the effects of submaximal and supramaximal cycling interval training on determinants of exercise performance in moderately endurance-trained men. Maximal oxygen consumption (VO2max ), peak power output (Ppeak ), and peak and mean anaerobic power were measured before and after 6 weeks (3 sessions/week) of submaximal (85% maximal aerobic power [MP], HIIT85 , n = 8) or supramaximal (115% MP, HIIT115 , n = 9) interval training to exhaustion in moderately endurance-trained men. High-intensity training volume was 47% lower in HIIT115 vs HIIT85 (304 ± 77 vs 571 ± 200 min; P &lt; 0.01). Exercise training was generally associated with increased VO2max (HIIT85 : +3.3 ± 3.1 mL/kg/min; HIIT115 : +3.3 ± 3.6 ml/kg/min; Time effect P = 0.002; Group effect: P = 0.95), Ppeak (HIIT85 : +18 ± 9 W; HIIT115 : +16 ± 27 W; Time effect P = 0.045; Group effect: P = 0.49), and mean anaerobic power (HIIT85 : +0.42 ± 0.69 W/kg; HIIT115 : +0.55 ± 0.65 W/kg; Time effect P = 0.01; Group effect: P = 0.18). Six weeks of submaximal and supramaximal interval training performed to exhaustion seems to equally improve VO2max and anaerobic power in endurance-trained men, despite half the accumulated time spent at the target intensity.</p

Effect of Different Simulated Altitudes on Repeat-Sprint Performance in Team-Sport Athletes

Purpose: This study aimed to assess the impact of 3 heights of simulated altitude exposure on repeat-sprint performance in teamsport athletes. Methods: Ten trained male team-sport athletes completed 3 sets of repeated sprints (9 × 4 s) on a nonmotorized treadmill at sea level and at simulated altitudes of 2000, 3000, and 4000 m. Participants completed 4 trials in a random order over 4 wk, with mean power output (MPO), peak power output (PPO), blood lactate concentration (Bla), and oxygen saturation (SaO2) recorded after each set. Results: Each increase in simulated altitude corresponded with a significant decrease in SaO2. Total work across all sets was highest at sea level and correspondingly lower at each successive altitude (P &lt; .05; sea level &lt; 2000 m &lt; 3000 m &lt; 4000 m). In the first set, MPO was reduced only at 4000 m, but for subsequent sets, decreases in MPO were observed at all altitudes (P &lt; .05; 2000 m &lt; 3000 m &lt; 4000 m). PPO was maintained in all sets except for set 3 at 4000 m (P &lt; .05; vs sea level and 2000 m). BLa levels were highest at 4000 m and significantly greater (P &lt; .05) than at sea level after all sets. Conclusions: These results suggest that "higher may not be better," as a simulated altitude of 4000 m may potentially blunt absolute training quality. Therefore, it is recommended that a moderate simulated altitude (2000-3000 m) be employed when implementing intermittent hypoxic repeat-sprint training for team-sport athletes.</p