title: Changes in Running Performance After Four Weeks of Interval Hypoxic Training in Australian Footballers: A Single-Blind Placebo-Controlled Study.
abstract: There is a paucity of data examining the impact of high-intensity interval hypoxic training (IHT) on intermittent running performance. This study assessed the effects of IHT on 17 amateur Australian Footballers, who completed 8 interval treadmill running sessions (IHT [FIO2 = 15.1%] or PLACEBO) over 4 weeks, in addition to normoxic football (2 per week) and resistance (2 per week) training sessions. To match relative training intensity, absolute IHT intensity reduced by 6% of normoxic vV[Combining Dot Above]O2peak compared with PLACEBO. Before and after the intervention, performance was assessed by Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) and a self-paced team sport running protocol. Standardized effect size statistics were calculated using Cohen's d to compare between the interventions. Compared with PLACEBO, IHT subjects experienced (a) smaller improvements in Yo-Yo IR2 performance (Cohen's d = -0.42 [-0.82 to -0.02; 90% confidence interval]); (b) similar increases in high-intensity running distance during the team sport protocol (d = 0.17 [-0.50 to 0.84]); and (c) greater improvements in total distance (d = 0.72 [0.33-1.10]) and distance covered during low-intensity activity (d = 0.59 [-0.07 to 1.11]) during the team sport protocol. The lower absolute training intensity of IHT may explain the smaller improvements in Yo-Yo IR2 performance in the hypoxic group. Conversely, the data from the self-paced protocol suggest that IHT may positively influence pacing strategies in team sport athletes. In conclusion, IHT alters pacing strategies in team sport athletes (i.e., increased distance covered during low-intensity activity). However, IHT leads to smaller improvements in externally paced high-intensity intermittent running performance (i.e., Yo-Yo IR2), which may be related to a reduced absolute training intensity during IHT sessions.
authors.affiliation: 1School of Exercise Science, Australian Catholic University, Melbourne, Australia; 2Department of Physiology, Australian Institute of Sport, Canberra, Australia; and 3Exercise Physiology Laboratory, Flinders University of South Australia, Bedford Park, Australia.
authors.forename: Blake D
authors.initials: BD
authors.lastname: McLean
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Tofari
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gore
authors.forename: Justin G
authors.initials: JG
authors.lastname: Kemp
mesh_terms: D000293:Adolescent; D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001315:Australia; D005080:Exercise Test; D005538:Football / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D064797:Physical Conditioning, Human / Q000379:methods*; D010807:Physical Endurance / Q000502:physiology; D012420:Running / Q000502:physiology*; D016037:Single-Blind Method; D055815:Young Adult