BACKGROUND Oxygen cost of running is largely influenced by endurance training strategies, including interval and continuous training. However, which training method better reduces the oxygen cost remains unknown. OBJECTIVE This study aimed to systematically review the scientific literature and performs a meta-analysis to address the effects of different endurance training modalities on the oxygen cost of running. METHODS A literature search on 3 databases (MEDLINE, SPORTDiscus and Web of Science) was conducted on February 28, 2019. After analysing 8028 resultant articles, studies were included if they met the following inclusion criteria: (a) studies were randomised controlled trials, (b) studies included trained runners without previous injuries (c) interventions lasted at least 6 weeks, with participants allocated to Interval (INT) or Continuous (CON) groups, and (d) oxygen cost was assessed pre- and post-training intervention. Six studies (seven trials) met the inclusion criteria and were included in the meta-analysis. This resulted in 295 participants (n = 200 INT; n = 95 CON training method). Standardised mean difference with 95% confidence intervals (CI) between INT and CON conditions and effect sizes were calculated. To assess the potential effects of moderator variables (such as, age, VO2max of participants, number of weeks of intervention) on main outcome (oxygen cost of running), subgroup analyses were performed. RESULTS Comparing changes from pre- to post-intervention, oxygen cost improved to a greater extent in CON when compared to INT interventions (0.28 [95% CI 0.01, 0.54], Z = 2.05, p = 0.04, I2 = 30%). Oxygen cost improvements were larger in participants with higher VO2max (≥ 52.3 ml kg-1 min-1) (0.39 [95% CI 0.06, 0.72], Z = 2.34, p = 0.02), and in programs greater or equal to 8 weeks (0.35 [95% CI 0.03, 0.67], Z = 2.13, p = 0.03). When the total volume per week of INT was ≥ 23.2 min, there was a significant improvement favorable to CON (0.34 [95% CI 0.01, 0.61], Z = 2.02, p = 0.04). CONCLUSION Continuous training seems, overall, a better strategy than interval training to reduce the oxygen cost in recreational endurance runners. However, oxygen cost reductions are influenced by several variables including the duration of the program, runners' aerobic capacity, the intervals duration and the volume of interval training per week. Practitioners and coaches should construct training programs that include both endurance training methods shown to be effective in reducing the oxygen cost of running.

中文翻译：

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间歇性和连续性训练对休闲跑步者的氧气成本的影响：系统评价和荟萃分析。

背景技术跑步的氧气成本在很大程度上受耐力训练策略的影响，包括间歇训练和连续训练。然而，哪种训练方法可以更好地降低氧气成本仍然未知。目的本研究旨在系统地回顾科学文献并进行荟萃分析，以解决不同耐力训练方式对跑步氧耗的影响。方法于2019年2月28日在3个数据库（MEDLINE，SPORTDiscus和Web of Science）上进行了文献检索。在对8028篇文章进行分析后，如果符合以下纳入标准，则将其纳入研究：（a）研究为随机对照试验， （b）研究包括没有受伤的训练有素的跑步者（c）干预至少持续6周，参与者被分为间隔（INT）或连续（CON）组，并且（d）在训练前后对氧气成本进行了评估。六项研究（七项试验）符合纳入标准，被纳入荟萃分析。这导致295名参与者（n = 200 INT； n = 95 CON训练方法）。计算了INT和CON条件与效应大小之间的标准均值差（95％置信区间（CI））。为了评估主持人变量（例如年龄，参与者的最大摄氧量，干预周数）对主要结局（跑步的氧气成本）的潜在影响，进行了亚组分析。结果比较干预前后的变化，与INT干预相比，CON的氧气费用有较大程度的改善（0.28 [95％CI 0.01，0.54]，Z = 2.05，p = 0.04，I2 = 30％）。最大摄氧量（≥52.3 ml kg-1 min-1）（0.39 [95％CI 0.06，0.72]，Z = 2.34，p = 0.02）和大于或等于8周的计划中的参与者的氧气费用改善更大（0.35 [95％CI 0.03，0.67]，Z ＝ 2.13，p ＝ 0.03）。当INT的每周总体积≥23.2 min时，CON显着改善（0.34 [95％CI 0.01，0.61]，Z = 2.02，p = 0.04）。结论总的来说，连续训练似乎比间隔训练更好的策略是减少休闲耐力跑步者的氧气消耗。但是，氧气消耗量的减少受几个变量的影响，包括计划的持续时间，跑步者的有氧能力，间歇时间和每周间歇训练的数量。