Because physical demands are surging in football (soccer, USA), clubs are more and more seeking players who have a high capacity to perform repeated intense exercise. High-intensity interval training (HIIT), comprising exercise performed at intensities near or exceeding the capacity of aerobic energy systems, effectively enhances the physical conditioning of players. But given that HIIT imposes high loads, it increases the risk of overload-associated match performance decline and injury. This makes some coaches inclined to conduct HIIT in the weeks leading up to the season and during the season. Therefore, the challenge is how to optimize and dose HIIT during these phases, as they can be decisive. Studies have highlighted the utility of conducting periods of intensified training to overcome the risk of overload while at the same time enhancing performance. During intensified training periods of typically a few weeks, intensity is increased by enlarging the amount of HIIT, for example, aerobic high-intensity training or speed endurance training, while volume at low-to-moderate intensity is significantly reduced. The outcome depends on training composition and prescription—most notably, intensity and duration of bouts and recovery. When work intervals are prescribed for a few minutes at intensities > 90% heart rate max (i.e., aerobic high-intensity training), then beneficial adaptations pertaining to aerobic power and capacity are apparent. But when work intervals are conducted at much higher intensities, as all-out efforts or sprinting of typically 10- to 40-s duration with longer recovery periods (i.e., speed endurance training), beneficial adaptations pertaining to anaerobic energy systems, ion handling, and fatigue resilience are commonly observed. In this review, we discuss the utility of conducting intensified training periods to enhance performance in elite football players during the late preparation phase and competitive season.

由于橄榄球运动（美国足球）对体能的需求激增，俱乐部越来越多地寻求能够进行反复剧烈运动的球员。高强度间歇训练 (HIIT) 包括以接近或超过有氧能量系统能力的强度进行的运动，可有效增强运动员的身体素质。但鉴于 HIIT 施加高负荷，它增加了与超负荷相关的比赛表现下降和受伤的风险。这使得一些教练倾向于在赛季前几周和赛季期间进行 HIIT。因此，挑战在于如何在这些阶段优化和剂量 HIIT，因为它们可能是决定性的。研究强调了进行强化训练以克服超负荷风险同时提高表现的效用。在通常为几周的强化训练期间，通过增加 HIIT 的量来增加强度，例如有氧高强度训练或速度耐力训练，而低到中等强度的训练量会显着减少。结果取决于训练组合和处方——最显着的是，训练和恢复的强度和持续时间。当强度 > 90% 最大心率（即有氧高强度训练）的工作间隔规定为几分钟时，与有氧能力和能力相关的有益适应就会显而易见。但是当工作间隔以更高的强度进行时，由于全力以赴或通常持续 10 到 40 秒的冲刺以及更长的恢复期（即速度耐力训练），通常观察到与无氧能量系统、离子处理和疲劳恢复力有关的有益适应。在这篇综述中，我们讨论了在后期准备阶段和赛季中进行强化训练以提高精英足球运动员表现的效用。