Better efficiency, more strength and power, and greater training volume without additional breakdown — these are the ways in which cross-training directly boosts running fitness.
更有效，更有力量，更有能量，更高的训练量而没有伤痛——这些是交叉训练直接提高跑步能力的方面。
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These are evident in the fish’s speed (up to 70kph) and extreme swimming efficiency, evolution having honed its body to reduce drag and thus conserve strength during transoceanic migrations.