锻炼动机谱系：其数量、形式和持久性方面可区分的自主动机和受控动机的梯度。

Sustaining physical activity, not merely starting it, is the harder half of the public health problem. Self-determination theory holds that the quality of motivation is tied to which half succeeds, yet population evidence is scarce. We designed and conducted the 2020 China National Fitness Survey and analysed 74,407 exercising adults aged 19 to 101 from every mainland province, measuring the motivational spectrum, psychological need satisfaction, and three axes of behaviour: amount, form, and durability. The autonomous-to-controlled continuum replicated across an independent adolescent sample,