Treadmill

A treadmill, comprising:

• a frame unit;
• a running belt unit including a front roller rotatably mounted on a front end of said frame unit, a rear roller rotatably mounted on a rear end of said frame unit, and a running belt sleeved on said front roller and said rear roller, said running belt having a front end portion and a rear end portion;
• a power unit including a driving motor mounted on said frame unit, and a transmission mechanism, said driving motor having an output shaft, said transmission mechanism being mounted between said output shaft and said front roller, said driving motor driving said front roller to rotate via said transmission mechanism;
• a protection unit including a protection shield mounted on said frame unit and adjacent to said rear end portion, a protection baffle mounted on said protection shield, and at least one biasing member mounted between said protection shield and said protection baffle, said protection shield extending rearwardly and upwardly from said rear end portion of said running belt, an interval space being formed between said protection shield and said rear end portion, said interval space having a top opening, said protection baffle being switchable between a blocking state and an open state relative to said protection shield, said protection baffle blocking said top opening when being in said blocking state, said protection baffle not blocking said top opening when being in said open state, said at least one biasing member resiliently biasing said protection baffle to switch to said blocking state;
• and
• a displacement sensing unit mounted on said frame unit and adjacent to said rear end portion of said running belt, said protection baffle triggering said displacement sensing unit when said protection baffle is in said open state.