It may be worth mentioning that unless your horse has an ailment you cannot answer. You have given no option for no ailments and also no text box to say whether there is another cause for pain or stiffness.
The last question is rather uninformative - I opted for no as I don't believe a study looking at changes in stride length will actually mean anything by itself - other than being a curiosity. However, a full biomechanical investigation of changes in joint angles / loading force / evenness / etc would be interesting if well designed. Obviously, you don't have the scope to do that sort of project, but it's the most honest answer to a rather two dimensional question.
Also only answered for one horse as the others fall into the "no lameness" catergory which doesn't exist in your survey...
Done, but agree with the other posts, it's not going to be an accurate reflection of what we all do because there aren't enough options, or even an "other" box with a box to give more detail.
agree! filled in the survey, but could have done with a "none" box in qu 2. i ticked swollen legs, as she does suffer from filled legs if stabled, but it is rare that she is stabled!