Here is how I fixed it, yet the fix is a bit like throwing the baby out with the bath water, for many things get "reset" to solve the "lack of sprint issue". Loading a game where the issue does not exist may be a better option than this one. I used the program "Save cleaner V 1.13 beta" to edit a save game. ( Called "Save game script cleaner", version 2.06, Created by Hadoram, available on nexusmods; Links are not allowed in post ) It does have a later version available, yet I had version 1.13 beta installed. Then there is the racemenu program ( created by Expired, version 3.4.5, available on nexusmods; Links are not allowed in post ) We are going to use it to save your character's "Presets". Once this program is installed, open up the console, in Skyrim, and type showracemenu, press the console button again to make the console disappear. Look in the top right corner for "Presets" flip. In there you have the option to "Save Preset". In the game, before you save the game, find a container and put everything into it. Save the game and open that save game in "Save cleaner". Look in the top right part of it to see the "Plugins" section. It has 2 options: something to select from a drop down menu, and a button. In the drop down menu select "Skyrim.esm", then press the button "Delete mod forms". Then you save the changes. In Skyrim, load the game you edited, at this point you will notice that it is not your character. It would appear that Skyrim has given you a default character to play, so that is where the program racemenu comes in. Now we use the console, again, to open racemenu: type "showracemenu" within the console. Again, in the top right corner there is the "Preset" flip, yet now we are going to "Load Preset". There is an small exception which is that if you are not the same gender, as the character Skyrim gives you by default, then you have to switch to the gender that the saved preset was made for. To do that, you use the "Sliders" flip that is along side the "Presets" flip. You change the gender with the top option under the filter "ALL" within the "sliders" flip. It does not matter in what order you do that: change gender, load preset. As long as you just click "Load Preset" a couple of times in the end.