I get it all the time, not just during sport, it is worsened with exercise though because I heat up during exercise, which triggers a fake/pseudo-exacerbation (a temporary worsening of symptoms) in many people with MS. Even a half a degree rise in body temperature can cause this for some where for others it may require a greater rise, it is referred to as Uhthoff's Phenomenon (or Uhthoff Phenomenon).
For some, hot weather can do it, as can hot showers, hot tubs, etc.
https://www.ncbi.nlm.nih.gov/books/NBK470244/
https://msfocusmagazine.org/Magazine/Magazine-Items/Understanding-and-avoiding-Uhthoff’s-phenomenon
https://mstrust.org.uk/a-z/uhthoffs-phenomenon