title: Letter to the editor regarding "Application of principal component analysis in clinical gait research" by Federolf and colleagues.
authors.affiliation: Applied Sports Performance Research, School of Health and Human Performance, Dublin City University, Dublin, Ireland; Insight Centre for Data Analytics, Dublin City University, Dublin, Ireland. Electronic address: kieran.moran@dcu.ie.
authors.forename: Kieran
authors.initials: K
authors.lastname: Moran
authors.affiliation: Applied Sports Performance Research, School of Health and Human Performance, Dublin City University, Dublin, Ireland; Insight Centre for Data Analytics, Dublin City University, Dublin, Ireland.
authors.forename: Chris
authors.initials: C
authors.lastname: Richter
authors.affiliation: Insight Centre for Data Analytics, Dublin City University, Dublin, Ireland.
authors.forename: Noel E
authors.initials: NE
authors.lastname: O'Connor
mesh_terms: D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology*