title: The effect of socks on vertical and anteroposterior ground reaction forces in walking and running.
abstract: BACKGROUND
  Previous research suggests that socks may have the potential for injury protection through the absorption and/or redistribution of impact forces. However, there is limited research regarding the shock attenuation qualities of athletic socks in sporting populations and previously observed pressure reductions have not been quantified using a force plate.
  
  
  OBJECTIVE
  Firstly to identify the effect of specialist athletic socks on vertical and anteroposterior ground reaction forces (GRFs) during walking and running. Secondly, to compare GRFs between specialist socks, non-specialist socks and barefoot walking and running conditions.
  
  
  METHODS
  Following ethical approval participants (n=5) completed five walking (1.52-1.68 m s(-1)) and running (3.8-4.2 m s(-1)) trials, unshod, over a force plate. This was completed before and after a 5000 m run (3.2 m s(-1)) in their own trainers in three conditions; barefoot, non-specialist socks and specialist running socks.
  
  
  RESULTS
  Significant differences were identified between barefoot and specialist sock conditions for pre-intervention time to impact peak (F=3.110((2)), P=.05, r=.11) and maximum propulsive force (F=8.126((2)), P=.001, r=.25) when walking. Post hoc analysis identified an increase of .0016 s in time to impact peak when walking barefoot compared to the specialist sock condition (T=-7.402((4)), P=.002, r=.71). During walking the specialist sock also demonstrated a significant decrease of .075 BWs in maximum propulsive force when compared to the barefoot condition (T=-7.624((4)), P=.002, r=.79). Both significant effects diminished following the 5000 m run.
  
  
  CONCLUSIONS
  Findings suggest that the specialist running sock has limited effects on GRFs and therefore may be responsible for a limited degree of shock attenuation experienced during walking.
authors.affiliation: Centre for Health, Exercise and Sport Science, Southampton Solent University, East Park Terrace, Hampshire, UK. tim.blackmore@solent.ac.uk
authors.forename: Tim
authors.initials: T
authors.lastname: Blackmore
authors.forename: Nick
authors.initials: N
authors.lastname: Ball
authors.forename: Joanna
authors.initials: J
authors.lastname: Scurr
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003020:Clothing; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D012420:Running / Q000502:physiology*; D019876:Sports Equipment; D016138:Walking / Q000502:physiology*