title: Diminutions of acceleration and deceleration output during professional football match play.
abstract: OBJECTIVE
  This study examined distances covered at low (1-2 ms(-2)), moderate (2-3 ms(-2)) and high (>3 ms(-2)) acceleration (L(ACC), M(ACC) and H(ACC) respectively) and deceleration (L(DEC), M(DEC), and H(DEC) respectively) during competitive football games. Temporal and transient patterns of acceleration and deceleration were also examined.
  
  
  METHODS
  Observational, repeated measures.
  
  
  METHODS
  Thirty-six professional male professional footballers were monitored using a 10 Hz non-differential global positioning system (NdGPS). Match data was organised into six 15 min periods (P1: 1-15 min, P2: 16-30 min, P3: 31-45 min, P4: 46-60 min, P5: 61-75 min, and P6: 76-90 min) for analysis of temporal patterns, and into eighteen 5 min periods for analysis of transient patterns. ANOVA with Bonferroni post hoc tests were used to identify significant (p<0.05) differences between periods.
  
  
  RESULTS
  Distance covered at L(ACC), M(ACC), H(ACC), L(DEC), M(DEC), and H(DEC) was 424±75 m, 242±25 m, 178±38 m, 365±54 m, 210±23 m and 162±29 m respectively. Between period decrements ranged from 8.0% to 13.2% from P1 to P3, 9.2% to 16.3% from P4 to P6, and from 14.9% to 21.0% from P1 to P6. Following PEAK H(ACC) (148% of mean 5 min H(ACC)), H(ACC) at 5POST was 10.4% lower than mean (p<0.01).
  
  
  CONCLUSIONS
  Time-dependent reductions in distances covered suggest that acceleration and deceleration capability are acutely compromised during match play. Further, the occurrence of transient fatigue may be supported by the findings that HACC and HDEC performance following PEAK was approximately 10% lower than mean values.
authors: School of Life Sciences, Northumbria University, Newcastle Upon Tyne, United Kingdom; Newcastle United Football Club, Newcastle Upon Tyne, United Kingdom. Electronic address: r.akenhead@northumbria.ac.uk.
authors: Richard
authors: R
authors: Akenhead
authors: Philip R
authors: PR
authors: Hayes
authors: Kevin G
authors: KG
authors: Thompson
authors: Duncan
authors: D
authors: French
mesh_terms: D001696:Biomechanical Phenomena; D005538:Football / Q000502:physiology*; D006801:Humans; D008297:Male; D055815:Young Adult
keywords: Acceleration; GPS; Time-motion analysis