title: Return to Play After Hamstring Injuries: A Qualitative Systematic Review of Definitions and Criteria.
abstract: BACKGROUND
  More than half of the recurrent hamstring injuries occur within the first month after return-to-play (RTP). Although there are numerous studies on RTP, comparisons are hampered by the numerous definitions of RTP used. Moreover, there is no consensus on the criteria used to determine when a person can start playing again. These criteria need to be critically evaluated, in an attempt to reduce recurrence rates and optimize RTP.
  
  
  OBJECTIVE
  To carry out a systematic review of the literature on (1) definitions of RTP used in hamstring research and (2) criteria for RTP after hamstring injuries.
  
  
  METHODS
  Systematic review.
  
  
  METHODS
  Seven databases (PubMed, EMBASE/MEDLINE, CINAHL, PEDro, Cochrane, SPORTDiscus, Scopus) were searched for articles that provided a definition of, or criteria for, RTP after hamstring injury. There were no limitations on the methodological design or quality of articles. Content analysis was used to record and analyze definitions and criteria for RTP after hamstring injury.
  
  
  RESULTS
  Twenty-five papers fulfilled inclusion criteria, of which 13 provided a definition of RTP and 23 described criteria to support the RTP decision. "Reaching the athlete's pre-injury level" and "being able to perform full sport activities" were the primary content categories used to define RTP. "Absence of pain", "similar strength", "similar flexibility", "medical staff clearance", and "functional performance" were core themes to describe criteria to support the RTP decision after hamstring injury.
  
  
  CONCLUSIONS
  Only half of the included studies provided some definition of RTP after hamstring injury, of which reaching the athlete's pre-injury level and being able to perform full sport activities were the most important. A wide variety of criteria are used to support the RTP decision, none of which have been validated. More research is needed to reach a consensus on the definition of RTP and to provide validated RTP criteria to facilitate hamstring injury management and reduce hamstring injury recurrence. PROSPERO systematic review registration number: CRD42015016510.
authors.affiliation: Department of Rehabilitation, Nursing Science and Sports, University Medical Center Utrecht, Rudolf Magnus Institute of Neurosciences, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands. n.vanderhorst-3@umcutrecht.nl.
authors.forename: Nick
authors.initials: N
authors.lastname: van der Horst
authors.affiliation: Department of Rehabilitation, Nursing Science and Sports, University Medical Center Utrecht, Rudolf Magnus Institute of Neurosciences, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: van de Hoef
authors.affiliation: Department of Orthopaedics, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Reurink
authors.affiliation: Department of Rehabilitation, Nursing Science and Sports, University Medical Center Utrecht, Rudolf Magnus Institute of Neurosciences, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Bionka
authors.initials: B
authors.lastname: Huisstede
authors.affiliation: Department of Rehabilitation, Nursing Science and Sports, University Medical Center Utrecht, Rudolf Magnus Institute of Neurosciences, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: Backx
mesh_terms: D001265:Athletic Injuries / Q000503:physiopathology* / Q000628:therapy; D000070633:Hamstring Muscles / Q000293:injuries*; D006801:Humans; D053580:Muscle Strength / Q000502:physiology; D063806:Myalgia / Q000209:etiology; D020127:Recovery of Function; D012008:Recurrence; D000068958:Return to Sport; D013997:Time Factors