title: The effects of a closed-chain, eccentric training program on hamstring injuries of a professional football cheerleading team.
abstract: OBJECTIVE
  Hamstring injuries are a common occurrence among professional football cheerleaders. The purpose of this study is to identify the effects of an eccentric, closed-chain hamstring exercise intervention on hamstring injury-associated pain during the course of the football season among professional football cheerleaders.
  
  
  METHODS
  Forty-three female cheerleaders participated in an eccentric, closed-chain hamstring exercise intervention protocol provided by doctors of chiropractic that incorporated loops of elastic-band or Thera-Band Loops (Hygenic Corporation, Akron, OH) during practice and at home during the regular football season. Hamstring injury-related pain was assessed in June, during team selection; in September, at the start of the season; and in December, at the end of season. No intervention was applied between June and September, although the sample participated in 4 hours of practice 2 to 3 times per week. The intervention was applied to the entire sample regardless of hamstring injury-related pain during the regular football season between September and December. The interventions included 2 exercises and were completed bilaterally 2 times per week at each biweekly practice and were encouraged to be done at least 3 additional times per week at home on nonpractice days.
  
  
  RESULTS
  Among the subsample who reported hamstring-related injury pain between June and September, the exercise intervention significantly decreased (P < .007) pain between September (6.07 ± 0.58) and December (3.67 ± 0.65).
  
  
  CONCLUSIONS
  The eccentric, closed-chain hamstring exercise intervention reduced hamstring injury-related pain among this group of professional football cheerleaders.
authors.affiliation: Sport and Spine Rehab Clinical Research Foundation, Rockville, MD, USA.
authors.forename: Jay S
authors.initials: JS
authors.lastname: Greenstein
authors.forename: Barton N
authors.initials: BN
authors.lastname: Bishop
authors.forename: Jean S
authors.initials: JS
authors.lastname: Edward
authors.forename: Robert V
authors.initials: RV
authors.lastname: Topp
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000534:rehabilitation*; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D006801:Humans; D007869:Leg Injuries / Q000534:rehabilitation*; D013708:Tendon Injuries / Q000534:rehabilitation*; D055815:Young Adult