title: A 10-week randomized trial comparing eccentric vs. concentric hamstring strength training in well-trained soccer players.
abstract: OBJECTIVE
  To compare the effects of a 10-week training program with two different exercises -- traditional hamstring curl (HC) and Nordic hamstrings (NH), a partner exercise focusing the eccentric phase -- on muscle strength among male soccer players.
  
  
  METHODS
  Subjects were 21 well-trained players who were randomized to NH training (n = 11) or HC training (n = 10). The programs were similar, with a gradual increase in the number of repetitions from two sets of six reps to three sets of eight to 12 reps over 4 weeks, and then increasing load during the final 6 weeks of training. Strength was measured as maximal torque on a Cybex dynamometer before and after the training period.
  
  
  RESULTS
  In the NH group, there was an 11% increase in eccentric hamstring torque measured at 60 degrees s(-1), as well as a 7% increase in isometric hamstring strength at 90 degrees, 60 degrees and 30 degrees of knee flexion. Since there was no effect on concentric quadriceps strength, there was a significant increase in the hamstrings:quadriceps ratio from 0.89 +/- 0.12 to 0.98 +/- 0.17 (11%) in the NH group. No changes were observed in the HC group.
  
  
  CONCLUSIONS
  NH training for 10 weeks more effectively develops maximal eccentric hamstring strength in well-trained soccer players than a comparable program based on traditional HC.
authors.affiliation: Oslo Sports Trauma Research Center, Norwegian University of Sport and Physical Education, Oslo, Norway.
authors.forename: Roald
authors.initials: R
authors.lastname: Mjølsnes
authors.forename: Arni
authors.initials: A
authors.lastname: Arnason
authors.forename: Tor
authors.initials: T
authors.lastname: Østhagen
authors.forename: Truls
authors.initials: T
authors.lastname: Raastad
authors.forename: Roald
authors.initials: R
authors.lastname: Bahr
mesh_terms: D000328:Adult; D006801:Humans; D007717:Knee / Q000502:physiology; D008297:Male; D009132:Muscles / Q000502:physiology*; D010806:Physical Education and Training / Q000379:methods*; D010809:Physical Fitness; D012916:Soccer; D013997:Time Factors