title: Influence of thigh muscle strength and balance on hop length in one-legged hopping in children aged 7-12 years.
abstract: BACKGROUND
  Lower extremity muscular strength and balance are essential components in many motor performance skills. One-legged hopping is considered to be the most advanced jumping skill, because it requires greater muscle strength and better balance than other jumping skills. To what degree muscle strength and balance have significant influence on hop length in children is, however, unknown.
  
  
  OBJECTIVE
  The purpose of the present study was to identify predictive factors for hop length in one-legged hopping. The main hypothesis was that both muscle strength of the thigh (quadriceps and hamstrings) and balance would be significant predictors in healthy children 7-12 years of age.
  
  
  METHODS
  341 girls and boys were included in the study. Hopping data was collected using the GAITRite system, muscle strength was tested isokinetically by a Cybex 6000 and one leg static balance was measured by the KAT 2000 system.
  
  
  RESULTS
  Hop length and thigh muscle strength showed increased values from one age group to the next from 7 to 12 years of age, while static balance only showed minor fluctuation. Multiple regression analysis showed that thigh strength, static balance, age and gender all together explained 53.4% of the variance in hop length. Age, quadriceps strength and hamstrings strength made the largest contributions with Beta 0.32, p<0.001, Beta 0.26, p=0.001 and Beta 0.18, p=0.003, respectively. Static balance and gender did not contribute significantly.
  
  
  CONCLUSIONS
  Of the measurements investigated in this study, age and thigh muscle strength are the strongest predictors for hop length in one-legged hopping skills in children.
authors.affiliation: Division of Rehabilitation, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway.
authors.forename: Anne Therese
authors.initials: AT
authors.lastname: Tveter
authors.forename: Inger
authors.initials: I
authors.lastname: Holm
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D012044:Regression Analysis; D013848:Thigh / Q000502:physiology*