title: Clinical assessment of trunk flexor muscle strength in healthy girls 3 to 7 years of age.
abstract: We developed a clinical method for assessing trunk flexor muscle strength in healthy children that can be applied to assist physical therapists in determining strength accurately in pediatric patients. In this study, we assessed trunk flexor muscle strength in 75 healthy girls 3 to 7 years of age. Muscle strength was graded on a scale of 0 to 5 using modified, manual muscle testing methods. These methods attempted to minimize the amount of hip flexor muscle activity during trunk flexion and allow more isolated action of the abdominal trunk flexor muscles. The frequency of Normal (Grade 5) strength first appeared to predominate at age 5 years with the majority of children demonstrating Normal (Grade 5) strength by age 7 years. Regression analysis illustrated a positive linear relationship (beta = .37, p less than .001) between mean muscle grade and age group. We discuss muscle cross-sectional area, muscle-fiber diameter, muscle-cell number, maturation of the central nervous system, and changes in body proportions with age as possible contributing factors to the results of this study.
mesh_terms: D000009:Abdominal Muscles / Q000502:physiology*; D000367:Age Factors; D001696:Biomechanical Phenomena; D001827:Body Height; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D004576:Electromyography; D005260:Female; D006801:Humans; D009119:Muscle Contraction; D026741:Physical Therapy Modalities / Q000379:methods*; D011187:Posture