Prolonged swing phase rectus femoris activity is not associated with stiff-knee gait in children with cerebral palsy: a retrospective study of 407 limbs.

Prolonged swing phase rectus femoris (RF) activity has been implicated as a cause of stiff-knee gait (SKG) in children with cerebral palsy (CP) and continues to be cited as an indicator for RF intervention. The purpose of this study was to determine what, if any, association exists between abnormal RF activity during preswing, initial swing and/or midswing and SKG in children with CP. This retrospective analysis involved three examiners independently reviewing sagittal plane knee kinematic and RF surface electromyographic (EMG) data from 407 affected limbs of 234 pediatric patients with CP. Five kinematic parameters were rated by each examiner as normal or pathologic: peak knee flexion, knee range of motion during initial swing, total knee range of motion, peak knee flexion timing, and rate of knee flexion. These ratings were used to classify each limb into one of three groups: SKG, Borderline SKG, or Non-SKG. From a representative EMG tracing, RF activity was examined during: the first half of preswing, the latter 2/3 of initial swing, and midswing. Chi-squared tests were used to determine if significant associations existed between SKG and RF activation during these three subphases. There was no association between SKG and prolonged RF activity during the latter 2/3 of initial swing or during midswing. However, a significant relationship between SKG and RF activity during the first half of preswing was found (p<0.001). Neither prolonged RF activity during initial swing, nor the presence of RF activity during midswing, were associated with SKG, thus refuting these commonly held associations.

The sacroiliac joint: review of anatomy, mechanics, and function.

The purpose of this paper is to review the anatomy and function of the pelvis in order to enhance the clinical understanding of this closed chain kinematic complex. The relevant bony and soft tissue anatomy is discussed with an emphasis on the complex and unique features of the related parts of the pelvis. Osteokinematics of the pelvis and the sacroiliac joints are discussed relevant to functional movements of the spine and lower extremities. Intrapelvic joint surface motion is presented in light of past and more recent experimental work. Questions regarding the validity of clinical sacroiliac models and future research are posed. J Orthop Sports Phys Ther 1991;13(2):71-84.

lsokinetic Shoulder Strength of High School and College-Aged Pitchers*.

The purpose of this study was to determine the isokinetic strength of the shoulders of high school and college-aged baseball pitchers. Twenty-four athletes ranging from 14 to 21 years of age volunteered for this study. The Cybex(R) II and U.B.X. T. were utilized to test the strength of the shoulder abductors/adductors, flexors/extensors, horizontal abductors/adductors, and external/internal rotators at 90, 120, 2 10, and 300 degrees /sec. There were no consistent differences between dominant and nondominant arm strength, except for the shoulder adductors and shoulder extensors. The shoulder abductors and flexors were approximately 50% as strong as the adductors and extensors, respectively. There was a 1:1 ratio between the horizontal abductors/ adductors. The external rotators were approximately two-thirds as strong as the internal rotators. A positive correlation was found between total body weight and shoulder strength. This information is relatively new to the literature and should provide clinicians with some training and rehabilitation guidelines. J Orthop Sports Phys Ther 1986;7(4):163-172.

Isokinetic strength characteristics of the quadriceps femoris and hamstring muscles in high school students.

The purpose of this study was to determine the isokinetic strength of the quadriceps femoris and hamstring muscles in high school-aged students. Forty-seven 15- to 18-year-old high school volunteers served as subjects. Data were gathered on each subject by a questionnaire, lower extremity musculoskeletal assessment, and isokinetic testing of the two muscle groups at 60 degrees/sec and 180 degrees/sec. This study found no age effect on peak torque and no significant differences in peak torque between dominant and nondominant limbs. Significant differences (p less than .001) occurred between the isokinetic strength of male and female subjects. The average hamstring muscle to quadriceps femoris muscle torque ratio was 57 percent at 60 degrees/sec and 70 percent at 180 degrees/sec. A value of foot pounds of torque per kilogram of body weight was provided as a guideline for clinicians. This investigation supports several findings already reported for other age groups.