In the analysis of human movement, researchers often sum individual joint kinetics to obtain a single measure of lower extremity function. The extent to which these summed measures relate to the mechanical objectives of the task has not been formally validated. The criterion validity of these measures was established with comparisons to the mechanical objective of two multiple-joint tasks. For the Work task 18 participants performed a loaded barbell squat using 4 resistances while instrumented for biomechanical analysis. For the Power they performed 2 predetermined amounts of work at both self-selected and fast speeds. Using inverse dynamics techniques, the peak net joint moment (PM) was calculated bilaterally in the sagittal plane at the ankle, knee, and hip and was summed into a single measure. This measure was correlated with the task objectives using simple linear regression. Similar procedures were used for the average net joint moment (AM), peak (PP), and average (AP) net joint moment power, and the net joint moment impulse (IM) and work (IP). For the Work task all 6 measures were significantly correlated with the task objective, but only AM, PM, and IP had correlation coefficients above 0.90. For the Power task, IM was not significantly correlated with the task objective, and only AP had a correlation coefficient above 0.90. These findings indicate that the validity of summing individual kinetic measures depends on both the measure chosen and the mechanical objective of the task.
Search Results
The Validity of Summing Lower Extremity Individual Joint Kinetic Measures
Sean P. Flanagan and George J. Salem
Lower Extremity Coupling Parameters during Locomotion and Landings
Mark D. Tillman, Chris J. Hass, John W. Chow, and Denis Brunt
During ballistic locomotion and landing activities, the lower extremity joints must function synchronously to dissipate the impact. The coupling of subtalar motion to tibial and knee rotation has been hypothesized to depend on the dynamic requirements of the task. This study was undertaken to look for differences in the coupling of 3-D foot and knee motions during walking, jogging, and landing from a jump. Twenty recreationally active young women with normal foot alignment (as assessed by a licensed physical therapist) were videotaped with high-speed cameras (250 Hz) during walking, jogging, hopping, and jumping trials. Coupling coefficients were compared among the four activities. The ratio of eversion to tibial rotation increased from the locomotion to the landing trials, indicating that with the increased loading demands of the activity, the requirements of foot motion increased. However, this increased motion was not proportionately translated into rotation of the tibia through the subtalar joint. Furthermore, the ratio of knee flexion to knee internal rotation increased significantly from the walking to landing trials. Together these findings suggest that femoral rotation may compensate for the increase in tibial rotation as the force-dissipating demands of the task increase. The relative unbalance among the magnitude of foot, tibial, and knee rotations observed with increasing task demands may have direct implications on clinical treatments aimed at reducing knee motion via controlling motion at the foot during landing tasks.
Effect of Graft Type on Thigh Circumference, Knee Range of Motion, and Lower-Extremity Strength in Pediatric and Adolescent Males Following Anterior Cruciate Ligament Reconstruction
Dai Sugimoto, Benton E. Heyworth, Brandon A. Yates, Dennis E. Kramer, Mininder S. Kocher, and Lyle J. Micheli
their lower-extremity muscles, and a tape measure was applied to the thigh at 10 cm from proximal patella bilaterally. 15 , 38 Range of Motion Test A goniometer was positioned lateral to the knee joint to measure passive knee extension and flexion ROMs. Pivot of the goniometer was placed at the joint
Lower Limb Flexibility in Children With Duchenne Muscular Dystrophy: Effects on Functional Performance
Lütfiye Akkurt, İpek Alemdaroğlu Gürbüz, Ayşe Karaduman, and Öznur Tunca Yilmaz
functional levels were at 1 or 2 according to the Brooke Lower Extremity Functional Classification Scale, were included in the study. The inclusion criteria for the patients were as follows: (1) They must have been diagnosed with DMD. (2) They must be in the ambulatory period and be able to climb 4 steps
The Effect of a Simulated Knee Effusion on Lower Extremity Performance
Lori A. Bolgla, Douglas R. Keskula, and Jewell B. Duncan
Context:
Researchers have suggested that quadriceps inhibition resulting from a simulated knee effusion would lead to decreased lower extremity performance.
Purpose:
To investigate the relationship between a simulated knee effusion and lower extremity performance.
Participants:
9 college students.
Methods:
Subjects performed 3 functional-performance tests before and after a simulated knee effusion. Measurement was the average distance hopped for a single hop and crossover hop for distance and time for completion on a timed hop test.
Results:
An analysis of variance revealed significant change in average test scores after injection only for the timed hop in subjects receiving a 60-ml injection.
Conclusion:
Nonsignificant differences might have resulted from compensation from other muscle groups, fluid movement within the knee joint, and absence of an inflammatory process. Further research on the relationship between simulated knee effusion and lower extremity performance is needed.
Joint Coordination and Stiffness During Landing in Individuals With Chronic Ankle Instability
Yumeng Li, Jupil Ko, Marika A. Walker, Cathleen N. Brown, and Kathy J. Simpson
sprains in sports activities. Therefore, the purpose of the present study was to examine the effect of CAI on lower-extremity joint coordination and stiffness during landing. Specifically, we compared the joint coordination (ankle–knee and knee–hip) and stiffness between the CAI and healthy control groups
The Effects of a Lateral In-flight Perturbation on Lower Extremity Biomechanics During Drop Landings
Jae P. Yom, Kathy J. Simpson, Scott W. Arnett, and Cathleen N. Brown
One potential ACL injury situation is due to contact with another person or object during the flight phase, thereby causing the person to land improperly. Conversely, athletes often have flight-phase collisions but do land safely. Therefore, to better understand ACL injury causation and methods by which people typically land safely, the purpose of this study was to determine the effects of an in-flight perturbation on the lower extremity biomechanics displayed by females during typical drop landings. Seventeen collegiate female recreational athletes performed baseline landings, followed by either unexpected laterally-directed perturbation or sham (nonperturbation) drop landings. We compared baseline and perturbation trials using paired-samples t tests (P < .05) and 95% confidence intervals for lower-extremity joint kinematics and kinetics and GRF. The results demonstrated that perturbation landings compared with baseline landings exhibited more extended joint positions of the lower extremity at initial contact; and, during landing, greater magnitudes for knee abduction and hip adduction displacements; peak magnitudes of vertical and medial GRF; and maximum moments of ankle extensors, knee extensors, and adductor and hip adductors. We conclude that a lateral in-flight perturbation leads to abnormal GRF and angular motions and joint moments of the lower extremity.
Does the FIFA 11+ Program Prevent Hamstring Injuries in College-Aged Male Soccer Players? A Critically Appraised Topic
Scott Benson Street and Thomas Kaminski
participating in the sport of soccer, accounting for 12% to 16% of all injuries. 3 The Fédération Internationale de Football Association (FIFA) has developed a warm-up program known as the FIFA 11+, with the focus of improving strength and reducing the incidence of lower-extremity injuries that soccer players
Lower Extremity Movement Preparation and Children with Attention Deficit Hyperactivity Disorder
Scott J. Pedersen and Paul R. Surburg
This study investigated the movement preparation (reaction time) and movement execution (movement time) of children with and without ADHD by manipulating the uncertainty of occurrence. Participants performed a seated lower extremity choice response time protocol, which contained either 10% catch trials or 30% catch trials along with 27 empirical stimuli to one of three target directions. Results indicated that children with ADHD were significantly slower at processing lower extremity movements than their peers for the condition with increased number of catch trials, but not the condition with fewer catch trials. These findings suggest that children with ADHD are more affected by the uncertainty of an empirical stimulus during the preparation phase of a movement response than their age-matched peers are.
The Effects of Vacuum-Molded Orthotics on Lower Extremity Overuse injuries
Matthew P. Callahan, Craig R. Denegar, and Craig A. Segree
Orthotics are commonly prescribed for the treatment of lower extremity injuries secondary to hyperpronation. However, the efficacy of vacuum-molded orthotics has not been established. We assessed the effects of vacuum-molded orthotics on pain and level of function in athletes suffering from plantar fasciitis, medial tibial stress syndrome, or knee pain secondary to hyperpronation. Fourteen athletes assessed their pain and level of function during athletic activity before being fitted for orthotics (Professional Rx, SuperFeet In-Shoe Systems Inc.) and weekly for 7 weeks following break-in. Five athletes (36%) reported complete pain resolution and eight (57%) reported substantial improvement. Eight athletes (57%) reported full return to athletic participation and five (36%) reported substantial improvement in athletic function. One athlete failed to respond to treatment. Results indicate that vacuum-molded orthotics are an effective treatment for lower extremity overuse injuries secondary to hyperpronation.
