addition, studies have implicated poor quadriceps strength as a risk factor in developing knee OA. 11 Individuals who are OB demonstrate decreased relative lower-extremity force-generating capacity compared with those who are not OB, which may be a compounding factor in this relationship. 15 , 24 , 25
Search Results
Obese Youth Demonstrate Altered Landing Knee Mechanics Unrelated to Lower-Extremity Peak Torque When Compared With Healthy Weight Youth
Matthew S. Briggs, Claire Spech, Rachel King, Mike McNally, Matthew Paponetti, Sharon Bout-Tabaku, and Laura Schmitt
Lower Extremity Joint Moments during Uphill Cycling
Graham E. Caldwell, James M. Hagberg, Steve D. McCole, and Li Li
Lower extremity joint moments were investigated in three cycling conditions: level seated, uphill seated and uphill standing. Based on a previous study (Caldwell, Li, McCole, & Hagberg, 1998), it was hypothesized that joint moments in the uphill standing condition would be altered in both magnitude and pattern. Eight national caliber cyclists were filmed while riding their own bicycles mounted to a computerized ergometer. Applied forces were measured with an instrumented pedal, and inverse dynamics were used to calculate joint moments. In the uphill seated condition the joint moments were similar in profile to the level seated but with a modest increase in magnitude. In the uphill standing condition the peak ankle plantarflexor moment was much larger and occurred later in the downstroke than in the seated conditions. The extensor knee moment that marked the first portion of the down-stroke for the seated trials was extended much further into the downstroke while standing, and the subsequent knee flexor moment period was of lower magnitude and shorter duration. These moment changes in the standing condition can be explained by a combination of more forward hip and knee positions, increased magnitude of pedal force, and an altered pedal force vector direction. The data support the notion of an altered contribution of both muscular and non-muscular sources to the applied pedal force. Muscle length estimates and muscle activity data from an earlier study (Li & Caldwell, 1996) support the unique roles of mono-articular muscles for energy generation and bi-articular muscles for balancing of adjacent joint moments in the control of pedal force vector direction.
Improvements in Lower-Extremity Function Following a Rehabilitation Program With Patterned Electrical Neuromuscular Stimulation in Females With Patellofemoral Pain: A Randomized Controlled Trial
Neal R. Glaviano, Ashley N. Marshall, L. Colby Mangum, Joseph M. Hart, Jay Hertel, Shawn Russell, and Susan Saliba
been identified in patients suffering from PFP. Lower-extremity muscle weakness, faulty lower-extremity activation patterns, and altered movement patterns are common in females with PFP. 8 – 13 These factors are modifiable, yet researchers have not identified whether these impairments result in PFP or
Lower-Extremity Kinematics During Ankle Inversion Perturbations: A Novel Experimental Protocol That Simulates an Unexpected Lateral Ankle Sprain Mechanism
Jeffrey D. Simpson, Ethan M. Stewart, Anastasia M. Mosby, David M. Macias, Harish Chander, and Adam C. Knight
mechanisms to ankle inversion perturbations. 4 , 16 However, studies assessing lower-extremity kinematic patterns prior to and after ground contact, especially in the proximal segments, with and without the knowledge of an inversion perturbation are limited. Examining lower-extremity kinematic patterns
Intrarater and Interrater Reliability and Agreement of a Method to Quantify Lower-Extremity Kinematics Using Remote Data Collection
Margaret S. Harrington, Ikeade C. Adeyinka, and Timothy A. Burkhart
]; age = 25.1 [5.6] y, height = 170 [10] cm, body mass = 69.8 (15.0) kg, body mass index = 24.0 [3.7] kg/m 2 ). Individuals were included if they were free from neurological or MSK disorders, injuries to the lower-extremity or back in the past 6 months, or any pain or discomfort that could affect their
Methods for Prediction of Core or Lower Extremity Injury Among High School Football Players as a Strategy for Longitudinal Reduction of Injury Risk
Marisa A. Colston, Gary B. Wilkerson, Hillary Dreyfus, and Ryan Ross
associated with core and lower extremity injury. Prevention of sports injuries is an often hyper-emphasized but under-utilized aspect of athletic medicine practice. Approximately 42% of injuries among high school football players affect the lower extremity, 1 compared to 54% among college players. 2 These
Neurocognitive Reaction Time Predicts Lower Extremity Sprains and Strains
Gary B. Wilkerson
Context:
Prevention of a lower extremity sprain or strain requires some basis for predicting that an individual athlete will sustain such an injury unless a modifiable risk factor is addressed.
Objective:
To assess the possible existence of an association between reaction time measured during completion of a computerized neurocognitive test battery and subsequent occurrence of a lower extremity sprain or strain.
Design:
Prospective cohort study.
Setting:
Preparticipation screening conducted in a computer laboratory on the day prior to initiation of preseason practice sessions.
Participants:
76 NCAA Division I-FCS football players.
Main Outcome Measures:
Lower extremity sprains and strains sustained between initiation of preseason practice sessions and the end of an 11-game season. Receiver operating characteristic analysis identified the optimal reaction time cut-point for discrimination between injured versus noninjured status. Stratified analyses were performed to evaluate any differential influence of reaction time on injury incidence between starters and nonstarters.
Results:
A total of 29 lower extremity sprains and strains were sustained by 23 of the 76 players. A reaction time cut-point of ≥ .545 s provided good discrimination between injured and noninjured cases: 74% sensitivity, 51% specificity, relative risk = 2.17 (90% CI: 1.10, 4.30), and odds ratio = 2.94 (90% CI: 1.19, 7.25).
Conclusions:
Neurocognitive reaction time appears to be an indicator of elevated risk for lower extremity sprains and strains among college football players, which may be modifiable through performance of exercises designed to accelerate neurocognitive processing of visual input.
Inter- and Intratester Reliability of Lower Extremity Circumference Measurements
Gary L. Harrelson, Deidre Leaver-Dunn, A. Louise Fincher, and James D. Leeper
The purpose of this study was to examine the inter- and intratester reliability of lower extremity circumference measurements obtained by two testers using the same tape measure and two different tape measures. Twenty-one male high school student-athletes participated in this study. Two testers measured lower extremity circumference at three sites using a standard flexible tape measure and a Lufkin tape measure with a Gulick spring-loaded handle attachment. Measurement sites were medial joint line, 20 cm above medial joint line, and 15 cm below medial joint line. Intraclass correlation coefficients were computed for inter- and intratester comparisons for each measuring device and each measurement site. Results indicated high reliability but a significant difference between the two tape measures. These findings indicate that the reliability of lower extremity circumference measurements is not influenced by tester experience and that the Lufkin tape measure with the Gulick handle attachment is the more accurate of the two tape measures.
An Alternative Model of the Lower Extremity during Locomotion
Saunders N. Whittlesey and Joseph Hamill
An alternative to the Iterative Newton-Euler or linked segment model was developed to compute lower extremity joint moments using the mechanics of the double pendulum. The double pendulum model equations were applied to both the swing and stance phases of locomotion. Both the Iterative Newton-Euler and double pendulum models computed virtually identical joint moment data over the entire stride cycle. The double pendulum equations, however, also included terms for other mechanical factors acting on limb segments, namely hip acceleration and segment angular velocities and accelerations Thus, the exact manners in which the lower extremity segments interacted with each other could be quantified throughout the gait cycle. The linear acceleration of the hip and the angular acceleration of the thigh played comparable roles to muscular actions during both swing and stance.
Lower-Extremity Muscle Activation during the Star Excursion Balance Tests
Jennifer Erin Earl and Jay Hertel
Objective:
To identify integrated EMG (I-EMG) activity of 6 lower-extremity muscles during the 8 Star Excursion Balance Tests (SEBTs).
Design and Setting:
Repeated measures, laboratory setting.
Subjects:
10 healthy young adults.
Interventions:
The SEBTs require the subject to balance on the stance leg and maximally reach with the contralateral foot along each of 8 lines extending from a common axis at 45° intervals.
Measures:
I-EMG activity of the vastus medialis obliquus (VMO), vastus lateralis (VL), medial hamstring (MH), biceps femoris (BF), anterior tibialis (AT), and gas-trocnemius.
Results:
Significant differences were found in all muscles (P < .05) except the gastrocnemius (P = .08). VMO and VL activity tended to be greatest with anteriorly directed excursions, whereas the MH and BF activity were greatest with posteriorly directed excursions. AT activity was lowest with the lateral excursion.
Conclusions:
Performance of the different SEBTs results in different lower-extremity muscle-activation patterns.
