Special Supplement
Marina U. McCulloch, Denis Brunt, Darl W. Vander Linden
Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1992, Newport Beach, CA.
Research on foot orthotics is primarily restricted to their effect on the lower limb during running. Research is limited, however, on the potential of foot orthotics to control the mechanics of the foot during walking. The purpose of this study was to examine the interactive effect of foot orthotics and two walking speeds on the angular changes at the rearfoot, ankle, and knee, and temporal events during stance. Ten subjects demonstrating a minimum of 3° of calcaneal eversion in relaxed standing participated in the project. All subjects routinely wore functional orthotics that were used during testing in conjunction with personal athletic shoes. Individuals were tested with and without the orthotics while walking on a treadmill at 2 and 3 mph. A four-camera motion analysis system was used to capture three-dimensional motion at 60 frames per second. Angle plots illustrated changes in joint motion at the knee, ankle, and rearfoot. Temporal data for heel strike, heel rise, and toe off of the foot during the stance were calculated. A two-factor repeated analysis of variance was used to determine the main and interactive effects of the orthotic and sped on the dependent variables. When walking with the orthotic, there was a significant reduction in the degree of pronation throughout stance as well as an increase in the duration of stance time as measured from heel strike to heel rise. The orthotic did not significantly reduce the velocity of pronation during the first 20% of stance. There was a speed effect for peak dorsiflexion and knee flexion. The data are discussed with respect to a biomechanical rationale for the effects noted and the need for the use of orthotics during walking as well as during more strenuous exercise.
J Orthop Sports Phys Ther 1993;17(1):2-10.
Key Words: orthotics, gait, kinematics
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Research Report
Doug Caylor, Ryan Fites, Teddy W. Worrell
Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1992, Newport Beach, CA.
Anterior knee pain syndrome (AKPS) represents a significant challenge for patients and for clinicians. The purposes of this study were: 1) to determine the reliability of the Q-angle measurement, 2) to quantify Q-angle changes that occur with knee flexion, and 3) to determine if subjects with AKPS (N = 52) have a significantly different Q-angle than subjects without AKPS (N = 50). With the knee in an extended position, intratester Q-angle intraclass correlation coefficients (ICC) ranged from .84 to .90, and standard error of measurement (SEM) values ranged from 2.01 to 2.23°. Intertester Q-angle ICC was .83, and the SEM was 2.49°. With the knee flexed, the intratester ICC was .83 for both testers, and SEM values ranged from 0.68 to 2.45°. Intertester ICC and SEM were .65 and 3.50°, respectively. No significant difference was found in intratester Q-angle values between the extended and flexed knee positions (p > 0.05). No significant difference in Q-angle was found between asymptomatic subjects (11.1 ± 5.5°) and symptomatic subjects (12.4 ± 5.1°) (p = 0.07). Increased Q-angles were not responsible for AKPS in this group of patients. Other factors were hypothesized to be responsible for their symptoms.
J Orthop Sports Phys Ther 1993;17(1):11-16.
Key Words: patellofemoral pain, chondromalacia, quadriceps angle
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Special Supplement
Kevin Helgeson, Richard L. Gajdosik
Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1992, Newport Beach, CA.
The ability to measure the stretch-shortening cycle of isolated muscle groups has been limited. The purpose of this study was to measure the stretch-shortening cycle of the quadriceps femoris muscle group. Twenty-four volunteer subjects, 12 men and 12 women, participated in one test session; five men and five women also participated in a retest session; to examine the reliability of the test. A concentric contraction of the left quadriceps was measured for peak torque and time to peak torque on a Biodex isokinetic dynamometer under three conditions: 1) passive stretch before a concentric contraction, 2) isometric preload before a concentric contraction, and 3) eccentric preload before a concentric contraction. Conditions 2 and 3 showed a significant increase in peak torque production compared to condition 1 (p < 0.01). A significant difference was found for all three conditions between the men and women, with the men producing greatest peak torques. Conditions 2 and 3 also showed a significantly decreased time to peak torque compared with condition 1 (p < 0.01). The testing protocol was found to have high reliability. This testing protocol could be used to further study the stretch-shortening cycle in the quadriceps femoris muscle group.
J Orthop Sports Phys Ther 1993;17(1):17-23.
Key Words: stretch-shortening cycle, dynamic resistive exercise, quadriceps femoris
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Special Supplement
Kevin E. Wilk, James R. Andrews
Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1992, Newport Beach, CA.
The purpose of this study was to compare the effects of proximal single resistance pad placement (PSPP) and distal single pad placement (DSPP) on tibial displacement during isokinetic exercise on anterior cruciate ligament (ACL)-deficient knees. This study is important to the clinician because it documents tibial displacement during open chain isokinetic knee extension exercise at various isokinetic speeds. In addition, this study documents the range of motion where the greatest amount of anterior tibial displacement occurs. The anterior displacement of the tibia was recorded by a computerized knee laxity testing device during isokinetic exercise. Data were collected from 12 ACL-deficient knees. Each subject was tested on an OSI Knee Signature System for quantifiable tibial displacement during a Lachman's test, anterior drawer test, and active vs. passive knee extension. Following this, each subject was tested on a Biodex isokinetic dynamometer at isokinetic velocities of 60, 180, and 300°/sec with the computerized knee laxity testing device in place. Pad placement consisted of distal single pad placement, which is 1 inch proximal to the medial malleolus, and proximal single pad placement, which is 3 inches proximal to the DSPP location. The testing procedure was standardized, and peak torque was monitored to ensure consistent maximal effort throughout the study. The results indicated that PSPP resulted in less anterior tibial displacement at all three test speeds. The peak anterior tibial displacement occurred in a range from 30 to 15° of knee flexion at both pad placements and all three test speeds. Lastly, the greatest amount of anterior tibial displacement occurred at the 60°/sec isokinetic velocity, whereas less displacement occurred at 180 and 300°/sec, respectively. This study documents that high-speed isokinetics result in less anterior tibial displacement than low-speed isokinetics, and if ACL graft strength or maturation is questionable, a 30° extension block or a proximal resistance pad may be used.
J Orthop Sports Phys Ther 1993;17(1):24-30.
Key Words: anterior cruciate ligament, tibial displacement, resistive exercise
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Special Supplement
Peter C. Douris
Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1992, Newport Beach, CA.
Exercise velocity may be an important variable in determining the amount of blood lactate accumulation during isokinetic exercise. The purpose of this study was to measure the effects of velocity-specific isokinetic exercise on blood lactate, muscle fatigue index, and rating of perceived exertion and to examine the relationship between blood lactate and muscle fatigue index. Ten experienced recreational weight trainers, aged 20-40 years, took part in a repeated measures design consisting of three separate treatments (constant angular velocity at 30, 120, and 300°/set performed at maximal effort for 1 minute by the right knee flexors and extensors). Rating of perceived exertion, blood lactate, and muscle fatigue index were measured in response to each treatment. Rating of perceived exertion was equal across all three speeds. Muscle fatigue and blood lactate increased significantly as the velocity of exercise increased. There was also a positive correlation coefficient (r = .82, p ≤ 0.01) between muscle fatigue index and blood lactate. The data suggested that the magnitude of muscle fatigue index and blood lactate responses are strongly dependent on the velocity of movement utilized during maximal isokinetic exercise, and there is a relationship between muscle fatigue index and blood lactate.
J Orthop Sports Phys Ther 1993;17(1):31-35.
Key Words: muscle fatigue, blood lactate, specific resistive exercise
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Special Supplement
John Cormier, Alice York, Elizabeth Domholdt, Sam Kegerreis
Portions of this paper were presented at the 1992 Annual Conferences of the National Athletic Trainers' Association and the American Physical Therapy Association, both held in Denver, CO
Increased use of athletic trainers in sports medicine clinics has created a need for information related to actual and ideal use of these professionals in these settings. The purposes of this study were to 1) describe the characteristics of sports medicine clinics and their personnel, 2) determine whether there were differences between opinions of certified athletic trainers (ATCs), physical therapists (PTs), and professionals with dual credentials (PT/ATCs) about the ideal role of the ATC in sports medicine clinics, and 3) determine whether there were differences in actual usage of ATCs between states with and without athletic training laws. Subjects included 46 PTs, 43 PT/ATCs, and 73 ATCs from six different states. A questionnaire ascertained opinions about ideal ATC utilization and about current practice of ATCs with respect to 28 different clinical procedures. For 27 of the 28 procedures, there were significant differences of opinion about ideal ATC utilization between individuals with the three credentials. No significant differences in actual athletic trainer use in sports medicine clinics were found between states with and without athletic training laws.
J Orthop Sports Phys Ther 1993;17(1):36-43.
Key Words: personnel utilization, professional issues, sports medicine
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