Journal of Orthopaedic & Sports Physical Therapy - Teddy W. Worrell, PT, EdD, SCS, ATC

The Influence of Hip Position on Quadriceps and Hamstring Peak Torque and Reciprocal Muscle Group Ratio Values

Teddy W. Worrell, David H. Perrin, Craig R. Denegar
The purpose of this investigation was to determine the effect of hip position and test velocity on the quadriceps and hamstring reciprocal muscle group ratio. Twelve subjects (7 male, 5 female) were tested for isokinetic peak torque at 60, 180, and 240°/sec from the seated and supine positions. Gravity correction was obtained to determine quadriceps and hamstring peak torque, and to determine the reciprocal muscle group ratios. Results indicated there was a decrease in production of peak torque with an increase in test velocity for both muscle groups. Also, peak torque values were greater in the seated than supine position for both muscle groups. The influence of test velocity on the quadriceps and hamstring reciprocal muscle group ratio was to increase the ratio with increasing test velocity. Also, the reciprocal muscle group ratio increased from the supine to the seated position at all test velocities. These findings suggest that determination of the quadriceps and hamstring reciprocal muscle group ratio is influenced by both hip position and test velocity. Because many athletic activities involving running and sprinting occur from a hip position closer to the supine test position, evaluation of peak torque and determination of the reciprocal muscle group ratio may be more appropriate from the supine position. Also, normative data establishing target ratios should be determined from several test velocities.

J Orthop Sports Phys Ther 1989;11(3):104-107.

Effect of Body Position on Hamstring Muscle Group Average Torque

Teddy W. Worrell, Craig R. Denegar, Susan L. Armstrong, David H. Perrin
The purpose of this investigation was to examine the effect of the supine and prone position on concentric and eccentric isokinetic strength of the hamstring muscle group. Twelve university female lacrosse players were tested for hamstring average torque on a Kinetic Communicator^® dynamometer at 60°/sec from the supine and prone positions. Analysis of variance indicated average torque generated from the prone was greater than the supine position. Greater torque was also generated during eccentric contraction than during concentric contraction. The influence of the tonic labyrinthine and the symmetrical tonic neck reflexes is proposed as the mechanism for the differences observed between the two test positions. The prone position facilitates optimal generation of torque while approximating a length-tension relationship observed during sprinting. These findings suggest consideration be given to assessment and strength training of the hamstring muscle group in the prone position.

J Orthop Sports Phys Ther 1990;11(10):449-452.

Comparison of Isokinetic Strength and Flexibility Measures Between Hamstring Injured and Noninjured Athletes

Teddy W. Worrell, David H. Perrin, Bruce M. Gansneder, Joe H. Gieck
The purpose of this study was to compare isokinetic strength and flexibility measures between hamstring injured and noninjured athletes. Sixteen university athletes with history of hamstring injury were matched by motor dominance, sport, and position to sixteen university athletes without history of hamstring injury. Each subject was tested for concentric and eccentric quadriceps and hamstring peak torque and reciprocal muscle group ratios on a Kinetic Communicator^® (KIN-COM) dynamometer at 60°/sec and 180°/sec. Each subject's hamstring flexibility was determined by passively extending the knee while the hip was maintained at 90° of flexion. Analysis of variance indicated that the injured extremity was significantly less flexible than the noninjured extremity within the hamstring injured group, and the hamstring injured group was less flexible than the noninjured group. No significant strength differences existed between the hamstring injured and noninjured group on any isokinetic measure evaluated. The importance of assessing hamstring flexibility is emphasized.

J Orthop Sports Phys Ther 1991;13(3):118-125.

Chronic Achilles Peritendinitis: Etiology, Pathophysiology, and Treatment

Nancy L. Reynolds, Teddy W. Worrell
Overuse injuries represent a significant percentage of injuries seen in a sports medicine setting. Sports medicine health professionals evaluate and treat patients with the overuse injury of chronic Achilles peritendinitis. This paper reviews the anatomy of the Achilles tendon and presents recent literature concerning the etiology, pathophysiology, and rehabilitation of chronic Achilles peritendinitis. A rehabilitation program is outlined addressing the specific demands of the chronically injured Achilles tendon.

J Orthop Sports Phys Ther 1991;13(4):171-176.

Effect of a Lateral Step-up Exercise Protocol on Quadriceps Isokinetic Peak Torque Values and Thigh Girth

Nancy L. Reynolds, Teddy W. Worrell, David H. Perrin
Knee injury rehabilitation often includes the step-up exercise. However, the authors have been unable to locate documentation of the effect of the step-up exercise on lower extremity strength indices. The purpose of this study was to determine the effect of a six-week lateral step-up exercise protocol on quadriceps muscle group strength. Twenty female nonathletes (age = 20 ± 1.5 yrs, ht = 162.6 ± 4.9 cm, wt = 64.1 ± 0.5 kg) were randomly assigned to a control or experimental group. Pretest concentric and eccentric strength measures were obtained at 60°/sec on a Kin-Com isokinetic dynamometer. Thigh girth measurements were obtained 10 and 20 cm superior to the knee joint line. An independent t-test of the difference between pre and post isokinetic strength and girth measurements between the control and experimental groups revealed no significant difference (p > .05). In addition, no significant difference was found for the exercised and nonexercised extremity for the experimental group (p > .05). These findings suggest that this lateral step-up protocol did not provide sufficient overload to increase isokinetic strength of the quadriceps muscle group or increase thigh girth in healthy subjects. In addition, open chain assessment of muscle strength may not adequately assess strength changes incurred via closed chain exercise. Clinicians should use caution in assuming that step-up exercises provide sufficient overload to increase thigh girth or isokinetic quadriceps peak torque values.

J Orthop Sports Phys Ther 1992;15(3):151-155.

Key Words: lateral step-ups, closed kinetic chain exercise, quadriceps

Hamstring Muscle Injury: The Influence of Strength, Flexibility, Warm-Up, and Fatigue

Teddy W. Worrell, David H. Perrin
Hamstring muscle injury is a complex problem for athletes, physicians, physical therapists, and athletic trainers. This injury tends to recur and to limit participation in athletic competition. The etiology of hamstring muscle injury continues to be confusing and incomplete for clinicians and researchers. The purposes of this paper are: 1) to review briefly hamstring muscle group anatomy and function, 2) to review the clinical and animal research literature concerning the role of strength, flexibility, warm-up, and fatigue in hamstring muscle injury, 3) to present an evaluation and rehabilitation scheme for hamstring muscle injury, 4) to describe a theoretical multiple factor hamstring injury model, and 5) to offer recommendations concerning prevention of hamstring muscle injury. During preseason screening and rehabilitation following hamstring muscle injury, clinicians should consider the influence of hamstring strength, flexibility, warm-up, and fatigue on muscle performance. Additional research concerning these factors is recommended.

J Orthop Sports Phys Ther 1992;16(1):12-18.

Key Words: hamstring muscle strain, eccentric contraction, rehabilitation

The Relationship between Quadriceps Angle and Anterior Knee Pain Syndrome

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

Reliability of Open and Closed Kinetic Chain Subtalar Joint Neutral Positions and Navicular Drop Test

Anne Marie Picciano, Megan S. Rowlands, Teddy W. Worrell
Subtalar joint (STJ) measurements are commonly made in the clinic to assess foot and ankle positions because of the high incidence of lower extremity dysfunctions. The purposes of this study were to investigate the intratester and intertester reliability of the open kinetic chain subtalar joint neutral (OKC STJN) and closed kinetic chain subtalar joint neutral (CKC STJN) positions and the navicular drop test (NDT). Two inexperienced testers performed repeated measurements on 15 subjects (N = 30 feet) during two testing sessions. Intratester and intertester reliability (ICC 1,1) and standard error of measurement (SEM) were determined for each dependent variable. For OKC STJN, the intratester ICC values were .06 and .27, and the intertester ICC value was .00. The intratester SEM values were 1.81 and 2.29°, and the intertester was 2.51°. The CKC STJN intratester ICC values were .14 and .18, with SEM values of 2.46 and 2.40°. The intertester CKC ICC value was .15, with an SEM of 2.43°. For the NDT, the intratester ICC values were .61 and .79, and the SEM values were 1.92 mm and 2.57 mm. The intertester ICC value was .57 and the SEM was 2.72 mm. The results reveal that both OKC and CKC STJN yield poor intratester and intertester reliability and the NDT yields poor to moderate intratester reliability and poor intertester reliability. We conclude that these foot and ankle measurements are not reliable when performed by inexperienced testers. Therefore, clinicians should practice these measurement techniques and determine their measurement error.

J Orthop Sports Phys Ther 1993;18(4):553-558.

Key Words: reliability, subtalar, navicular

Effect of a Lateral Step-Up Exercise Protocol on Quadriceps and Lower Extremity Performance

Teddy W. Worrell, Bonnie Borchert, Kristi Erner, Julie M. Fritz, Pamela J. Leerar
Closed kinetic chain exercises have been promoted as more functional and more appropriate than open kinetic chain exercises. Limited research exists demonstrating the effect of closed kinetic chain exercise on quadriceps and lower extremity performance. The purpose of this study was to determine the effect of a lateral step-up exercise protocol on isokinetic quadriceps peak torque and the following lower extremity activities: 1) leg press, 2) maximal step-up repetitions with body weight plus 25%, 3) hop for distance, and 4) 6-m timed hop.

Twenty subjects participated in a 4-week training period, and 18 subjects served as controls. For the experimental group, a repeated measure ANOVA comparing pretest and posttest values revealed significant improvements in the leg press (p≤.05), step-ups (p≤.05), hop for distance (p≤.05), and hop for time (p≤.05) and no significant increase in isokinetic quadriceps peak torque (p≥.05). Over the course of the training period, weight used for the step-up exercise increased (p≤.05), repetitions decreased (p≤.05), and step-up work did not change (p≥.05). For the control group, no significant change (p≥.05) occurred in any variable.

The inability of the isokinetic dynamometer to detect increases in quadriceps performance is important because the isokinetic values are frequently used as criteria for return to functional activities. We conclude that closed kinetic chain testing and exercise provide additional means to assess and rehabilitate the lower extremity.

J Orthop Sports Phys Ther. 1993;18(6):646-653.

Key Words: hop tests, lateral step-up, muscle strength

The Relationship Between Self-Reported and Clinical Measures and the Number of Days to Return to Sport Following Acute Lateral Ankle Sprains

Kevin M. Cross, Teddy W. Worrell, James E. Leslie, Renee Van Veld Khalid
Study Design: This is a prospective observational study.

Objective:To determine the relationship of self-reported and clinical measures to the number of days to return to sport following acute lateral ankle sprains.

Background: In order to direct rehabilitation, injury classification schemes should include self-reported and clinical measures that help prognosticate the number of days to return to sport (DAYS).

Methods and Measures: Twenty Division II college athletes (7 men, 13 women; mean age = 19.2 ± 1.1 years) were assessed following an acute lateral ankle sprain and upon return to sport. Athletes were assessed by 3 self-reported measures: global function question, Short Form–36 Physical Function scale (SF36PF), visual analog pain scale, and 4 clinical measures: ankle active range of motion (AROM), ankle dorsiflexion strength, ankle plantar flexion strength, ambulation status. Simple regression, multiple regression, and effect sizes (ES) were used to analyze these data.

Results: The simple regression revealed a statistically significant relationship between DAYS and the global function question (r2 = .22), the SF36PF (r2 = .28), and the patient’s ambulation status (r2 = .27). A multiple regression using these 3 variables in combination was also statistically significant (P = .015) and explained approximately one-third of the variance in DAYS, (r2 = .37). All dependent variables revealed large or moderate ES.

Conclusion: Self-reported functional measures in conjunction with the athlete’s ambulation status are important factors in predicting the number of days to return to sport following acute lateral ankle sprains. Further research using large sample sizes and other clinical and functional measures is necessary.

J Orthop Sports Phys Ther. 2002; 32(1):16–23.

Key Words: ankle sprains, injury classification, prognosis