Journal of Orthopaedic & Sports Physical Therapy - Craig R. Denegar, PT, PhD, 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.

Influence of Transcutaneous Electrical Nerve Stimulation on Pain, Range of Motion, and Serum Cortisol Concentration in Females Experiencing Delayed Onset Muscle Soreness

Craig R. Denegar, David H. Perrin, Alan D. Rogol, Richard A. Rutt
β-Endorphin (BEP) has been implicated in the analgesic response to transcutaneous electrical nerve stimulation (TENS). The anterior pituitary gland is a source of β-endorphin which shares the prohormone proopiomelanocortin (POMC) with adrenocorticotropin (ACTH). Current theory proposes that the stimulation-induced breakdown of POMC results in ACTH release with a subsequent elevation in blood cortisol levels. The purpose of this study was to determine the potential application and mechanism of TENS as an anti-inflammatory agent. Eight female subjects received low frequency, 300 μsec pulse width TENS at four sites associated with relief of upper arm pain once when pain free and again while experiencing delayed onset muscle soreness (DOMS) of the elbow flexor muscle group. Blood samples were withdrawn 15 and 1 minute before and 1, 20, and 40 minutes after treatment. Serum was analyzed for cortisol by radioimmunoassay. TENS treatment failed to elevate serum cortisol concentration, but there was a significant reduction in perception of pain (p < 0.05) and an improvement in range of elbow extension (p < 0.05) when subjects were treated for DOMS. These results suggest that the anterior pituitary is not a source of BEP in TENS-induced analgesia.

J Orthop Sports Phys Ther 1989;11(3):100-103.

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.

The Relationships among Isometric, Isotonic, and Isokinetic Concentric and Eccentric Quadriceps and Hamstring Force and Three Components of Athletic Performance

Mark A. Anderson, Joe H. Gieck, David H. Perrin, Arthur Weltman, Richard A. Rutt, Craig R. Denegar
This study was supported in part by a grant from the Foundation for Physical Therapy, Inc.

The purpose of this study was to compare the relationships among isometric, isotonic, and isokinetic concentric and eccentric quadriceps and hamstring forces and three components of athletic performance in college-aged, male athletes. Bilateral quadriceps and hamstring muscle torque were obtained (N = 39) using a KinCom^® for concentric (rate at 60°/sec and 180°/sec), eccentric (rate at 30°/sec and 90°/sec), isotonic, and isometric (knee angles at 30° and 60°) contractions. Athletic performance was assessed using vertical jump performance, 40-yard dash time, and agility run time. The best predictor of 40-yard dash time was the right peak isokinetic concentric hamstring force at 60°/sec (R = .57; p < 0.05). The best predictor of agility run time was the left mean isokinetic eccentric hamstring force at 90°/sec (R = .58; p < 0.05). There were no significant correlations between any quadriceps or hamstring force and vertical jump. It was concluded that isokinetic eccentric quadriceps and hamstring forces were no better predictors of athletic performance than muscle forces assessed in other ways. However, they may be more predictive of some specific components of performance.

J Orthop Sports Phys Ther 1991;14(3):114-120.

Key Words: muscle strength, motor performance, knee

The Effect of Lateral Ankle Sprain on Dorsiflexion Range of Motion, Posterior Talar Glide, and Joint Laxity

Craig R. Denegar, Jay Hertel, Jose Fonseca
Study Design: Retrospective study.

Objective:Assess range of motion, posterior talar glide, and residual joint laxity following ankle sprain in a population of athletes who have returned to unrestricted activity.

Background: Lateral ankle sprains occur frequently in athletic populations and the reinjury rate may be as high as 80%. In an effort to better understand risk factors for reinjury, the sequelae to injury in a sample of college athletes were assessed.

Methods and Measures: Twelve athletes with a history of lateral ankle sprain within the last 6 months and who had returned to sport participation were tested. Only athletes who reported never injuring the contralateral ankle were included. The injured and uninjured ankles of subjects were compared for measures of joint laxity, ankle dorsiflexion range of motion, and posterior talar glide. Friedman’s test of rank order was used to analyze the laxity measures and a MANOVA was used to assess the dorsiflexion and posterior talar glide measures.

Results: Laxity was significantly greater at the talocrural and subtalar joints of the injured ankles. There were no significant differences in any of the ankle dorsiflexion measurements between injured and uninjured ankles, but posterior talar glide was significantly reduced in injured ankles as compared to uninjured ankles.

Conclusion: In our sample of subjects, residual ligamentous laxity was commonly found following lateral ankle sprain. Dorsiflexion range of motion was restored in the population studied despite evidence of restricted posterior glide of the talocrural joint. Although restoration of physiological range of motion was achieved, residual joint dysfunction persisted. Further research is warranted to elucidate the role of altered arthrokinematics after lateral ankle sprain.

J Orthop Sports Phys Ther. 2002; 32(4):166-173.

Key Words: arthrokinematic motion, inversion ankle sprain, ligamentous laxity

Influence of Compression Therapy on Symptoms Following Soft Tissue Injury From Maximal Eccentric Exercise

William J. Kraemer, Jill A. Bush, Robbin B. Wickham, Craig R. Denegar, Ana L. G�mez, Lincoln A. Gotshalk, Noel D. Duncan, Jeff S. Volek, Margot Putukian, Wayne J. Sebastianelli

Study Design: A between groups design was used to compare recovery following eccentric muscle damage under 2 experimental conditions. Objective: To determine if a compression sleeve donned immediately after maximal eccentric exercise would enhance recovery of physical function and decrease symptoms of soreness. Background: Prior investigations using ice, intermittent compression, or exercise have not shown efficacy in relieving symptoms of delayed onset muscle soreness (DOMS). To date, no study has shown the effect of continuous compression on DOMS, yet this would offer a low cost intervention for patients suffering with the symptoms of DOMS. Methods and Measures: Twenty nonimpaired non-strength-trained women participated in the study. Subjects were matched for age, anthropometric data, and one repetition maximum concentric arm curl strength and then randomly placed into a control group (n = 10) or an experimental compression sleeve group (n = 10). Subjects were instructed to avoid pain-relieving modalities (eg, analgesic medications, ice) throughout the study. The experimental group wore a compressive sleeve garment for 5 days following eccentric exercise. Subjects performed 2 sets of 50 passive arm curls with the dominant arm on an isokinetic dynamometer with a maximal eccentric muscle action superimposed every fourth passive repetition. One repetition maximum elbow flexion, upper arm circumference, relaxed elbow angle, blood serum cortisol, creatine kinase, lactate dehydrogenase, and perception of soreness questionnaires were collected prior to the exercise bout and daily thereafter for 5 days. Results: Creatine kinase was significantly elevated from the baseline value in both groups, although the experimental compression test group showed decreased magnitude of creatine kinase elevation following the eccentric exercise. Compression sleeve use prevented loss of elbow motion, decreased perceived soreness, reduced swelling, and promoted recovery of force production. Conclusions: Results from this study underline the importance of compression in soft tissue injury management.

J Orthop Sports Phys Ther. 2001;31(6):282-290.

Key Words: compressive garment, DOMS, muscle soreness

Transmissivity of Coupling Agents Used to Deliver Ultrasound Through Indirect Methods

Brian Klucinec, Matthias Scheidler, Craig R. Denegar, Elizabeth Domholdt, Sharon Burgess

Ultrasound continues to be a popular modality among physical therapists and athletic trainers. Whether the intent of the ultrasound treatment is for thermal or nonthermal effects, it can be difficult to deliver an effective treatment over an irregular surface. Thermal ultrasound treatments are typically used to decrease muscle spasms, treat pain, increase circulation, and increase tissue extensibility. Draper and Prentice describe the “direct” technique of ultrasound as involving "actual contact between the applicator and the skin, with a thin film of couplant between." Although the direct technique has been recommended when therapeutic heating is desired, several authors discuss alternate, indirect techniques for performing thermal ultrasound treatments over irregular surfaces, thereby promoting a more uniform energy distribution during treatment. These indirect techniques have included water bath immersion, use of a commercial gel pad, and use of gel- or water-filled bladders. The effectiveness of water bath immersion as a method of delivering acoustic energy for purposes of tissue heating has, over the past years, yielded inconsistent results. Water has been found to be a good conductor, a poor conductor, and equivalent to other coupling agents when used to transmit ultrasound. Despite this conflicting evidence, authors continue to present the water bath technique as an appropriate indirect treatment alternative. It is our observation that clinicians continue to utilize this method in the athletic training room and physical therapy clinic. Research regarding the transmissivity of gel pads, bladder techniques, and water bath immersion are inconclusive and warrant investigation. The purpose of this in vitro study was to examine the relative transmissivity of a commercial gel pad, bladder techniques, and water bath immersion in the transmission of therapeutic ultrasound.

J Orthop Sports Phys Ther. 2000;30(5):263-269.

Key Words: thermal, nonthermal, water bath, gel pad, conductor