The purpose of this study was to determine the strength of trunk flexors and extensors in normal male subjects during isometric, concentric, and eccentric contractions. Subjects were tested in the sidelying position to minimize the effects of gravity. The pelvis and lower extremities were measured on a custom built force table (lowa Force Table). Muscle strength was expressed as a moment of force (external force times the moment arm) in Newton-meter (N∙m) units. Greater N∙m were registered in the muscle-lengthened position than in the muscle-shortened position for all isometric contractions. The N∙m registered for eccentric contractions always exceeded the N∙m registered for concentric contractions of the same muscle group. The N∙m registered during contractions of trunk extensors always exceeded the values obtained during corresponding modes of contractions (isometric, eccentric, and concentric) of trunk flexors.

J Orthop Sports Phys Ther 1980;1(3):165-170.

Clinical problems at the glenohumeral joint, whether chronic or induced by trauma, tend to manifest joint hypomobility with accompanying. muscle weakness. Fractures at the proximal humerus tend to occur more frequently in older patients, but in the presence of violent trauma this injury may occur in the younger patient as well.' The initial treatment often includes some form of immobilization followed by remobilization and muscle strengthening. There is a clinical need to document the sequence and form of physical therapy treatment and quantitatively reflect changes in joint motion and strength.

A case study of a patient with a proximal humeral fracture is presented to (a) dezcribe the clinical findings and treatment associated with a shoulder injury, (b) describe and illustrate some methods of assessment and treatment, and (c) report results for joint motion and muscle strength.

The hope of the author is that this paper might provide an example of physical therapy evaluation and treatment for such a case and demonstrate a model for expected results. Further, this paper might be used as a teaching model for therapists who are unexperienced with this type of patient.

J Orthop Sports Phys Ther 1980;2(1):25-34.

Objective laboratory measurements were obtained preoperatively and up to 24 months postoperatively for 102 patients (140 knees). This longitudinal study was an effort to determine changes in functional status as a result of surgery and rehabilitation. In the main, the function improved in arthritic patients who received a geometric knee implant and subsequent physical therapy in a manner described in this study. Function improved in terms of joint motion, muscle strength, standing posture, and gait in both rheumatoid and osteoarthritic groups. Some functional abnormalities which seemed to persist were deficits in knee extension motion and knee extensor strength, and that the subjects stand with the knee in a flexed position. Time asymmetries of foot placement were present during gait, patient's stance phase time and body accelerations were excessive, and body accelerations were arrhythmic in the forward-backward directions.

J Orthop Sports Phys Ther 1984;6(1):25-29.

The therapeutic effectiveness of inversion traction has only recently come under investigation. The purpose of this study was to use noninvasive methods to determine traction, cardiovascular, and perceived effects of inversion. The Gravity Gym® and Gravity Boot® inversion systems were compared. Treatment order was randomized and 18 normal subjects between the ages of 22 and 31 were suspended in each inversion device for 7 minutes. A computerized method was used for assessing posture. Three-dimensional coordinates were determined for spinous processes C7 through L5 relative to the midpoint of a line drawn between posterior superior iliac spines (S2). Heart rate was palpated and blood pressure was recorded using a standard sphygmomanometer. Pre-, initial, late, and postinversion measurements were taken. Questionnaires administered following each inverted posture assessed levels of discomfort. One-way analysis of variance was conducted to test the significance of results (p < 0.05). Measurements for both systems revealed an increase in L5-S2 distance, a decrease in C7-T12 distance, and a decrease in depth of the thoracolumbar curves. Segments C7-S2, L 1 -S2, L 1 -L2, L3-L4, and L4-L5 were increased in length by the Gravity Gym but not the Gravity Boots. Heart rate decreased and blood pressure increased an average of 20 mm Hg for both systems as subjects were inverted. This pattern was observed throughout the inversion period. Upon return to stand, heart rate increased for both systems while blood pressure decreased only for the Gravity Boot system. Subjects indicated that the Gravity Gym was the more tolerable inversion system.  lnversion can be an effective means of spinal traction but due to elevated blood pressure, inversion may be contraindicated for some patients.

J Orthop Sports Phys Ther 1986;7(5):254-260.

J Orthop Sports Phys Ther 1990;12(1):16-23.

This paper was presented at the First International Orthopaedic Symposium in Ottawa, Canada, in May, 1990. This study was supported by Grant RR59 from the General Clinical Research Centers Program, Division of Research Resources, NIH, and by an Aging Seed Grant from The University of Iowa.

Fifty-five women with an average age of 56 years participated in a study to determine the effects of a quantitatively based home exercise program on trunk muscle strength. The same body positions were used for testing trunk strength and for the exercise program. During the strength tests, the external forces generated by the subjects were measured using the trunk attachment of the Muscle Evaluation and Exercise Dosimeter (MEED) 3000 System. The standardized exercise program utilized the body segments and cuff weights on the extremities to achieve the desired resistance level for the sit-up, prone trunk extension, and double-leg flexion exercises. Three sets of 10 were performed for each exercise at least three times a week over a 12-month period. Large, significant (p < .05) strength gains (25-30%) were made by the exercise group for each exercise. The performance of the exercise group was superior to the control group. The reliability of the strength-using tests determined by interday trials using the MEED 3000 was high-all correlations were r = .93 or higher. This study demonstrates that older women can tolerate and increase trunk muscle strength using controlled, progressive, resistive exercise over a long period of time. The exercise approach in this study might be considered for use in treatment of low back dysfunction.

J Orthop Sports Phys Ther 1991;13(6):300-309.

J Orthop Sports Phys Ther 1992;16(4):182-188.

Key Words: skeletal landmarks, evaluation, measurement system

Frequently, joint range of motion is reported for a single plane (eg, sagittal, coronal, or transverse). However, the arc of joint motion during functional activities and many clinical tests encompasses motion in all 3 planes simultaneously. The purposes of this paper are to discuss a method to obtain relative joint 3-dimensional angular displacement measurements using coordinates from skeletal landmarks and provide an analytical example of the method using 3-dimensional angular displacement of the knee joint as a model.

In order to calculate the 3-dimensional relative motion, an orthogonal reference frame for each bone needs to be established. To establish the local reference frame, 3 noncollinear points are used to define unit vectors that are mutually perpendicular. Three-dimensional angles can be determined to describe the magnitude of the moving body rotation angles about the X, Y, and Z axes. These angles indicate the relative motion of body segments for abduction/adduction, flexion/extension, and internal/external rotation.

The technique provides a more vigorous biomechanical understanding of joint motion and may have implications for measuring patient progress and evaluating joint mobilization treatment. This technique may also serve as a basis for developing new evaluation and treatment techniques.

 J Orthop Sports Phys Ther. 1993;18(6):687-691.

Key Words: range of motion, kinematics, biomechanics

The purpose of this study was to characterize the scapulohumeral rhythm in the normal shoulder during dynamic elevation of the arm in the scapular plane and to compare the scapulohumeral rhythm during 3 different states of loading: 1) arm completely unloaded and passively elevated, 2) light load consisting of active elevation against the weight of the limb, and 3) heavy loading against maximal resistance. Electromagnetic tracking was used to record 3-dimensional scapular and humeral kinematics on 25 normal subjects. Cardan angles were calculated to assess the dynamic relationship of humeral elevation to scapular upward rotation. The results show that during dynamic humeral elevation, the scapulohumeral rhythm changes depending on the phase of elevation and the external load on the arm. During passive range of motion, the scapulohumeral rhythm decreased from 7.9:1 to 2.1:1 as the arm was elevated. Light shoulder loads caused an increase of the scapulohumeral rhythm from 3.1:1 to 4.3:1 as the arm was elevated. Heavy shoulder loading resulted in an increasing scapulohumeral rhythm from 1.9:1 to 4.5:1 as the arm was elevated. The results suggest that the historical assumption of a simple linear 2:1 scapulohumeral rhythm ratio may be overly simplistic and may not accurately describe the scapulohumeral rhythm under varying dynamic conditions. Therapists need to understand the normal changing relationships of the scapulohumeral rhythm under different conditions for accurate interpretation of clinical observations.

J Orthop Sports Phys Ther. 1998;27(2):125-133.

Key Words: biomechanics, shoulder, scapula, scapulohumeral rhythm

Clinical examinations and biomechanical analysis of the shoulder often include an assessment of the scapulohumeral rhythm. It is important to understand factors which may affect the scapulohumeral rhythm so that optimal diagnostic and therapeutic strategies can be devised. The purpose of this study was to determine if the scapulohumeral rhythm, when assessed under dynamic conditions, is altered as a result of a fatigue-inducing exercise. Twenty-five subjects were required to elevate their arm against maximum resistance until they were no longer able to completely elevate their arm. Three-dimensional kinematics were measured using an electromagnetic tracking system. Electromyographic activity was recorded from the upper trapezius, lower trapezius, serratus anterior, and the middle deltoid muscles. Power frequency spectrum using the Fast Fourier Transform and the root mean square signal amplitudes were determined for each muscle. The scapulohumeral rhythm was determined using least squares regressions of humeral elevation to scapular upward rotation for 20% intervals (phases) of elevation for each subject. The results showed that during the midrange of elevation to maximum elevation [phases 3-5 (60-150°)], the scapulohumeral rhythm decreased with fatigue, and that the decrease in the scapulohumeral rhythm was associated with myoelectric indicators of fatigue (median power frequency). The study suggests that shoulder fatigue affects the way in which the scapula moves concomitantly with the humerus. Fatigue tends to result in increased motion of the scapula, which alters the scapulohumeral rhythm.

J Orthop Sports Phys Ther. 1998;28(2):74-80.

Key Words: shoulder, muscle fatigue, biomechanics, scapulohumeral rhythm