Journal of Orthopaedic & Sports Physical Therapy - Richard W. Bohannon, PT, EdD, NCS

Contribution of Neural and Muscular Factors to the Short Duration Tension- Developing Capacity of Skeletal Muscle

Neural and muscular factors contributing to the short duration tension-developing capacity of muscle are reviewed. Among the neural factors discussed are pyramidal tract activity, and the order, extent, frequency, and synchrony of motor unit recruitment. Muscular factors included within the review are muscle size, fiber type, and fiber number. Alterations in neural and muscular factors that accompany training are also presented as are the interactions between them.

J Orthop Sports Phys Ther 1983;5(3):139-147.

Upper Extremity Strength and Strength Relationships Among Young Women

Richard W. Bohannon
The static strength of 10 upper extremity muscle groups of 3 1 young women was tested bilaterally to gain a preliminary estimate of the strength of the muscle groups and the relationship between the strength of the muscle groups. Strength was measured using a hand-held dynamometer. Descriptive statistics were calculated for the measurements obtained. Inferential statistics revealed a significant difference in strength between the left and right side for only three muscle groups. The only antagonistic muscle groups that differed significantly on both the left and right side were the elbow flexor and extensor muscles. The strength of each muscle group was significantly related to the strength of every other muscle group on each side. The strength values and strength relationships reported herein should prove useful to clinicians testing the upper extremity strength of young women.

J Orthop Sports Phys Ther 1986;8(3):128-133.

Accuracy of Spring and Strain Gauge Hand-held Dynamometers

Richard W. Bohannon, A. Williams Andrews

The accuracy of two spring gauge and two strain gauge hand-held dynamometers was determined using certified weights. Each dynamometer, which had extensive prior use, was vertically loaded with the certified weights in 5 lb increments from 5-55 lbs. Analysis of variance was used to compare the actual certified weights with the weights measured by each dynamometer. Additionally, Pearson product moment correlations were calculated between the weights measured by each device. The two spring gauge dynamometers measured comparably as did the two strain gauge dynamometers. Only the two strain gauge dynamometers, however, registered (measured) weights not differing significantly from the actual weights with which they were loaded. The correlations between each device's measurements were 0.98 or above. If the dynamometers tested are indicative, strain gauge dynamometers may be more accurate than spring gauge dynamometers after extensive use.

J Orthop Sports Phys Ther 1989;10(8):323-325.

Intrasession Reliability of Angle Specific Knee Extension Torque Measurements with Gravity Corrections

Richard W. Bohannon, Melissa B. Smith
The purpose of this study was to determine the intrasession reliability of gravity corrected angle specific knee extension torque measurements (GCASKETMs) from a Cybex^® II isokinetic dynamometer. Forty subjects (20 men, 20 women) performed three warm-up, then four maximal knee extension efforts at 60°/sec on a Cybex II isokinetic dynamometer. The torques at 30 and 45 degrees of flexion were corrected for the effects of gravity. Analysis of variance demonstrated no difference in the four GCASKETMs at each knee angle. The intraclass correlation coefficients for the GCASKETMs were 0.958 at 30° and 0.971 at 45°. The results indicate that the reliability of isokinetic knee extension torque measurements is not compromised by the use of undamped angle specific measurements that are corrected for the effects of gravity. Such measures should be considered for clinical application because they more accurately reflect true torque production.

J Orthop Sports Phys Ther 1989;11(4):155-157.

Shoulder Position Influences Elbow Extension Force in Healthy Individuals

Richard W. Bohannon
The purpose of this study was to compare measurements of elbow extension force obtained with the shoulder in four different positions. The four positions in which 24 healthy subjects (13 men, 11 women, mean age = 29.9 years) were tested twice with a hand-held dynamometer were: 1) body supine, shoulder adducted and neutrally rotated; 2) body sitting, shoulder flexed and internally rotated; 3) body sitting, shoulder flexed and externally rotated; 4) body supine, shoulder abducted and externally rotated. Although repeated measurements in each position were reliable (intraclass correlation coefficients ≥ 0.980), the magnitude of the elbow extension force was significantly different between positions (F = 13.435, p < 0.001). The lowest and highest forces were measured in positions one and four (above), respectively. If an individual is retested at a later time, the same positions as used previously should be employed if real changes in elbow extension strength are to be disclosed. The specific position used is probably best selected on the basis of patient, tester, and environmental factors.

J Orthop Sports Phys Ther 1990;12(3):111-114.

Motion Measured from Forefoot and Hindfoot Landmarks During Passive Ankle Dorsiflexion Range of Motion

Richard W. Bohannon, David Tiberio, Gregory Waters
This project was funded, in part, by the Research Foundation, University of Connecticut, Storrs, CT 06269-2101.

The purpose of this study was to document and compare, using surface landmarks, the magnitude of forefoot and hindfoot motion accompanying passive ankle dorsiflexion range of motion (ADROM). Twenty-two healthy subjects had their right ankle passively dorsiflexed two times from a resting position to a maximum dorsiflexion while they were supine and their subtalar joints were positioned in neutral. Initial resting position and maximum ADROM were measured from surface markings over the fibula, fifth metatarsal, and heel in pictures taken with a 35 mm camera. The difference between the maximum ADROM and the initial measurements obtained from the markings over the fifth metatarsal and heel were used to represent motion of the forefoot and hindfoot, respectively. The grand mean forefoot motion (39.8°) and hindfoot motion (37.1°) were significantly different (F = 13.62, p ≤ 0.001). The motions, however, were significantly correlated for the two trials (r = 0.905 and 0.704). The small magnitude of the difference (= 2.7°) in forefoot and hindfoot motion and significant correlations between the motions challenge the need for foot stabilization other than maintaining the subtalar joint in neutral.

J Orthop Sports Phys Ther 1991;13(1):20-22.

Hand-held Dynamometer Measurements: Tester Strength Makes a Difference

Joan B. Wikholm, Richard W. Bohannon

Three examiners with measurably different strengths and three muscle groups with distinctly different maximum force productions were used to investigate the effect of tester strength on the magnitude and reliability of hand-held dynamometer (HHD) force measurements. Each examiner measured the shoulder external rotator, elbow flexor, and knee extensor muscles of 27 healthy adults twice during two sessions (one week apart). Intrarater/intrasession, intrarater/intersession, and interrater/intrasession reliability coefficients (ICCs) were calculated. Interrater ICCs decreased in magnitude (.932 to .226) as the tested muscle groups increased in force production. Intrarater/intersession ICCs indicated a similar trend. High intrarater/intrasession and interrater/intrasession ICCs calculated from shoulder external rotator measurements indicated that HHD testing for muscle groups generating a mean maximum force of about 120 N may be reliable for clinicians with strengths equal to or exceeding those of the weakest tester in this study. Above 120 N, tester strength appeared to be a major determinant of the magnitude and reliability of the forces measured with a HHD. Further investigation into the relationship between tester strength and the intrarater and interrater reliability of HHD measurements is warranted.

J Orthop Sports Phys Ther 1991;13(4):191-198.

Intraexaminer, Interexaminer, and Interdevice Comparability of Leg Length Measurements Obtained with Measuring Tape and Metrecom

David A. Hoyle, Michael Latour, Richard W. Bohannon
Leg length inequalities result from a variety of clinical abnormalities. The purpose of this study was to compare repeated leg length measurements taken by two examiners with two devices during a single session. The two devices that were used were a standard tape measure and a Metrecom. Since reliability coefficients do not fully describe the comparability of measurements, ANOVAs were used to describe differences, and Pearson correlations were used to describe relationships between measurements of leg length obtained by the two examiners using the two instruments. Results of the study showed that although reliability and correlation coefficients are high between testers and devices, significant differences in measurements exist between both testers and devices. The measures found to be most comparable were those taken by one examiner using one device. The authors concluded that for clinical purposes, the tape measure may be the more practical device based on its price. It was theorized, however, that in cases of asymmetry or orthopaedic deformity, the accuracy of the Metrecom may be superior.

J Orthop Sports Phys Ther 1991;14(6):263-268.

Key Words: leg length inequality, linear measurement, evaluation of methods

Relationship between Active Knee Extension and Active Straight Leg Raise Test Measurements

Denise M. Cameron, Richard W. Bohannon
This study was conducted to determine the relationship between two alternative tests for indicating hamstring musculotendinous length, active knee extension (AKE) and active straight leg raise (ASLR). Before alternatives to a commonly practiced clinical test such as AKE can be recommended for application, their convergent validity should be established. Twenty-three healthy subjects (age = 29.4 years) were tested. A 35-mm camera was used to record the position of the right side of the pelvis and lower limb during the performance of the ASLR test on the right. The camera set-up was also used to record the position of the right knee and pelvis during the performance of AKE with the right hip flexed to 90°. For ASLR, the angle of the straight leg to the horizontal was measured. For AKE, the angle of knee extension was measured. The intraclass correlation coefficients for the AKE (.861) and ASLR (.953) tests were good and high, respectively. There was a significant relationship (r = -.718; r² = .515; p < .001) between AKE and ASLR. The significant correlation between the measurements obtained using these two tests suggests that both are providing an indication of the same basic phenomenon, presumably hamstring musculotendinous length. For this reason, the AKE test may be a useful alternative to the straight leg raise test for providing an indication of hamstring muscle length.

J Orthop Sports Phys Ther 1993;17(5):257-260.

Key Words: straight leg raise, joint mobility, flexibility, active knee extension

Comparability of Force Measurements Obtained with Different Strain Gauge Hand-Held Dynamometers

Richard W. Bohannon
With multiple hand-held devices now available for measuring muscle strength, clinicians need to know if the measurements obtained with the different devices are comparable. This study was performed to determine the comparability of force measurements obtained with two different strain gauge hand-held dynamometers. Specifically examined to establish comparability were differences, reliabilities, and correlations between measurements obtained with the different devices. Thirty-one healthy volunteers were tested with each device during a single session. The muscle groups tested isometrically were the elbow flexors, shoulder external rotators, and hip flexors. Although the magnitude of forces measured with the two dynamometers differed significantly, they demonstrated good to high reliabilities and correlations. Thus, the dynamometers should not be used interchangeably on the same patient. Either of the dynamometers, however, can be used (alone) to document muscle force production.

J Orthop Sports Phys Ther 1993;18(4):564-567.

Key Words: muscle strength, dynamometry, extremities