Richard L. Gajdosik

Passive compliance and length of the hamstring muscles of healthy men anc women

This study examined the passive compliance and length of the hamstring muscles of 15 healthy men and 15 healthy women (ages 21-37) with passive straight-leg-raising between 65° and 80°. Subjects were positioned on their left sides with the pelvis stabilized and the right thigh fixed at 90° on a horizontal platform. After three practice trials of maximal passive knee extension, subjects received three trials for data collection. Muscle activity was monitored with surface EMG and passive resistance to knee extension was measured with a dynamometer as the limb was photographed at six force-dependent positions. The passive compliance was computed as the ratio of the change in the knee angle (ΔAngle) to the change in passive torque (ΔTorque), (ΔAngle/ΔTorque). Hamstring muscle lengths were measured simultaneously. An ANovA revealed a difference (P = 0·001) between the passive compliance ratios of the men (1·4 ± 0·-03) and women (2·2 ± 0·08) but not between their initial knee angles or their maximal knee angles. Independent t-tests showed a difference (P < 0·001) between the maximal passive torque of the men (41·4 ± 5·7 Nm) and women (27·4 ± 7·7 Nm). The torques were not different when standardized to body mass. Although ANOVAS showed that the absolute hamstring muscle lengths differed between genders, they were not different when standardized as a percentage of the femur length.

Influence of short hamstring muscles on the pelvis and lumbar spine in standing and during the toe-touch test.

This study examined the influence of short hamstring muscles of healthy men on: (1) the angles of pelvic inclination and the lumbar curve in standing, and (2) the flexion range of motion of the pelvis and lumbar spine during the toe-touch test. Surface markers over bony landmarks and photography were used to examine ten men without short hamstrings and ten men with short hamstrings while standing and after assuming the toe-touch position for two repeated trials. ANOVAS showed no significant differences between groups for the angles of pelvic inclination and lumbar curve in standing. During the toe-touch test, the mean flexion range of motion of the pelvis on the thigh was less for the men with short hamstrings (52°; SD, 9°) than for the men without short hamstrings (72°; SD, 4°) (P < 0.001), but the lumbar flexion range of motion was not significantly different.

Influence of age on concentric isokinetic torque and passive extensibility variables of the calf muscles of women

The purpose of this study was to investigate the influence of age on concentric isokinetic torque (CIT) and passive extensibility (PE) variables of the calf muscles of healthy women. Ten younger women [31.9 (SD 6.1) years] and ten older women [71.1 (SD 6.6) years] were tested using a KIN-COM 500H dynamometer. The PE was tested by stretching the muscles from relaxed plantarflexion to the maximal dorsiflexion (DF) angle at 5°·s−1 without raw electromyogram (EMG) activity exceeding 0.05 mV. The maximal CIT was tested from the maximal DF angle 60° into plantarflexion at four randomly ordered velocities of 30, 60, 120, and 180°·s−1. Separate analysis of variance (ANOVA) tests showed that the standardized (% body mass) concentric peak and mean torques were lower for the older women for all isokinetic velocities (p < 0.001). The “angular delay” from the onset of concentric activation to peak torque was smaller for the older women at 120 and 180°·s−1 (p < 0.05). Age showed negative relationships (Pearson r) with all standardized peak torques (p ⩽ 0.001) and mean torques (p < 0.001), and the “angular delay” at 120 and 180°·s−1 (p ⩽ 0.05). Independent t-tests showed that the maximal DF angle and the change in the PE angle from an initial angle (defined at 10% of the maximal passive torque) to the maximal DF angle were less for the older women (p < 0.05). Age was negatively related to the maximal DF angle and the change in the PE angle (p < 0.01). The results suggest an age-related decrease in calf muscle CIT, muscle length and PE. The smaller “angular delay” for the older women at 120 and 180°·s−1 indicates that CIT testing at rapid velocities can be used to examine age-related changes in calf muscle contractile properties in relation to rapid velocities of movement.

Passive compliance and length of clinically short hamstring muscles of healthy men

This study examined the passive compliance and length of short hamstring muscles in relation to hamstring muscles not considered short in healthy men (ages 18-37). The right hamstrings of 30 men with straight-leg raising of 73.8° (group I) and 24 men with straight-leg raising of 61.0° (group 11) were compared. Subjects were positioned on their left sides with the pelvis stabilized and the right thigh fixed at 90°. Subjects received three maximal passive knee extension trials for data collection. Muscle activity was monitored with surface electromyography and passive resistance was measured with a dynamometer as the limb was photographed at force-dependent positions. Passive compliance was computed as the ratio of change in the knee angle to change in passive torque. Hamstring lengths were measured simultaneously. Results showed that the passive compliance curves for group II were shifted left compared to group I. Anovas revealed that the initial knee angles for group 11 were greater than for group I (P = 0.001), as were the maximal knee angles (P < 0.001). Passive compliance ratios for group 11 (1.29) were less than for group I (1.45), but not significantly different. Maximal passive torques were not different between groups. The change from initial muscle lengths to maximal lengths was less for group 11 than group I for the: (1) absolute length change (P = 0.027), (2) per cent change beyond initial length (P = 0.005), and (3) length change standardized as a percentage of femur length (P = 0.011).

Influence of knee positions and gender on the Ober test for length of the iliotibial band

OBJECTIVE Examine the influence of knee positions and gender on the Ober test for the length of the iliotibial band. DESIGN A cross-sectional comparative repeated measures design. BACKGROUND The Ober test is in widespread use, yet the influence of knee positions and gender on the test has not been reported. Such information is needed to help clarify test results. METHODS The Ober test was administered with the knee flexed to 90 degrees and extended to 0 degrees to the right lower limb of 26 women and 23 men. The limb was lowered from abduction and the end point of hip abduction (positive angle) or hip adduction (negative angle) was measured in relation to neutral. RESULTS The hip adduction movement was restricted more with the knee flexed than with the knee extended for both genders (P<0.009). With the knee flexed the mean hip abduction angle was less for men (+4 degrees) than for women (+6 degrees) (P<0.001), and with the knee extended the mean hip adduction angle was greater for men (-9 degrees) than for women (-4 degrees) (P<0.001). CONCLUSIONS The Ober test with the knee flexed limited hip adduction more than with the knee extended for both men and women, and women had greater limitations than men. RELEVANCE The Ober test with the knee flexed and with the knee extended yielded different results and may be considered different tests. Normal Ober test values for the two knee positions should be defined separately for men and women in order to understand how deviations from normal are related to pathologies.

Relation of Age and Passive Properties of an Ankle Dorsiflexion Stretch to the Timed One-Leg Stance Test in Older Women:

26 older women (aged 65 to 89 years) participated in this study, which examined the relationship of age and passive properties of a dorsiflexion stretch of the calf muscle-tendon unit with one-leg stance times. Age was negatively correlated with the time stance (r = –.75). The maximal passive dorsiflexion angle, length extensibility, maximal passive dorsiflexion torque, and the area under the passive curve (total passive elastic energy) were all positively correlated with the stance time (range: r = .49–69). A multiple regression analysis indicated age was the best predictor of the times. Age and the maximal passive dorsiflexion angle together accounting for 71% of the variance in the time (R = .84, R2 = .71). The addition of the remaining passive measurements did not improve the variance accounted for in the one-leg stance time. The results indicated that the maximal ankle dorsiflexion range of motion may be important for one-leg standing balance of older women. Accordingly, stretching exercises designed to increase the maximal dorsiflexion angle may have a role for maintaining or improving their standing balance.

Electrically evoked knee flexion torque increases with increased pelvifemoral angles

This study was designed to determine the extent to which knee flexion torques would differ when submaximal hamstring muscle contractions were evoked by constant levels of electrical stimulation and when the pelvifemoral angle was increased. Nineteen healthy subjects (ten women and nine men) underwent electrical stimulation of the hamstring muscles while randomly positioned either supine, sitting upright, or sitting leaning forward. The pelvifemoral angle for each position was measured from lateral photographs: the knee flexion torque was calculated from the knee flexion force, and lever arms measured directly at a constant knee angle. A repeated measures ANOVA demonstrated significant differences for pelvifemoral angles (F = 485·00, P < 0·001) and knee flexion torques (F = 21·97, P < 0·001) among the positions. The mean torques in the upright and leaning forward positions were 2·2 and 3·7 times greater, respectively, than mean torques in the supine position. The increase between the supine and leaning forward positions exceeded the increase previously reported in the literature for subjects performing maximal voluntary knee flexion efforts.

Relation of Maximal Ankle Dorsiflexion Angle and Passive Resistive Torque to Passive-Elastic Stiffness of Ankle Dorsiflexion Stretch

The maximal passive ankle dorsiflexion angle and the maximal passive resistive torque at this angle were measured for 81 women 20 to 84 years of age and correlated with the passive-elastic stiffness (stiffness) of an ankle dorsiflexion stretch. Pearson correlation coefficients and multiple regression analyses were used to examine whether the two clinical measurements could predict ankle stiffness. The maximal passive resistive torque showed a moderate correlation with stiffness in the full stretch range (r = .69) and high correlation with stiffness in the last half of the full stretch range (r = .84). The maximal dorsiflexion angle showed a low correlation with stiffness in the full stretch range (r = .27) and in the last half of the full stretch range (r = .36). The maximal passive resistive torque and the dorsiflexion angle together accounted for 54% of the stiffness variance in the full stretch range and 76% of the stiffness variance in the last half of the full stretch range. Thus, the clinical measurements of the maximal passive dorsiflexion angle and the maximal passive resistive torque were directly and significantly related to the ankle dorsiflexion passive-elastic stiffness and good predictors of stiffness in the last half of the passive ankle dorsiflexion stretch.

Accuracy and Variability of Leg Velocities during Concentric and Eccentric Actions of the Quadriceps Femoris Muscles

This study examined the ability to control leg velocities during concentric and eccentric actions of the right quadriceps muscles. Ten healthy women (M age = 25.9 ± 3.5 yr.) were tested using the Isotonic Program of the KIN-COM II 500H dynamometer. They attempted to match velocity tracings of 10°, 20°, and 40°/sec. through 70° of knee range of motion at a load equal to 10% of their maximal mean concentric force. The actual mean velocities, mean percent deviation from the target velocities, and the coefficient of variation for both actions were calculated for 15°–75° (full range of motion), 15°—45° (shorter range of motion), and 46°–;75° (longer range of motion). Separate one-way analyses of variance with two trial factors (action x velocity) showed faster concentric velocities through the full and longer ranges of motion, and faster eccentric velocities through the shorter range of motion. Mean percent deviations indicated that the eccentric velocities were generally more accurate within all ranges of motion. Larger concentric coefficients of variation were found within the full and longer ranges of motion, and the coefficients of variation for both actions decreased as the velocities increased. An exaggerated ‘velocity overshoot’ at the onset of both actions probably contributed to differences in the velocities and coefficients of variation. The results indicated differences between the concentric and eccentric actions, explained in part by the testing methodology used and by the known mechanical and physiological characteristics of the two muscle actions.

Passive insufficiency of two-joint shoulder muscles

This preliminary study examined the effects of full elbow flexion and full elbow extension on the end-point of active range of motion of shoulder flexion and shoulder extension respectively. The end-points were measured from lateral photographs of the right upper limbs of 30 men after they flexed and extended their shoulders with their elbows held in full flexion and full extension. Angular measurements showed that full elbow flexion limited shoulder flexion range of motion and that full elbow extension limited shoulder extension range of motion. The results indicated that passive muscle insufficiency of active shoulder flexion and extension was probably brought about by lengthening the triceps brachii and the biceps brachii muscles respectively. Clinicians are encouraged to considerthis passive insufficiency when measuring range of motion of shoulderflexion and extension and when implementing therapeutic interventions.