Ira M. Fiebert

The reliability of hand-held dynamometry in measuring isometric strength of the shoulder internal and external rotator musculature using a stabilization device.

Although hand-held dynamometry is considered an objective method of measuring strength, the reliability of the procedure can be compromised by inadequate tester strength and insufficient stabilization of the dynamometer and subject. The purpose of this study was to investigate the test-retest reliability of a hand-held dynamometer with the use of a portable stabilization device while testing the shoulder internal and external rotator musculature. The isometric strength of the shoulder rotator musculature was tested twice in 30 asymptomatic adult volunteers (15 male and 15 female) between 18 and 63 years of age by using an intrasession design. Consistency of the testing protocol was maintained through the use of an arm stabilization apparatus, which fixed the arm in 30° of the scapular plane and a portable dynamometer stabilization device. Intraclass correlation coefficients (ICCs) were high, ranging from ICC (3,1) = 0.971–0.972 for the test-retest trials of internal and external rotation. There was no significant difference between sessions one and two for maximum internal rotation (p = 0.431) and maximum external rotation strength (p = 0.780). The results indicate that the testing protocol with stabilization device is a reliable method for measuring strength of the internal and external rotator shoulder musculature.

Postural Compensations and Subjective Complaints Due to Backpack Loads and Wear Time in Schoolchildren

Purpose: This study investigated the effects of carrying weighted backpacks of up to 20% of body weight on the posture and pain complaints of elementary-school children. Methods: Craniovertebral, forward trunk lean and pelvic tilt angles were measured from sagittal photographs of 62 children (8-11 years old) before and after walking while carrying backpacks containing 10%, 15%, or 20% of body weight. Pain severity after a 6-minute walk with the loaded backpack was recorded. Subjective complaints of pain were assessed using a visual analog scale after walking. Results: Repeated-measures ANOVA revealed statistically significant differences in postural angles and increased complaints of pain after walking with increased backpack loads. Conclusion: These results indicate that typical backpack loads create worsening postural changes due to backpack loads and time spent carrying those loads, putting children at increased risk for injury and pain, the latter of which is a strong predictor for back pain in adulthood.

Effect of backpack load carriage on cervical posture in primary schoolchildren

OBJECTIVE This study examined the effects of various backpack loads on elementary schoolchildrens posture and postural compensations as demonstrated by a change in forward head position. SUBJECTS A convenience sample of 11 schoolchildren, aged 8-11 years participated. METHODS Sagittal digital photographs were taken of each subject standing without a backpack, and then with the loaded backpack before and after walking 6 minutes (6MWT) at free walking speed. This was repeated over three consecutive weeks using backpacks containing randomly assigned weights of 10%, 15%, or 20% body weight of each respective subject. The craniovertebral angle (CVA) was measured using digitizing software, recorded and analyzed. RESULTS Subjects demonstrated immediate and statistically significant changes in CVA, indicating increased forward head positions upon donning the backpacks containing 15% and 20% body weight. Following the 6MWT, the CVA demonstrated further statistically significant changes for all backpack loads indicating increased forward head postures. For the 15 & 20%BW conditions, more than 50% of the subjects reported discomfort after walking, with the neck as the primary location of reported pain. CONCLUSIONS Backpack loads carried by schoolchildren should be limited to 10% body weight due to increased forward head positions and subjective complaints at 15% and 20% body weight loads.

Cervical range of motion and strength during resting and neutral head postures in healthy young adults

The purposes of this investigation were: 1) to determine whether cervical range of motion and strength differ when measured in resting head posture (RHP) vs. neutral head posture (NHP), 2) to examine gender differences in cervical range of motion, strength, and neck girth, and 3) to examine the relationship between cervical range of motion and strength with: a) neck girth, b) height, and c) weight. Fortysix graduate students (10 males, 36 females) age 20–40 with no history of cervical or shoulder girdle pathology were recruited. Height, weight, and neck girth were measured for each subject. The Cervical Range of Motion (CROM) device was used to determine the amount of forward head posture and active range of motion for flexion (FLEX), extension (EXT), right and left lateral flexion (RLF and LLF), and right and left rotation (RROT and LROT) with subjects seated in a straight-back chair. Isometric cervical strength for FLEX, EXT, RLF, LLF, RROT, and LROT was then determined using the Microfet hand-held dynamometer with subjects seated in a chair which stabilized the trunk. Subjects performed the six active range of motion and the six isometric contractions in the RHP and NHP. Greater range of motion for EXT was achieved in the NHP, while greater RLF, RROT and LROT was achieved in the RHP. LROT in the RHP was the only contraction to demonstrate significantly greater strength. Females had greater cervical extension than males in both postures. Males were consistently stronger than females for all contractions in both postures and had larger neck girths. Strength correlated with neck girth, weight, and then height.

Cervical range of motion in geriatric individuals

Recent research concerning the active range of motion (AROM) of the cervical spine of older individuals has been limited. The purpose of this study was to describe cervical AROM in individuals sixty years of age and older. Forty-five healthy subjects (28 females and 17 males) between the ages of 60 and 82 participated in this study. The Cervical Range of Motion Instrument (CROM) was used to measure flexion, extension, left and right lateral flexion, left and right rotation, and the neutral position, while the subjects were seated. Results showed that the differences of cervical range of motion in geriatric individuals is statistically significant (p< .05) from the American Academy of Orthopaedic Surgeions (AAOS) standards for five of the six motions. Cervical flexion was greater in this study than the AAOS data. The AAOS data reported greater motion for extension, left and right lateral flexion, and left and right rotation. with only extension not being statistically significant. Additionally, females had...

Integrated EMG study of the medial and lateral heads of the gastrocnemius during isometric plantar flexion with varying cuff weight loads

Both heads of the gastrocnemius muscle contribute to ankle plantar flexion. This study utilized integrated electromyography to investigate whether the percent electrical activity contributed by each head remained constant or changed during isometric contractions at five different resistance levels. Fifty healthy volunteers ranging in age from 19 to 34 years, with no history of musculoskeletal or neuromuscular disorders involving the right lower extremity, were studied. All tasks were performed in the prone position, knee in extension, with the leg and foot in neutral with respect to rotation. Motor points of the medial head and lateral head were identified and surface electrodes were placed just distal to them. The subjects maintained 20° of plantar flexion under five conditions: a maximal isometric plantar flexion contraction (one trial only), and with a 5-, 10-, 15- and 20-lb cuff weight attached to the right foot (three trials each). EMG recordings, 8 s in length, were taken during the isometric contractions. Integrated EMGs were averaged for each cuff weight and the resulting values used in the analysis. A repeated measures ANOVA was performed and a significance level of p≤0.05 was used to determine statistical significance. As weight increased, the absolute value of the integrated EMG recorded over both muscles increased, but the percent contributed by each head remained essentially equal (50%) within the four submaximal loads tested. However, for the maximal isometric contraction, the medial head contributed a significantly higher percentage of the total integrated EMG (58%). Therefore, in the open-chain activity described, the two heads of the gastrocnemius demonstrate similar neural drive at submaximal levels of contraction, but this changes as maximum isometric levels are reached.

Medial-lateral hamstring electromyographic activity during maximum isometric knee flexion at different angles

The purpose of this study was to investigate knee flexion torque and changes in electro myographic (EMG) activity of the medial and lateral hamstrings during isometric knee flexion at different angles. Thirty-four subjects, 17 female and 17 male, between 21 and 33 years of age, with no history of right knee pathology volunteered to participate. Subjects were positioned prone on the Cybex II with their right lower extremity secured in knee flexion. Surface electrodes were placed over the medial and lateral hamstring muscles. Each test session consisted of nine maximal isometric knee flexion contractions. Three contractions, of six seconds each, were recorded at 30, 60, and 90 degrees of knee flexion. Recordings of maximum torque and averaged EMG were made by the Cybex II and the Bioscope, respectively. The results showed statistically significant findings: (1) decreased torque as knee flexion increased (P < 0.0005); (2) men demonstrated greater torque than women (P < 0.05); and (3) EMG activity for both the medial and lateral hamstrings decreased as knee flexion increased with differences between 90 and 30°, and 90 and 60° (P < 0.05). We concluded that the decrease in torque output with increased knee flexion is consistent with present knowledge. The coordinated pattern of declining EMG activity with increased knee flexion for both the medial and lateral hamstring muscles requires further investigation. Copyright

EMG activity of medial and lateral hamstrings at three positions of tibial rotation during low-force isometric knee flexion contractions

The purpose of this investigation was to determine how the position of tibial rotation effects the EMG activity of the medial and lateral hamstrings during low-force isometric knee flexion contractions. Forty-five subjects (ages 18-35) with no history of lower extremity injury or disease volunteered for this study. While lying prone, and with surface EMG electrodes secured to the bellies of their right medial (semitendinous and semimembranosus) and lateral (long head of the biceps femoris) hamstring muscles, each subject held the knee in 45° of flexion for 8 s against 5% of their body weight. This was performed three times in each of the positions of neutral tibial rotation, external tibial rotation, and internal tibial rotation. The root-mean-square (RMS) of the EMG activity from these muscles was determined for each of the contractions. A repeated measures ANOVA was used to compare the RMS values of the two muscle groups in the three positions. The average RMS values (in microvolts [mV]) obtained were (means and standard deviation): medial hamstrings in external rotation: 50.74 ± 23.11; in neutral: 65.57 ± 25.35; in internal rotation: 70.73 ± 31.86; lateral hamstrings in external rotation: 66.08 ± 46.99; in neutral: 46.18 ± 39.34; in internal rotation: 27.68 ± 17.86. A statistically significant interaction was found between tibial rotation and hamstring muscle (p < 0.0001). These results are consistent with the presumed function of these muscles in that EMG activity in the medial hamstrings increased when the tibia was rotated internally, whereas the lateral hamstring EMG activity increased when the tibia was rotated externally.

Elbow, Forearm, and Wrist Passive Range of Motion in Persons Aged Sixty and Older

Passive rangc of motion (ROM) was measured in 124 subjects 60-99 years at the elbow, forearm, and wrist. Passive ROM for elbow flexion, forearm pronation and supination, wrist flexion and extension, radial and ulnar deviation were obtained using the Ortho Ranger II Inclinometer. Passive ROM for elbow extension was obtained using a twelve inch universal goniometer. Results showed the means for ROM of elbow flexion and extension, foream pronation and supination, and wrist flexion, extension, radial and ulnar deviation to be 147, -1, 84, 85, 80, 75, 20, and 30 degrees. No difference was found between elbow, forearm, and wrist ROM in the elderly sample and Le AAOS standards.

An Overview of Functional Progressions in the Rehabilitation of Low Back Patients

Low back pain is one of the most common dysfunctions seen by health care professionals. Eighty percent of the population will suffer from low back pain in their adult life.1-4 Accordingly, this societal problem has taken its toll via missed days of work and the adverse economic impact that results.3-9The good news is that most people with low back pain improve within a short period of time.1,9-11 Acute attacks of back pain and sciatica can last up to two weeks with chronic attacks persisting for more than three months.10 Vukmir reported that 74.2% of patients with low back pain improved within one month, 87.3% within three months, and 92.6% within six months.1 Additional good news is the fact that surgery is the appropriate solution for only a small percentage of the patients with low back pain.12,13 Saal and Saal report that nonoperative treatment for lumbar disorders, including intervertebral disc dysfunction prove most successful.13 Weber, in a landmark study, reported that patients who received surgery for lumbar disc herniations showed statistically better results at the one-year follow-up examination. However, at the four-year follow-up, there were no statistically significant differences in how patients who received surgery compared to the patients who did not receive surgery.14On a less positive note, people who suffer an episode of low back pain, have a greater chance of developing future episodes.10,15 Those patients who develop repeated episodes of low back pain and those patients who do not improve spontaneously over a short period of time can fall into the group known as chronic low back pain. This group creates a major drain on our economic resources and leads to a large number of people who are deemed disabled.1,7,8,12 Therefore, if the health care community is unable to cure all types of low back pain, keeping patients with low back pain functional should be of prime importance. Through the performance of functional activities, such as activities of daily living and working, the societal drain caused by low back pain, would hopefully decrease.