Study Design: A repeated-measures, counterbalanced design.

Objectives: To test the effectiveness of 7 commercial abdominal machines (Ab Slide, Ab Twister, Ab Rocker, Ab Roller, Ab Doer, Torso Track, SAM) and 2 common abdominal exercises (crunch, bent-knee sit-up) on activating abdominal and extraneous (nonabdominal) musculature.

Background: Numerous abdominal machine exercises are believed to be effective in activating abdominal musculature and minimizing low back stress, but there are minimal data to substantiate these claims. Many of these exercises also activate nonabdominal musculature, which may or may not be beneficial.

Methods and Measures: A convenience sample of 14 subjects performed 5 repetitions for each exercise. Electromyographic (EMG) data were recorded for upper and lower rectus abdominis, external and internal oblique, pectoralis major, triceps brachii, latissimus dorsi, lumbar paraspinals, and rectus femoris, and then normalized by maximum muscle contractions.

Results: Upper and lower rectus abdominis EMG activities were greatest for the Ab Slide, Torso Track, crunch, and Ab Roller, while external and internal oblique EMG activities were greatest for the Ab Slide, Torso Track, crunch, and bent-knee sit-up. Pectoralis major, triceps brachii, and latissimus dorsi EMG activities were greatest for the Ab Slide and Torso Track. Lumbar paraspinal EMG activities were greatest for the Ab Doer, while rectus femoris EMG activities were greatest for the bent-knee sit-up, SAM, Ab Twister, Ab Rocker, and Ab Doer.

Conclusions: The Ab Slide and Torso Track were the most effective exercises in activating abdominal and upper extremity muscles while minimizing low back and rectus femoris (hip flexion) activity. The Ab Doer, Ab Twister, Ab Rocker, SAM, and bent-knee sit-up may be problematic for individuals with low back pathologies due to relatively high rectus femoris activity.

J Orthop Sports Phys Ther. 2006;36(2):45-57.

Key words: EMG, low back pain, lumbar spine, rectus abdominis, sit-up

Study Design: Cross-sectional, secondary analysis.

Objectives: To examine whether there were differences in the numbers and types of impairments on examination between 2 groups of people with low back pain (LBP), those who participated in symmetric leisure activities and those who participated in asymmetric leisure activities.

Background: It has been proposed that people who repeatedly perform an activity that involves trunk movements and alignments in the same direction will develop strategies that are generalized to many activities. The repeated use of these strategies is proposed to contribute to impairments identifiable on examination and to LBP.

Methods and Measures: Forty males and 40 females (mean ± SD age, 41.4 ± 13.9 years) with LBP who reported participation in either a symmetric or an asymmetric leisure activity participated in a standardized examination. Responses from 10 trunk-rotation-related impairment tests were analyzed using the Mann-Whitney U and chi-square statistics.

Results: Thirty people participated in asymmetric leisure activities and 50 people participated in symmetric leisure activities. The total number of rotation-related impairments was different for the 2 groups (U = 1112, P<.01). The asymmetric group displayed more total rotation-related impairments (median, 4.0; range, 7) than the symmetric group (median, 2.0; range, 6). A greater percentage of the asymmetric group displayed more impairments on 5 out of 10 individual tests, as compared to the symmetric group (P≤.05 for all comparisons).

Conclusions: Our results provide preliminary data to suggest that trunk-rotation related impairments, identified on examination, may be related to the general type of movements and alignments used repeatedly by patients with LBP.

 J Orthop Phys Ther. 2006;36(2):58-71.

Key Words: examination, lumbar spine, spinal disorders, sports

Study Design: A comparative study.

Objectives: To assess whether in subjects with unilateral chronic ankle instability the dynamic reaction time of the affected ankle differs from the healthy ankle and from ankles of a control group.

Background: Reaction time is an essential element in joint protection against sudden unexpected excessive movement requiring fast and coordinated muscle action. During a sudden ankle inversion movement, a reflex action of the evertor muscles is needed to counteract the movement. Adequate neuromuscular response is crucial and a delayed response could contribute to inversion trauma and subsequently to chronic ankle instability. The isokinetic dynamometer acceleration time (ACC-TIME) provides valuable information on dynamic neuromuscular ability.

Material and Methods: Patients with unilateral chronic ankle instability (n = 11) and healthy individuals in a control group (n = 11) were tested on an isokinetic dynamometer during 3 sets of 3 reciprocal inversion/eversion movements of both ankles at 30°/s and 120°/s. Analysis of variance models were used to compare the ACC-TIME of the affected ankle to the unaffected ankle of the same subjects and a control group.

Results: For the evertor muscles at 30°/s and 120°/s, a significantly prolonged ACC-TIME was found when comparing the affected ankles to the contralateral ankles and both ankles of the control group. For the invertor muscles at 120°/s a significantly prolonged ACC-TIME was found when comparing the affected ankle to the unaffected ankles of patients and those of the control group.

Conclusions: Because the most important evertor muscles are innervated by the fibular nerve, the significantly prolonged ACC-TIME of the affected ankle is consistent with the finding of a lower motor nerve conduction velocity of the fibular nerve after inversion trauma. The results support the concept of a delayed neuromuscular response as an important factor in the etiology of chronic ankle instability.

J Orthop Sports Phys Ther. 2006;36(2):72-79.

Key Words: ankle instability, fibularis muscles, isokinetics, neuromuscular response

Study Design: Resident’s case problem.

Background: Identifying stress fractures of the hip can be a challenging differential diagnosis. Pain presentation is not always predictable and radiographs may not show the fracture, especially during its early stages. Hip stress fractures left untreated can displace and necessitate open reduction internal fixation or total hip arthroplasty.

Diagnosis: A 70-year-old woman presented to the physical therapy clinic with complaints of right hip pain. A physician had evaluated her, and radiographs of the hip, which revealed some arthritic changes, were otherwise normal. Upon examination, the physical therapist observed an antalgic gait, a noncapsular pattern of limitation of hip motion, an empty painful end feel at the end range of motion (ROM) for hip abduction, external rotation, and flexion, and extreme tenderness to palpation over the anterior hip region. The therapist suspected a more pernicious problem than osteoarthritis and discussed his suspicion with the physician. The physician subsequently requested an MRI that revealed a femoral neck and head stress fracture that was later confirmed with a bone scan. The patient was provided with a walker for ambulation with a non-weight-bearing status for 6 weeks, after which she returned to physical therapy for progressive weight bearing and strengthening. She was discharged with a relatively pain-free hip and was ambulating with a cane. A 2-month follow-up examination revealed a pain-free hip and a return to all premorbid activities, including ambulation without an assistive device.

Discussion: The presence of a normal radiograph of the hip should not be considered conclusive in ruling out a stress fracture in the hip region. The current case demonstrates how careful evaluation can reveal occult pathologies and prevent potentially catastrophic morbidity.

J Orthop Sports Phys Ther. 2006;36(2):80-88.

Key Words: bone scan, imaging, MRI, physical therapy examination

Study Design: Case report of a professional ice hockey goaltender who underwent an arthroscopically assisted lateral meniscus repair.

Background: Rehabilitation of isolated meniscal repairs is not well documented in the literature. There is little knowledge about the healing time and the choice of rehabilitation exercises to be applied to a repaired meniscus. The objective of this case report is to describe a criterion-based, supervised, sport-specific rehabilitation protocol for a high-level athlete with a lateral meniscus repair from the first postoperative day until return to competitive sport, including a 5-year follow-up.

Case Description: The criterion-based protocol used with this athlete was based on a sport-specific neuromuscular rehabilitation approach. Data collected included range of motion, strength, neuromuscular control, and magnetic resonance images.

Outcomes: This high-level athlete was able to return to sport 103 days after surgery and no reinjury of the lateral meniscus occurred up to 5 years after surgery.

Discussion: The sport-specific, criterion-based, supervised rehabilitation program described in this case report showed a safe return to sport and a good long-term outcome.

J Orthop Sports Phys Ther. 2006;36(2):89-100.

Key Words: knee, meniscal repair, surgery

Study Design: Descriptive study.

Objectives: To determine the presence of median and ulnar neuropathies in both upper extremities of university guitarists.

Background: Peripheral nerve entrapment syndromes of the upper extremities are well documented in musicians. Guitarists and plucked-string musicians are at risk for entrapment neuropathies in the upper extremities and are prone to mild neurologic deficits.

Methods and Measures: Twenty-four volunteer male and female guitarists (age range, 18-26 years) were recruited from the Belmont University School of Music and the Vanderbilt University Blair School of Music. Individuals were excluded if they were pregnant or had a history of recent upper extremity or neck injury. Subjects completed a history form, were interviewed, and underwent a physical examination. Nerve conduction status of the median and ulnar nerves of both upper extremities was obtained by performing motor, sensory, and F-wave (central) nerve conduction studies. Descriptive statistics of the nerve conduction study variables were computed using Microsoft Excel.

Results: Six subjects had positive findings on provocative testing of the median and ulnar nerves. Otherwise, these guitarists had normal upper extremity neural and musculoskeletal function based on the history and physical examinations. When comparing the subjects’ nerve conduction study values with a chart of normal nerve conduction studies values, 2 subjects had prolonged distal motor latencies (DMLs) of the left median nerve of 4.3 and 4.7 milliseconds (normal, <4.2 milliseconds). Prolonged DMLs are compatible with median neuropathy at or distal to the wrist. Otherwise, all electrophysiological variables were within normal limits for motor, sensory, and F-wave (central) values. However, comparison studies of median and ulnar motor latencies in the same hand demonstrated prolonged differences of greater than 1.0 milliseconds that affected the median nerve in 2 additional subjects, and identified contralateral limb involvement in a subject with a prolonged distal latency. The other 20 subjects demonstrated normal comparison studies of the median and ulnar nerves in both upper extremities.

Conclusions: In this descriptive study of a population of 24 university guitarists, 4 musicians (17%) were found to have electrophysiologic evidence of median neuropathy at or distal to the wrist or carpal tunnel syndrome. Ulnar nerve electrophysiological function was within normal limits for all subjects examined.

J Orthop Sports Phys Ther. 2006;36(2):101-111.

Key Words: median nerve, nerve conduction study, ulnar nerve