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When several treatment methods are available for the same problem, many clinicians are faced with the task of deciding which treatment to use. Many clinicians may have conducted informal "mini-experiments" on their own to determine which treatment is best suited for the problem. These results are usually not documented or reported in a formal manner because many clinicians feel that they are "statistically challenged." Another reason may be because clinicians do not feel they have controlled enough test conditions to warrant analysis. In this update, a statistic is described that does not involve complicated statistical assumptions, making it a simple and easy-to-use statistical method. This update examines the use of two statistics and does not deal with other issues that could affect clinical research such as issues affecting credibility. For readers who want a more in-depth examination of this topic, references have been provided. The Kruskal-Wallis one-way analysis-of-variance-by-ranks test (or H test) is used to determine whether three or more independent groups are the same or different on some variable of interest when an ordinal level of data or an interval or ratio level of data is available. A hypothetical example will be presented to explain when and how to use this statistic, how to interpret results using the statistic, the advantages and disadvantages of the statistic, and what to look for in a written report. This hypothetical example will involve the use of ratio data to demonstrate how to choose between using the nonparametric H test and the more powerful parametric F test.

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STUDY DESIGN: This study analyzed cervical axial rotation initiated from five different starting positions in asymptomatic subjects. The results were analyzed to ascertain if rationale for certain clinical assessment methods could be justified. SUMMARY OF BACKGROUND DATA: In the assessment of the cervical spine, many clinicians use assessment techniques that propose to isolate anatomic structures by using various permutations and combinations of the three gross rotational movements, for example, evaluation of axial rotation in flexion and extension. OBJECTIVES: The primary purpose of this study was to compare the magnitude of cervical axial rotation when started from neutral, flexion, extension, protraction, and retraction, and the protraction-retraction range of motion also was determined. METHODS: Two groups of 30 subjects, one group aged 18-30 years and the other group aged 50-65 years and stratified by gender, participated in the study. The 3Space Tracker system (Polhemus, A Kaiser Aero-space and Electronics, Co., Colchester, VT), art electromagnetic tracking device, was used to determine the angular and linear position of the head relative to the sternum by detecting the position and orientation of two sensors attached to the forehead and sternum. RESULTS: Analysis of variance of the data revealed a statistically significant difference (p < 0.05) in axial rotation between all of the five starting positions. The younger age group demonstrated greater range of motion when rotation was initiated from neutral and extension, whereas the older group had greater range when the motion was initiated from protraction, retraction, and flexion. CONCLUSIONS: The results suggest that varying the starting sagittal head position may affect the anatomic structures involved in restraining axial rotation. This supports the clinical approach to range of motion assessment in combined movement patterns.

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STUDY DESIGN: This investigation measured the immediate effects of 10, 20, and 30 repeated neck retraction movements on the retraction range of motion and resting neck posture in asymptomatic subjects. OBJECTIVES: The results provide baseline gross kinematic data concerning the effects of neck retraction movements. Future work involving patients is anticipated and proposed. SUMMARY OF BACKGROUND INFORMATION: Neck retraction movements are an assessment maneuver and a treatment technique advocated by Robin McKenzie for patients with neck pain. They are a commonly prescribed physical therapy technique used to treat patients with neck pain and dysfunction. No previous studies of this maneuver have been reported. METHODS: Two groups of 15 subjects, one group 20-29 years old and the other 50-59 years old, participated. Each group performed three sets of 10 repeated movements. The position of the head and neck were recorded by the 3Space Isotrak System using markers placed over the spinous processes of selected vertebrae and the tragus of the ear. RESULTS: After the repeated movements, no statistically significant difference was found in neck retraction range of motion, but a statistically significant change in the resting neck posture was detected. CONCLUSIONS: Any changes in neck retraction range of motion observed after the execution of this maneuver in patients with neck pain may be the result of changes in a pathological process. If the postural change were to occur in patients, this treatment maneuver could be beneficial for those attempting to maintain a more retracted neck position for pain relief.

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STUDY DESIGN: This study analyzed relative lumbar and pelvic motion during sagittal plane trunk motion. Patterns of movement were compared during loaded trunk flexion and extension. OBJECTIVES: The purpose of this study was to examine the dynamic relationship between the lumbar spine and pelvis during trunk motion and to determine the effect of direction of lift (up vs. down) on lumbar-pelvic rhythm. SUMMARY OF BACKGROUND DATA: There is disagreement in the literature regarding whether rotations of the pelvis and lumbar spine occur sequentially or simultaneously during bending and lifting tasks. METHODS: Thirty healthy women, ranging in age from 19 to 35 years, participated in the study. The 3Space Tracker System, an electromagnetic tracking device, was used to monitor simultaneous lumbar and pelvic motion as subjects lifted and lowered a 9.5 kg box with knees extended. RESULTS: Although lumbar and pelvic motion occurred simultaneously during flexion and extension, there was greater separation of these movements during the "up lifts" than during the "down lifts." CONCLUSIONS: Lumbar-pelvic rhythm varied depending on whether the trunk was flexing or extending. During trunk flexion (down lift) there was a greater tendency for lumbar and pelvic rotations to occur simultaneously, whereas during extension (up life) they tended to occur more sequentially.

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Although previous studies have been conducted to ascertain the outcome of rotator cuff repair, the greatest majority have utilized subjective evaluation. The purpose of this study was to objectively compare the strength, as determined isokinetically, of the muscles around the shoulder complex a minimum of 1 year following surgical rotator cuff repair. Twenty-four subjects from two geographically separate university centers participated. Bilateral isokinetic comparisons were made of the subjects' ability to perform flexion/extension, abduction/adduction, and internal/external rotation. Paired t-tests were used to analyze the deficiencies encountered for the shoulder flexors, abductors, and external rotators, while the sign test was used to analyze the comparisons for the remaining movement patterns. Significant deficits were only found in the shoulder flexors and external rotators. All other movement patterns were not significant. It was interesting to note that although objective differences were found across the shoulders, no complaints or weakness were expressed by the patients. This is explained by a lessening of intensity among these elderly patients. J Orthop Sports Phys Ther 1992;15(5):215-222.

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The torque generated by the shoulder internal and external rotator muscles duringconcentric isokinetic contractions has been investigated. Recordings were made in three positions: neutral, 90 degrees of flexion, and 90 degrees of abduction; and at three speeds of contraction (60, 120, and 180 /sec) in each of these positions. Twelve healthy female university students were randomly selected from a 100 female volunteer population. Testing was accomplished using an isokinetic dynamometer. A two-way analysis of variance for position and speed was conducted. The greatest torque values for the internal rotator muscles were achieved in the neutral position, while maximum values for the external rotators were developed in 90 of shoulder flexion. The test speed of 60 degrees /sec was shown to produce the highest torque values for the external rotator muscles. However, no difference in test speeds of contraction was found when analyzing the torque values generated by the internal rotator muscles. Implications for strength training are discussed.J Orthop Sports Phys Ther 1987;9(6):217-222.

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The torque produced by the wrist extensors during maximal isometric and isokinetic eccentric contractions has been investigated. The torque produced by eccentric contractions was measured at three different velocities: 0.36, 0.93, and 1.64 cmlsec. The speeds of contraction were generated by a specially designed apparatus, consisting of a gear drive and an electric motor that would maintain its speed irrespective of the load applied. Tenison produced by the wrist extensors was measured using a load cell. The results indicated that eccentric contractions of the wrist extensors exceed those produced by isometric contractions. The force-velocity relationship during eccentric contractions was determined to be different from that during concentric contractions. Force values were found to increase as the velocity of eccentric contraction increased. No signficant effect of wrist joint angle on torque values was found, nor was there an interaction effect of velocity and joint angle. The implications for rehabilitation of these findings are outlined. J Orthop Sports Phys Ther 1986;8(6):288-293.

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Five profoundly mentally retarded cerebral-palsied children were studied in order to determine the effectiveness of music as a biofeedback mechanism in the training of head control. The method used a Head Position Trainer and Time Event Counter, developed at the Ontario Crippled Children's Centre in Toronto. Improvement was obtained in three of the five children in their ability to control their head movements when music was used as the biofeedback stimulus. However, these results should be treated cautiously because the sample was small and the training period was brief.

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Surface electrodes were utilized to pick up the electromyographic signals of the peroneus longus and brevis while foot switches recorded the gait cycle. The phasic activity of the two muscles was then recorded while the subject walked on a treadmill, first with it placed on the level and then at 5% incline. The two muscles were found to work synchronously. This was later verified by using fine wire electrodes.

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