What are the factors associated with the implementation of a peer-led health promotion program? Insights from a multiple-case study.

Peer education is widely used as a health promotion strategy. However, few efforts have been undertaken to understand the implementation of peer-led health promotion programs (HPPs). This multiple-case study identifies factors facilitating the implementation of a peer-led HPP for older adults presenting with fear of falling (Vivre en �quilibre) and their mechanisms of action. It used a conceptual framework postulating factors that may influence peer-led HPPs implementation and mechanisms through which such factors may generate implementation outcomes. Six independent-living residences for older adults in Quebec (Canada) implemented Vivre en �quilibre as part of a quasi-experimental study. Implementation factors and outcomes were documented through observation diaries, attendance sheets, peers' logbooks, questionnaires administered to participants and semi-structured interviews conducted among peers, activity coordinators of residences and a subgroup of participants. The analysis revealed three categories of factors facilitating program implementation, related to individuals, to the program and to the organizational context. Three action mechanisms identified in the framework (interaction, self-organization and adaptation) were facilitated by some of these factors. These findings support the application of the peer-led program implementation conceptual framework used in this study and provide insights for practitioners and researchers interested in implementing peer-led HPPs.

A static dynamometer measuring multidirectional torques exerted simultaneously at the hip and knee.

The function of a static dynamometer measuring torques exerted simultaneously in the different anatomical planes of the hip (flexion-extension, abduction-adduction and internal-external rotation) and knee (flexion-extension) is described. Muscular torques were calculated in real time using a desktop computer from measurements of orthogonal forces applied at two locations and the lever arm values measured in each subject. The reliability of the force transducers was explored by examining their output, using calibrated weights, on three different days. The results were identical over this period of time, indicating that the transducers are highly reliable. A mechanical simulator of a lower limb was constructed to generate specific or combined torques of known values at the hip and knee. The torques measured by the dynamometer were found to be highly concordant with the known torques applied by the simulator, indicating that the torque measurements were valid. The usefulness of the dynamometer is demonstrated by evaluating the activity of the rectus femoris and biceps femoris muscles during static efforts exerted in various directions at the hip. In addition, the mechanical action of biarticular muscles at the hip was evaluated by quantification of hip torques during efforts exerted at the knee. From these results, it has been concluded that the present biarticular and multidirectional dynamometer is a valid, reliable and precise instrument that may prove to be useful in evaluating the muscular function of the lower limb.

Characterization of contralateral torques during static hip efforts in healthy subjects and subjects with hemiparesis.

Contralateral torques exerted at the hip were measured in healthy subjects and subjects with hemiparesis performing unilateral static hip efforts in abduction, adduction, flexion and extension, in a sitting position, at two torque levels. In general, the ipsilateral hip efforts were accompanied by mirrored contralateral torques in both groups of subjects. The directionality of these contralateral torques indicates that their action at the pelvis is mechanically opposite to the ipsilateral efforts, suggesting that they ensure the stabilization of the pelvis. In healthy subjects, analyses of variance showed no difference in the magnitude of the contralateral torques with regard to which limb was used to perform the task. However, a significant increase in magnitude was demonstrated in the contralateral torques concurrent with the increasing level of effort requested ipsilaterally. In hemiparetic subjects, when performing the tasks with their paretic limb, the magnitude of the contralateral torques was significantly increased in the non-paretic limb when compared with those measured in the paretic limb during non-paretic limb efforts. Based on the present results, a model of postural control is presented to explain the relationship between the ipsilateral and contralateral torques. Using this model, it is hypothesized that the increased contralateral torques observed in hemiparetic subjects when performing the tasks with their paretic limb is related to the weakness of the paretic muscles. The clinical importance of exercises used for the re-education of the paretic lower limb in this population, which consist of resisting the non-paretic hip movements in order to strengthen the paretic hip muscles, is discussed in light of these results.

A method for quantification of directional patterns of muscle activation at the lower limb.

Several studies have examined muscle activation patterns during movements or static torques exerted in different directions in human subjects as well as in trained monkeys. However, no statistical approach has ever been proposed to characterize directional patterns of muscle activation in a given population. This report describes a method for the quantification and statistical analysis of directional patterns of muscle activation at the lower limb. This method was used with a group of 18 healthy subjects. Using a multidirectional dynamometer for the lower limb, subjects were asked to exert static torques (at approximately 5 and 15% of the maximal voluntary contraction) in eight directions covering a 360 degrees range at the hip. These were hip abduction, adduction, flexion, extension, and the intermediate directions (e.g., hip flexion and abduction). Electromyographic (EMG) activities of eight lower limb muscles were recorded during these efforts using surface electrodes. For each muscle, the mean rectified EMG activity obtained in each direction was considered a vector. Then, the overall directional pattern of activation for a given muscle was quantified for each subject by a vectorial summation of these vectors. The angle of the resultant vector was used along with the other subjects' angular values to calculate a mean vector representing the muscle's directional pattern of activation for the complete sample. This mean vector was used to perform the statistical analysis of the data. More specifically, the Rayleigh test for circular data was performed at both torque levels to determine, through the length of the mean vector, if a muscle showed a directional specificity in its activity, i.e., a tendency to be preferentially recruited toward a specific direction. In general, hip muscle activity demonstrated significant directional specificity during hip efforts in contrast to knee and ankle muscle activity. Moreover, the angle of the mean vector calculated for each hip muscle across the sample remained relatively stable at both torque levels. These results indicate that directional patterns of muscle activation are unaffected by the level of torque produced. It is concluded that the method used in the present study is effective in characterizing directional patterns of muscle activation in a given population. Also, this method provides new perspectives for further quantification of muscle activation patterns disturbances in populations presenting various neuromuscular disorders.

Directional patterns of muscle activation at the lower limb in subjects with hemiparesis and in healthy subjects: A comparative study.

This article reports the results of a comparative study on directional patterns of muscle activation at the lower limb in 15 subjects with hemiparesis and 18 healthy subjects. Subjects were required to exert static hip and knee torques using multidirectional and biarticular dynamometers designed for the lower limbs. Hip torques were performed in abduction, adduction, flexion, extension, and in combined directions (e.g., hip flexion and abduction) and knee torques were exerted in flexion and extension. The required torque levels corresponded to approximately 5% of the maximal voluntary contraction of healthy subjects. Electromyographic (EMG) activities of the rectus femoris, biceps femoris, gracilis, gluteus medius, gluteus maximus, vastus lateralis, tibialis anterior, and soleus were recorded during these torques. The descriptive analysis involved comparison between either the polar plots (for hip tasks) or the histograms (for knee tasks) representing the mean muscle activity obtained across subjects during torques exerted in each direction for the three groups of muscles analyzed (normal, paretic, and nonparetic muscles). Ciucular statistics were also used to characterize directional patterns of activation in each muscle during hip tasks while linear statistics permitted one to analyze these patterns during knee tasks. In general, the results of both the descriptive and inferential statistical analyses indicated that directional patterns of muscle activation during hip and knee torques are not altered in subjects with hemiparesis. These results are in contrast to the disturbances observed previously in a study of directional patterns of muscle activation at the upper extremity in this population. It is suggested that the contrast between the present results and those obtained at the upper limb in subjects with hemiparesis may reflect the difference in the motor recovery of upper and lower paretic limbs or in the severity of spasticity in the muscles involved at the studied joints. Results of this study also showed that the paretic muscles often demonstrate larger EMG signals than normal and nonparetic muscles, especially during knee flexion torques. These last observations, in addition to the fact that some subjects with hemiparesis could not complete all of the tasks with their paretic limb, under-score the muscle weakness inherent to this population.

Motor function and activities of daily living assessments: a study of three tests for persons with hemiplegia.

The relationship between upper extremity motor function and independence in basic activities of daily living in subjects with hemiplegia was explored. The Barthel Index (Mahoney & Barthel, 1965) and the Fugl-Meyer Test (Fugl-Meyer, Jääskö, Leyman, Olsson, & Steglind, 1975) were selected as the standard instruments for the evaluation of activities of daily living and upper extremity motor function, respectively, because their validity and reliability have been demonstrated many times. The Functional Test for the Hemiplegic/Paretic Upper Extremity (Wilson, Baker, & Craddock, 1984a, 1984b) was also used for the evaluation of upper extremity motor function. The results obtained in 18 subjects with hemiplegia indicate that the scores on the Barthel Index are poorly correlated with both the Fugl-Meyer Test and the Functional Test for the Hemiplegic/Paretic Upper Extremity scores. It is suggested that variables other than motor function, such as the learning of compensatory techniques and perceptual-cognitive status, are responsible for this discrepancy because they can influence activities of daily living performance in persons with hemiplegia. The high correlation between the scores on the Fugl-Meyer Test and the Functional Test for the Hemiplegic/Paretic Upper Extremity indicates that either test may be used for the assessment of upper extremity motor function.