Denise M. Connelly

Quadriceps muscle strength, contractile properties, and motor unit firing rates in young and old men

Changes with age in the voluntary static and dynamic strength of the quadriceps muscle group have been well characterized, and the importance of the muscle group for locomotion and independent living have been highlighted in both normal human aging and in clinical studies. Surprisingly few studies of this muscle group have described age‐related changes in voluntary activation ability using twitch interpolation and changes in stimulated contractile properties, and none have assessed the influence of old age on motor unit firing rates. We compared in 13 young (mean age 26 years) and 12 old (mean age 80 years) men the voluntary isometric strength, stimulated contractile properties, and average steady state motor unit firing rates in the quadriceps muscle. Maximum voluntary contraction (MVC) force and twitch tension were ∼50% lower in the old men, but contractile speed was only ∼10% slower than in the young men. There was no difference in the ability of either group to activate the quadriceps to a high degree (94–96%). At all isometric force levels tested (10%, 25%, 50%, 75%, and 100% MVC), there were no differences in mean motor unit firing rates. In both groups, the range of firing rates was similar and not large (∼8 Hz at 10% MVC and 26 Hz at MVC). Thus, the substantial age‐related weakness in this muscle does not seem to be related to changes in neural drive.

‘Getting back to real living’: a qualitative study of the process of community reintegration after stroke

Objectives: To examine the process of community reintegration over the first year following stroke, from the patient’s perspective. Design: Qualitative, longitudinal, grounded theory study involving ten participants. During the first year post discharge from inpatient rehabilitation, 46 one-on-one semi-structured interviews were conducted with ten participants. Interviews were completed with participants before discharge from inpatient stroke rehabilitation and in their homes at two weeks, three months, six months and one year post discharge. Analysis was guided by grounded theory methods described by Corbin and Strauss. Subjects: Four women and six men (mean age 59.6 ± 18.0, all with left hemiparesis and without aphasia) who had sustained their first hemispheric stroke and were returning to the community following inpatient rehabilitation. Results: The process of community reintegration after stroke involved transitioning through a series of goals: gaining physical function, establishing independence, adjusting expectations and getting back to real living. The ultimate challenge for stroke survivors during this process of community reintegration was to create a balance between their expectations of themselves and their physical capacity to engage in meaningful roles. Conclusions: Over the first year after stroke, participants reported that the process of community reintegration was marked by ongoing changes in their goals. Formal and informal caregivers need to work with stroke survivors living in the community to facilitate realistic and achievable goal setting. Tools which identify meaningful activities should also be incorporated to provide stroke survivors with the opportunity to contribute and engage with others in the community.

Motor skill learning of concentric and eccentric isokinetic movements in older adults.

Neuromuscular adaptation at the onset of resisted exercise can be observed as increases in torque and surface electromyography. The effect of learning the motor task has been hypothesized to contribute to these early increases, especially for older people. Thus, the purpose of this study was to investigate the facilitatory effects of practice on motor performance in older adults during short-term isokinetic training of the ankle dorsiflexors (DF). Twenty-eight men and women (M = 76.3 +/- 4.6 years) volunteered for a 2-week, 3-days/week strength training program. They were tested in a sitting position on a KinCom isokinetic dynamom eter at 30, 90, and 180° s-1 through 40° of DF movement (concentric and eccentric contractions). Criterion curves of lever arm angle patterns were cross-correlated with subject-generated angle patterns, showing significantly better correlations on posttest versus baseline. Smoothness and proficiency of muscle contraction improved with practice by fewer hesitations in movement and increased ability to change between concentric and eccentric muscle contractions. Increased agonist electromyography and torque were hypothesized to be secondary to greater neural drive and/or synchronization of motor unit firing rate and/or recruitment during maximal voluntary contraction, improved coordination, and adapted neural control of concentric and eccentric muscle contraction.Neuromuscular adaptation at the onset of resisted exercise can be observed as increases in torque and surface electromyography. The effect of learning the motor task has been hypothesized to contribute to these early increases, especially for older people. Thus, the purpose of this study was to investigate the facilitatory effects of practice on motor performance in older adults during short-term isokinetic training of the ankle dorsiflexors (DF). Twenty-eight men and women (M = 76.3 +/- 4.6 years) volunteered for a 2-week, 3-days/week strength training program. They were tested in a sitting position on a KinCom isokinetic dynamometer at 30, 90, and 180 degrees s-1 through 40 degrees of DF movement (concentric and eccentric contractions). Criterion curves of lever arm angle patterns were cross-correlated with subject-generated angle patterns, showing significantly better correlations on posttest versus baseline. Smoothness and proficiency of muscle contraction improved with practice by fewer hesitations in movement and increased ability to change between concentric and eccentric muscle contractions. Increased agonist electromyography and torque were hypothesized to be secondary to greater neural drive and/or synchronization of motor unit firing rate and/or recruitment during maximal voluntary contraction, improved coordination, and adapted neural control of concentric and eccentric muscle contraction.

Pragmatism in practice: mixed methods research for physiotherapy.

The purpose of this paper is to provide an argument for the place of mixed methods research across practice settings as an effective means of supporting evidence-based practice in physiotherapy. Physiotherapy practitioners use both qualitative and quantitative methods throughout the process of patient care—from history taking, assessment, and intervention to evaluation of outcomes. Research on practice paradigms demonstrates the importance of mixing qualitative and quantitative methods to achieve ‘expert practice’ that is concerned with optimizing outcomes and incorporating patient beliefs and values. Research paradigms that relate to this model of practice would integrate qualitative and quantitative types of knowledge and inquiry, while maintaining a prioritized focus on patient outcomes. Pragmatism is an emerging research paradigm where practical consequences and the effects of concepts and behaviors are vital components of meaning and truth. This research paradigm supports the simultaneous use of qualitative and quantitative methods of inquiry to generate evidence to support best practice. This paper demonstrates that mixed methods research with a pragmatist view provides evidence that embraces and addresses the multiple practice concerns of practitioners better than either qualitative or quantitative research approaches in isolation.

Utility of portable electromyography for quantifying muscle activity during daily use.

Background: Mobility has been studied using performance, questionnaire, pedometer and accelerometer measures, but these tools do not provide information about muscle activity. To better understand mechanisms associated with movement impairment as they relate to function, it is valuable to quantify muscle activity during everyday activities. Objective: This report presents electromyography (EMG) during daily activities from the affected and unaffected limbs of a 74-year-old man who survived a stroke 12 years ago, compared to 7 older healthy men who had not experienced a stroke. Methods: The biceps brachii, triceps brachii, quadriceps and hamstring muscles were recorded continuously for one 8-hour session in the unaffected limbs of the stroke survivor and control subjects. On a second day, EMG from these same muscles of the affected side was recorded for 4 h. Bursts (amplitude >2% maximum effort, duration >0.1 s) and gaps (amplitude <1% maximum effort, duration >0.1 s) of EMG were quantified for the number of times they occurred, mean event duration (seconds), mean peak amplitude (percent maximum voluntary efforts) and rate of activity (event activity/second). Results: Burst and gap patterns of the unaffected limb muscles were similar between the stroke survivor and controls. Increased numbers of bursts (approx. 40%) and gaps (approx. 44%) were seen in the subject’s lower limb muscles of his affected versus unaffected side. Biceps brachii burst activity of the affected limb was increased, whereas triceps brachii burst activity was decreased. These muscle activity changes in the affected limb suggest that the triceps brachii was relatively inactive and the biceps brachii and lower limb muscles were active in an ‘on’ and ‘off’ pattern. Conclusion: Muscle activity in the unaffected limb of the stroke survivor was similar compared to control subjects, but the affected limb differed from the unaffected after stroke. Portable EMG to monitor muscle activity for prolonged periods was not reported to be an impediment by the case or control subjects. Using this technology, EMG bursts and gaps can be recorded and used to describe muscle activity. Future work may consider the feasibility of this technique to monitor rehabilitation progression or long-term plasticity of muscle activity.

Phenomenology and physiotherapy: meaning in research and practice

Abstract Background: Phenomenological research has emerged as an important qualitative research methodology in health care, contributing to a comprehensive approach to evidence-informed practice among health-care professionals. Evidence-informed practice in physiotherapy will benefit from integrating phenomenological research in order to attend to the lived-experiences of both clients and therapists involved in physiotherapist–client encounters, building a more sensitive and holistic approach to physiotherapy practice. Objective: This paper explores five major strands of philosophy within the phenomenological tradition and outlines their implications for the study of lived-experiences related to physiotherapy care. Major findings: The phenomenological positions of Edmund Husserl, Martin Heidegger, Maurice Merleau-Ponty, Alfred Schutz, and Max van Manen are discussed. Following a description of each phenomenological view, a brief scenario of how their approach to phenomenological study might be applied to problems in physical therapy practice is addressed. The approaches to phenomenology discussed in the paper are considered in the context of a conceptualization of rigour for phenomenological research. Conclusion: The paper concludes by advocating for multiple approaches to phenomenological research to benefit a diversity of approaches to physiotherapy care.

Neuromuscular contributions to the age-related reduction in muscle power: Mechanisms and potential role of high velocity power training

Although much of the literature on neuromuscular changes with aging has focused on loss of muscle mass and isometric strength, deficits in muscle power are more pronounced with aging and may be a more sensitive measure of neuromuscular degeneration. This review aims to identify the adaptations to the neuromuscular system with aging, with specific emphasis on changes that result in decreased muscle power. We discuss how these changes in neuromuscular performance can affect mobility, and ultimately contribute to an increased risk for falls in older adults. Finally, we evaluate the literature regarding high-velocity muscle power training (PT), and its potential advantages over conventional strength training for improving functional performance and mitigating fall risk in older adults.

Threshold Berg Balance Scale Scores for Gait-Aid Use in Elderly Subjects: A Secondary Analysis

PURPOSE To determine the threshold Berg Balance Scale (BBS) scores that discriminate among levels of gait-aid use in elderly subjects. METHODS A secondary analysis of data combined from two projects was performed. Both projects determined BBS performance, self-selected gait speed, and gait-aid use in samples of community-dwelling, independently ambulant individuals older than 65 years of age. Receiver operating characteristic curves were used to identify BBS scores that optimized identification of individuals with different levels of ambulation. RESULTS Previously determined associations between BBS score and various indicators of ambulatory ability were reproduced with the combined data set. Threshold BBS scores were identified for ability to walk without an aid (≥49/56) and ability to walk without a four-wheeled walker (≥43/56). The percent agreement values for the identified threshold scores ranged from 51% to 87%. CONCLUSIONS Although some threshold BBS scores could be determined, the accuracies of the scores render them of limited use for guiding gait-aid prescription in individual clients.

Fall Risk Beliefs and Behaviors Following a Fall in Community-Dwelling Older Adults: A Pilot Study

ABSTRACT Real uptake of recommendations is at the crux of community-based fall prevention. This mixed methods intervention study investigated how knowledge of ones own fall risk influenced self-reported behaviors and beliefs about falls and fall prevention in the home by older adults. Between one-on-one semi-structured interviews, participants received their individual scores compared to age-matched normative values for the Falls Efficacy Scale, Activities-specific Balance Confidence Scale, Biodex™ Fall Risk Test, and cut scores for the Timed Up and Go and Berg Balance Scale. Change scores on the Falls Behavioural Scale for Older Adults were reviewed as norm values were not found in the literature. Findings from the fall-related assessments and interviews reiterated the complexity of falls and fall prevention in a fluctuating curve of “awareness” comprised of “having concern, being careful,” “accepting,” and “action/behavior related to fall prevention.” Despite some uptake of recommended fall prevention advice, being perceived as susceptible to falls remained unacceptable to these participants, limiting real transfer or expressed belief in fall risk.

The Impact and Use of Walkers among Older Adults: A Pilot

This study examined the effect of a prescribed walker on functional performance and explored the personal experiences of four community-dwelling older adults with impaired mobility. A mixed method sequential explanatory design was used with a repeated case study approach. Standardized measures of timed mobility, balance confidence, and participation were collected twice, one month apart, followed by a one-on-one, semistructured interview. The International Classification of Functioning, Disability and Health framework was used to integrate quantitative and qualitative data and promote an understanding of the interactions among contributing factors to the impact and use of a walker in four “real” clinical practice scenarios. The findings suggest the need for rehabilitation professionals to explore a range of personal, performance, and environmental factors to optimize adoption of a walker into daily life by community-dwelling older adults.