EFFECTS OF MUSCLE STRENGTHENING AND PHYSICAL CONDITIONING TRAINING ON TEMPORAL, KINEMATIC AND KINETIC VARIABLES DURING GAIT IN CHRONIC STROKE SURVIVORS Luci Fuscaldi Teixeira-Salmela, 1 Sylvie Nadeau, 2 Ian Mcbride 3 and Sandra Jean Olney 3 From the 1 Universidade Federal de Minas Gerais, Brazil, 2 University of Montreal, Quebec, 3 School of Rehabilitation Therapy, Queen’s University, Kingston, Ontario, Canada The purpose of this study was to evaluate the impact of a combined program of muscle strengthening and physical conditioning on gait performance in subjects with chronic stroke, using a single group pre- and post-test design. Thirteen subjects were recruited for the 10-week program (3 days/week), which consistedof warm-up, aerobic exercises, lower extremity muscle strengthening and cool-down. Data from cinematographic lm and a force plate obtained during multiple walking trials were used in a four-segment kinetic model to yield spatiotemporal, kinematic and kinetic vari- ables. Gait analysis revealed that the 10 week training resulted in signicant increases in gait speed associated with improvementsin walking patterns as determinedby increases in selected kinematic and kinetic measures. After training, subjects were able to generate higher levels of powers and demonstrated increases in positive work performed by the ankle plantar exor and hip exor/extensor muscles. Key words: stroke, gait, biomechanics, muscle strength, physical conditioning. J Rehab Med 2001; 33: 53–60 Correspondence address: Dr. Sylvie Nadeau, Professeure Adjointe, University of Montreal, Faculty of Medicine, School of Rehabilitation, C.P. 6128, Succursale Centre- ville, Montreal (Quebec), H3C 3J7 Canada (Accepted July 7, 2000) INTRODUCTION Initial walking function is impaired in two-thirds of the stroke populationand this decit is the greatestcontributorto functional disabilityafterstroke(1). A singlecommonpatternof hemiplegic gait does not exist and disturbances of the temporal, spatial and kinematic patterns are well documented (2, 3). The self-selected gait speed is a well-known indicator of overall gait performance and has been commonly used to monitor performance and evaluate the effects of treatment in stroke rehabilitation (4). However, when used alone, gait speed assists in neither under- standing the nature of the gait deciencies nor directing future training. By the same token, while the use of kinematic proles is well known, it is generally agreed that they yield little information about the mechanisms underlying abnormal move- ment patterns (5). More recently, kinetic analyses for the diagnosis of pathological data have provided strategies for diagnosing the causes of abnormal motor patterns observed in pathological gait proles (2, 3, 5). Since kinetic variables are causal factors in kinematic and spatiotemporal outcomes of gait, this information is particularly useful in understanding not only abnormal gait patterns, but also the causes underlying improve- ments in performance (2). Measurement of mechanical work and power performed by major muscle groups has been used to predict gait performancein stroke subjects(3). Both the push-off power burst of the ankle plantar exors and the pull-off burst of the hip exors are of particular interest (2, 3) because of their importance in the required power generation for walking. Muscle weakness has been implicated as a factor underlying decits in gait performance in subjects with stroke (6). Muscle strength and associated declines in functional performance related to normal ageing can be ameliorated through strengthen- ing programs and also may prove useful in promoting long-term independencefor both stroke subjects and the elderly population (7). Previousstudieshaverevealedthe positiveeffectsof strength training on gait speed for subjects with chronic stroke (4). Endurance training has also been recognized as an important component in rehabilitation. The effects of a combined strength and aerobic conditioning program have improved strength, muscular endurance and functional performance in the elderly (8). A previous randomized controlled trial study demonstrated the benets of such a program in reducing impairment and disability in chronic stroke subjects (9). This study further assessedthe effectsofthe trainingon gaitperformancein subjects with chronic stroke using spatiotemporal, kinematic and kinetic analyses,including joint moments, joint powers and work. It was expected that gains in gait speed would be associated with changes in kinematic proles, higher joint moments and higher levels of power produced by major lower extremity muscle groups. SUBJECTS AND METHODS Subjects Thirteen volunteer subjects with unilateral stroke, who had residual weakness and/or spasticity of the affected lower extremity, were recruited from a local stroke club and through newspaper and cable television advertisements. All subjects were screened to ensure that their mean time since onset of stroke was at least 9 months, were independently ambulatory with or without assistive devices for 15 minutes, had an activity tolerance of 45 minutes with rest intervals, and had no com- prehensive aphasia. Those with non-stroke-related disabilities were excluded. Subjects were also required to obtain their physicians’ consent to participate in the program and underwent dobutamine stress echocar- diography (10) to rule out evident relative cardiac risk prior to program entry. Eligible subjects provided consent prior to their screening test based Ó 2001 Taylor & Francis. ISSN 1650–1977 J Rehab Med 33 J Rehab Med 2001; 33: 53–60