Hindawi Publishing Corporation BioMed Research International Volume 2013, Article ID 173148, 7 pages http://dx.doi.org/10.1155/2013/173148 Research Article Differences in Muscle Activation Patterns during Sit to Stand Task among Subjects with and without Intellectual Disability Antonio I. Cuesta-Vargas 1,2 and Manuel González-Sánchez 2 1 School of Clinical Sciences, Faculty of Health, Queensland University of Technology (QUT), Victoria Park Road, Kelvin Grove, QLD 4059, Australia 2 Department of Physiotherapy, Faculty of Health Sciences, University of Malaga, 29071 M´ alaga, Spain Correspondence should be addressed to Antonio I. Cuesta-Vargas; acuesta.var@gmail.com Received 24 May 2013; Revised 2 September 2013; Accepted 3 September 2013 Academic Editor: Stephen E. Alway Copyright © 2013 A. I. Cuesta-Vargas and M. Gonz´ alez-S´ anchez. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. he aim of this study is to analyse the diferences in muscle activity between subjects who have intellectual disability and healthy subjects when they make the transition from sitting to standing positions. A cross-sectional study. A group of adults was divided into two subgroups: with and without intellectual disability (ID). he means of the basic features in both groups were 22.13 and 22.83 for age, 66.38 and 67.67 for weight, and 173.38 and 174.33 for height, for the ID (=8) and without ID (=7) groups, respectively. Each subject performed three sets of ive repetitions during which, starting from sitting, they had to get up and sit on the chair. he recording of muscle activity was performed using surface electromyography taking the measures of muscle activity of diferent muscles of the lower limbs. he results showed diferences in the pattern of muscle activity between groups during sitting to standing movement. 1. Introduction Muscle activation (MA) that generates force is required for many activities of daily living (ADL), including eating, dressing, walking, or rising from a chair (sit to stand move- ment (STS)). Each of these activities is essential to ensure the maintenance of a person’s physical independence [1]. herefore, it is not surprising to discover that the progressive loss of efectiveness in MA is associated with a deiciency of basic capabilities, such as those previously mentioned and which, therefore, decreases a person’s independence [2]. he sequences of STS and sitting are very common in ADL. he ability to develop STS movements is considered a very important feature for determining the degree of inde- pendence and the quality of life of a person [2]. his sequence is considered the most mechanical movement within ADL [3, 4], due to the high level of muscle activation that it requires, as individuals need to coordinate a transfer from a horizontal to a vertical position in one movement [5]. Furthermore, it is necessary for nervous system stability and alignment of the various body segments both dynamically [6] and statically. Nevertheless, for the realisation of this sequence, muscle strength [7, 8], balance [9, 10], and synergy of muscle activation [11, 12] are required. Individuals with intellectual disabilities (ID) oten have diferent MAs from those who do not have ID [13–15]. It appears that this MA would result in a poorer physical proile whose explanations could be found in chronotropic failure, reduced motivation, or even in the diiculty of advising this population [16]. It appears that this diference in the MA is associated with qualitative and quantitative deiciencies of muscle tissue, especially related to a sedentary lifestyle [14]. On the other hand, itness in people with ID appears to be closely related to the vocational performance level of the individual and it has been shown that when individuals were removed from competitive environments, there was a decline in the quality of life and ability to perform the tasks [17, 18], leading to a progressive increase in the dependency of the person and a decline of their integration in society [1, 19]. MA could be deined as the distribution of activation or muscle strength of individual muscles to produce a joint motion [20], which can be studied using electromyography (EMG), using diferent models to estimate muscle strength [21]. In addition, several studies have shown that a muscle