Context: Functional subdivisions are proposed to exist in the gluteus medius (GM) muscle. Dysfunction of the GM, in particular its functional subdivisions, is commonly implicated in lower limb pathologies. However, there is a lack of empirical evidence examining the role of the subdivisions of the GM. Objectives: To compare the activation of the functional subdivisions of the GM (anterior, middle, and posterior) during isometric hip contractions. Design: Single-session, repeated-measures observational study. Setting: University research laboratory. Participants: Convenience sample of 15 healthy, pain-free subjects. Intervention: Subjects performed 3 maximal voluntary isometric contractions for hip abduction and internal and external rotation on an isokinetic dynamometer with simultaneous recording of surface electromyography (sEMG) activity of the GM subdivisions. Main Outcome Measures: sEMG muscle activity for each functional subdivision of the GM during each hip movement was analyzed using a 1-way repeated-measures ANOVA (post hoc Bonferroni). Results: The response of GM subdivisions during the 3 different isometric contractions was significantly different (interaction effect; P = .003). The anterior GM displayed significantly higher activation across all 3 isometric contractions than the middle and posterior subdivisions (main effect; both P < .001). The middle GM also demonstrated significantly higher activation than the posterior GM across all 3 isometric contractions (main effect; P = .027). There was also significantly higher activation of all 3 subdivisions during both abduction and internal rotation than during external rotation (main effect; both P < .001). Conclusions: The existence of functional subdivisions in the GM appears to be supported by the findings. Muscle activation was not homogeneous throughout the entire muscle. The highest GM activation was found in the anterior GM subdivision and during abduction and internal rotation. Future studies should examine the role of GM functional subdivisions in subjects with lower limb pathologies.

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People with MS do not use more energy than healthy controls during everyday activities at a self-selected pace. People with MS take significantly fewer steps during activities of daily living's. People who use bilateral support for gait have greater energy cost per step for walking and stairs activities. Implications for Rehabilitation This study found that the energy cost of movement is greater for people with MS with significant disability. Energy expenditure is an important consideration when prescribing physical activity and structured exercise for people with disability. It may be more appropriate to have energy, rather than movement, targets when prescribing physical activity for this population.

Abstract-Accurate estimation of Energy Expenditure (EE) in ambulatory settings provides greater insight into the underlying relation between different human physical activity and health. This paper describes the development and validation of energy expenditure estimation algorithms. A total of 4 healthy subjects and 3suffering from multiple sclerosis were monitored using a goldstandard energy expenditure measurement system, a heart rate monitor and accelerometry. We demonstrated that greater improvements can be achieved by estimating energy expenditure during normal activities of daily living by combining both whole body acceleration estimates, vertical body acceleration estimates, body posture and heart rate data as part of a flex heart rate algorithm in subject specific models when compared to using accelerometry or heart rate data alone. This will allow more accurate EE estimation during normal activities of daily living.

Background: Regular physical activity (PA) is a key component in the maintenance of a healthy lifestyle and is known to decrease the risk of numerous chronic health conditions. Accurate measurement of PA is essential to determine the effect of exercise interventions on long-term PA levels and to identify population health behaviours. However, measurement of PA is complex and multimodal with numerous measurement tools available. Objectives: The aim of this review is to improve conceptual clarity regarding PA and to examine the difficulties relating to PA measurement in order to enable clinicians to choose the optimal PA measurement tool. Major findings: PA is a multidimensional concept. Movement and energy expenditure (EE) are the most common dimensions used in the quantification of PA. There are numerous PA measurement options including doubly labelled water, calorimetry, heart rate monitors and motion sensors (pedometers and accelerometers). Choosing the optimal measurement tool is influenced by the parameter of PA that is of most relevance. Motion sensors appear to provide the most promising and accurate cost-effective method of measuring free-living PA, particularly when accelerometer and physiological data are integrated. However, consideration must be given to the intrinsic difficulties associated with motion monitors, particularly the use of generic values and algorithms in calculating EE, which limit the external validity and applicability of motion sensors in different populations. Conclusions: Although the optimal method of measuring PA remains unknown, forming appropriate research and clinical questions and providing conceptual clarity should guide clinicians in selecting the most appropriate measurement option.