Gavin, James

Bournemouth University Research Online

Important notes:   You MUST use this template. If you don’t use it your abstract WILL be rejected. Do NOT enter author and institution information on this form. You will be able to enter this information online when you submit the abstract. Do NOT write outside the boxes. Any text or images outside the boxes will be deleted. Do NOT alter this form by deleting parts of it or adding new boxes. Simply enter your information into the boxes. We use automatic processing – if you alter it your submission will not be processed correctly. Save this file in .doc or .docx format.  Title: Functional sit-to-stand exercises evoke greater neuromuscular activation, than isometric bed exercises in community-dwelling, older adults  Abstract:  (Your abstract must use 10 point New Times Roman style and must fit into the box. Do not enter author details) Introduction: Rehabilitation after hip-replacement surgery routinely includes isometric bed exercises. However, these have little impact on pain, hip motion, strength and functional mobility [1]. Sit-standing is required for mobilisation and discharge, involving: asymmetrical weight-bearing, stability and concentric-eccentric hip muscle contractions. Therefore, sit-stands may be a preferential exercise to bed exercises in the hours after hip-replacement surgery. Research Question: Is muscle activation of the hip and thigh muscles greater during isometric bed exercises, than sit-stands in older adults? Methods: 24 participants performed: isometric bed exercises and sit-stand exercises (random-order) on one occasion. Bed exercises were ten submaximal contractions (each 5 s) separately for gluteal, abductor, quadriceps and inner range quadriceps muscles (60 s rests). Sit-stands involved chair rising to an upright position (sit-stand), then returning to a seated position (stand-sit) as many times possible within 30 s. Electromyograms (EMG) were recorded from the rectus femoris, vastus medialis, gluteus medius, biceps femoris and gluteus maximus, via a Biometrics PS850 system, during exercises. Signals were normalised to % of isometric maximal voluntary contraction, with separate analysis for standing and sitting phases. One-way, Friedman’s repeated measures ANOVA identified activation differences between each muscle during exercise modes. Paired Wilcoxon Signed-Rank tests located specific activation differences. Results: Quadriceps activation ranged from: 2-60% for bed exercises and 54-81% for sit-stands (quadriceps); 10-20% for bed exercises and 27-45% for sit-stands (hamstrings); 10-44% for bed exercises and 34-59% for sit-stands (gluteals). Vastus medialis activation was greater sit-standing, than gluteal (by 65%; p<0.0001), abductor (by 60%; p<0.0001) and inner range quadriceps bed exercises (by 36%; p<0.0005). Biceps femoris activation was greater sit-standing, than gluteal (by 29%; p=0.01), abductor (by 36%; p<0.0001), inner range quadriceps (by 34%; p<0.0001) and quadriceps bed exercises (by 24; p=0.04). Gluteus maximus activation was greater sit-standing, abductor (by 46%; p<0.0001), inner range quadriceps (by 50%; <0.0001) and quadriceps bed exercises (by 44%; p<0.0001). Gluteus medius activation was greater sit-standing, than inner range quadriceps (by 30%; p<0.0001) and quadriceps bed exercises (by 22%; p=0.01); chair rising activation exceeded sitting activation (by 19%; p=0.03). GlutealsAbduc torInne r rangeQuadr ic epsSit-standStand-sit0 .00 .20 .40 .60 .81 .0V a s tu s  m e d ia l i sE x e r c i s eNormalized RMS activity (%)GlutealsAbduc torInne r rangeQuadr ic epsSit-standStand-sit0 .00 .20 .40 .60 .8B ic e p s  f e m o r i sE x e r c i s eNormalized RMS activity (%)GlutealsAbduc torInne r rangeQuadr ic epsSit-standStand-sit0 .00 .20 .40 .60 .81 .0G lu t e u s  m a x im u sE x e r c i s eNormalized RMS activity (%)GlutealsAbduc torInne r rangeQuadr ic epsSit-standStand-sit0 .00 .20 .40 .60 .8G lu te u s  m e d iu sE x e r c i s eNormalized RMS activity (%) Discussion: Hip and thigh muscles were activated differently between isometric bed and sit-stand exercises, with rising during the sit-stand requiring greatest activation. For no bed exercise did muscle activity exceed that required to chair rise. All muscles were activated over 40% only for sit-stands; the level required stimulating muscle strength adaptation [2]. A larger, subsequent study will examine these observations in patients recovering from total hip-replacement surgery, and determine functionally how they relate to gait performance and balance. If similar results are found, practice could change to replace bed exercises with sit-stands and other functional exercises in the acute recovery after surgery. References: [1] Smith et al, Physiotherapy 2008; 94(4):286-291 [2] Andersen et al, Phys Ther 2006;86(5):683-69  

Functional sit-to-stand exercises evoke greater neuromuscular activation, than isometric bed exercises in community-dwelling, older adults.

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