M Newman1,2, R Newman3, T Hughes4, K Vadher5,6, K L Barker4,5. 1. Physiotherapy Research Unit, Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Trust, Windmill Rd, Oxford, OX3 7HE, UK. meredith.newman@ouh.nhs.uk. 2. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Windmill Rd, Oxford, OX3 7HE, UK. meredith.newman@ouh.nhs.uk. 3. Mind Foundry Ltd, Eagle House, Walton Well Rd, Oxford, OX2 6ED, UK. 4. Physiotherapy Research Unit, Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Trust, Windmill Rd, Oxford, OX3 7HE, UK. 5. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Windmill Rd, Oxford, OX3 7HE, UK. 6. Oxford Clinical Trials Research Unit, Centre for Statistics in Medicine, NDORMS, Botnar Research Centre, Windmill Rd, Oxford, OX3 7HE, UK.
Abstract
Timed loaded standing (TLS) is a suggested measure of back muscle endurance for people with vertebral osteoporosis. Surface electromyography revealed back muscles work harder and fatigue during TLS. The test end-point and total time were associated with back fatigue. The findings help demonstrate the concurrent validity of the TLS test. INTRODUCTION: The TLS test is suggested as a measure of back muscle endurance for patients with vertebral osteoporosis. However, to date, no study has demonstrated that TLS does measure back extensor or erector spinae (ES) muscle endurance. We used surface electromyography (sEMG) to investigate the performance of the thoracic ES muscles during TLS. METHODS: Thirty-six people with vertebral osteoporosis with a mean age of 71.6 (range 45-86) years participated. sEMG recordings were made of the ES at T3 and T12 bilaterally during quiet standing (QS) and TLS. The relative (%) change in sEMG amplitude between conditions was compared. Fatigue was evaluated by analysing the change in median frequency (MF) of the sEMG signal during TLS, and the correlation between maximal TLS time and rate of MF decline was examined. RESULTS: Activity in the ES increased significantly during TLS at all electrode locations. During TLS, the MF declined at a mean rate of -24.2% per minute (95% C.I. -26.5 to -21.9%). The MF slope and test time were strongly correlated (r2 = 0.71), and at test end, the final MF dropped to an average 89% (95% C.I. 85 to 93%) of initial MF. Twenty-eight participants (78%) reported fatigue was the main reason for stopping, and for eight (22%), it was pain. CONCLUSIONS: This study demonstrates that TLS challenges the ES muscles in the thoracic region and results in ES fatigue. Endurance time and the point at which the TLS test ends are strongly related to ES fatigue.
Timed loaded standing (TLS) is a suggested measure of back muscle endurance for people with vertebral osteoporosis. Surface electromyography revealed back muscles work harder and fatigue during TLS. The test end-point and total time were associated with back fatigue. The findings help demonstrate the concurrent validity of the TLS test. INTRODUCTION: The TLS test is suggested as a measure of back muscle endurance for patients with vertebral osteoporosis. However, to date, no study has demonstrated that TLS does measure back extensor or erector spinae (ES) muscle endurance. We used surface electromyography (sEMG) to investigate the performance of the thoracic ES muscles during TLS. METHODS: Thirty-six people with vertebral osteoporosis with a mean age of 71.6 (range 45-86) years participated. sEMG recordings were made of the ES at T3 and T12 bilaterally during quiet standing (QS) and TLS. The relative (%) change in sEMG amplitude between conditions was compared. Fatigue was evaluated by analysing the change in median frequency (MF) of the sEMG signal during TLS, and the correlation between maximal TLS time and rate of MF decline was examined. RESULTS: Activity in the ES increased significantly during TLS at all electrode locations. During TLS, the MF declined at a mean rate of -24.2% per minute (95% C.I. -26.5 to -21.9%). The MF slope and test time were strongly correlated (r2 = 0.71), and at test end, the final MF dropped to an average 89% (95% C.I. 85 to 93%) of initial MF. Twenty-eight participants (78%) reported fatigue was the main reason for stopping, and for eight (22%), it was pain. CONCLUSIONS: This study demonstrates that TLS challenges the ES muscles in the thoracic region and results in ES fatigue. Endurance time and the point at which the TLS test ends are strongly related to ES fatigue.
Authors: Wendy B Katzman; Eric Vittinghoff; Deborah M Kado; Anne L Schafer; Shirley S Wong; Amy Gladin; Nancy E Lane Journal: Phys Ther Date: 2015-08-06
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Authors: K L Barker; M Newman; N Stallard; J Leal; C M Lowe; M K Javaid; A Noufaily; T Hughes; D Smith; V Gandhi; C Cooper; S E Lamb Journal: Osteoporos Int Date: 2019-11-12 Impact factor: 4.507
Authors: Jenna C Gibbs; Caitlin McArthur; John D Wark; Lehana Thabane; Samuel C Scherer; Sadhana Prasad; Alexandra Papaioannou; Nicole Mittmann; Judi Laprade; Sandra Kim; Aliya Khan; David L Kendler; Keith D Hill; Angela M Cheung; Robert Bleakney; Maureen C Ashe; Jonathan D Adachi; Lora M Giangregorio Journal: Phys Ther Date: 2020-04-17