Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength

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Abstract

Background

The ability to generate muscle strength is a pre-requisite for all human movement. Decreased quadriceps muscle strength is frequently observed in older adults and is associated with a decreased performance and activity limitations. To quantify the quadriceps muscle strength and to monitor changes over time, instruments and procedures with a sufficient reliability are needed. The Q Force is an innovative mobile muscle strength measurement instrument suitable to measure in various degrees of extension. Measurements between 110 and 130° extension present the highest values and the most significant increase after training.

The objective of this study is to determine the test-retest reliability of muscle strength measurements by the Q Force in older adults in 110° extension.

Methods

Forty-one healthy older adults, 13 males and 28 females were included in the study. Mean (SD) age was 81.9 (4.89) years. Isometric muscle strength of the Quadriceps muscle was assessed with the Q Force at 110° of knee extension. Participants were measured at two sessions with a three to eight day interval between sessions. To determine relative reliability, the intraclass correlation coefficient (ICC) was calculated. To determine absolute reliability, Bland and Altman Limits of Agreement (LOA) were calculated and t-tests were performed.

Results

Relative reliability of the Q Force is good to excellent as all ICC coefficients are higher than 0.75. Generally a large 95 % LOA, reflecting only moderate absolute reliability, is found as exemplified for the peak torque left leg of −18.6 N to 33.8 N and the right leg of −9.2 N to 26.4 N was between 15.7 and 23.6 Newton representing 25.2 % to 39.9 % of the size of the mean. Small systematic differences in mean were found between measurement session 1 and 2.

Conclusion

The present study shows that the Q Force has excellent relative test-retest reliability, but limited absolute test-retest reliability. Since the Q Force is relatively cheap and mobile it is suitable for application in various clinical settings, however, its capability to detect changes in muscle force over time is limited but comparable to existing instruments.

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Most cited references 42

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Statistical methods for assessing agreement between two methods of clinical measurement.

J Bland, D Altman (1986)

In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old. Such investigations are often analysed inappropriately, notably by using correlation coefficients. The use of correlation is misleading. An alternative approach, based on graphical techniques and simple calculations, is described, together with the relation between this analysis and the assessment of repeatability.

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Muscle type and fiber type specificity in muscle wasting.

Stefano Ciciliot, Alberto Rossi, Kenneth A. Dyar … (2013)

Muscle wasting occurs in a variety of conditions, including both genetic diseases, such as muscular dystrophies, and acquired disorders, ranging from muscle disuse to cancer cachexia, from heart failure to aging sarcopenia. In most of these conditions, the loss of muscle tissue is not homogeneous, but involves specific muscle groups, for example Duchenne muscular dystrophy affects most body muscles but spares extraocular muscles, and other dystrophies affect selectively proximal or distal limb muscles. In addition, muscle atrophy can affect specific fiber types, involving predominantly slow type 1 or fast type 2 muscle fibers, and is frequently accompanied by a slow-to-fast or fast-to-slow fiber type shift. For example, muscle disuse, such as spinal cord injury, causes type 1 fiber atrophy with a slow-to-fast fiber type shift, whereas cancer cachexia leads to preferential atrophy of type 2 fibers with a fast-to-slow fiber type shift. The identification of the signaling pathways responsible for the differential response of muscles types and fiber types can lead to a better understanding of the pathogenesis of muscle wasting and to the design of therapeutic interventions appropriate for the specific disorders. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting. Copyright © 2013 Elsevier Ltd. All rights reserved.

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Human quadriceps cross-sectional area, torque and neural activation during 6 months strength training.

B Kayser, M. Narici, Fabio M Conti … (1996)

Quadriceps muscle and fibre cross-sectional areas (CSA), torque and neural activation were studied in seven healthy males during 6 months of weight training on alternate days with six series of eight unilateral leg extensions at 80% of one repetition maximum. After training, the quadriceps cross-sectional area increased by 18.8 +/- 7.2% (P < 0.001) and 19.3 +/- 6.7% (P < 0.001) in the distal and proximal regions respectively, and by 13.0 +/- 7.2% (P < 0.001) in the central region of the muscle. Hypertrophy was significantly different between and within the four constituents of the quadriceps. Biopsies of the vastus lateralis at mid-thigh did not show any increase in mean fibre cross-sectional area. Maximum isometric voluntary torque increased by 29.6 +/- 7.9%-21.1 +/- 8.6% (P < 0.01-0.05) between 100 degrees and 160 degrees of knee extension, but no change in the optimum angle (110 degrees-120 degrees) for torque generation was found. A 12.0 +/- 10.8% (P < 0.02) increase in torque per unit area together with a right shift in the IEMG-torque relation and no change in maximum IEMG were observed. Time to peak isometric torque decreased by 45.8% (P < 0.03) but no change in time to maximum IEMG was observed. In conclusion, strength training of the quadriceps results in a variable hypertrophy of its components without affecting its angle-torque relation. The increase in torque per unit area, in the absence of changes in IEMG, may indicate changes in muscle architecture. An increase in muscle-tendon stiffness may account for the decrease in time to peak torque.

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Author and article information

Contributors

K. W. Douma: 0031(0)505957736/0031(0)505953539 , k.w.douma@pl.hanze.nl

G. R. H. Regterschot: g.r.h.regterschot@med.umcg.nl

W.P. Krijnen: w.p.krijnen@pl.hanze.nl

G. E. C. Slager: g.e.c.slagers@pl.hanze.nl

C. P. van der Schans: c.p.van.der.schans@pl.hanze.nl

W. Zijlstra: zijlstra@dshs-koeln.de

Journal

Journal ID (nlm-ta): BMC Sports Sci Med Rehabil

Journal ID (iso-abbrev): BMC Sports Sci Med Rehabil

Title: BMC Sports Science, Medicine and Rehabilitation

Publisher: BioMed Central (London )

ISSN (Electronic): 2052-1847

Publication date (Electronic): 19 February 2016

Publication date PMC-release: 19 February 2016

Publication date Collection: 2016

Volume: 8

Electronic Location Identifier: 4

Affiliations

[ ]Research and Innovation Group in Healthy Aging, Allied Health Care and Nursing, Hanze University of Applied Sciences Groningen, Groningen, The Netherlands

[ ]Department of Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands

[ ]University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences Groningen, Groningen, The Netherlands

[ ]School of Health Care Studies Hanze University of Applied Science Groningen, Groningen, The Netherlands

[ ]Institute of Movement and Sport Gerontology, German Sport University, Cologne, Germany

Article

Publisher ID: 29

DOI: 10.1186/s13102-016-0029-x

PMC ID: 4759727

PubMed ID: 26900478

SO-VID: 34bb51f6-40e3-40c8-8961-a539fbe88313

License:

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

History

Date received : 23 June 2015

Date accepted : 2 February 2016

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Keywords: quadriceps,isometric muscle strength,q force,elderly

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Keywords: quadriceps, isometric muscle strength, q force, elderly

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Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength

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Abstract

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Most cited references 42

Statistical methods for assessing agreement between two methods of clinical measurement.

Muscle type and fiber type specificity in muscle wasting.

Human quadriceps cross-sectional area, torque and neural activation during 6 months strength training.

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Cited by 3

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