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Vassis K1, Misiris I1, Kanellopoulos A1, Kapreli E1, Poulis I1
1Technological Educational Institute of Central Greece, Department of Physical Therapy, Lamia, Greece
Background: Muscle performance deficits affect the general population, including high-level athletes and older people. Reliable strength evaluation tests are important to accurately measure and quantify muscular performance and determine the effectiveness of any therapeutic intervention. The use of isokinetic dynamometer, despite its high reliable measurements, is somewhat limited due to size and cost requirements of the equipment. The use of functional performance tests to evaluate muscular performance has been supported since they exhibit a higher correlation to function and they incorporate a variety of motion principles imitating dynamic knee stability requirements during sports or everyday life activities. Nevertheless, studies have not shown a stable constant strong correlation between isokinetic and functional measures with some researchers showing mild and moderate to good correlations, while others show little or no correlations. A good correlation between laboratory testing and functional testing could be of great value for determining performance in an environment where sophisticated equipment is not easily accessible.
Purpose: Τo further study the relationship between isokinetically tested knee flexor and extensor muscular performance and three commonly used functional performance tests in healthy population.
Methods: 26 subjects, (14 males and 12 females), aged 18-45 years with no history of low back, hip, knee, or ankle injury that was treated by a physician, participated in the study. Isokinetic concentric bilateral knee flexion and extension muscular performance values [Mean Peak Torque (MPT), Total Work (TW) and Average Power (AP)] were assessed isokinetically at the angular velocities at 60°/s, 180°/s and 300°/s. Functional performance was assessed using: 1) single hop for distance (SHD), 2) triple hop for distance (THD) and 3) single timed hop (STH). Isokinetic and functional data were normalized to body weight (BW).
Results: Twenty-six individuals, 14 males and 12 females (mean age = 23 ± 4.32 years; mean height = 172.42 ± 8.92 cm; mean mass = 69.49 ± 12.21 kg) participated in this study. The results showed that there is no strong correlation between isokinetic and functional measures. Fair and moderate to good correlations were found between normalized to BW functional tests and the normalized isokinetic variables.
Flexors' isokinetic variables had better correlations with normalized to BW functional tests than the extensor values, while none of the evaluation angular velocities (60°/s, 180°/s, or 300°/s) appeared to be more indicative to functional performance. TW/BW and AP/BW had a better correlation than MPT/BW concerning the SHD test. In contrast, MPT/BW was better correlated with the THD functional test, and better correlations were observed between MPT/BW and AP/BW with STH in relation to TW/BW.
Conclusion(s): The results of the present study showed moderate correlations between the functional hop values and the isokinetic parameters.
Implications: An isokinetic evaluation of the strength alone may not give an insight for function of an individual. It is recommended to use isokinetics in conjunction with the functional tests for a more objective evaluation of knee muscular performance. Α combination of OKC and CKC evaluation can provide more valid information for knee muscles' functional assessment and performance.
Keywords: isokinetics, muscular performance, functional testing
Funding acknowledgements: The authors in this research report no conflict of interest. This study does not involve any external research grant support.
Purpose: Τo further study the relationship between isokinetically tested knee flexor and extensor muscular performance and three commonly used functional performance tests in healthy population.
Methods: 26 subjects, (14 males and 12 females), aged 18-45 years with no history of low back, hip, knee, or ankle injury that was treated by a physician, participated in the study. Isokinetic concentric bilateral knee flexion and extension muscular performance values [Mean Peak Torque (MPT), Total Work (TW) and Average Power (AP)] were assessed isokinetically at the angular velocities at 60°/s, 180°/s and 300°/s. Functional performance was assessed using: 1) single hop for distance (SHD), 2) triple hop for distance (THD) and 3) single timed hop (STH). Isokinetic and functional data were normalized to body weight (BW).
Results: Twenty-six individuals, 14 males and 12 females (mean age = 23 ± 4.32 years; mean height = 172.42 ± 8.92 cm; mean mass = 69.49 ± 12.21 kg) participated in this study. The results showed that there is no strong correlation between isokinetic and functional measures. Fair and moderate to good correlations were found between normalized to BW functional tests and the normalized isokinetic variables.
Flexors' isokinetic variables had better correlations with normalized to BW functional tests than the extensor values, while none of the evaluation angular velocities (60°/s, 180°/s, or 300°/s) appeared to be more indicative to functional performance. TW/BW and AP/BW had a better correlation than MPT/BW concerning the SHD test. In contrast, MPT/BW was better correlated with the THD functional test, and better correlations were observed between MPT/BW and AP/BW with STH in relation to TW/BW.
Conclusion(s): The results of the present study showed moderate correlations between the functional hop values and the isokinetic parameters.
Implications: An isokinetic evaluation of the strength alone may not give an insight for function of an individual. It is recommended to use isokinetics in conjunction with the functional tests for a more objective evaluation of knee muscular performance. Α combination of OKC and CKC evaluation can provide more valid information for knee muscles' functional assessment and performance.
Keywords: isokinetics, muscular performance, functional testing
Funding acknowledgements: The authors in this research report no conflict of interest. This study does not involve any external research grant support.
Topic: Musculoskeletal: lower limb; Outcome measurement
Ethics approval required: Yes
Institution: Technological Educational Institute of Central Greece
Ethics committee: Bioethics commission of the Department of Physiotherapy
Ethics number: 118/02-10-2008
All authors, affiliations and abstracts have been published as submitted.
