| 1. |
- Antonopoulos (Kvist), Joanna, et al.
(författare)
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Anterior tibial translation related to isokinetic concentric quadriceps torques
- 1996
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 6:2, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- Sagittal translation of the tibia was examined in a static test with 90 N force at 20°of knee flexion and dynamically during knee extension in a Biodex machine using increasing quadriceps torque in six healthy volunteers. The translation increased in a non-linear fashion with increasing torque. Similar relative increases in quadriceps torque caused similar relative increases in translation in the different individuals. The dynamic translation at the individual maximum quadriceps torque was equal to the static 90-N translation. There was a negative correlation between the maximum quadriceps torque and the static 90-N translation. The results indicate that the quadriceps torque is related to the amount of translation in the knee joint possibly by some feed back mechanism from the ligaments preventing abnormal translation. The findings also imply that a limitation of quadriceps torque around 80% of maximum would limit the strain in an injured ligament to a level not higher than what is caused by normal laxity measurements.
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| 2. |
- Bohannon, Richard W., et al.
(författare)
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Consolidated reference values for grip strength of adults 20 to 49 years : a descriptive meta-analysis
- 2006
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 14:3, s. 221-224
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Tidskriftsartikel (refereegranskat)abstract
- Building on a previous meta-analysis, this study focused on the utility of consolidating grip strength data from apparently healthy subjects 20-49 years of age. All data were obtained using a Jamar dynamometer and procedures generally consistent with the recommendations of the American Society of Hand Therapists. The meta-analysis revealed that the seven sources provided homogeneous data (Q = 0.21 -0.81, p ≥ 0.667) for the left and right sides of men and women subjects. Means and confidence intervals are provided that can be used to interpret the normality of grip strength obtained from men and women 20-49 years of age. By consolidating the data from multiple studies conducted in five countries, a better overall estimate of normal is obtained. Providing reference values for three decades combined simplifies normative comparisons.
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| 3. |
- Drake, Anna Maria, et al.
(författare)
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Reproducibility of isokinetic ankle dorsiflexor strength and fatigue measurements in healthy older subjects.
- 2007
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Ingår i: Isokinetics and Exercise Science. - 1878-5913 .- 0959-3020. ; 15:4, s. 263-270
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the test-retest (two occasions seven days part) reproducibility of isokinetic (Biodex) concentric (CON) and eccentric (ECC) ankle dorsiflexor strength and fatigue measurements in older subjects using several statistical methods. Thirty healthy men (n=15) and women (n=15) aged between 70 and 85 years participated in the study. To determine the reproducibility of strength measurements, the 30 individuals performed three maximal CON and ECC contractions at 30°/s and 90°/s. The intraclass correlation coefficient (ICC_{2.1}) for CON and ECC strength measurements was high and ranged from 0.94 to 0.98. Bland & Altman graphs and analyses indicted no systematic bias. The standard error of measurement (SEM), representing the smallest change that indicates a real improvement (or deterioration) for a group of individuals, was small (< 2.3 Nm). The smallest real difference (SRD), representing the smallest detectable change that indicates a real improvement (or deterioration) for a single subject, was also small ('error bands' from −7.2 Nm to 5.6 Nm). A high correlation (Pearson's r > 0.94) between CON peak torque at 30°/s and 90°/s, as well as ECC peak torque at 30°/s and 90°/s, suggested that any of these two velocities could be used as a reference. To determine the reproducibility of fatigue measurements, 28 of the 30 individuals performed 50 maximal CON contractions at 60°/s. Reproducibility of the loss in work (work fatigue) and the relative loss in peak torque, comparing the first three to the last three contractions (3-3), was determined and the ICC was 0.71 and 0.60, respectively. In addition, the SEM was small (< 8.4%) and the 'error bands' to define the SRD for a single subject were also small (from −23.5% to 24.5%). In conclusion, these values indicate small measurement errors and thus provide a clinically acceptable basis for testing ankle dorsiflexion strength and fatigue of the dominant side in healthy older people.
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| 4. |
- Flansbjer, Ulla-Britt, et al.
(författare)
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Reproducibility of ankle dorsiflexor muscle strength measurements in individuals with post-polio syndrome
- 2011
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Ingår i: Isokinetics and Exercise Science. - 1878-5913 .- 0959-3020. ; 19:1, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to assess the reproducibility of isokinetic and isometric ankle dorsiflexor strength measurements in individuals with post-polio syndrome (PPS). Thirty-one men and women (mean age 63 +/- 7.0 years) with verified PPS, participated in an intra-rater test-retest reproducibility study. Strength of the ankle dorsiflexor muscles in both lower limbs were measured twice, seven days apart, with a Biodex dynamometer (isokinetic concentric; 30 degrees/s and isometric; ankle plantar flexion angle 10 degrees). Reproducibility was evaluated with the intraclass correlation coefficient (ICC2,1), the mean difference between the test sessions ((d) over bar) and the 95% confidence intervals for (d) over bar, the standard error of measurement (SEM, 95% SEM and SEM%) and Bland & Altman graphs. All 31 individuals completed the measurements in the less affected lower limb, but only 14 in the more affected lower limb due to severe weakness and/or joint stiffness. The analysis was therefore based on data from the two lower limbs separately. The test-retest agreements were high, (ICC2,1 0.85 to 0.94) and measurement errors generally small, and there was no discernible difference between the less and more affected lower limbs. The mean isokinetic and isometric peak torque (Nm) for the two lower limbs from the two test sessions ranged from 22.7 to 25.8. The SEM, which represents the limit for the smallest change that indicates a real change for a group of individuals, ranged from 2.51 to 3.74 Nm. In conclusion, isokinetic and isometric muscle strength measurements of the ankle dorsiflexor muscles in individuals with PPS are reproducible and can be used to detect changes over time or after an intervention for groups of individuals.
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| 5. |
- Gomez-Piqueras, Pedro, et al.
(författare)
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Are we making SMART decisions regarding return to training of injured football players? Preliminary results from a pilot study
- 2018
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Ingår i: Isokinetics and exercise science. - : IOS PRESS. - 0959-3020 .- 1878-5913. ; 26:2, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: "When will I be able to play again?" is the most frequent question asked by injured athletes. Due to the complex nature of sports injury, deciding when an injured athlete may safely return to training is a critical and difficult decision. OBJECTIVE: To study if the Safe Multidimensional Algorithm for Return to Training (SMART) scores, applied before the release to full return to training after injury differs between football players who suffer a subsequent re-injury and football players who do not. METHOD: Seventy one male professional football players were prospectively monitored for injuries during two seasons. The SMART tool was applied in injured players with an absence amp;gt; 10 days. The injured player had to carry out 17 multidimensional tests included in the algorithm in his final days of the planned rehabilitation. The results of the SMART were compared between players who sustained re-injuries and those who did not. RESULTS: Fifty-five injuries with absence amp;gt; 10 days were recorded and re-injuries occurred in 12 of these cases (22%). There was a lower re-injury rate in players who presented a better recovery in pain (p amp;lt; 0.001), agility (RR 21.0, 95% CI: 2.0 to 213.2), advanced agility (RR 26.7, 95% CI: 4.9 to 142.8), anxiety (RR 8.6, 95% CI: 2.0 to 36.2), depression (RR 10.3, 95% CI: 1.5 to 65.7), self-perception (p amp;lt; 0.001), advanced skills mode (RR 20.5, 95% CI: 3.3 to 125.9) and group skills mode (p amp;lt; 0.001). CONCLUSIONS: A multidimensional approach of Return to Training that includes objective measures may indicate potential deficiencies in the recovery of injured players.
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| 6. |
- Hébert-Losier, Kim, et al.
(författare)
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The reproducibility of three different indicators of fatigue from plantar- flexion isokinetic testing at two knee flexion angles is not sufficient to be termed 'acceptable'
- 2013
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 21:3, s. 227-236
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To characterize the reproducibility of three indicators of fatigue (FIs) specific to concentric plantar-flexion isokinetic testing at knee flexion (KF) angles of 0 degrees (straight) and 45 degrees (bent). METHODS: On two separate days one week apart, thirty-four males performed 50 consecutive maximal concentric isokinetic plantar-flexion contractions at 60 degrees/s with 0 degrees and 45 degrees of KF. Differences in the pre- and post-maximal voluntary isometric contraction torques (FIstatic), powers during the initial five and last five isokinetic contractions (FIdynamic) and powers during the 50 isokinetic contractions (FIslope) were used as FIs. Changes in means, intra-class correlation coefficients (ICCs) and coefficients of variations (CVs) were computed to quantify the reproducibility of the FIs. Comparisons were made between the two KF angles and three FIs using two-way repeated measures ANOVA. RESULTS: For both KF angles and three FIs, ICCs ranged from 0.52 to 0.71 and CVs from 10.0 to 29.3%. The CVs from the two isokinetic-based FIs were lower than those from the isometric FI and a trend towards larger ICCs at 0 degrees was observed. CONCLUSIONS: The reproducibility of the three FIs was not sufficient to be termed 'acceptable'. The FIslope and FIdynamic were more reproducible than FIstatic and are recommended - with the knee straight rather than bent - until more reliable indicators become available.
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| 7. |
- Hedlund, Mattias, et al.
(författare)
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Torque-angle relationship are better preserved during eccentric compared to concentric contractions in patients with stroke
- 2012
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 20:2, s. 129-140
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare the effect of isokinetic contraction mode and velocity on the torque-angle relationship during maximum voluntary elbow flexion in patients with stroke, age-matched healthy subjects and young subjects. To eliminate the effect of torque amplitude differences between subjects and groups, the torque values throughout the ROM were individually normalized to the peak value for each contraction velocity. The results indicate that in stroke patients the normalized torque angle relationship during the eccentric contractions was better preserved than during concentric contractions. Specifically, during eccentric contractions, stroke patients exhibited a torque-angle relationship that was closer to normal as the test velocity increased. The opposite trend could be seen in concentric contractions where the torque-angle relationship became more divergent from normal with a rise in the velocity. The torque-angle relationships were essentially the same for the control groups, irrespective of contraction mode or velocity. These findings may have significance for loading patterns of resistance training exercises used with stroke patients as such exercises normally are biomechanically designed for normal torque angle relationships. In clinical practice, these findings may partly explain why the strength increases due to resistance training are limited for patients with stroke.
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| 8. |
- Kadi, Fawzi, et al.
(författare)
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Strength, muscular endurance and EMG characteristics of thigh adductors
- 2006
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 14:3, s. 235-239
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Tidskriftsartikel (refereegranskat)abstract
- The assessment of thigh adductors' strength and endurance and electromyographical (EMG) characteristics has received little attention compared to other muscle groups. The aim of this study was to investigate strength, endurance performance and EMG characteristics of m. adductor longus and m. gracilis during concentric thigh adduction in soccer and bandy players. Muscular endurance was evaluated using the torque reduction during 70 repeated maximum concentric adductions at an angular velocity of 60°/s. The EMG mean frequency (MNF) and the signal amplitude ratio (SAR, index for muscles' ability to relax between contractions) were analysed. Peak torque decreased significantly throughout the test and no significant differences were found between the two groups. In both muscles, MNF decreased significantly throughout the test. There were no significant differences in MNF and in SAR variables between soccer and bandy players. In conclusion, the present findings reveal a number of significant aspects related to strength and electromyography of hip adductors. © 2006 - IOS Press and the authors. All rights reserved.
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| 9. |
- Larsson, Barbro, et al.
(författare)
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Muscle performance during maximum repeated knee extensions in children with hemiplegic cerebral palsy
- 2008
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 16:4, s. 221-230
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to compare isokinetic muscle performance of the knee extensors including surface EMG during repetitive maximum contractions between children with hemiplegic CP and healthy controls. A group of children with hemiplegic cerebral palsy (CP) (16 boys and eight girls; mean age 11 years with SD 2; range 7 to 15 years) and a control group (14 boys and eight girls; mean age 10 years with SD 2; range 7 to 15 years) participated. The relationships between maximum peak torque and the surface electromyography (EMG) variable root mean square (RMS) were obtained during 100 concentric knee extensions at 90°/s. Surface EMG was recorded from rectus femoris, vastus lateralis, and biceps femoris. The children with CP were also tested using Gross Motor Function Measure (GMFM). There were no differences between the groups in muscle endurance for the younger children. The results indicated that the children with CP had less strength enhancement in the hemiplegic leg during puberty. Peak torque correlated with GMFM and with RMS in rectus femoris and vastus lateralis. Co-activation was found in biceps femoris, but it did not affect muscle strength.
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| 10. |
- Lexell, Jan, et al.
(författare)
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Isokinetic torque and surface electromyography during fatiguing muscle contractions in young and older men and women
- 2006
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Ingår i: Isokinetics and exercise science. - 0959-3020 .- 1878-5913. ; 14:3, s. 225-234
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Tidskriftsartikel (refereegranskat)abstract
- The overall aim was to investigate the fatigue pattern and perceived fatigue during repetitive dynamic contractions in young and older men and women. Sixteen older men and women (mean age 73 ± 3 years) and 22 young men and women (mean age 28 ± 6 years) performed 100 repeated maximum concentric isokinetic knee extension contractions at 90°·s-1 (1.57 rad·s-1). Throughout the 100 contractions, peak torque (PT) and surface electromyography (EMG) signals from the rectus femoris muscle and the vastus lateralis muscle were recorded simultaneously, together with perceived fatigue (CR-10 scale of Borg). The mean frequency of the power spectrum (MNF) and the root mean square of the signal amplitude (RMS) of the EMG were affected by age and with a sex related difference but for PT the difference of the fatigue pattern was most evident between the sexes. In addition, the young men rated the highest fatigue. Based on EMG, PT and ratings of perceived fatigue it was concluded that the old men fatigued most, the old women fatigued least and the young men perceived greatest fatigue.
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| 11. |
- Whyte, S., et al.
(författare)
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Tests of muscle function and health related quality of life in healthy older adults in Sweden
- 2021
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Ingår i: Isokinetics and Exercise Science. - : IOS Press. - 0959-3020 .- 1878-5913. ; 29:1, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Life expectancy among older adults has dramatically increased and they are one of the fastest growing populations worldwide. Maintaining quality of life and the ability to live independently are often of greater importance than overall life expectancy. OBJECTIVE: To present reference values for tests of muscle function, and to study the relationship to a commonly used tool of generic health related quality of life (HRQL) in older Swedish adults. METHODS: The study consisted of 192 individuals (105 women) aged between 65 and 80. The tests included hand grip and isometric knee extension strength measurements, the standing heel rise test and a 30 m walking test. Health-related quality of life (HRQOL) was evaluated using the SF-36. RESULTS: Reference values for the measured parameters are presented. There were high correlations (n = 192) between handgrip and leg extension strength (r = 0.72-0.75; p < 0.01). The walking test's self-selected speed demonstrated the strongest correlation with the physical component summary of the SF-36 (r = 0.57; p < 0.01) and with maximal speed, moderate correlations were demonstrated with muscle strength (r = 0.43-0.56; p < 0.01) and the heel rise test (r = 0.45; p < 0.01). CONCLUSIONS: This study presents reference values for simple tests of muscle function which are relatively easy to perform, used in a Swedish clinical setting performing screening for older adults.
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| 12. |
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| 13. |
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| 14. |
- Carlsson, Håkan, et al.
(författare)
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The relationship between isokinetic and isometric knee muscle strength and maximal step-up height after stroke: A pilot study.
- 2015
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Ingår i: Isokinetics and Exercise Science. - 1878-5913. ; 23:3, s. 143-149
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A novel way to evaluate muscle strength and functioning in the lower limbs is to measure how high a person could step up on a platform, the so called Maximal Step-up Test (MST). Studies of healthy persons and overweight women have shown that the maximal step-up height (MSH) is associated with both muscle strength and physical function, but no study has assessed persons after stroke. OBJECTIVE: To evaluate the relationship between isokinetic and isometric knee muscle strength and maximal step-up height after stroke. METHODS: A convenience sample of 21 ambulatory persons with stroke (13 men and eight women; mean age 63 +/- 12 years; mean time since stroke onset 26 +/- 36 months). Isokinetic concentric knee extension and knee flexion strength at 60 degrees/s and isometric knee extension strength at 90. were measured for both lower limbs with a Biodex dynamometer. Maximal step-up height was measured using a 40 cm x 60 cm platform, which could be raised from 3 cm to 45 cm with 3 cm intervals. The relationship between knee muscle strength (normalized to body weight) and the maximal step-up height was analysed with the Pearson's correlation coefficient (r). RESULTS: There were significant but only moderate relationships between the paretic isokinetic knee extension, and flexion, strength and maximal step-up height, r = 0.49; p < 0.05, and r = 0.57; p < 0.01, respectively. CONCLUSION: These moderate relationships indicate that muscle weakness is only partially associated with maximal step-up height after stroke. The MST may therefore have limited value in the assessment of muscle strength after stroke.
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| 15. |
- Flansbjer, Ulla-Britt, et al.
(författare)
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Isokinetic knee extension and flexion strength in individuals with hemiparesis after stroke
- 2012
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Ingår i: Isokinetics and Exercise Science. - 1878-5913. ; 20:2, s. 91-97
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to assess knee extensor and flexor muscle torque in individuals with hemiparesis after stroke and determine the relationship with muscle tone. Fifty individuals (mean age 58 +/- 6.4 years), 6 to 48 months after stroke, participated in the study. Maximal concentric knee extension and flexion torque at 60 degrees/s and 120 degrees/s and maximal eccentric knee extension contractions at 60 degrees/s were measured with a Biodex dynamometer. Muscle tone was assessed with the modified Ashworth Scale. The relative weakness in the paretic knee muscles ranged from 30% to 42% and was greater for the flexors and at higher velocities (p < 0.05). The knee flexion/extension torque ratio in the non-paretic lower limb was 0.53 for both velocities and significantly lower (p < 0.01) for the paretic lower limb (0.44 at 60 degrees/s and 0.39 at 120 degrees/s). The eccentric/concentric ratio in the paretic lower limb (1.66) was significantly higher (p < 0.05) than in the non-paretic lower limb (1.31). Concentric torque in the paretic lower limb was significantly correlated (p < 0.05) with muscle tone. In conclusion, post-stroke weakness of the knee muscles was most prominent in the flexors and at higher velocities, whereas eccentric strength seemed to be preserved. Strength was also associated with the spasticity that can occur after stroke. This post-stroke muscle weakness pattern could be of importance for gait performance and should therefore be accommodated when planning rehabilitation interventions.
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