Age-specific differences in the time-frequency representation of surface electromyographic data recorded during a submaximal cyclic back extension exercise: a promising biomarker to detect early signs of sarcopenia.

PURPOSE: Motivated by the goal of developing new methods to detect early signs of sarcopenia, we investigated if surface electromyographic (SEMG) data recorded during the performance of cyclic, submaximal back extensions are marked by age-specific differences in their time and frequency characteristics. Furthermore, day-to-day retest reliability of the EMG measures was examined. METHODS: A total of 86 healthy volunteers used a back dynamometer to perform a series of three maximal voluntary contractions (MVC) consisting of isometric back extensions, followed by an isometric back extension at 80% MVC, and finally 25 slow cyclic back extensions at 50% MVC. SEMG data was recorded bilaterally at L1, L2, and L5 from the iliocostalis lumborum, longissimus, and multifidus muscles, respectively. Tests were repeated two days and six weeks later. A linear mixed-effects model with fixed effects "age, sex, test number" and the random effect "person" was performed to investigate age-specific differences in both the initial value and the time-course (as defined by the slope of the regression line) of the root mean square (RMS-SEMG) values and instantaneous median frequency (IMDF-SEMG) values calculated separately for the shortening and lengthening phases of the exercise cycles. Generalizability Theory was used to examine reliability of the EMG measures. RESULTS: Back extensor strength was comparable in younger and older adults. The initial value of RMS-SEMG and IMDF-SEMG as well as the RMS-SEMG time-course did not significantly differ between the two age groups. Conversely, the IMDF-SEMG time-course showed more rapid changes in younger than in older individuals. Absolute and relative reliability of the SEMG time-frequency representations were comparable in older and younger individuals with good to excellent relative reliability but variable absolute reliability levels. CONCLUSIONS: The IMDF-SEMG time-course derived from submaximal, cyclic back extension exercises performed at moderate effort showed significant differences in younger vs. older adults even though back extension strength was found to be comparable in the two age groups. We conclude that the SEMG method proposed in this study has great potential to be used as a biomarker to detect early signs of sarcopenic back muscle function.

Reliability of surface electromyographic measurements.

OBJECTIVES: The aim of the study was to investigate short-term, intermediate-term and long-term reliability of surface electromyographic (EMG) measurements. METHODS: Eighteen healthy subjects performed 810 isometric knee extension tests. Reliability for maximum voluntary contraction (MVC) and 50% MVC was assessed with retest intervals of 3 min, 90 min and 6 weeks. Reliability for sustained contractions was assessed with retest intervals of 90 min and 6 weeks. EMG was recorded from the rectus femoris, vastus lateralis and vastus medialis muscles. The root mean square (RMS) and the median frequency (MF) parameters were extracted. At sustained contraction tasks, estimated linear regression values of both parameters were analyzed. Bland-Altman-plots, coefficient of repeatability, Pearson's coefficient of correlation and intra class correlation (ICC) procedures were applied to assess test-retest reliability. RESULTS: EMG recordings taken at short-term intervals were generally better reproducible than those of the longer-term intervals. Moreover, 50% MVC EMG recordings demonstrated better reproducibility than 100% MVC measurements, and EMG recorded from the rectus femoris were more constant than that from the vastus lateralis or vastus medialis. The MF parameter recorded from the rectus femoris was the only reliable parameter of EMG fatigue change. CONCLUSION: In our set up, EMG measurement is best suited for clinical applications if submaximal MVC measurements are performed and signal is taken from rectus femoris muscle.

Load-dependence of fatigue related changes in tremor around 10 Hz.

OBJECTIVES: The aim of the study was to investigate the effects of different loads on tremor around 10 Hz during fatiguing contractions. METHODS: Eighteen healthy volunteers performed sustained isometric knee extensions at 30%, 50% and 70% maximum voluntary contraction (MVC). During the fatiguing contractions, mechanical recordings were made with a high-resolution force sensor. Tremor-power was calculated for the 6-20 Hz frequency window as a function of time normalized to endurance time. RESULTS: Initial tremor power was different between the high and low load tasks. Changes of tremor with contraction time differed between the three tasks, in that tremor of the 30% MVC contraction showed the least decrease throughout the sustained contraction, whilst that of the 50% and 70% MVC showed progressively higher decreases. At failure, all 3 contractions merged to the same tremor level. CONCLUSION: Load-dependent, fatigue-related 6-20 Hz tremor changes during sustained submaximum voluntary contractions seem mainly the consequence of recruitment of new units and fatigue-related properties of the high threshold motor units of muscles.

Force distribution across the heel of the hand during simulated manual chest compression.

According to most published guidelines of cardiopulmonary resuscitation chest compression is performed on the lower half of the sternum by compressing the sternum with the heel of one hand and the other hand on top of the first. In all guidelines and during CPR training great importance is attributed to exact localisation of the so-called compression point. In a laboratory investigation we assessed the force distribution across the heel of the hand and defined the total breadth in contact with the sternum. In order to find out whether there is any difference in the force pattern with the right or the left hand in direct contact with the sternum we determined the resultant maximal force of that part of the heel of the hand exerting the maximal force. A total of 12 anaesthetists performed simulated chest compressions onto a flat surface covered with an integrated force sensor mat. The distance between the most ulnar part and the most radial part of the hand was determined to be 9.2 cm. Similar mean total forces were measured (right hand in contact: 644 N; left hand in contact: 621 N). In all except one anaesthetist the hypothenar part of the heel exerted a significantly higher force compared to the thenar part, independent of whether the right hand or the left hand was in contact. The distance between points of maximal force when the right hand or when the left hand in contact was 2.2 cm corresponding to the breadth of one and a half fingers. To reduce the potential risk of sternal fractures by chest compressions applied too far in a cephalad direction, we recommend use of the right hand in contact if the rescuer kneels at the right side of the patient and vice versa.

Effects of back extensor strength training versus balance training on postural control.

PURPOSE: Aim of this study was to investigate effects of 1) regular back extensor strength training as opposed to balance training, and 2) the influence of the sequence of both training types on postural control, force, and muscle efficiency. METHODS: Twenty-six young, healthy subjects were investigated at baseline, 1 month and 2 months later. At each examination, subjects completed a posturographic, balance skill, and isometric maximum voluntary (MVC) back extension testing, including surface electromyographic (SEMG) recordings. After baseline evaluation, subjects were assigned to either daily strength training or balance training. After 1 month, the type of training was exchanged between groups. RESULTS: After 1 month, back extensor strengthening led to decreased postural stability on hard surface, whereas there were no change after balance skill training. Analysis of the low- and high-frequency components of the sway signal revealed that strength training increased control efforts as indicated by an increased high-frequency component in order to maintain postural stability and unchanged low-frequency component. Balance skill training, however, increased postural stability as indicated by a decreased low-frequency component. The control effort remained unchanged. After completing either sequence of training, all postural parameters remained unchanged in both groups. Muscular efficiency as measured by SEMG root mean square during a standardized motor skill task revealed improved muscle economy regardless of the type of training. Back extension torque improved in both groups. CONCLUSION: To avoid reduction of postural stability in rehabilitation processes, we recommend to include antagonist muscles in a comprehensive strength training regime or balance skill training.

Sensory-motor control of the lower back: implications for rehabilitation.

Although low back pain (LBP) is a widespread and disabling health problem, there is a lack of evidence based medicine with respect to its treatment and rehabilitation. A major reason for this is the poor understanding of the underlying mechanisms of the LBP syndromes. In an attempt to fill this gap, the present review article provides an overview of the sensory-motor control aspects of trunk stabilization and postural control of the trunk, and how they may relate to the evolution of LBP. In particular, the anatomy and physiology of the sensory-motor control mechanisms of the trunk muscles that contribute to general and segmental stability of the lumbar spine will be elucidated. Furthermore, a brief overview of current theories of postural control will be provided with respect to spinal stabilization. Finally, a concept of the pathophysiological changes within the sensory-motor control mechanisms of the lumbar spine in the presence of muscle injury and pain will be presented. The impact of pain and muscle injury on the muscular support for the lumbar motion segment will be discussed along with the deficits in neuromuscular control in LBP patients with decreased segmental lumbar stability.

The effect of calisthenic home exercises on postmenopausal fractures--a long-term observational study.

OBJECTIVES: To evaluate the long-term effects of calisthenic home exercises on the incidence of fractures in postmenopausal women. DESIGN: Controlled long-term observational study. METHODS: Postmenopausal women between 45 and 75 years of age who had been randomly assigned to an exercise or control group in the course of a previous study conducted 5-10 years ago, were invited for follow-up. The number of fractures before and during the observation time were recorded by means of a questionnaire. Vertebral deformities due to fractures were diagnosed by X-rays at entry and at follow-up. Walking speed, muscle strength, static posturography, and maximum oxygen uptake were measured in addition. RESULTS: After an average follow-up time of 7.6+/-1.1 years, 73 women of the exercise group and 64 subjects of the control group were investigated. Thirty-three per cent (n=24) of the exercise group reported to have exercised continuously at least three times a week for 20 min. No intergroup differences between the compliant and non-compliant exercisers and the control group were seen in the number of fractures. However, the incidence of fracture was lowest in women with a baseline bone mass less than one standard deviation (SD) below the mean for young adults (high BMC) and highest in those with more than 2.5 SD below the mean for young adults (low BMC) (P<0.001, odds ratio 2.9 [95% CI, 1.59-5.39]). CONCLUSION: This long-term follow-up did not produce any evidence that prescription of a calisthenic home exercise program may prevent fractures in postmenopausal women aged between 61+/-6.4 and 68+/-6.5 years.

[Value of impedance rheography as a screening method in comparison with Doppler index in peripheral arterial occlusive disease]. / Wertigkeit der Impedanzrheographie als Screeningmethode im Vergleich zum Doppler-Index bei peripherer arterieller Verschlusskrankheit.

BACKGROUND: Determination of the ankle-arm-index (AAI) by Doppler ultrasound is the method of choice as a screening test for peripheral arterial occlusive disease (PAOD). The easily performed Impedance Rheography (IR) may serve as an alternative screening method. This study investigates the correlations between parameters obtained by IR curve to the AAI. METHODS: 56 patients (62.8 +/- 13 years, m = 37, f = 19) were included in the study. IR was performed on both shanks using ring electrodes below the knee and above the ankle (bipolar leads, frequency 90 kHz, test voltage 2.5 Vpp). The AAI was obtained by a 8 Mz ultrasound probe. RESULTS: AAI < or = 0.85 showed significant correlations (p < 0.0001) to parameters of the IR curve: Crest Time (GZ, r = 0.67), Rise of the Pulse Wave (PA, r = 0.82), Relative Pulse Volume (RP, r = 0.82) and the Rheographic Quotient (RQ, r = 0.86). AAI > 0.85 showed no or only weak correlations to RI parameters. Underlying the following limits for rheographic parameters (GZ = 159 ms, PA = 3.3, RP = 0.43 vp/s and RQ = 0.4 vp), sensitivity and specify was determined: GZ: 68% and 100%, PA: 84% and 88%, RP: 68% and 92%, RQ: 77% and 88%. CONCLUSIONS: Impedance rheography correlates significantly with the AAI. Therefore this method seems to be well suited as a screening test for PAOD.

[Functional follow-up of combined musculocutaneous tensor fasciae latae and rectus femoris flap repair. Supplementary information on the Handchir. Mikrochir. Plast. Chir. 21 (1989) 315-317 contribution]. / Funktionelle Nachuntersuchung nach kombinierter muskulokutaner Tensor fasciae latae- und Rectus femoris-Lappenplastik. Ergänzung zur Arbeit Handchir. Mikrochir. Plast. Chir. 21 (1989) 315-317.

As a supplement to our publication in the Journal Handchirurgie, Mikrochirurgie, Plastische Chirurgie 21 (1989) 315-317, we would like to report a five-year follow up of a patient with recurrent sigmoid carcinoma, infiltrating all layers of the abdominal wall. Treatment was by radical tumor excision and reconstruction with a combined tensor fasciae latae and rectus femoris flap. Abdominal wall, hip, and knee functions were evaluated by gait-analysis (Motion Analysis Corporation AMTI) and dynamometry (Cybex 6000). The dynamometry of knee motion showed a slight deficit of the operated side regarding the parameters of strength-endurance as well as work-recovery. All other parameters (peak-torque) were equal for both sides corresponding to the activities of daily living of the patient. Gait-analysis showed a reduced rotation of the pelvis as well as a functional deficit of extension of the knee during stance and swing phase. We can document a good functional result in all motions without major impairment of every-day activities.

An investigation of the effectiveness of exercise and manual therapy in treating symptoms of TMJ osteoarthritis.

UNLABELLED: The background and purpose of this investigation was to evaluate the use of a treatment protocol which included active and passive jaw movements, manual therapy techniques, correction of body posture, and relaxation techniques for the treatment of temporomandibular joint (TMJ) osteoarthrosis (OA). Twenty consecutive patients suffering from TMJ OA participated in this study. INCLUSION CRITERIA: a. pain in the temporomandibular region; b. symptoms lasting at least three months; and c. radiologically proven OA. All patients were assigned to a waiting list, serving as a no treatment control period. Nineteen patients completed the study. No adverse effects occurred. During the control period (mean duration 35 days), the parameters did not change significantly. After treatment (mean duration 46 days) pain, impairment, and incisal edge clearance improved significantly (Wilcoxon test p < 0.001). At follow-up, pain and impairment were further reduced. The number of patients experiencing no pain at rest (80%), chi-square test p = 0.02) and stress (47%), chi-square test p = 0.03), and no impairment (37%), chi-square test p = 0.05) increased significantly. This therapeutic treatment protocol seems to be useful treatment for the symptoms of clinical dysfunction in OA of the TMJ.

Multi-segment trunk kinematics during a loaded lifting task for elderly and young subjects.

The trunk is frequently modelled as one fixed segment ignoring possible multi-segmental contributions during manual handling. This study compared segmental trunk motion in a young and older population during a lifting task. Twelve elderly and 19 young subjects repeatedly lifted a 5 kg box from bench to shelf under two stance conditions. Displacement and angular trunk segment kinematics were recorded with an electromagnetic tracker system and then analysed. The elderly subjects displayed significantly increased pelvic and trunk displacement and significantly reduced pelvic and lower thorax (T10-L1) range of motion in both stance conditions. Upper thorax (C7-T10) motion was at times greater than lumbar motion and opposite to the lower segments and was related to the task while the lower segments contributed to both equilibrium and task requirements. Decreased segmental trunk angular kinematics may contribute to increased displacement kinematics and place the elderly at increased risk of injury and falling. The pelvis, lumbar spine, low thorax (T10-L1), upper thorax (C7-10) contributed uniquely and synchronously to trunk (C7-S2) mechanics during a lifting task. Reduced angular kinematics of the pelvis and low thorax contributed to increased displacement kinematics and hence increased the risk of falling in the elderly compared to the young. Investigations of trunk mechanics should include multi-segment analysis.

EMG fatigue patterns accompanying isometric fatiguing knee-extensions are different in mono- and bi-articular muscles.

OBJECTIVES AND METHODS: Isometric, fatiguing knee-extensions at 30%, 50% and 70% maximum voluntary contraction (MVC) were performed by 18 healthy human subjects. Surface electromyographic (SEMG) activity was recorded from the mono-articular vastus medialis (VM) and vastus lateralis (VL) muscles, and the bi-articular rectus femoris muscle (RF). To make the bi-articular muscle work under (1) constant and (2) similar working conditions as the two mono-articulars do, the hip was fixed in a flexed position. The root mean square (RMS) SEMG recorded during fatigue was standardized to the respective values of MVC. The mean coefficients of regression of the RMS and median frequency (MF) changes were then analyzed by multivariate analysis of variance. RESULTS: The load effect upon the muscle fatigue changes, as measured by increase in RMS EMG, differed between the bi-articular muscle and the two mono-articulars, in that the parameter dropped with maximum load for the bi-articular, whilst it remained stable or even increased for the mono-articulars. This might suggest that the mono- and bi-articular muscles have different roles in fatigue tasks where the bi-articulars function purely as mono-articulars. By contrast, such a clear dichotomy between the bi-articular RF and the two mono-articulars, VM and VL, was lacking for the fatigue parameter of MF. CONCLUSIONS: As these findings were confined to the changes in RMS EMG, different neuronal coding mechanisms for the mono- and bi-articular muscles in the central nervous system may be inferred.

The role of the biarticular agonist and cocontracting antagonist pair in isometric muscle fatigue.

Isometric knee extensions until exhaustion at 30%, 50%, and 70% of maximum voluntary contraction were performed by 18 healthy subjects. During muscle fatigue, surface electromyographic activity was recorded from the knee-extensors vastus lateralis, vastus medialis, and rectus femoris, and the coactive antagonistic biceps femoris. The electromyographic parameter median frequency (MF) served as a measure of fatigue. Coefficients of regression of the MF fatigue changes were analyzed statistically. MF fatigue occurred within the coactive biceps femoris and was significantly more pronounced than in the quadriceps. When the MF fatigue shifts of the coactive biceps femoris were compared with each of the three investigated parts of the quadriceps separately, MF fatigue shifts were similar in shape for the biarticular coactive biceps femoris and the biarticular rectus femoris, but differed significantly between the biceps femoris and the two monoarticular muscles, vastus medialis and vastus lateralis. As both the biarticular agonist and coactive antagonist muscles fatigued at a higher rate than the two monoarticular muscles, it seems likely that this biarticular agonist/antagonist pair determines the time to the limit of endurance.

Strength improvement of knee extensor muscles in patients with chronic heart failure by neuromuscular electrical stimulation.

Patients with severe chronic heart failure (CHF) suffer from marked weakness of skeletal muscles. Neuromuscular electrical stimulation (NMES) proved to be an alternative to active strength training. The objective of this study was to test the feasibility and effectiveness of NMES in patients with chronic heart failure. Seven patients (56.0 +/- 5.0 years, CHF for 20 +/- 4 months, left ventricular ejection fraction 20.1 +/- 10.0%) finished an 8 week course of NMES of the knee extensor muscles. The stimulator delivered biphasic, symmetric, constant voltage impulses of 0.7 ms pulse width with a frequency of 50 Hz, 2 s on and 6 s off. No adverse effects occurred. After the stimulation period, the isokinetic peak torque of the knee extensor muscles increased by 13% from 101.0 +/- 8.7 Nm to 113.5 +/- 7.2 Nm (p = 0.004). The maximal isometric strength increased by 20% from 294.3 +/- 19.6 N to 354.14 +/- 15.7 N (p = 0.04). This increased muscle strength could be maintained in a 20 min fatigue test indicating decreased muscle fatigue. These results demonstrate that NMES of skeletal muscles in patients with severe chronic heart failure is a promising method for strength training in this group of patients.

Functional impact of unvarying exercise program in women after menopause.

Low bone mass, functional impairment, low muscle strength, and postural instability are predictors of the risk of fracture in an elderly person. The purpose of this study was to investigate the functional impact of an unvarying long-term exercise program to be carried out at home. The exercises had been shown to delay bone loss in an elderly population. At the Department of Physical Medicine and Rehabilitation, University of Vienna, postmenopausal women who had been stratified into exercise or control groups 5 to 10 yr ago were called in for a follow-up examination. Frequency of training, habits, and pain causing disability in activities of daily living were recorded. Walking velocity, muscle strength, and postural stability were measured. Functional assessment, blood analysis, and x-rays of the spine were performed additionally. One hundred twenty-four women aged 68.3 +/- 6.8 yr (mean +/- SD) underwent a follow-up investigation at the outpatient clinic. After 7.7 +/- 1.1 yr the compliance of the training group was still 36%. Self-chosen gait velocity was slightly higher in the regular exercisers than in the controls. No intergroup differences were found for pain induced disability, muscle strength, body sway, and fracture rate. The pain disability index was significantly associated with corrected self-chosen gait velocity. The results suggest that an unvarying home-based exercise program may support general agility but does not yield enough force to improve muscle strength and postural stability in healthy, nondisabled, postmenopausal women who start exercising at the age of 60 yr. Further studies are needed to define more appropriate exercise programs for a comprehensive improvement of functional outcome in a population at high risk for osteoporosis.

Muscle fatigue and fatigue-related biomechanical changes during a cyclic lifting task.

STUDY DESIGN: Electromyographic and biomechanical methods were utilized to investigate correlations between indexes of localized muscle fatigue and changes in the kinematics and kinetics of motion during a cyclic lifting task. SUMMARY OF BACKGROUND DATA: Recent advances in time-frequency analysis procedures for electromyographicic signal processing provide a new way of studying localized muscle fatigue during dynamic contractions. These methods provide a means to investigate fatigue-related functional impairments in patients with low back pain. OBJECTIVES: To study the relationship between localized muscle fatigue and the biomechanics of lifting and lowering a weighted box. Fatigue-related changes in the electromyographicic signal of trunk and limb muscles were evaluated and compared to kinematic and kinetic measures in order to determine whether lifting strategy is modified with fatigue. METHODS: A total of 14 healthy male subjects (26 +/- 5 years) cyclically lifted and lowered a 13 kg box (12 lifts/min) for 4.5 minutes. A 5-second static maximum lifting task was included immediately before and after the cyclic lifting task to measure changes in lifting strength and static electromyographicic fatigue indexes. Electromyographic signals from 14 muscle sites (including paravertebral and limb muscles) were measured. Changes in the electromyographicic Instantaneous Median Frequency, a fatigue index, were computed using time-frequency analysis methods. This index was compared with more standardized measures of fatigue, such as those based on electromyographicic median frequency acquired during a static trunk extension test, subjective fatigue measures, and maximal static lifting strength. Biomechanical measures were gathered using a motion analysis system to study kinematic and kinetic changes during the lifting task. RESULTS: During the cyclic lifting task, the electromyographic Instantaneous Median Frequency significantly decreased over time in the paravertebral muscles, but not in the limb muscles. Paravertebral electromyographicic Instantaneous Median Frequency changes were consistent with self-reports of fatigue as well as decreases in trunk extension strength. The magnitude of muscle-specific changes in electromyographicic Instantaneous Median Frequency was not significantly correlated with electromyographicic median frequency changes from the static trunk extension task. The load of the box relative to the maximal static lifting strength significantly affected the electromyographicic Instantaneous Median Frequency changes of paravertebral back muscles. Significant changes with fatigue during the task were found in the angular displacements at the knee, hip, trunk, and elbow. These biomechanical changes were associated with increased peak torque and forces at the L4-L5 vertebral segment. CONCLUSIONS: Our results demonstrate correlation between localized muscle fatigue and biomechanical adaptations that occur during a cyclic lifting task. This new technique may provide researchers and clinicians with a means to investigate fatigue-related effects of repetitive work tasks or assessment procedures that might be useful in improving education, lifting ergonomy, and back school programs. Although both the dynamic and static tasks resulted in spectral shifts in the electromyographicic data, the fact that these methods led to different muscle-specific findings indicates that they should not be considered as equivalent assessment procedures.

Effectiveness of exercise therapy in patients with internal derangement of the temporomandibular joint.

This study intended in evaluating the effectiveness of exercise therapy in patients with craniomandibular disorders (CMD). Twenty consecutive patients suffering from CMD with anterior disc displacement without reduction consulting a CMD service were included in the study if they met following criteria: (i) pain in the temporomandibular region, (ii) reduced incisal edge clearance (<35 mm), (iii) magnet resonance imaging confirmed anterior disc displacement without reduction and (iv) evidence of postural dysfunction. All patients were assigned to a waiting list, serving as a no-treatment control period, according to a before-after trial. The treatment consisted of active and passive jaw movement exercises, correction of body posture and relaxation techniques. A total of 18 patients completed the study, no adverse effects occurred. Following main outcome measures were evaluated: (1) pain at rest (2) pain at stress (3) impairment (4) mouth opening at base-line, before and after treatment and at 6 month follow-up. As a result of treatment pain, impairment and mouth opening improved significantly more than during control period (paired samples t-test P < 0.05). After treatment four patients had no pain at all (chi-square: P < 0.05) and only seven patients revealed an impaired incisal edge clearance after treatment. (chi-square Test, P < 0.001). At follow up, seven patients had no pain and experienced no impairment. Exercise therapy seems to be useful in the treatment of anterior disc displacement without reduction.

Reliability of pelvic floor muscle strength measurement in elderly incontinent women.

Pelvic floor muscles (PFM) play an important role in maintaining urinary continence with increasing age. Therefore, their contractile properties need to be evaluated. The aim of the study was to examine the reliability and correlation of simple techniques to measure PFM strength in elderly women with urinary incontinence. An interview was used to evaluate the ability to stop the urinary stream during micturition and to calculate the incontinence index. A pad test was applied to objectively evaluate the severity of the disease. Functional testing included a digital examination to measure the force and duration of one contraction, a perineometer measurement (Peritron) to assess maximal contraction force and contraction force of 5 s, and a cone-retention test (Femcon) while walking for 1 min and during Valsalva's manoeuvre. This procedure was performed on three separate occasions within one week. The 37 participating women with a mean age of 62+/-8 (mean+/-SD) years had a severity index of 4.4+/-2.6 and a urine loss of 9.5+/-13.6 mg during the pad test. Sixteen women were able to completely stop the urinary stream during micturition. The digital examination showed no intratester variability. The perineometer measurement showed that the absolute difference in maximal contraction force and mean contraction force within 5 s was less than 5.3 mm Hg and 4.5 mm Hg, respectively, with a probability of 0.95. While walking and during Valsalva's manoeuvre, 19 and 20 women, respectively, held the same cone in place on all three occasions. The maximal contraction force and mean force during the 5-s contraction correlated well with the ability to stop the urinary stream and the digital examination but only weakly with the cone-retention tests. The reliability of PFM strength measurement is highest in the digital examination, followed by perineometer measurements, and then by vaginal cone tests. As PFM function is easy to assess, it should be routinely done in the assessment of urinary incontinence in elderly women.