Updated reliability and normative values for the standing heel-rise test in healthy adults.

OBJECTIVES: The heel-rise test is used to assess the strength and endurance of the plantar flexors in everyday clinical practice. However, several factors may affect outcomes, including sex, age, body mass index and activity level. The aims of this study were to revisit the reliability and normative values of this test, and establish normative equations accounting for several factors. DESIGN: Cross-sectional observational study with test-retest. SETTING: Community. PARTICIPANTS: Volunteers (n=566, age 20 to 81 years). INTERVENTIONS: Subjects performed single-legged heel rises to fatigue, standing on a 10° incline, once on each leg. A subset of subjects (n=32) repeated the test 1 week later. Reliability was quantified using intraclass (ICC) correlation coefficients and Bland-Altman plots {mean difference [95% limits of agreement (LOA)]}, whereas the impact of sex, age, body mass index and activity level on the number of heel rises was determined using non-parametric regression models. RESULTS: The test showed excellent reliability (ICC=1.0 right leg, 1.0 left leg), with mean between-day differences in the total number of heel-rise repetitions of 0.2 (95% LOA -6.2 to 6.5) and 0.1 (95% LOA -6.1 to 6.2) for right and left legs, respectively. Overall, males completed more repetitions than females (median 24 vs 21). However, older females (age >60years) outperformed older males. According to the model, younger males with higher activity levels can complete the most heel rises. CONCLUSIONS: The heel-rise test is highly reliable. The regression models herein can be employed by clinicians to evaluate the outcomes of heel-rise tests of individuals against a comparable normative population.

Stretch-shortening cycle muscle power in women and men aged 18-81 years: Influence of age and gender.

This study explored the age-related deterioration in stretch-shortening cycle (SSC) muscle power and concurrent force-velocity properties in women and men across the adult life span. A total of 315 participants (women: n = 188; men: n = 127) aged 18-81 years performed maximal countermovement jumps on an instrumented force plate. Maximal SSC leg extension power expressed per kg body mass (Ppeak) was greater in men than in women across the adult age span (P < 0.001); however, this gender difference was progressively reduced with increasing age, because men showed an ∼50% faster rate of decline in SSC power than women (P < 0.001). Velocity at peak power (VPpeak) was greater in men than in women (P < 0.001) but declined at a greater rate in men than in women (P = 0.002). Vertical ground reaction force at peak power (FPpeak) was higher in men than in women in younger adults only (P < 0.001) and the age-related decline was steeper in men than in women (P < 0.001). Men demonstrated a steeper rate of decline in Ppeak than women with progressive aging. This novel finding emerged as a result of greater age-related losses in men for both force and velocity. Consequently, maximal SSC power production was observed to converge between genders when approaching old age.

Energy expenditure in chronic obstructive pulmonary disease-evaluation of simple measures.

BACKGROUND/OBJECTIVES: Almost 50% of all chronic obstructive pulmonary disease (COPD) patients become underweight. One possible reason for nutritional treatment to fail could be miscalculation of patients' energy requirements. The aim of this study was, therefore, to evaluate simple measures that may be used to assess the energy requirement of COPD patients. SUBJECTS/METHODS: This cross-sectional evaluation study includes 68 COPD patients (42 women). Resting metabolic rate (RMR) was assessed by indirect calorimetry, while total energy expenditure (TEE) was assessed by a 7-day monitoring using the ActiReg. Simple measures to evaluate was body weight (kg) multiplied by 125 kJ (30 kcal), predicted RMR multiplied by 1.7 and two simple questionnaires. RESULTS: Mean physical activity level (PAL) from the ActiReg was 1.46. Calculation of energy expenditure multiplying body weight with 125 kJ resulted in a TEE of 8614 kJ compared with ActiReg 8317 kJ (P=0.10). To multiply predicted RMR by 1.7 resulted in a statistically significant overestimation of 1335 kJ (P<0.01). Both questionnaires showed a clear 'dose-response' regarding PAL from ActiReg in the different activity categories. CONCLUSIONS: This study shows that simple measures of energy expenditure could, on group level, assess COPD patient's energy needs. However, for individual assessment of energy need, more thorough procedures are necessary.

Muscular strength after different types of training in physically active patients with cystic fibrosis.

Physical training is important in the treatment of patients with cystic fibrosis (CF). Optimal types of training and intensity are unknown. The aim of the study was to evaluate the effect on muscular strength after 6 months of endurance training (ET) and/or resistance training (RT). Twenty patients (eight females) participated, 16-35 years, with mean forced expiratory volume in 1 s 91% of the predicted. ET or RT for 30-45 min three times a week for 3 months was followed by a mixed program for another 3 months. Heart rate recording, diaries and frequent personal contacts were used for monitoring. Vitamin E and cytokines were analyzed. Fifteen tests of muscular strength were used. Handgrip strength in females and quadriceps strength in males were significantly decreased compared with healthy age- and sex-matched controls and positively associated with lung function. Sixteen patients completed the program. By ET, quadriceps strength was further decreased and after 6 months quadriceps isometric strength was also decreased in females. There was a tendency toward different effects on the serum levels of IL-6 and vitamin E by the different types of training. CF patients showed no improvements in muscular strength after 6 months of controlled training, suggesting a physiological muscular impairment despite normal anthropometry, but associated with lung function.

Injuries and preventive actions in elite Swedish volleyball.

The purpose of this study was to examine the prevalence of injury and the extent of preventive actions in elite Swedish volleyball players. Injuries to players in the elite male and female Swedish division, during the 2002-2003 season, were registered by using a questionnaire. Of the 158 volleyball players (70% response rate), a total of 82 players (52%) reported 121 injuries, during a total exposure time of 24 632 h, representing an overall incidence of 0.77 injuries per player. The majority of the injuries were located in the ankle (23%), followed by the knee (18%) and the back (15%). Most injuries (62%) were classified as being of minor severity. Most injuries occurred during training (47%), and 41% of the injuries had a gradual onset. Fifty-four percent of the injuries that could be related to a specific court situation occurred during blocking, and 30% during spiking. Most players (96%) participated in injury prevention training of some kind, generally performed without supervision (58%). Although most players took part in some kind of preventive action, one out of two players incurred an injury during the season, which indicates that the risk of suffering an injury in elite volleyball is relatively high.

Quality of life assessment for patients with eating disorders.

The purpose of this study was to examine the construct validity of Visual Analogue Scale (VAS)-quality of life for patients with eating disorders in relation to the following instruments: Body Awareness Scale Health, (BAS-H) and its Interview Scale for Body Ego (ISBE), Eating Disturbances Scale (EDS-5), Body Attitude Test (BAT) and Comprehensive Body Examination (CBE), part of respiration, subscale 1. In total 87 individuals were examined: 26 patients with anorexia nervosa (AN), 20 patients with bulimia nervosa (BN) and 41 patients with eating disorders not otherwise specified (EDNOS). The highest significant correlations (0,43-0,61) were found between VAS-quality of life and BAS-H (subscale grounding), variables of EDS-5 (feeling of control and guilt), BAT (subscale 2) and CBE (breathing variables). In conclusion, this study indicated that VAS-quality of life seemed to more accurately capture mental and psychosomatic factors than physical and health-related factors.

Plantar flexor muscle function in open and closed chain.

In the present study, the torque or work produced during isometric, pure concentric and eccentric-concentric plantar flexions, performed in sitting, standing and prone were measured. The electromyographic (EMG) activity was measured from the soleus, gastrocnemius medialis, tibialis anterior and rectus femoris muscles. The isometric tests showed the highest torques in the standing test. The rectus femoris and gastrocnemius activities were lower in the prone than in the standing test. The sitting test showed lower activities in all muscles of the lower leg compared with the standing test. No differences in work between the prone and sitting tests were found during the concentric phases. Higher rectus femoris activity in the eccentric-concentric test and lower activity in the triceps surae during the concentric phases were seen in the sitting compared with the prone test. We conclude that tests of overall functional ability should be performed in the standing position while specific tests of the plantar flexors should be performed in the prone position.

Postural control and torque of the knee joint after healed tibial shaft fracture.

Muscular atrophy occurs as a consequence of trauma and immobilisation. This cohort comparison study was conducted to evaluate the limb function after healed tibial shaft fractures, which were treated by casting versus nailing. Balance (as centre of pressure) and muscle strength (as torque of the knee joint during knee extension) have been measured in 27 patients with tibial shaft fractures with a mean age of 39 (19-73) years, 1 year after fracture healing. Fourteen patients were treated by intramedullary nailing 'nailed group' and 13 by plaster cast with or without minimal internal fixation 'casted group'. Centre of pressure was measured on a force platform. Knee extension torque was measured during isometric and concentric muscle actions by an isokinetic dynamometer. Centre of pressure tended to be more towards the uninjured leg in patients who had been treated by plaster cast (P<0.05). Side-to-side differences for isometric torque were significantly higher within the casted group (P<0.05). Patients with tibial shaft fractures treated by intramedullary nailing showed better postural control, one-leg standing test, and side-to-side differences for isometric muscle strength compared with patients treated by cast. Therefore, we recommend intramedullary nailing as a better method of treatment for tibial shaft fractures, with regard to recovery of muscle function.

Postural disturbance in patients with normal pressure hydrocephalus.

The postural function in 52 patients with normal pressure hydrocephalus (NPH) and in 19 patients with subcortical arteriosclerotic encephalopathy (SAE) was analysed bedside and in 17 of the NPH, 10 of the SAE and 23 healthy individuals (HI) also examined with a force platform. At the bedside examination, no differences in postural functions between NPH and SAE patients were found. The NPH patients improved more in the postural than in motor functions after shunt surgery. The NPH patients had a larger sway area and a higher backward directed velocity of centre of pressure than HI. The direction of the inclination in the sagittal plane was neutral or forward in the NPH and the SAE patients while it was backward in HI. The postural function was better in positions with open eyes in all 3 groups, but significantly less in the NPH patients, indicating a misinterpretation of afferent visual stimuli in the brainstem postural centre.

Muscle and tendon stiffness in patients with upper motor neuron lesion following a stroke.

The objective of this study was to investigate muscle and tendon stiffness in the triceps surae muscles in patients who had previously had a stroke. The participants were 12 men showing slight to moderate degrees of muscle tonus in the affected leg. All patients showed minimal or no overt clinical motor symptoms, and all walked without mechanical aid. Muscle strengths in isometric and isokinetic activities were measured, as was passive resistance during plantarflexion in each leg. Walking speed was also measured. Evaluations of physical performance and muscle tone were made. Muscle and tendon stiffness was calculated from measurements whilst passively stretching during electrical stimulation, separately for each leg. Muscle strength was significantly higher in the non-affected than in the affected leg. Muscle stiffness was significantly higher in the affected leg than in the non-affected leg. Tendon stiffness was significantly higher in the non-affected than in the affected leg. The higher muscle stiffness in the affected leg might enhance the possibility for storing elastic energy during preactivation. Lower tendon stiffness in the affected leg might reduce the development of fatigue in movements at low velocities.

Muscle performance in an urban population sample of 40- to 79-year-old men and women.

An urban population sample of 40 to 79-year-old men and women was investigated to evaluate the influence of age and activity level on muscle strength and endurance and to establish a reference material. During the investigation 144 persons were tested bilaterally, except for ankle strength, when only the right side was examined. Isometric muscle strength was determined in the knee extensors and flexors. Isokinetic (at 60 degrees/s and at 180 degrees/s) muscle strength was determined concentrically and eccentrically in the knee extensors and flexors. The dynamic and static endurance of the extensors was measured. Isometric strength was determined in the ankle plantar and dorsiflexor muscles. Isokinetic ankle plantar flexion strength was determined concentrically at 60 degrees/s with and without prior eccentric muscle contraction. Hand-grip strength was evaluated with a dynamometer. Walking velocity and the number of heel-rises were recorded. Physical activity level was assessed by questionnaire. Muscle biopsies were taken from the vastus lateralis muscle for histochemical and enzymatic analyses. Walking and the different muscle tests declined with age, and with a slight gender difference. Muscle biopsies showed a trend toward smaller muscle fibers with age. The results of our study can be used as reference material for clinical studies in different age groups.

Development of fatigue during repeated eccentric-concentric muscle contractions of plantar flexors in patients with stroke.

OBJECTIVE: To better understand the mechanisms behind fatigue in muscles affected by a neuromuscular disease. DESIGN: Patients recruited by convenience compared to age-matched healthy subjects from a population study. SETTING: University hospital laboratory. METHODS: Repetitive eccentric-concentric plantar flexions at 60 degrees/sec were performed on a dynamometer until exhaustion. The mean power frequency and root mean square of the electromyogram were recorded, and work was calculated. SUBJECTS: Both legs of seven patients with upper motor neuron lesion from stroke and one leg of healthy men were tested. RESULTS: There were no significant (p > .05) differences in number of cycles performed or decrease of work between any of the tested legs. There was a significant (p > .05) difference in work performed by the affected leg and the reference group. Mean power frequency decreased significantly (p > .05) for the gastrocnemius muscle in the nonaffected leg and for the reference group, while no such decreases were found in the affected leg. The statistical methods used were the nonparametric tests: the Wilcoxon one-sample for differences between paired observations, and the Mann-Whitney U for differences between groups. CONCLUSION: A reduction in work in high-intensity dynamic muscle activity may not be associated with a reduction in mean power frequency, especially in patients with altered supraspinal control. There may be peripheral fatigue factors not reflected in the electromyographic activity.

Tests of functional limitations in fibromyalgia syndrome: a reliability study.

OBJECTIVE: To evaluate the reliability and discriminative ability of a test battery consisting of 7 tests designed for the assessment of functional limitations in patients with fibromyalgia syndrome (FMS). METHODS: The intrarater reliability of the test battery was evaluated for 15 women with FMS. Interrater reliability was calculated on 4 tests separately. Fifteen healthy women constituted a reference group. RESULTS: The intrarater coefficient of variation was < 8% for the shoulder range of motion tests, chair test, and 6-minute walk test, and < 21% for the shoulder endurance test, with correlation coefficients above 0.80 for all tests. Kappa was 0.70-0.80 for the hand-to-scapula tests. The interrater coefficient of variation was < 5% for shoulder range of motion. The performances of the FMS patients were significantly decreased in comparison with healthy subjects in all the tests except for the hand-to-scapula movement. CONCLUSIONS: All but 1 of the selected 7 tests were considered to possess acceptable intrarater reliability for use in FMS in clinical physical therapy practice.

Upper motor neuron lesions: their effect on muscle performance and appearance in stroke patients with minor motor impairment.

OBJECTIVE: To evaluate muscular performance and appearance in patients with prior stroke who were ambulatory. DESIGN: Nonrandomized study. SETTING: University hospital laboratory. SUBJECTS: Sixteen persons (11 men, 5 women) with minor motor impairments, 6 to 24 months after stroke, were included. As reference, data were used from a population-based sample of 144 men and women. MAIN OUTCOME MEASUREMENTS: Muscle performance was evaluated using a Kin-Com dynamometer in both the affected and the nonaffected leg. Peak isometric strength was measured at a 60 degree angle in both extension and flexion. Maximal isokinetic strength was measured at 60 degrees/sec and at 180 degrees/sec. Endurance was evaluated during isometric and dynamic knee extensions. Muscle biopsies were taken on nine patients and muscle tissue areas were determined with computed tomography. RESULTS: The affected leg was weaker but not different in relative endurance compared with the nonaffected side. The performance of the nonaffected side was somewhat lower than that of a matched reference population. No major difference in fiber composition between the affected and nonaffected legs was noted, except for a lower degree of capillarization in the affected leg. CONCLUSION: In well-functioning stroke patients with good motor performance, further muscle training that includes resistance exercise might be indicated.

Comparison of muscle and tendon stiffness, jumping ability, muscle strength and fatigue in the plantar flexors.

An isokinetic dynamometer was used to measure plantar flexion muscle strength at 60 degrees/s and 200 degrees/s in 10 healthy young men (mean age 25 years). Muscle and tendon stiffnesses were determined on the dynamometer by the use of electrical stimulation and passive stretch (200 degrees/s). Differences in jumping heights between squat and counter-movement jumps were calculated from flight times. The number of heel-rises performed until exhaustion, standing on one leg, were counted. Stepwise regression analysis showed that differences in jumping height increased with lower muscle strength and with higher muscle and tendon stiffnesses, indicating that elastic components may be of more importance in persons with lower muscle strength. The number of heel-rises was negatively dependant on tendon stiffness, indicating that increased stiffness may enhance the development of fatigue.

Muscle fatigue in a standing heel-rise test.

The fatigue process of the triceps surae was evaluated during a standing heel-rise test, comprising of eccentric and concentric muscle actions. Ten healthy women with a mean age of 24 years participated. The heel-rise test was performed until exhaustion. Work and electromyographic activity expressed as root mean square and mean power frequency of the gastrocnemius and soleus muscles were calculated. The average number of heel-rises performed was 25 +/- 1. Work decreased significantly during the test. Mean power frequency decreased significantly in both phases. During the eccentric phase the decrease was significantly larger in the gastrocnemius than in the soleus muscle. There were no significant changes in root mean square except for a decrease in the soleus muscle during the eccentric phase. The present results, showing different fatigue patterns in the two muscles, could be used as reference when testing the fatigue process in different clinical conditions. Recommendations for standardization of a heel-rise test are given.

The standing heel-rise test in patients with upper motor neuron lesion due to stroke.

The objective was to investigate the fatigue process in the triceps surae during the heel-rise test (eccentric and concentric phases) in comparison with a walking test and muscle strength. Eight men with prior stroke and 8 age-matched healthy men participated. The electromyographic activity in form of root mean square and mean power frequency of the gastrocnemius and soleus muscles were measured and work estimated. Walking speed and maximal peak torque were measured and differed significantly between the patient and reference groups. There were no significant differences between the groups nor legs concerning the number of heel-rises or work performed. In the eccentric phase, mean power frequency decreased significantly more in the gastrocnemius than in the soleus muscle in the reference group, while mean power frequency in the soleus muscle tended to decrease more, though non-significantly, in the affected leg. The conclusion is that the capacity to perform the heel-rise test in patients with prior stroke is better than plantarflexor peak torque and walking speed.

Weight training of the thigh muscles using closed vs. open kinetic chain exercises: a comparison of performance enhancement.

Resistance training is commonly used in sports for prevention of injuries and in rehabilitation. The purpose of this study was to compare closed vs. open kinetic chain weight training of the thigh muscles and to determine which mode resulted in the greatest performance enhancement. Twenty-four healthy subjects were randomized into a barbell squat or a knee extension and hip adduction variable resistance weight machine group and performed maximal, progressive weight training twice a week for 6 weeks. All subjects were tested prior to training and at the completion of the training period. A barbell squat 3-repetition maximum, an isokinetic knee extension 1-repetition maximum, and a vertical jump test were used to monitor effects of training. Significant improvements were seen in both groups in the barbell squat 3-repetition maximum test. The closed kinetic chain group improved 23 kg (31%), which was significantly more than the 12 kg (13%) seen in the open kinetic chain group. In the vertical jump test, the closed kinetic chain group improved significantly, 5 cm (10%), while no significant changes were seen in the open kinetic chain group. A large increase of training load was observed in both subject groups; however, improvements in isotonic strength did not transfer to the isokinetic knee extension test. The results may be explained by neural adaptation, weight training mode, and specificity of tests.

Fatigue during repeated eccentric-concentric and pure concentric muscle actions of the plantar flexors.

OBJECTIVE: To compare the fatigue development during pure concentric actions with eccentric-concentric actions in standardized isokinetic, open-chain conditions. DESIGN: The study was performed with measurement of muscular strength and EMG of the plantar flexors on an isokinetic dynamometer. BACKGROUND: Fatigue development on a dynamometer has mostly been studied with repeated pure concentric actions. Eccentric-concentric actions are, however, often used in normal activities. An eccentric action has an immediate effect on a following concentric action and therefore it is of interest to follow the fatigue process in repeated combined actions. METHODS: Ten healthy young women participated. The pure concentric test was performed with the same number of cycles as in the eccentric-concentric test, which was performed until exhaustion. Development of MPF and RMS of the EMG in the triceps surae, as well as work, were evaluated. RESULTS: The total amount of work was significantly higher in the eccentric-concentric test than in the pure concentric test. The work decreased similarly (32-39%) with no significant difference between the two tests. A significant decrease (12-16%) in MPF was only seen in the eccentric-concentric test. No changes in RMS were seen. CONCLUSION: The similar reductions of work seen in both tests should primarily be sought in the contractile process as such. Changes in MPF may then be viewed as a phenomenon dependent on the timing of the duty cycle. RELEVANCE: The eccentric-concentric test lead to exhaustion and showed EMG changes and should therefore be recommended when evaluating the development of fatigue in muscular performances in different groups of patients.

Torque, work and EMG development in a heel-rise test.

OBJECTIVE: To study the fatigue process in the calf muscle during a standing heel-rise test. DESIGN: Heel-rises were performed on a force plate measuring development of torque in the ankle joint. BACKGROUND: The heel-rise test is a commonly employed clinical test to evaluate the function of the calf muscle by counting the number of heel-rises before exhaustion. Development of fatigue during other eccentric-concentric actions has earlier been studied as decreases in force, work and EMG. METHODS: Ten healthy males (mean age 25 yr) participated in the study. Torque and work were calculated using measurements from a force plate. Mean power frequency and root-mean-square of the EMG in the triceps surae were evaluated separately in the eccentric and concentric phases. RESULTS: Increases of mean torque during both the eccentric and concentric phases were found. Work performed decreased during the concentric phases due to decreased range of motion. No changes in root-mean-square and decreases in mean power frequency during the concentric phases indicated development of muscular fatigue, whereas decreases in both root-mean-square and mean power frequency during the eccentric phases indicated decreasing muscular activity. CONCLUSIONS: Accordingly, the limiting factor for the heel-rise test was not loss of muscle force at the range of motion used, but rather a failure to maintain the initial range of motion owing to muscle fatigue. RELEVANCE: This method of calculating torque development in the ankle joint provides an opportunity to study the fatigue process in terms of performance. The results show that the heel-rise test reflects muscle endurance rather than strength of the calf muscle.