| | Effects of Concurrent Strength and Endurance Training on Physical Fitness and Symptoms in Postmenopausal Women With Fibromyalgia: A Randomized Controlled Trial published online 04 August 2008. Abstract Valkeinen H, Alén M, Häkkinen A, Hannonen P, Kukkonen-Harjula K, Häkkinen K. Effects of concurrent strength and endurance training on physical fitness and symptoms in postmenopausal women with fibromyalgia: a randomized controlled trial. ObjectiveTo examine the effectiveness of concurrent strength and endurance training on muscle strength, aerobic and functional performance, and symptoms in postmenopausal women with fibromyalgia (FM). DesignRandomized controlled trial. SettingLocal gym and university research laboratory. ParticipantsTwenty-six women with FM. InterventionProgressive and supervised 21-week concurrent strength and endurance training. Main Outcome MeasuresMuscle strength of leg extensors, upper extremities, and trunk; peak oxygen uptake (Vo2peak), maximal workload (Wmax), and work time; 10-m walking and 10-step stair-climbing time and self-reported functional capacity (Health Assessment Questionnaire); and symptoms of FM. ResultsAfter concurrent strength and endurance training, the groups differed significantly in Wmax (P=.001), work time (P=.001), concentric leg extension force (P=.043), walking (P=.001) and stair-climbing (P<.001) time, and fatigue (P=.038). The training led to an increase of 10% (P=.004) in Wmax and 13% (P=.004) in work time on the bicycle but no change in Vo2peak. ConclusionsConcurrent strength and endurance training in low to moderate volume improves the muscle strength of leg extensors, Wmax, work time, and functional performance as well as perceived symptoms, fatigue in particular. Concurrent strength and endurance training is beneficial to postmenopausal women with FM without adversities, but more extensive studies are needed to confirm the results. List of Abbreviations: FM, fibromyalgia, HAQ, Health Assessment Questionnaire, NS, not significant, 1-RM, 1-repetition maximum, RCT, randomized controlled trial, Vo2peak, peak oxygen intake, Wmax, maximal workload EXERCISE TRAINING HAS BEEN recommended to be included in rehabilitation programs of patients with FM to attenuate the symptoms and to improve overall physical fitness.1 To improve physical fitness, the exercise programs should include both aerobic and strength training.2 In general, endurance training induces increases in mitochondrial and capillary density, glycogen stores of the muscle cells, and maximal oxygen capacity,3 whereas strength training leads to neural and hypertrophic adaptations of trained muscles resulting in increased strength of muscles.4, 5 In addition, both training modes improve health through several mechanisms.6 Aerobic training improves cardiovascular and respiratory endurance and lipid and carbohydrate metabolism, whereas strength training develops functional performance through improved neuromuscular functions. Therefore, it appears logical to recommend both training modes also to persons with FM. RCTs of pure strength training have led to remarkable improvements in isometric and concentric force of different muscle groups in premenopausal7, 8, 9 and postmenopausal women with FM.10, 11 In these studies, training frequency was twice a week and the training was usually progressive (40%–80% of 1-RM). On the other hand, RCTs of pure aerobic training have improved aerobic performance in premenopausal women with FM.12, 13, 14 Training frequency was either 212 or 3 times a week,13, 14 whereas the training intensity was reported either by using heart rate range, by percentage of maximal heart rate, or by heart rate under anaerobic threshold. However, 2 strength training and 2 aerobic training sessions weekly might be too much, especially for sedentary postmenopausal patients with FM because of the symptoms of the disease. Therefore, training studies are needed to find an effective but also safe and feasible combination of these 2 training modes commonly recommended to enhance physical fitness and health in general and in FM.6, 15 Training results of healthy subjects have suggested that simultaneous aerobic training (with strength training) may negatively interfere with muscle strength improvements when the volume and frequency of training are high,16, 17, 18 although interference has not always been observed.19, 20, 21 The exercise dose should be large enough to improve physical fitness and health but simultaneously remain compatible with daily life, and, especially, it should not cause exacerbation in FM symptoms. Especially with regard to FM patients, the exercise prescription should be carefully tailored and the training monitored because the prevailing symptoms are chronic pain and fatigue.1 In previous studies22 with FM applying both training modes, endurance and strength training usually have been performed during the same exercise session. Thus, it remains unknown how concurrent training performed on separate days influences the development of muscle strength and aerobic performance. Therefore, the purpose of this study was to examine the effectiveness of concurrent strength and endurance training on muscle strength, aerobic performance, functional performance, and symptoms in postmenopausal women with FM. We hypothesized that progressive concurrent strength and endurance training for 21 weeks with moderate volume would improve muscle strength, aerobic and functional performance, and symptoms without adverse effects in women with FM compared with those women with FM who did not receive progressive concurrent strength and endurance training. Methods  Participants Altogether 180 postmenopausal women with FM who had previously visited an outpatient clinic were sent an invitation letter concerning the study. The main inclusion criteria were women, age over 50 years, and diagnosis of FM.23 A total of 71 women were willing to participate, and they were assessed for eligibility (fig 1). Thirty-three volunteers were excluded because of severe cardiovascular disease, diabetes, severe osteoarthritis of the large joints, disorders of thyroid gland, or any other diseases that might confound the results of the study. Participation in regular aerobic and strength training and predictable difficulties for attending training sessions were also exclusion criteria. Thus, the rheumatologist (P.H.) examined 38 volunteers, of whom 8 women were excluded because of the previously mentioned criteria. Before baseline measurements, 4 women were unable to participate for personal reasons. Thus, 26 women with FM participated in the study. They were randomly assigned (pairwise randomization) to a training group (n=15) and a nontraining control group (n=11). The women were allowed to use their previous medications for FM and other diseases. The Ethics Committee of the Jyväskylä Central Hospital approved the study, and all subjects gave their informed consent in writing before inclusion. Aerobic Performance Vo2peak was measured by using a bicycle ergometera test under a physician's supervision. After a 3-minute warm-up at the intensity of 50W, the load was increased by 20W every second minute until exhaustion. Electrocardiography was monitored continuously, and heart rate and Wmax were recorded at the end of every load. Also, total work time (in minutes) was recorded. Oxygen uptake was monitored by the breath-and-breath method.b Vo2peak was reached when the measured Vo2 reached a plateau or started to decrease, respiratory exchange ratio was over 1.0, heart rate was ±10 beats from the predicted maximum, or the subject felt that she had reached her maximal level and wanted to stop the test. Capillary blood samples were taken from the fingertip at the end of each 2-minute workload during the test for lactate analysis. The samples were deproteinized with perchloric acid, and lactate concentration was analyzed by using an enzymatic method and a spectrophotometer. Muscle Strength Maximal concentric bilateral leg-extension force (1-RM) was measured in both legs simultaneously by using a David 210 dynamometer.c The subject was in a seated position with the hip and knee joints at 110° and 70° of flexion, respectively. The 1-RM of the leg extensors was determined by increasing the load after every trial until the subject was unable to extend the legs to a full extension against the resistance. The highest load with the full knee extension was accepted as the result.24 Maximal isometric bilateral leg extension force was measured in both legs simultaneously on an electromechanical dynamometer (horizontal leg press). The subject sat on the device with the hip and knee joints at 110° and 107°, respectively.24 Maximal isometric force of the right elbow flexors was measured in a seated position by using a dynamometer.d The subject's upper arm was aligned with the trunk, the elbow was in 90° of flexion, and the wrist was in a neutral position. Grip strength (the mean of the left and right hands) was measured by using a handgrip dynamometer with the elbow in 90° of flexion supported on a table. The maximal isometric force of the trunk extensors and flexors was measured by using a dynamometer.25 During the extension action, the subject pushed the forceplate with her upper back and during the flexion action with her upper chest. The waist was supported by a belt. During the isometric strength tests, the subject was asked by verbal command to produce her maximal force as fast as possible during 3 to 5 seconds. A rest period between the trials was 1 minute. After warm-up trials, at least 3 maximal trials were measured for each subject, and the best result was used in the statistical analyses. The force signals of all actions, except trunk and grip strength, were recorded, digitized, and analyzed with a Codase computer system.24 Measured and self-reported functional performance The maximal walking time(s) for 10m and the time(s) to climb 10 steps without handrails were measured by using photo cells.10 The shortest time of 3 attempts in each measurement was used in the analyses. Self-reported functional capacity was assessed by the Stanford HAQ.26 Perceived symptoms Subjectively perceived pain, general fatigue, general well-being, and sleep quality were assessed by using a 100-mm visual analog scale.27 The adverse events of concurrent strength and endurance training were asked by open questions so that the subjects reported if they had experienced any adverse incidents or unpleasant feelings during the training. Experimental design The physiologic measurements of all subjects were assessed twice before the intervention (week −2, week 0) to control for learning effect and again at week 21. At weeks 7 and 14, the strength and walking and stair-climbing tests were measured in the training group. The aerobic test, HAQ, and perceived symptoms were assessed before and after the experimental period. The aerobic test was performed first, and the muscle strength measurements were performed a week later followed by walking tests about 3 to 5 days later. The muscle strengths were measured in the following order: grip, isometric leg extension, concentric leg extension, elbow flexion, and finally trunk flexion and extension. In the aerobic test, the supervising physician did not know the randomization group of the subjects, but the staff members did. The first author (H.V.) supervised the strength and walking measurements, and she knew the randomization. However, she did not analyze the data before it was recorded in a numeric form in the SPSS program.f Subjects were allowed to continue their ordinary daily activities. They kept a training diary to record all leisure time physical activity, and the subjects of the training group also recorded the intervention exercise sessions. Concurrent strength and endurance training The concurrent strength and endurance training included 3 weekly training sessions (table 1). The program progressed so that during the first week the subjects performed 2 strength training sessions and 1 endurance training session and during the second week 1 strength training and 2 endurance training sessions and again vice-versa on alternate weeks. Thus, on an average, 1.5 strength and 1.5 endurance training sessions were performed in each week, which can be defined as training of low to moderate volume. | | |  | Strength Training | Aerobic Training | |
|---|
| Week | Intensity (%) | Sets/Session | Week | Intensity | Duration of Session (min) | |
|---|
| 1–4 | 40–60⁎ | 2–4 | 1–7 | Basic, 30min | 30 | | | 5–7 | 50–70⁎ | 2–4 | 8–4 | Basic, 15min; speed, 10min; max, 5min; basic, 15min | 45 | | | 8–11 | 60–70⁎ | 2–6 | 15–21 | Basic, 10min; speed, 10min; basic, 4min; speed, 10min | | | | 12–14 | 60–70–80⁎ | 2–6 | | Basic, 4min; max, 5min; basic, 4min; max, 5min; basic, 8min | 60 | | | 15–18 | 60–70–80⁎ | 2–6 | | | | | | 19–21 | 70–80⁎ | 2–6 | 2–20 | When 2 aerobic sessions in a week, one was supervised bicycle training as described here and the other unsupervised walking or cycling session (basic, 60min) | 60 | | | | |
| ⁎ Number of repetitions: 40% 1-RM = 15–20; 50% 1-RM = 12–15; 60% 1-RM = 10–12; 70% 1-RM = 8–10; 80% 1-RM = 5–8. |
Strength training All the training sessions were supervised and lasted from 60 to 90 minutes. The loads were individually determined during the sessions throughout the 21-week training period according to the maximum-repetition method (see table 1). Each training session included 2 dynamic exercises for the leg extensor muscles and 5 to 6 other exercises for the other main muscle groups of the body.28 Endurance training During each week 1 endurance training session was supervised. When there were 2 weekly sessions, the second session was unsupervised. Subjects were instructed to perform this latter session with low intensity (see table 1) either by walking or cycling for 60 minutes. During the supervised endurance training sessions, the subjects trained by bicycle ergometer according to the training program (see table 1). All the subjects used heart rate monitorsg during the supervised sessions to maintain the intensity of exercise at the prescribed level based on the aerobic test.28 Statistical Analyses Standard statistical methods were used to calculate means with 95% confidence intervals and SDs as well as Pearson product moment correlation coefficients. Normality of the variables was analyzed by using the Shapiro-Wilks test. At the baseline, the differences between the groups were tested with a Student t test for unpaired samples. After the 21-week training, changes between the groups and the changes within the groups were analyzed by analysis of variance with repeated measures and the probability adjusted (Bonferroni) t tests were used for pairwise comparisons when the measurements included more than 2 time points (muscle strength and functional performance tests). The SPSS statistical programf was applied. Results Two subjects from the training group dropped out after few weeks of training because of moving away and cardiovascular symptoms unrelated to the present training. Thus, the results are presented from 13 subjects of the training group and 11 subjects of the control group, except the aerobic test results from 12 subjects of the training group because 1 subject felt uncomfortable with the face mask. The baseline characteristics were comparable between the groups (table 2). The FM diagnosis had been defined, on average, 6±4 (range, 1–13) years before the study entrance. Fourteen subjects used analgesics, antidepressants, and hormone-replacement therapy, and 8 subjects used also muscle relaxants. Seven of the training subjects were employed, 1 was unemployed, 2 were on disability pension, and 3 had retired. The corresponding numbers for the control group were 6, 1, 2, and 2. Four subjects reported asthma and 4 hypertension, but they were medically well controlled. Another 4 subjects had osteoarthritis in small joints. At baseline, with the exception of significantly lower Vo2peak (P<.01) uptake, the noncompleters did not differ from the completers (data not shown). The exercise intervention did not have an effect on the use of medication. The mean body weight did not change during the intervention in either group. | | | | Characteristics | FMT (n=13) | FMC (n=11) | |
|---|
| Age (y) | 59±3 | 58±3 | | | Height (cm) | 162.0±0.1 | 161.0±0.1 | | | Weight (kg) | 71±8 | 72±12 | | | Body mass index | 27±2 | 28±4 | | | No. of FM tender points | 17±2 | 16±2 | | | | |
Parameters of physical fitness did not differ significantly between week –2 and week 0 in either group. At baseline, the groups were comparable in all main outcome measures (Table 3, Table 4, fig 2). The average proportion of completed workouts was 84% (range, 52%–97%) in the training group (87% of all the strength training, 82% of all the endurance training sessions). Aerobic Performance The increase after the intervention period differed significantly between the groups in Wmax (P=.001) and work time (P=.001) (see table 3). The Wmax increased by 10% (P=.004) and work time by 13% (P=.004) in the training group, whereas they decreased by 4% and 5% in the control group (P=NS). Capillary lactate concentration at the end of the aerobic test was higher at week 21 than at week 0 (P=.017) in the training group, but the corresponding increase in the control group remained small (P=NS). No changes occurred in Vo2peak and maximal heart rate during the training in either group. Maximal Muscle Force The change of concentric leg-extension force differed significantly between the study groups (P=.043; +2% in the training group vs –6% in the control group) after the training (see table 3, fig 2). The training group reached the highest values in concentric leg extension force at week 14 (increase, +6%; P=.028). The increases in the grip strength (P=.025) and elbow flexion force (P=.040) were statistically significant in the training group after the training period, but no differences were observed between the groups. When within-subjects contrasts were adjusted by Bonferroni adjustment, all the previously mentioned changes in the training group disappeared. In the control group, the maximal forces remained statistically unchanged after the study period. The changes (pre- vs posttraining) in maximal forces of leg extensors did not correlate with those of Vo2peak (in L/min), Wmax, and work time in either group. Functional Performance After the training period, the changes in walking (P=.001) and stair-climbing (P<.001) times differed significantly between the groups (fig 3). Both walking (P=.007) and stair-climbing times (P<.001) improved in the training group, whereas in the control group the improvement was only seen in stair climbing (P=.002). Functional capacity by the self-report HAQ did not change in either of the groups. Subjectively Perceived Symptoms The changes in fatigue differed statistically between the groups (P=.038) at the training assessment. In the training group, pain (P=.039) decreased and fatigue, general well-being, and sleep quality showed a tendency to improve (P=NS). No such favorable changes were observed in the control group (see table 4). Discussion Our results showed that aerobic performance as measured by maximal workload (Wmax) and work time, muscle strength as measured by concentric force of the leg extensors, and functional performance as assessed by walking and stair-climbing time improved in postmenopausal women with FM after concurrent strength and endurance training. The present training protocol loaded lower extremities and, thus, contributed to their improved function. Moreover, the training decreased fatigue. In addition, the training proved to be suitable to these patients with no adverse effects. In the present study, the subjects performed concurrent strength and endurance training for 21 weeks so that they had on average 1.5 weekly training sessions of each exercise mode. By using an analogous training program for premenopausal women with rheumatoid arthritis in a controlled study, we have shown previously that such training increased both isometric upper-body and concentric lower-body muscle strengths, Vo2peak, Wmax, and walking and stair-climbing times throughout the 21-week study period.21 However, in our present study, the same training program led, in general, to smaller changes in muscle strength and to no improvement in Vo2peak. On the other hand, the improvements of Wmax and functional performance were well in line with the results of Häkkinen et al.21 It is difficult to explain the difference between these 2 studies. Women with rheumatoid arthritis21 had a lower muscle strength level at baseline compared with our women with FM. This difference could have led to larger improvements in the previous study than in our participants and, therefore, could partly explain the results. In another previous randomized study by our group,11 postmenopausal women with FM performed pure progressive strength training twice a week for 21 weeks and were able to improve neuromuscular functions markedly throughout the intervention. Perhaps because of the lower frequency of strength training in our present study, the overall strength development remained relatively small. However, the muscle strength of leg extensors was at the highest level already at week 14 (see fig 2). This indicates that the training frequency was probably enough until this phase of training, but, despite readjustment of loading at week 14, it was insufficient to cause further increases in muscle force. One reason for the small improvements in Vo2peak is most likely the low amount of high-intensity aerobic training, although the present training was sufficient to cause a clear improvement in Wmax and work time probably because of increased dynamic muscle strength of leg extensors. Aerobic training was performed mainly under the aerobic threshold, and periods with higher intensity were short and perhaps they were not repeated frequently enough to lead to increased Vo2peak. Previous studies regarding concurrent strength and endurance training with high frequency have resulted in impaired strength development in healthy persons.16, 19, 20 Leveritt et al29 suggested that concurrent strength and endurance training cause a conflict to muscles' function and metabolism, especially resulting in impaired development in muscle strength. For patients with FM, it is essential to prescribe sufficient recovery times between the exercise sessions and to plan carefully training progression to avoid excessive fatigue after both endurance as well as strength training–type sessions. A number of FM patients anticipate that training worsens their symptoms. Reviewing the pure aerobic training studies including solely women with FM, the results regarding pain have been conflicting.12, 13, 14 On the other hand, randomized strength training studies have consistently shown a minor decrease in pain perception,7, 8, 9, 10, 30 but the present training intervention did not decrease pain while fatigue improved (when the groups were compared). The improvements in overall physical performance remained rather minor during the low-volume concurrent training. To our knowledge, this is the first study applying concurrent strength and endurance training in (postmenopausal) women with FM. Furthermore, a limited amount of evidence exists regarding responses of postmenopausal women with FM to strength training.11 Therefore, the present study gives relevant information for further studies. Study Limitations One should be careful with the interpretations of the results. The recruited small number of women with FM may represent an active subgroup with the syndrome and limit the generalization of the results. On the other hand, Vo2peak of women with FM was low both before and after the training period, which indicates that their aerobic fitness was not very good, although the Vo2peak values are within the reference values given by Shvartz and Reibold31 for healthy women of that age group. The fact that they could not, for some reason, improve their Vo2peak needs more study, and, therefore, the results should be confirmed with a large sample size. In addition, a common problem in a population with FM is that despite careful preparation and encouragement during the tests it is possible that the subjects will not perform a maximal effort in the test because fear of pain and/or lack of motivation. This may explain, at least partly, the conflicting results on physical fitness in patients with FM. Nevertheless, we apparently succeeded to keep the program suitable by a moderate intensity and frequency of training because our postmenopausal women with FM were able to perform regularly 3 weekly training sessions and to implement training in their daily life. Conclusions This study showed that postmenopausal women with FM were able to practice concurrent strength and endurance training with beneficial effects on symptoms and without training injuries. The observed changes in physical fitness were mainly seen as increased dynamic muscle strength of leg extensors, improved Wmax, work time, and walking and stair-climbing time because both training modes loaded the same muscle groups. However, the amount of strength training was most likely too low to improve the strength of other muscle groups, and the endurance training regimen was not intensive enough to improve Vo2peak. More importantly, the training did not aggravate the symptoms of FM but decreased fatigue and showed a favorable trend in other symptom profiles. It has to be emphasized that among aging people, especially with chronic conditions, the maintenance of the current physical fitness or, even better, obtaining some improvements in it is sufficient and are realistic goals for the training. In any case, more studies are needed to show the effects of different exercise modes in various doses on physical performance capacity and health-related fitness in subjects with FM. Suppliers References 1. 1Goldenberg DL, Burckhardt C, Crofford L. Management of fibromyalgia syndrome. JAMA. 2004;292:2388–2395.
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30. 30Valkeinen H, Häkkinen A, Hannonen P, Häkkinen K, Alén M. Acute heavy-resistance exercise-induced pain and neuromuscular fatigue in elderly women with fibromyalgia and in healthy controls: effects of strength training. Arthritis Rheum. 2006;54:1334–1339. MEDLINE 31. 31Shvartz E, Reibold RC. Aerobic fitness norms for males and females aged 6 to 75 years: a review. Aviat Space Environ Med. 1990;61:3–11. MEDLINE a Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland b Department of Biology of Physical Activity and Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland c Department of Physical Medicine and Rehabilitation, Central Hospital, Jyväskylä, Finland d Department of Internal Medicine, Central Hospital, Jyväskylä, Finland e UKK Institute for Health Promotion Research, Tampere, Finland  Reprint requests to Heli Valkeinen, PhD, Dept of Health Sciences, University of Jyväskylä, PO Box 35, FIN-40 014 Jyväskylä, Finland
Supported by the Ministry of Education of Finland and Peurunka-Medical Rehabilitation Foundation, Laukaa, Finland. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. PII: S0003-9993(08)00394-8 doi:10.1016/j.apmr.2008.01.022 © 2008 American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved. | |
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