Endurance exercise improves walking distance in MS patients with fatigue

Objectives – Effects of endurance training in multiple sclerosis (MS) patients complaining of motor fatigue. Materials and methods – Thirty MS patients complaining of fatigue with low to moderate disabilities randomly allocated to the intervention (thrice weekly 45‐min intervals of endurance exercise) or control treatment (three 45‐min episodes of stretching, balance training and coordination), both as ‘add‐on’ therapy for 3 weeks during inpatient rehabilitation. Results – Maximal walking distance before intervention averaged 1043 ± 568 and 1163 ± 750 m in the two groups. The intervention group increased its maximal walking distance by 650 ± 474 m. The control group extended its walking distance by 96 ± 70 m. Conclusions – The present data confirm a strong effect of endurance exercise on maximal walking distance. Remarkably, there were no parallel improvements on the Modified Fatigue Impact Scale, the Beck Depression Inventory and the Hamburg Quality of Life Questionnaire for MS.     

踏车锻炼对慢性阻塞性肺疾病患者运动耐力和中枢驱动的影响

目的 探讨踏车锻炼对慢性阻塞性肺疾病(COPD)患者运动耐力和中枢驱动的影响.方法 选择南方医科大学珠江医院呼吸内科自2009年10月至2010年10月收治的中、重度COPD缓解期COPD患者22例,其中康复组(12例)接受12周中等强度踏车运动训练,对照组(10例)不接受训练.在训练前后分别进行常规肺通气功能、弥散功能和肺容量测定以及运动心肺功能测试及高强度持续恒定功率运动试验,监测运动过程中呼吸流量、容量和膈肌肌电的变化.比较患者试验前后运动耐力和呼吸困难评分的变化.结果 康复组患者锻炼后运动时间比锻炼前延长,峰运动功率增加,差异均有统计学意义(P＜0.05);等时间点呼吸频率(RR)、分钟通气量(VE)、平均吸气流速(VT/Ti)、膈肌电电压的均方根(RMS)、Borg评分较锻炼前下降,差异均有统计学意义(P＜0.05); COPD患者△Borg分别与△VE、△VT/Ti、△RMS呈正相关关系(P＜0.05).结论 下肢运动训练可显著改善COPD患者的运动耐力,降低COPD患者在相同运动强度下的通气需求和中枢驱动,改变了COPD患者的呼吸应答方式,从而减轻了COPD患者呼吸困难的主观感觉.     

Aerobic conditioning: an effective therapy in McArdle's disease

OBJECTIVE: Susceptibility to exertional cramps and rhabdomyolysis in myophosphorylase deficiency (McArdle's disease [MD]) may lead patients to shun exercise. However, physical inactivity may worsen exercise intolerance by further reducing the limited oxidative capacity caused by blocked glycogenolysis. We investigated whether aerobic conditioning can safely improve exercise capacity in MD. METHODS: Eight MD patients (4 men and 4 women; age range, 33-61 years) pedalled a cycle ergometer for 30 to 40 minutes a day, 4 days a week, for 14 weeks, at an intensity corresponding to 60 to 70% of maximal heart rate. We monitored serum creatine kinase levels; changes in peak cycle work, oxygen uptake, and cardiac output; presence and magnitude of a spontaneous and glucose-induced second wind; and citrate synthase and beta-hydroxyacyl coenzyme A dehydrogenase enzyme activities in quadriceps muscle. RESULTS: The prescribed exercise program increased average work capacity (36%), oxygen uptake (14%), cardiac output (15%), and citrate synthase and beta-hydroxyacyl coenzyme A dehydrogenase enzyme levels (80 and 62%, respectively) without causing pain or cramping or increasing serum creatine kinase. A spontaneous and glucose-induced second wind was present and was of similar magnitude in each patient before and after training. INTERPRETATION: Moderate aerobic exercise is an effective means of improving exercise capacity in MD by increasing circulatory delivery and mitochondrial metabolism of bloodborne fuels.     

Short-term aerobic training response in chronic myopathies.

We have previously demonstrated that patients with mitochondrial myopathies can benefit from short-term aerobic exercise training. In this study, we compared the responses to short-term aerobic training of patients with mitochondrial myopathies, patients with nonmetabolic myopathies, and sedentary normal subjects. Training consisted of 8 weeks of treadmill exercise at 70% to 85% of estimated maximum heart rate reserve. All groups showed significant improvements in estimated aerobic capacity as well as heart rate and blood lactate at submaximal exercise intensities. The increase in estimated aerobic capacity was greater in the mitochondrial myopathy patients than in the other two groups. Phosphorus magnetic resonance spectroscopy demonstrated increased oxidative capacity of muscle in patients with mitochondrial myopathies in response to this training but not in patients with other, nonmetabolic myopathies or sedentary control subjects. A self-assessed measurement of functional status (SF-36) suggested improved quality of life associated with the training. This study demonstrates that short-term aerobic training at low intensity can benefit patients with nonmetabolic myopathies but to a lesser extent than patients with mitochondrial myopathies.     

Exercise intolerance in mitochondrial myopathy is not related to lactic acidosis

In a double-blinded, placebo-controlled, crossover study in seven mitochondrial myopathy patients (MM), we investigated whether lowering of lactate with dichloroacetate (DCA) can improve exercise tolerance and oxidative capacity in MM. DCA lowered plasma lactate at rest and during exercise (from 10.5 +/- 2.0 to 5.0 +/- 1.6 mM; p = 0.005) but did not improve maximal work load or VO2 in cycle exercise or phosphorous magnetic resonance spectroscopy (31P-MRS)-assessed indices of muscle oxidative metabolism. This indicates that lactate acidosis is not the primary cause of exercise intolerance in MM.     

Combined Aerobic and Resistance Training for Cardiorespiratory Fitness,Muscle Strength,and Walking Capacity after Stroke: A Systematic Review and Meta-Analysis

BackgroundCardiorespiratory fitness, measured as peak oxygen consumption, is a potent predictor of stroke risk. Muscle weakness is the most prominent impairment after stroke and is directly associated with reduced walking capacity. There is a lack of recommendations for optimal combined aerobic training and resistance training for those patients. The purpose of this study was to systematically review and quantify the effects of exercise training on cardiorespiratory fitness, muscle strength, and walking capacity after stroke.MethodsFive electronic databases were searched (until May 2019) for studies that met the following criteria: (1) adult humans with a history of stroke who ambulate independently; (2) structured exercise intervention based on combined aerobic training and resistance training; and (3) measured cardiorespiratory fitness, muscle strength, and/or walking capacity.ResultsEighteen studies (602 participants, average age 62 years) met the inclusion criteria. Exercise training significantly improved all 3 outcomes. In subgroup analyses for cardiorespiratory fitness, longer training duration was significantly associated with larger effect size. Likewise, for muscle strength, moderate weekly frequency and lower training volume were significantly associated with larger effect size. Furthermore, in walking capacity, moderate weekly frequency and longer training duration were significantly associated with larger effect size.ConclusionsThese results suggest that an exercise program consisting of moderate-intensity, 3 days per week, for 20 weeks should be considered for greater effect on cardiorespiratory fitness, muscle strength, and walking capacity in stroke patients.     

Musculation à haute intensité et paralysie cérébrale : utopie ou révolution ?

AimOur study aimed at testing whether high intensity strength training protocols (20 minutes duration, twice a week, without exercise machine) improve functional independence and quality of life in cerebral palsy patients.MethodEighteen children (eleven boys, seven girls, aged eight to twenty years old) suffering from cerebral palsy and receiving physical therapy interventions. The experimental group received 20 minutes of high intensity strength training twice a week (during the physical therapy session) for three months. The control group receives classical physical therapy intervention. Before and after the protocol, two test sessions measured: muscle force and muscle endurance (maximum number of repetitions in 30 s, four exercises; maintain isometric positions for a maximal duration, four positions), walking speed (six minutes walking test), functional motor abilities (EMFG scale item D and E) and quality of life (Kidscreen 27 scale).ResultsThe group receiving high intensity strength training significantly improved his performance (force, endurance and function) compared to the control group. A similar trend was observed for the quality of life although differences did not reach significance.ConclusionThis study shows that patients suffering from cerebral palsy can benefit from short high intensity strength training protocols. Twenty minutes of such an intervention, twice a week, without any exercise machine, seems to be an effective and realistic strategy to improve force, endurance, motor function and quality of life.     

Functional Electrical Stimulation‐Supported Interval Training Following Sensorimotor‐Complete Spinal Cord Injury: A Case Series

Objective. To investigate the effect of interval training supported by Functional Electrical Stimulation (FES) on ambulation ability in complete spinal cord injury (SCI). Methods. We trained four men with sensorimotor‐complete (ASIA A) SCI, who achieved gait through FES of the quadriceps femoris, gluteus maximus, and common peroneal nerve on each side on a motorized treadmill. Training involved progressive interval walking exercise, consisting of periods of activity followed by equal periods of rest, repeated until muscle fatigue. We used time to muscle fatigue during continuous treadmill ambulation as the primary outcome measure. We also recorded the patterns of incremental stimulation for all training and testing sessions. Results. All subjects increased their ambulation capacity; however, the responses varied from subject to subject. Some subjects increased the total distance walked by as much as 300% with progressive improvement over the entire training period; however, others made more modest gains and appeared to reach a performance plateau within a few training sessions. Conclusions. FES‐supported interval training offers a useful and effective strategy for strength‐endurance improvement in the large muscle groups of the lower limb in motor‐complete SCI. We believe that this training protocol offers a viable alternative to that of continuous walking training in people with SCI using FES to aid ambulation.     

Short‐ and long‐term effects of endurance training in patients with mitochondrial myopathy

Background and purpose: It is unknown whether prolonged training is a safe treatment to alleviate exercise intolerance in patients with mitochondrial DNA (mtDNA) mutations. Methods: The effect of 3 and 12 months training and 3–12 months deconditioning was studied in four patients carrying different mtDNA mutations. Results: Three‐month moderate‐intensity training increased oxidative capacity by 23%, which was sustained after 6–12 months of low‐intensity training. Training and deconditioning did not induce adverse effects on clinical symptoms, muscle morphology and mtDNA mutation load in muscle. Conclusion: Long‐term training effectively improves exercise capacity in patients with mitochondrial myopathy, and appears to be safe.     

Improvement in strength following resistance training in MS patients despite varied disability levels

Strength and endurance data from 67 participants with multiple sclerosis (MS) were compared before, during and after a 6-month program of standardized resistance training. The hypothesis was that a standardized, structured resistance training exercise program improves strength in MS patients with different levels of disability. The range of EDSS scores was 1-8: (40% - EDSS of 1-4.5), (35% - EDSS of 5-7) (25% - EDSS of 7.5 or higher). This unique study evaluated patients with differing levels of disability for a change in strength and endurance following a 6-month training program. Data were analyzed by repeat measures and analysis of variables using Proc GLM in SAS to account for variability between subjects, and within subjects, due to repeated measures at 3 time points. Each treatment was blocked by disability class. Every within-treatment analysis was significant. Each exercise showed significant improvement in strength for participants, despite disability levels. Increases in strength followed parallel improvement pathways, at all disability levels. All but one treatment displayed highly significant improvement (p-value < 0.0001). The results demonstrated that all individuals with MS, despite disability levels, show parallel improvement in strength and endurance. This study supports the use of exercise, including resistance programs, for all MS patients.     

Endurance training: an effective and safe treatment for patients with LGMD2I

We studied the effect of aerobic training on conditioning in patients with limb-girdle muscular dystrophy type 2I (LGMD2I). Nine patients with LGMD2I cycled fifty 30-minute sessions at 65% of their maximal oxygen uptake over 12 weeks. Training significantly improved work capacity, paralleled by self-reported improvements. Creatine kinase levels did not increase significantly, and muscle morphology was unaffected. Moderate-intensity endurance training is a safe method to increase exercise performance and daily function in patients with LGMD2I.     

The effects of physical activity on psychogenic movement disorders

Psychogenic movement disorders (PMD) are a diagnostic fascinating challenge in both neurologic and psychiatric setting. Many factors influence response to treatment, but few treatment strategies are available. Physical activity proves to be effective in the treatment of depression, anxiety, and other psychiatric disorders, but the effects of regular walking exercise on patients with PMD have never been investigated in a single‐blind study. Sixteen outpatients [13 women; mean age 33.0 years (range 22–51)] with primarily mild‐to‐moderate PMD completed a thrice‐weekly, 12‐weeks mild walking program. Assessments included DSM‐IV interview, the Psychogenic Movement Disorder Rating Scale (PMDRS), Beck Anxiety Inventory (BAI), Hamilton Depression Scale (HDS), V02 Max, and body mass index (BMI). Changes in total score on the PMDRS were the primary endpoint. A comparison of all measures taken at study onset and after completing the exercise program indicates statistically significant improvements. We observed a relevant improvement in 10 of 16 patients (62%). The mean difference for the primary outcome (PMDRS total) corresponded to about 70%. Compliance was good, and there were no adverse effects. This study provides preliminary evidence for regular low‐medium intensity exercise as a safe, adequate, and pleasing intervention for PMD. Furthermore, well‐designed studies appear justified to confirm these findings. © 2010 Movement Disorder Society     

Effects of high-intensity endurance exercise training in the G93A mouse model of amyotrophic lateral sclerosis

The G93A transgenic mouse has a mutation in copper/zinc superoxide dismutase (CuZnSOD) that results in oxidative stress and motor neuron loss. Endurance exercise training is known to increase antioxidant capacity in skeletal muscle. Therefore, we hypothesized that endurance training may extend onset of disease or survival in the G93A mouse. We examined the effects of high-intensity endurance exercise training (45 min/day, 5 times/week, progressive increase from 9 to 22 m/min) on disease onset and survival in G93A mice. Endurance training did not affect clinical onset, although it hastened death in male mice (P < 0.05). Endurance-trained males had a statistically significant decrease in rotarod performance at 112 days (P < 0.05), whereas sedentary males decreased at 119 days (P < 0.05). Endurance-trained and sedentary females decreased at 126 days and 129 days, respectively (P < 0.05). Female mice lived longer than males (P < 0.05), and there was a trend for hastened clinical onset in males (P = 0.062). We conclude that high-intensity endurance exercise training does not affect onset of clinical symptoms in G93A mice but hastens a decrease in motor performance and death following onset of clinical symptoms in male mice only. In light of a recent report describing increased survival following low-intensity endurance training, it appears that training intensity is an important determinant of survival in the G93A mouse.     

A pilot study of proximal strength training in Charcot‐Marie‐Tooth disease

Gait analysis of people with Charcot‐Marie‐Tooth (CMT) disease revealed proximal adaptive gait strategies to compensate for foot drop. We previously demonstrated that hip flexor muscle fatigue can limit walking endurance. This pilot study used a single‐blinded cross over design to investigate the effect of a 16‐week home‐based programme of resistance training on hip flexor muscle strength. Measures of walking endurance, gait speed, exertion, fatigue, and general activity were also recorded. The exercise protocol was based on American College of Sports Medicine recommendations. A mixed effects model was used for analysis. Twenty‐six people finished the study, with average reported exercise participation of 93%. No negative effects of exercise were observed. Significant increase in hip flexor muscle strength was observed on the left, but not the right. No changes were observed in walking speed and endurance measures. This pilot study of home‐based resistance training showed a modest improvement in hip strength but only on one side. The lack of a more significant improvement and no improvement in walking measures suggests that this training protocol may not be optimal for people with CMT and that patients may need to stratified differently for training studies in CMT.     

Aerobic endurance exercise improves executive functions in depressed patients

BACKGROUND: Aerobic endurance exercise has been shown to improve higher cognitive functions such as executive control in healthy subjects. We tested the hypothesis that a 30-minute individually customized endurance exercise program has the potential to enhance executive functions in patients with major depressive disorder. METHOD: In a randomized within-subject study design, 24 patients with DSM-IV major depressive disorder and 10 healthy control subjects performed 30 minutes of aerobic endurance exercise at 2 different workload levels of 40% and 60% of their predetermined individual 4-mmol/L lactic acid exercise capacity. They were then tested with 4 standardized computerized neuropsychological paradigms measuring executive control functions: the task switch paradigm, flanker task, Stroop task, and GoNogo task. Performance was measured by reaction time. Data were gathered between fall 2000 and spring 2002. RESULTS: While there were no significant exercise-dependent alterations in reaction time in the control group, for depressive patients we observed a significant decrease in mean reaction time for the congruent Stroop task condition at the 60% energy level (p = .016), for the incongruent Stroop task condition at the 40% energy level (p = .02), and for the GoNogo task at both energy levels (40%, p = .025; 60%, p = .048). The exercise procedures had no significant effect on reaction time in the task switch paradigm or the flanker task. CONCLUSION: A single 30-minute aerobic endurance exercise program performed by depressed patients has positive effects on executive control processes that appear to be specifically subserved by the anterior cingulate.     

A forearm exercise screening test for mitochondrial myopathy

BACKGROUND: The authors hypothesized that impaired oxygen extraction in mitochondrial myopathy (MM) results in a high oxygen saturation in venous effluent blood from working muscle and that this phenomenon can be used as a diagnostic tool for MM. METHODS: Twelve patients with MM, 10 patients with muscular dystrophy, and 12 healthy subjects were studied. All subjects performed intermittent static handgrip exercise (1/2 Hz) at 40% of maximal voluntary contraction (MVC) for 3 minutes. Cubital venous oxygen saturation and brachial artery flow were measured in the exercised arm. RESULTS: Exercise-induced venous oxygen desaturation was smaller in patients with MM (Delta - 7 +/- 5%) than in subjects with muscular dystrophy (Delta - 38 +/- 2%; p = 0.00001) and healthy subjects (Delta - 43 +/- 2%; p = 0.0000002). MVC and exercise blood flow were similar in patients with MM (18 +/- 3 kg; 436 +/- 65 mL/min) and patients with muscular dystrophy (15 +/- 3 kg; 460 +/- 85 mL/min), but were higher in healthy subjects (32 +/- 4 kg; 630 +/- 58 mL/min; p < 0.03). In seven patients with MM and seven patients with McArdle disease, studied with a slightly different protocol, exercise-induced oxygen desaturation was also impaired in MM (Delta - +/- 5%) compared with McArdle disease (Delta - 26 +/- 3%; p = 0.007). CONCLUSION: Oxygen desaturation in venous blood from exercising muscle is markedly lower in patients with mitochondrial myopathy than in subjects with other muscle diseases and healthy subjects, suggesting that a forearm exercise test can be a diagnostic screening tool for mitochondrial myopathy.     

Aerobic conditioning in patients with mitochondrial myopathies: physiological, biochemical, and genetic effects

Aerobic training has been shown to increase work and oxidative capacity in patients with mitochondrial myopathies, but the mechanisms underlying improvement are not known. We evaluated physiological (cycle exercise, 31P-MRS), biochemical (enzyme levels), and genetic (proportion of mutant/wild-type genomes) responses to 14 weeks of bicycle exercise training in 10 patients with heteroplasmic mitochondrial DNA (mtDNA) mutations. Training increased peak work and oxidative capacities (20-30%), systemic arteriovenous O2 difference (20%), and 31P-MRS indices of metabolic recovery (35%), consistent with enhanced muscle oxidative phosphorylation. Mitochondrial volume in vastus lateralis biopsies increased significantly (50%) and increases in deficient respiratory chain enzymes were found in patients with Complex I (36%) and Complex IV (25%) defects, whereas decreases occurred in 2 patients with Complex III defects (approximately 20%). These results suggest that the cellular basis of improved oxygen utilization is related to training-induced mitochondrial proliferation likely resulting in increased levels of functional, wild-type mtDNA. However, genetic analysis indicated the proportion of wild-type mtDNA was unchanged (3/9) or fell (6/9), suggesting a trend toward preferential proliferation of mutant genomes. The long-term implications of training-induced increases in mutant relative to wild-type mtDNA, despite positive physiological and biochemical findings, need to be assessed before aerobic training can be proposed as a general treatment option.     

Le réentraînement à l’effort chez l’enfant atteint de paralysie cérébrale (PC). Revue de littérature

The exercise training now appears to be an effective way to combat and reduce the chronic deficiencies in adults with chronic pathology and more recently in the adolescent (or child) suffering from neurological disorders, including cerebral palsy. Numerous studies to date have produced encouraging results in improving some quality of life factors in young patients with cerebral palsy. Firstly, a rehabilitation training based on exercises carried out in endurance improves aerobic capacity and the distance and speed of walking and the GMFCS. A strength training will help improve muscle mass and GMFCS as well. Finally, the type of exercise training to focus now is a “mixed” training, i.e. based on exercises involving the two training protocol before. But to clarify the procedures for carrying out such training, it will take into account various parameters such as muscle fatigue.     

Cycle ergometry is not a sensitive diagnostic test for mitochondrial myopathy

Cycle exercise has repeatedly been used to diagnose patients suspected of having mitochondrial myopathy (MM), in whom exercise intolerance and lactic acidosis are common. No standardized test, however, has been established. We evaluated the diagnostic value of incremental and constant workload (20 min at 65 % VO(2max)) cycle tests for the diagnosis of MM. Plasma lactate and oxidative capacity (VO(2) and workload) were measured in 15 well-characterized MM patients during cycling. Findings were compared with those in 10 myotonic dystrophy patients and 18 sedentary, healthy subjects.All MM patients had ragged red or COX-negative fibers on muscle biopsy. VO(2max) and maximal workload were lower in MM than in control groups (P < 0.02). Resting plasma lactate was higher in MM than in control groups (P < 0.005; sensitivity = 93 %; specificity = 85 %), while exercise-induced increases in plasma lactate were only higher during the constant workload protocol in MM patients vs. control groups (P < 0.05; sensitivity = 27 %; specificity = 86 %). The findings indicate that the diagnostic value of a constant workload protocol is superior to an incremental cycle test, but that the test is less sensitive for MM than simple testing of resting lactate and muscle morphology. Cycle testing of MM patients remains an important research tool, but should not be a standard diagnostic procedure for MM.     

Effects of aerobic training on lactate and catecholaminergic exercise responses in mitochondrial myopathies

The aim of this study was to evaluate the effects of an aerobic training program on the metabolic and sympathetic responses to exercise in 12 patients with mitochondrial myopathies. A 10-week course of aerobic training, consisting of supervised exercise every other day on an electrically braked pedal-rate bicycle ergometer was prescribed to each patient and four healthy controls. Venous lactate, epinephrine (EP) and norepinephrine (NEP) levels were assessed at baseline and after the aerobic training by means of constant-workload exercise performed at near lactate threshold (LT). In patients, a decrease in exercise peak values, significant for lactate (-38.6%, P < 0.01) but not for catecholamines (EP: -26.0%, NEP: -22.1%) was observed after training, findings confirmed by the lactate/EP and lactate/NEP area ratios. The results show that lactate accumulation during exercise is decreased after aerobic training in mitochondrial myopathies and that the effect is partially dissociated from the catecholaminergic response. This in turn suggests that the lactate decrease can be explained, at least in part, by the improved muscle oxidative metabolism consequent to the proposed training program.