Time course of strength adaptations following high-intensity resistance training in individuals with multiple sclerosis

High-intensity interval training improves bone remodeling, lipid profile, and physical function in multiple sclerosis patients

Multiple sclerosis (MS) is a demyelinating and neurodegenerative disease due to an autoimmune chronic inflammatory response, yet the etiology is currently not completely understood. It is already known that physical activity plays an essential role in improving quality of life, especially in neuropathological conditions. The study was aimed to investigate the possible benefits of high-intensity interval training (HIIT) in bone and lipid metabolism markers, and neuromotor abilities in MS patients. 130 participants were recruited; 16 subjects with MS met the inclusion criteria and were included in the data analysis. The patients were randomly assigned to two groups: a Control group (CG) (34.88 ± 4.45 yrs) that didn't perform any physical activity and the Exercise group (EG) (36.20 ± 7.80 yrs) that performed HIIT protocol. The training program was conducted remotely by a kinesiologist. It was performed three times a week for 8 weeks. At the beginning (T0) and the end of the study (T1) physical function tests, bone remodelling markers, and lipid markers analyses were performed. After 8 weeks of training the wall squat (s) (T0 = 27.18  ±  4.21; T1 = 41.68 ± 5.38, p ≤ 0.01) and Time Up and Go test (s) (T0 = 7.65 ± 0.43; T1 = 6.34 ± 0.38 p ≤ 0.01) performances improved; lipid markers analysis showed a decrease in Total (mg/dl) (T0 = 187.22 ± 15.73; T1 = 173.44 ± 13.03, p ≤ 0.05) and LDL (mg/dl) (T0 = 108 ± 21.08; T1 = 95.02 ± 17.99, p < 0.05) cholesterol levels. Additionally, the levels of osteocalcin (µg/L), a marker of bone formation increased (T0 = 20.88 ± 4.22; T1 = 23.66 ± 6.24, p < 0.05), 25-OH Vitamin D (µg/L) improved after 8 weeks (T0 = 21.11 ± 7.11; T1 = 27.66 ± 7.59, p < 0.05). HIIT had an effect on lower limb strength and gait control, improved bone formation, and lipid management, in MS patients.

High intensity exercise training on functional outcomes in persons with multiple sclerosis: A systematic review

BACKGROUND

There is growing interest and evidence for high intensity training (HIT) in clinical populations, including persons with multiple sclerosis (MS). While HIT has been shown to be a safe modality in this group, it is still unclear what collective knowledge exists for HIT on functional outcomes. This study examined HIT modalities (e.g., aerobic, resistance, functional training) on functional outcomes such as walking, balance, postural control, and mobility in persons with MS.

METHODS

High intensity training studies, including RCTs and non-RCTs, that targeted functional outcomes in persons with MS were included in the review. A literature search was conducted in MEDLINE, EMBASE, PsycINFO, SPORTSDiscus, and CINAHL in April 2022. Other literature search methods were performed via website and citation searching. The methodological quality of included studies was assessed by TESTEX for RCTs and ROBINS-I for non-RCTs. This review synthesized the following data: study design and characteristics, participant characteristics, intervention characteristics, outcome measures, and effect sizes.

RESULTS

Thirteen studies (6 RCTs and 7 non-RCTs) were included in the systematic review. The included participants (N = 375) had varying functional levels (EDSS range: 0-6.5) and phenotypes (relapsing remitting, secondary progressive, primary progressive). HIT modalities involving high intensity aerobic training (n = 4), high intensity resistance training (n = 7), and high intensity functional training (n = 2), revealed a significant and consistent benefit on walking speed and walking endurance in response to HIT, while the evidence regarding balance and mobility improvement was less clear.

CONCLUSION

Persons with MS can successfully tolerate and adhere to HIT. While HIT appears to be an effective modality for improving some functional outcomes, the heterogeneous testing protocols, HIT modalities, and exercise doses among the studies preclude any conclusive evidence for its effectiveness thus necessitating future inquiry.

Effects and optimal dosage of resistance training on strength, functional capacity, balance, general health perception, and fatigue in people with multiple sclerosis: a systematic review and meta-analysis

PURPOSE

To analyze the effectiveness of resistance training programs (RTP) on strength, functional capacity, balance, general health perception, and fatigue for people with Multiple Sclerosis (MS) and to determine the most effective dose of RTP in this population.

METHODS

Studies examining the effect of RTP on strength, functional capacity, balance, general health perception, and fatigue in MS patients were included. 44 studies were included. The meta-analysis, subgroup analysis and meta-regression methods were used to calculate the mean difference and standardized mean difference.

RESULTS

Significant group differences were observed in knee extensor (p = 0.01) and flexor (p < 0.001), but not in 1-repetition maximum. Regarding functional capacity and balance, differences between groups, in favour of the RTP group, were found in the Timed Up and Go Test (p = 0.001), walking endurance, (p = 0.02) gait speed (p = 0.02) and balance (p = 0.02). No significant differences between groups were observed in fatigue or general health perception. The results regarding the optimal dose are inconsistent.

CONCLUSIONS

RTP improves strength, functional capacity, balance, and fatigue in people with MS. Registration: (PROSPERO): CRD42020182781Implications for rehabilitationResistance training is a valid strategy to improve isometric strength and functional capacity in MS patients.RTP using long durations (more than 6 weeks), high intensity (more than 80% 1-RM) and two-day weekly training frequency may be a correct stimulus to improve strength, functional capacity, balance, and fatigue in people with MS.Trainers and rehabilitators should consider these indicators in order to maximize muscular and functional adaptations in this population.

Are trunk muscles weaker in adolescent females with adolescent idiopathic scoliosis compared with their healthy counterparts?

BACKGROUND: Adolescent Idiopathic Scoliosis (AIS) requires complex medical care because of multiple consequences especially on daily activities. Muscular involvement is part of the problem and may be treatable. OBJECTIVE: To analyze trunk muscle strength using an isokinetic dynamometer in female adolescents with AIS one year after orthopedic treatment by brace and compare the findings to a matched group of an asymptomatic cohort. METHODS: The trunk flexors and extensors strength was measured using an isokinetic dynamometer at 60, 90 and 120∘/s. Peak Moment (PM), Mean Power (MP) and the flexor/extensor ratio in 100 patients aged 14 to 18 years old were compared to a control group (N= 32) of asymptomatic age-matched females. In the AIS group, correlation analyses were computed to search for contributing factors to isokinetic performances, including morphological characteristics of patients, as well as clinical and radiological characteristics of the scoliosis. RESULTS: The trunk flexors in the AIS group were significantly but moderately (15%) weaker across speeds compared to their control counterparts at all speeds. No parallel weakness was noted for the extensors. While the MP of AIS patients was significantly weaker than that of the controls, 33% for flexors and by 31% for extensors, no significant differences were observed for the F/E ratios. The correlational analyses has indicated that weight and BMI were contributing factors at all speeds. CONCLUSION: Adolescents with AIS had weaker trunk extensors and mostly flexors compared to healthy females. Within this AIS population, weight and BMI seem to have a negative impact on muscular performances, whereas clinical and radiological characteristics of the scoliosis do not seem to contribute.

How does cross-education affects muscles of paretic upper extremity in subacute stroke survivors?

INTRODUCTION

This study aimed to evaluate the benefits of adding electromuscular stimulation (EMS) to the flexors of wrist muscles on the nonparetic limb in conventional stroke training to strengthen homologous agonist and antagonist muscles on the paretic side in patients with subacute stroke.

METHODS

The EMS group patients (n = 15) received conventional therapy for 30 sessions for 6 weeks (60 min/session) with 30 min of electrical stimulation to their nonparetic forearm using wrist flexors, with 5 min of pre- and post-warm-up. The transcutaneous electrical nerve stimulation (TENS) group patients (n = 15) received the same conventional rehabilitation training with 30 min of conventional antalgic TENS at a barely sensible level to their nonparetic forearm. The Fugl-Meyer motor function assessment for upper extremity (FMA-UE), functional independence measure (FIM), Brunnstrom staging of recovery for hand, maximum and mean wrist flexion force (flexion_max and flexion_mean), and wrist extension force (extension_max and extension_mean) of paretic untrained limb were evaluated before and after the treatment.

RESULTS

EMS and TENS group patients improved similarly in terms of FMA-UE, FIM, and Brunnstrom staging for hand recovery. However, flexion_max and flexion_mean of the paretic limb increased more in the EMS group than in the TENS group. Extension_max and extension_mean on the paretic side increased in the EMS group but did not differ in the TENS group.

CONCLUSION

Cross-education via EMS may have a beneficial effect as an adjunct to conventional treatment methods. This study is retrospectively registered and is available at www.clinicaltrials.gov (ID: NCT04113369).

A systematic review of aerobic and resistance exercise and inflammatory markers in people with multiple sclerosis

Inflammation is a driver in the demyelination process in patients with multiple sclerosis (MS) and can influence disability levels. Both single and repeated bouts of exercise can decrease inflammatory markers in people with MS (PwMS). This systematic review evaluates whether exercise can influence inflammation and disability in individuals with MS. Experimental studies were reviewed that had to meet the following eligibility requirements: a sample of PwMS, an intervention of exercise (either aerobic, resistance, or a combination of each), and an outcome that included at least one inflammatory (cytokine) reaction. The main outcome measure was an evaluation of inflammation, as indicated by a change in any cytokine level. Other measures included muscle strength, balance, flexibility, walking ability, disability statues, and quality of life (QOL). A total of nine studies were included in the final review. Exercise interventions included predominantly cycling, although a few resistance training trials were mentioned. Small decreases were found in IL-17 and IFN-γ after exercise. Functional outcome measures and perceived disability status were improved posttraining. We conclude that while interventions such as exercise may impact QOL, they do not have a significant influence on inflammation associated with MS. Exercise is an accessible alternative that not only helps to decrease impairments but also limit the restrictions associated with participation in society. While functional outcomes after exercise improved, these improvements may not be attributable to changes in levels of cytokines or inflammatory markers.

The importance of lower-extremity muscle strength for lower-limb functional capacity in multiple sclerosis: Systematic review

BACKGROUND

Lower-limb functional capacity is impaired in most people with multiple sclerosis (PwMS). Reductions in lower-extremity muscle mechanical function (e.g., muscle strength) appear to have critical implications for lower-limb functional capacity. However, no review has summarized the current knowledge about the importance of muscle strength for functional tasks in PwMS. Expanding the current knowledge would advance the design of both clinical and research interventions aiming to improve functional capacity in PwMS.

OBJECTIVES

(1) To identify studies that measured lower-extremity muscle mechanical function and lower-limb functional capacity outcomes in PwMS, and (2) to map associations between muscle strength and functional capacity.

METHODS

This review was based on a literature search (databases: PubMed, Embase). Included studies had to report data on lower-extremity muscle mechanical function and lower-limb functional capacity outcomes in PwMS. The associations between muscle strength and functional capacity were analyzed by using the reported correlation coefficients (R) recalculated to the determination coefficient R². Randomized trials and observational studies were included.

RESULTS

A total of 59 articles were reviewed; 17 (773 participants) reported associations between muscle strength and functional capacity. Lower-extremity muscle mechanical function explained a significant part of the variance in most lower-limb functional capacity tests (approximately 20-30%). This was particularly evident in muscle strength from the weakest leg. Muscle strength was predominantly tested on knee extensors and knee flexors by using isokinetic dynamometry during maximal isometric (0°/s) and dynamic (30-60°/s) contractions. Walking tests such as the timed 25-Foot Walk Test and 10-Min, 2-Min and 6-Min Walk Test were the most frequently performed functional capacity tests.

CONCLUSIONS

In PwMS, muscle strength of particularly the weakest limb explains 20% to 30% of the variance across a number of lower-limb functional capacity tests. Thus, exercise programs should focus on increasing lower-extremity muscle mechanical function in PwMS and minimizing strength asymmetry between limbs.

Isokinetic predictors of gait speed increase following high-intensity resistance training of the ankle dorsiflexors in people with multiple sclerosis: A pilot study

BACKGROUND

Maximal strength is a predictor of functional capacity for people with multiple sclerosis (PwMS), who frequently exhibit unilateral weakness of the ankle dorsiflexors. Aims of this study were to investigate the relationships between dorsiflexors' weakness and gait speed, the effects of high-intensity training of the affected dorsiflexors on gait performance and to identify isokinetic predictors of changes in gait speed in PwMs.

METHODS

Twenty patients aged 45 (10.3) years, illness duration 14.9 (8.5) years, median EDSS 3, underwent isokinetic dorsiflexors' strength testing at 10°/s and 45°/s angular velocities and gait analysis before and after a 6-week training of dorsiflexors. Pre-to-post differences in strength and gait parameters were analyzed by paired t-test; association between gait speed and isokinetic parameters was tested through correlation and regression analyses.

FINDINGS

Dorsiflexors' strength (peak moment at 10°/s: +14.9%, p = 0.02; at 45°/s: +21.7%, p = 0.03) and gait parameters (speed: +9.6%; p = 0.004; stride time: -5.7%; p = 0.01; cadence: +6.2%; p = 0.001; ankle power: +27.5%, p = 0.003) increased significantly. Of the thirteen isokinetic descriptors of strength, only peak moment, maximal and total work significantly correlated with gait speed increase. Regression analyses revealed high beta coefficients only for maximal work (10°/s: B = -6.528; beta = -1.825; p = 0.008; 45°/s: B = -1.466; beta = -1.364; p = 0.03).

INTERPRETATION

In PwMS, high-intensity training of weakened ankle dorsiflexors induced significant improvements in maximal strength and gait speed. The finding of maximal work as a significant predictor of training-induced changes in gait speed suggests that PwMS with reduced muscle work may benefit from strength training approaches aimed at increasing gait speed. Registration number: ClinicalTrials.gov Identifier: NCT02010398.

Perspectives on neurorehabilitation of unilateral impairments through cross-education

Background: Cross-education is being increasingly investigated as an unconventional, exercise-based intervention to manage severely lateralized weakness. To date, however, cross-education seems more important to research than clinical practice. Aim: To provide foundation and context for an informed employment of cross-education in severely or predominantly unilateral weakness or motor impairment. Method: Qualitative, narrative commentary. Results: Based on the comprehensive overview on contralateral strength training approaches to hemiplegia and unilateral weakness in stroke survivors performed by Russell and colleagues as well as on our experiences in multiple sclerosis, there is a potential for cross-education as a useful training approach to hemiplegia and unilateral weakness in stroke survivors and multiple sclerosis patients and, overall, in neurorehabilitation. However, some limitations of this non-conventional approach have to be pointed out, such as the apparent lack of translation of the performance gains of the weaker untrained side into functional improvement, particularly for the lower limb. Conclusion: Cross-education may serve as a viable option for those patients presenting severe unilateral weakness who are not able to fully exercise their weaker side directly. However, it should not be recommended straightaway if the training goal is to improve outcomes other than strength. As such, contralateral training may prove as a primer to establish a minimum level of strength that may suffice to sustain direct training, which has been proved to prompt more meaningful functional changes. Implications for rehabilitation Cross-education consists of training the stronger limb to increase strength in the untrained weaker homologous muscles. This unconventional strategy is receiving increasing attention for possible applications in neurological populations exhibiting severe unilateral impairment. For those patients who are not able to fully exercise their weaker side it may represent a viable exercise option. However, cross-education should not be recommended straightaway if the training goal is to improve outcomes other than strength.

Multiple Sclerosis and Exercise: A Literature Review

Multiple sclerosis (MS) is the most common autoimmune disabling neurological conditions of young adults and affects more than 2.3 million people worldwide. Given the high likelihood for disability and decreased neurological function, there have been concerns about the role of exercise in MS patients with a fear of increased injury. This article looks at recent articles evaluating the role of exercise in MS and can hopefully be used by patients, caregivers, and health care providers to guide decision making about the role of exercise in patients with MS.