Abstract Background Multiple sclerosis (MS) is a chronic disease in the central nervous system which causes a number of physical symptoms including impairments of muscle mechanical function (muscle ...strength, muscle power and explosive muscle strength (~ rate of force development, RFD)). However, a full overview of the existing knowledge regarding muscle mechanical function in persons with MS (PwMS) is still pending. Objectives To systematically review 1) the psychometric properties of isokinetic dynamometry testing in PwMS, and 2) studies comparing muscle mechanical function in PwMS to matched healthy controls (HC). In addition, a meta-analysis will evaluate 3) the effects of progressive resistance training on muscle mechanical function in PwMS. Methods A systematic literature search was performed in eight databases. To be included in the review, the study had to 1) enroll participants with a confirmed diagnosis of MS; 2) assess muscle mechanical function 3) had undergone peer-review. The psychometric properties of isokinetic dynamometry were reviewed with respect to validity, reliability, and responsiveness. Comparison of muscle strength between PwMS and HC was performed across contraction velocities, contraction modes and muscle groups, as were the rate of force development. The effects of progressive resistance training on muscle mechanical function were evaluated in a meta-analysis using a random effects model and standardized mean difference (SMD). Results A total of four, twenty-four, and ten studies were identified for aim 1, 2, and 3, respectively. High Intraclass correlations coefficients (range: 0.87–0.99) for isokinetic dynamometry was reported when assessing knee extensor and knee flexor muscle strength independent of contraction velocity. Compared to match HC, PwMS display impaired muscle strength, power and explosive muscle strength. Muscle strength impairments were most pronounced during maximal moderate to fast dynamic muscle contractions of the lower extremities. Progressive resistance training has a small but significant effect on muscle mechanical function in PwMS (SMD = 0.45, 95% CI: 0.18–0.72, p = 0.001). Conclusions The present review showed that 1) isokinetic dynamometry has a high reliability in PwMS; 2) muscle strength, power and rate of force development is impaired in PwMS compared to HC, and muscle strength impairments are most pronounced during maximal moderate to fast dynamic muscle contractions of the lower extremities; and 3) progressive resistance training can improve muscle mechanical function in PwMS. Future studies should evaluate progressive resistance training designed to optimize maximal moderate to fast dynamic muscle contractions of the lower extremities.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Impairments across multiple domains are a disabling consequence of multiple sclerosis (MS). Originating from preventive medical strategies, the “time matters”-perspective has become a focal point ...when treating MS. In particular, early detection of physical and cognitive deficits, along with deficits in patient-reported outcomes seems crucial to further optimize both pharmacological and non-pharmacological MS treatment strategies. Therefore, this topical review investigates the level of impairments across multiple domains (physical function, cognitive function, and patient-reported outcomes) in the early stage of MS (⩽5 years since diagnosis, including clinically isolated syndrome (CIS)), when compared to matched healthy controls. Even at early disease stages, studies show impairments corresponding to 8%–34% and small-to-large numerical effect sizes (0.35–2.85) in MS/CIS patients across domains. This evidence call for early screening programs along with early interventions targeting the multiple impaired domains. This further highlights the importance of preventive initiatives preserving and/or restoring physical and cognitive reserve capacity if possible.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
No studies have synthesized the literature regarding mechanical muscle function (ie, strength, power, rate of force development RFD) in people with Parkinson disease (PD). Here, we aimed to expand ...our understanding of mechanical muscle function in people with PD (PwPD) by systematically reviewing (1) the psychometric properties of isokinetic/isometric dynamometry in PD, (2) the literature comparing mechanical muscle function in PwPD with healthy controls (HC), and (3) reported associations between muscle mechanical muscle function and functional capacity and/or disease severity.
Systematic literature search in 6 databases. Included studies had to (1) enroll and report data on PwPD, (2) include assessment(s) of psychometric properties (ie, validity, reliability, responsiveness) of isokinetic/isometric dynamometry in PD, and/or (3) assess mechanical muscle function in both PwPD and HC using isokinetic/isometric dynamometry.
A total of 40 studies were included. Aim 1 studies (n = 2) showed high reliability for isometric dynamometry (hip-abductor/dorsiflexor/trunk flexor-extensor/handgrip: intraclass correlations coefficients range = 0.92-0.98). Aim 2 studies (n = 40) showed impaired mechanical muscle function (ie, strength, power, RFD) in PwPD compared with HC (effect sizes range = 0.52-1.89). Aim 3 studies (n = 11) showed weak-to-strong associations between overall and lower extremities muscle strength and functional capacity and/or disease severity outcomes (ie, Unified Parkinson Disease Rating Scale).
Sparse methodological evidence suggests high reliability when using dynamometry in PwPD. Muscle strength, power, and RFD are impaired in PwPD compared with HC. Muscle strength is associated with functional capacity and disease severity.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A403 ).
Little is known about potential differences in contractile properties of muscle fibers of the same type in arms and legs. Accordingly, the present study was designed to compare the force-generating ...capacity and Ca
sensitivity of fibers from arm and leg muscles of highly trained cross-country skiers.
Single muscle fibers of
and
of eight highly trained cross-country skiers were analyzed with respect to maximal Ca
-activated force, specific force and Ca
sensitivity.
The maximal Ca
-activated force was greater for myosin heavy chain (MHC) II than MHC I fibers in both the arm (+62%,
< 0.001) and leg muscle (+77%,
< 0.001), with no differences between limbs for each MHC isoform. In addition, the specific force of MHC II fibers was higher than that of MHC I fibers in both arms (+41%,
= 0.002) and legs (+95%,
< 0.001). The specific force of MHC II fibers was the same in both limbs, whereas MHC I fibers from the
were, on average, 39% stronger than fibers of the same type from the
(
= 0.003). pCa
was not different between MHC I and II fibers in neither arms nor legs, but the MHC I fibers of
demonstrated higher Ca
sensitivity than fibers of the same type from
(
= 0.007).
Comparison of muscles in limbs equally well trained revealed that MHC I fibers in the arm muscle exhibited a higher specific force-generating capacity and greater Ca
sensitivity than the same type of fiber in the leg, with no such difference in the case of MHC II fibers. These distinct differences in the properties of fibers of the same type in equally well-trained muscles open new perspectives in muscle physiology.
•Physical activity was significantly related to fatigue impact on physical and psychosocial functioning.•Physical activity tended to be associated with fatigue impact on cognitive ...functioning.•Tobacco smoking contributed significantly to fatigue impact on psychosocial functioning.•Alcohol intake did not contribute to fatigue impact in any functioning domains.•Physical activity and not smoking seems to be a useful approach for patients with MS manage fatigue.
Background: The lack of medical treatment options to reduce fatigue in patients with multiple sclerosis (MS) emphasize the importance of identifying potential non-pharmacological modifiable factors, as this may help advance current treatment strategies. The aim of this study was to identify potential modifiable lifestyle factors as well as patient- and disease-related characteristics, that are associated with fatigue in a large sample of clinically well-characterized patients with MS.
Methods: This study was a secondary analysis of a pragmatic randomized controlled trial of inpatient multidisciplinary rehabilitation in Denmark. MS patients aged 18 to 65 years and with a disease severity score ≤ 7.5 according to the Expanded Disability Status Scale participated. Data on patient- and disease-related characteristics, fatigue impact (Modified Fatigue Impact Scale (MFIS)), and on lifestyle factors (tobacco smoking, alcohol intake, and physical activity), were collected at baseline.
A linear mixed model was used to compare MFIS total, physical, cognitive, and psychosocial scores across subgroups of selected characteristics. Regression analyses were used to examine associations between lifestyle factors and MFIS total, physical, cognitive, and psychosocial scores.
Results: In the sample of 417 MS patients, median age was 51 years, 69% were female, median time since diagnosis was 8 years, with 41% having relapsing remitting MS.
Higher MFIS total scores were observed in MS patients with shorter time since diagnosis, being a tobacco smoker, and not undertaking regular physical activity. Somewhat similar findings were observed for MFIS subscores (physical, cognitive, psychosocial), especially MFIS physical scores.
In the multivariate analyses, physical activity was significantly associated with fatigue impact on total, physical and psychosocial functioning. Tobacco smoking was significantly associated with fatigue impact on psychosocial functioning. Alcohol intake was not associated with fatigue impact. None of the lifestyle factors were associated with fatigue impact on cognitive functioning. In the adjusted models time since diagnosis was significantly associated with fatigue impact on total, physical and cognitive functioning, as was disease severity with fatigue impact on physical and cognitive functioning.
Conclusion: Physical activity showed the most pronounced associations with fatigue impact on physical and psychosocial functioning, while the impact on cognitive functioning showed a trend. Tobacco smoking contributed significantly to impact on psychosocial functioning, while alcohol intake did not contribute to fatigue impact. Introducing or supporting maintenance of physical activity/exercise and cessation of tobacco smoking seems to be a useful approach for rehabilitation services to help patients with MS manage fatigue.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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