Deterioration of Muscle Function after 21-Day Forearm Immobilization

Kitahara, Ayao; Hamaoka, Toshiyuki; Murase, Norio; Homma, Toshiyuki; Kurosawa, Yuko; Ueda, Chihoko; Nagasawa, Takeshi; Ichimura, Shiro; Motobe, Mayuko; Yashiro, Koji; Nakano, Shouichi; Katsumura, Toshihito

doi:10.1249/01.mss.0000089339.07610.5f

Cited by 44 publications

(74 citation statements)

References 20 publications

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“…However, if we take the decreased O 2 ,fast to mean a more facilitated recruitment of type II fibers or a delayed response in O 2 , this would indicate that the energy-supplying system becomes dependent on glycolysis more than oxidation and that more lactate is produced. This possibility is supported by reports demonstrating that muscle oxidative capacity decreases after inactivity [7,24]. Therefore after ULLS, the subjects might be harder pressed to carry out the exercise tasks.…”

Section: What the Declined Asymptote In The Fast Component Of O 2 Impmentioning

confidence: 54%

“…Previous studies have demonstrated that limb disuse by casting attenuated the muscle oxidative capacity in the immobilized limb [7], that ULLS reduced the femoral artery diameter in the side of the suspended leg [9], and that the number and luminal diameter of capillaries in the muscles of rats decreased after hind limb suspension [8]. Accordingly, there was a possibility that ULLS would slow response speed of the fast component.…”

Section: Response Speed Of the Fast Componentmentioning

confidence: 98%

“…Previous studies have reported that even limb disuse attenuates muscle oxidative capacity [7], function of peripheral circulation [8,9], and muscle strength [10]. Thus even limb disuse might have an influence on O 2 kinetics.…”

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confidence: 99%

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Oxygen Uptake Kinetics Following 20 Days of Unilateral Lower Limb Suspension

et al. 2006

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Abstract:The purpose of the present study was to examine the effect of unilateral lower limb suspension (ULLS) deconditioning on oxygen uptake kinetics. Eight healthy males underwent ULLS for 20 days and performed a series of 6-min square-wave transitions from rest to 60-W single-leg cycling exercises just before and after ULLS. To characterize the kinetics of the oxygen uptake response, a single exponential model was applied to the data until the end of the fast component omitted the first 15 s of the on-transit using a nonlinear least-squares fitting procedure. The following results were found: (i) the time constant of oxygen uptake was unchanged before and after ULLS; (ii) although there was no significant difference in the baseline and the asymptotic amplitude of the fast component, the asymptote, i.e., the absolute asymptotic amplitude of the fast component (the sum of the baseline and the asymptotic amplitude), and the end exercise oxygen uptake were decreased after ULLS; (iii) the contribution of the slow component to the total response of oxygen uptake was unchanged at pre-and post-ULLS. In conclusion, the asymptote in the fast component and the end exercise oxygen uptake were decreased after 20-d ULLS, though the response speed and the amplitude of the slow component of oxygen uptake were not changed. It is suggested that deconditioning as a result of limb disuse affects oxygen uptake response. In general, to analyze oxygen uptake ( O 2 ) kinetics in exercising humans, O 2 is usually measured at the mouth by means of the breath-by-breath method. The response speed of O 2 to exercise, i.e., the time constant of O 2 kinetics of the fast component in which O 2 increases exponentially and reaches a steady state within 2-3 min after the onset of exercise, is affected by O 2 delivery systems consisted of central and peripheral circulation, and the function of O 2 utilization, such as the activity of oxidative enzymes in the muscle [1,2]. In cases where the intensity of exercise is heavy, O 2 increases moderately after the end of the fast component, and this is known as the slow component. Although the mechanisms remain speculative, it is thought that the recruitment of fast twitch fibers or the added recruitment of muscle fibers, which have not yet participated in muscle contraction, is the primary cause [3].It is known that the fast component of O 2 kinetics is faster in trained than in untrained individuals [4]. This would indicate that because the time to start producing lactic acid obstructing muscular contraction is shortened, burdens of exercise decrease. Further, Carter et al. [5] revealed that the O 2 slow component was attenuated by 6 weeks of endurance training. This would imply that the subjects were able to accomplish the same level of exercise without the mobilization of added muscular fibers or fast twitch fibers. The endurance tolerance of each muscle fiber would be increased. Therefore it is conceivable that endurance training would speed up O 2 kinetics and would lead to the elimination of th...

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Section: What the Declined Asymptote In The Fast Component Of O 2 Impmentioning

confidence: 54%

Section: Response Speed Of the Fast Componentmentioning

confidence: 98%

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Oxygen Uptake Kinetics Following 20 Days of Unilateral Lower Limb Suspension

et al. 2006

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“…Kitahara et al 24 did not find differences in arm perimeter or in the magnetic resonance images after 21 days of elbow immobilization in healthy subjects. McDougall et al 25 , however, found a 5% reduction in arm perimeter after five weeks of elbow immobilization in healthy subjects.…”

Section: Discussionmentioning

confidence: 87%

“…Although limited and indirect, it is used in the clinical set-up to determine inter-limb differences and has been used to estimate muscle mass 1,2,24 . The arm perimeters were similar between the pre-and post-immobilization evaluation, suggesting that the perimeter is not a good tool to estimate muscle mass, that the reduction in muscle mass was offset by an increase in subcutaneous fat tissue, or that muscle mass does not change after fourteen days of immobilization in healthy subjects.…”

Section: Discussionmentioning

confidence: 99%

Two-weeks of elbow immobilization affects torque production but does not change muscle activation

Karolczak¹,

Diefenthaeler²,

Geremia³

et al. 2009

Rev. bras. fisioter.

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The role of muscle disuse in muscular and cardiovascular fitness: A systematic review and meta‐regression

Casuso,

Huertas,

Aragón‐Vela

2024

European Journal of Sport Science

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We aimed to assess the effects of muscle disuse on muscle strength (MS), muscle mass (MM) and cardiovascular fitness. Databases were scrutinized to identify human studies assessing the effects of muscle disuse on both (1) MM and (2) maximal oxygen uptake (VO2max) and/or MS. Random‐effects meta‐analysis and meta‐regression with initial physical fitness and length of the protocol as a priori determined moderators were performed. We quantitatively analyzed 51 different studies, and the level of significance was set at p < 0.05. Data from the participants in 14 studies showed a decline in both VO2max (SMD: −0.93; 95% CI: −1.27 to −0.58) and MM (SMD: −0.34; 95% CI: −0.57 to −0.10). Data from 47 studies showed a decline in strength (−0.88; 95% CI: −1.04 to −0.73) and mass (SMD: −0.47; 95% CI: −0.58 to −0.36). MS loss was twice as high as MM loss, but differences existed between anatomical regions. Notably, meta‐regression analysis revealed that initial MS was inversely associated with MS decline. VO2max and MS decline to a higher extent than MM during muscle disuse. We reported a more profound strength loss in subjects with high muscular strength. This is physiologically relevant for athletes because their required muscular strength can profoundly decline during a period of muscle disuse. It should however be noted that a period of muscle disuse can have devastating consequences in old subjects with low muscular strength.

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Deterioration of Muscle Function after 21-Day Forearm Immobilization

Abstract: In this model, 21-d forearm immobilization caused no significant changes in forearm muscle morphology, but the muscle function showed remarkable deterioration ranging from 18 to 45%.

Cited by 44 publications

References 20 publications

Oxygen Uptake Kinetics Following 20 Days of Unilateral Lower Limb Suspension

Oxygen Uptake Kinetics Following 20 Days of Unilateral Lower Limb Suspension

Two-weeks of elbow immobilization affects torque production but does not change muscle activation

The role of muscle disuse in muscular and cardiovascular fitness: A systematic review and meta‐regression

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