Age‐related changes in force and efficiency in rat skeletal muscle

Haan, A. de; Ruiter, C.J. de; Lind, A.; Sargeant, A. J.

doi:10.1111/j.1748-1716.1993.tb09511.x

Cited by 27 publications

(23 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this way, the measured force was constant when the muscle passed Lo during shortening. 7 Between contractions, there was at least 2-min rest.…”

Section: Methodsmentioning

confidence: 99%

“…9 Experimental allergic encephalomyelitis (EAE) is an experimental inflammatory demyelinating dis-ease of the central nervous system, and serves as an animal model to study demyelinating diseases of the central nervous system in general, and MS in particular. 24,25 In the induction phase (days [1][2][3][4][5][6][7][8][9][10], animals are immunized with myelin components to induce an anti-myelin immune response. 22,25 In particular, the effector phase of EAE (days 10 -18), during which local inflammatory responses cause the actual tissue damage, is relevant for studying the damaging events in MS.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Changes in characteristics of rat skeletal muscle after experimental allergic encephalomyelitis

et al. 2004

View full text Add to dashboard Cite

Experimental allergic encephalomyelitis (EAE) serves as an animal model for certain neuroinflammatory diseases of the central nervous system, in particular multiple sclerosis (MS). EAE is accompanied by transient weakness or paralysis of hind limbs. We have investigated the effect of partial and transient conduction failure in the central nervous system on skeletal muscle function. At ϳ2.5 days after development of maximal clinical signs, body and medial gastrocnemius muscle mass were lower (by ϳ21 and 33%, respectively; P Ͻ 0.05) in EAE rats compared with controls. Fiber cross-sectional area was lower by 40 -50% in all fiber types. Maximal force and power were substantially lower (by 58% and 73%) in EAE rats, as was the force normalized for muscle mass (35%). However, no such weakness was found when lower stimulation frequencies were used. Generation of similar submaximal forces was attributable to a slower relaxation in EAE muscles. This advantage for the EAE muscles was lost during repeated exercise. While fatigability was similar, the difference in relaxation rate between EAE and control disappeared in fatigue. Our data suggest that, as a result of central neuroinflammatory diseases, maximal performance of skeletal muscle is impaired but submaximal performance is relatively well maintained.

show abstract

“…In this way, the measured force was constant when the muscle passed Lo during shortening. 7 Between contractions, there was at least 2-min rest.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Changes in characteristics of rat skeletal muscle after experimental allergic encephalomyelitis

et al. 2004

View full text Add to dashboard Cite

show abstract

“…The medial gastrocnemius consists mainly of fast-twitch fatigable muscle fibres (more than 95 %; de Haan, de Ruiter, Lind & Sargeant, 1993;de Ruiter, de Haan & Sargeant, 1995). Thus, it appears that the fatigued fibre population was able to maintain a certain performance level (16 % of power output) for a long period, probably supported by a small population of unaffected fatigue-resistant fibres.…”

Section: Level Offatiguementioning

confidence: 99%

Mechanical behaviour of rat skeletal muscle during fatiguing stretch‐shortening cycles

Ettema

1997

Experimental Physiology

View full text Add to dashboard Cite

SUMMARYThe effects of muscle fatigue on the mechanical efficiency of muscle work performance were studied in situ, in stretch-shortening cycles that resembled physiological conditions. The experiments were performed on the medial gastrocnemius muscles of seven rats. To calculate efficiency, a simple Hill-type model was used, consisting of the contractile component (CC) and the series elastic component (SEC). Mechanical efficiency was defined as the external work done by the muscle-tendon complex divided by the external work done upon the muscle-tendon complex plus work done by the CC. The fatiguing protocol consisted of a 1 Hz stretch-shortening cycle with a 0.3 duty factor (i.e. the muscle was stimulated for 300 ms in each cycle). In total, 240 cycles were imposed. The mechanical performance (work, force and mechanical efficiency) was determined throughout the fatiguing process. Fatigue reduced muscle power and force production to approximately 17 and 30 %, respectively. SEC stiffness increased, but did not have any effect on muscle performance and probably reflects altered cross-bridge characteristics. Mechanical efficiency was enhanced during the imposed stretch-shortening cycles from 0.74 to 0 83. As a result of the lower peak forces, proportionally less series elastic energy was wasted during the relaxation period of each stretch-shortening cycle in the fully fatigued muscles. These results indicate that, in vivo, the timing of muscle contractions in the fresh and the fatigued state may be different in order to perform muscle work efficiently. After a period of 30 min recovery, the condition of the muscles had (partially) returned to the fresh state in all aspects.

show abstract

“…There seems to be no dfference of opinion in the literature that AGcH, has a magnitude of about -2,880 Wmole (.&strand & Rodahl, 1977;Brooks, Fahey, & White, 1995;Kammermeier, 1993;McArdle, Katch, & Katch, 1991). Though different estimates for AG, are used in the literature (up to -52 Wmole; Haan, Ruiter, Lind, & Sargeant, 1993), the quantity of AGAn = 4 6 kJ/ mole appears most consistent (Brooks et al, 1995;Whipp & Wasserman, 1969;. Since 1 mole CHO can resynthesize 36 mole ATP, these measures for AG lead to an ep value of 0.575.…”

Section: Difficulties In the Assessment Or Interpretation Of Agmentioning

confidence: 99%

Does Elastic Energy Enhance Work and Efficiency in the Stretch-Shortening Cycle?

Schenau¹,

Bobbert²,

Haan³

1997

Journal of Applied Biomechanics

189

View full text Add to dashboard Cite

This target article addresses the role of storage and reutilization of elastic energy in stretch-shortening cycles. It is argued that for discrete movements such as the vertical jump, elastic energy does not explain the work enhancement due to the prestretch. This enhancement seems to occur because the prestretch allows muscles to develop a high level of active state and force before starting to shorten. For cyclic movements in which stretch-shortening cycles occur repetitively, some authors have claimed that elastic energy enhances mechanical efficiency. In the current article it is demonstrated that this claim is often based on disputable concepts such as the efficiency of positive work or absolute work, and it is argued that elastic energy cannot affect mechanical efficiency simply because this energy is not related to the conversion of metabolic energy into mechanical energy. A comparison of work and efficiency measures obtained at different levels of organization reveals that there is in fact no decisive evidence to either support or reject the claim that the stretch-shortening cycle enhances muscle efficiency. These explorations lead to the conclusion that the body of knowledge about the mechanics and energetics of the stretch-shortening cycle is in fact quite lean. A major challenge is to bridge the gap between knowledge obtained at different levels of organization, with the ultimate purpose of understanding how the intrinsic properties of muscles manifest themselves under in-vivo-like conditions and how they are exploited in whole-body activities such as running. To achieve this purpose, a close cooperation is required between muscle physiologists and human movement scientists performing inverse and forward dynamic simulation studies of whole-body exercises.

show abstract

Age‐related changes in force and efficiency in rat skeletal muscle

Cited by 27 publications

References 23 publications

Changes in characteristics of rat skeletal muscle after experimental allergic encephalomyelitis

Changes in characteristics of rat skeletal muscle after experimental allergic encephalomyelitis

Mechanical behaviour of rat skeletal muscle during fatiguing stretch‐shortening cycles

Does Elastic Energy Enhance Work and Efficiency in the Stretch-Shortening Cycle?

Contact Info

Product

Resources

About